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Journal Cover Process Safety Progress
  [SJR: 0.359]   [H-I: 28]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1066-8527 - ISSN (Online) 1547-5913
   Published by John Wiley and Sons Homepage  [1616 journals]
  • The physics and Metaphysics of the sensitivity of calorimetric instruments
           and human senses
    • Authors: Dilip K. Das
      Abstract: The onset temperature for a reaction detected by an apparatus in an experimental study is an overestimated value compared with the actual value existing within large batches. Models are used to estimate the “actual value” for large batches. The onset temperature is dependent on the Phi-factor (thermal inertia), adiabaticity, and detection sensitivity of the calorimeter. It is therefore advisable to penalize the detected onset temperature by an arbitrary number, such as 50°C for Accelerating Rate Calorimeter (ARC), to arrive at the recommended (Adjusted) onset decomposition or reaction temperature for the purpose of setting control parameters in operations.The influence of Phi-factor and detection- sensitivity of the Heat-Wait-Search mode in the ARC on the detected onset temperature is discussed. A parallel is drawn between the instrumental sensitivity in the phenomenal world and the mental sensitivity in the noumenal world. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2017-03-21T08:03:14.763256-05:
      DOI: 10.1002/prs.11871
       
  • Cover Picture: Plasma Process. Polym. 3∕2017
    • Authors: Marco Boselli; Cristina Chiavari, Vittorio Colombo, Matteo Gherardi, Carla Martini, Fabio Rotundo
      Abstract: Front Cover: Two different atmospheric pressure non-thermal plasmas have been used to clean the surface of a corroded 19th century daguerreotype. The figures on top show the figure visage untreated; after 2nd plasma-jet treatment on the left half-side only; and after DBD-plasma treatment of the right half-side too. The figures at the bottom show optical micrographies in white light of the woman's eye on the left daguerreotype portion in (a) untreated conditions and (b) after plasma-jet treatment. Further details can be found in the article by M. Boselli et al. on 1600027.
      PubDate: 2017-03-17T08:52:08.335069-05:
      DOI: 10.1002/ppap.201770003
       
  • Issue Information: Plasma Process. Polym. 3∕2017
    • PubDate: 2017-03-17T08:52:07.503386-05:
      DOI: 10.1002/ppap.201770004
       
  • New model for predicting thermal radiation from flares and high pressure
           jet fires for hydrogen and syngas
    • Authors: Derek Miller
      Abstract: Current flare and jet fire models used in the process industry are primarily based on hydrocarbon gases and have been found not to be particularly effective for low luminosity gases such as hydrogen and syngas mixtures. This article presents a new model for such gases, for low to high pressure releases in both vertical and horizontal orientations. The model, which predicts flame geometry and thermal radiation, allowing for jet momentum, buoyancy, wind and flame radiant fraction, is based on extension of established models, with the addition of several new correlations. Validation against existing published data and new previously unpublished test data collected at both pilot and full scale is presented. This article provides the complete set of equations for the model. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2017-03-13T02:11:13.628487-05:
      DOI: 10.1002/prs.11867
       
  • Method for CFD facilitated pressure rise calculation due to deflagration
           in heat recovery steam generator
    • Authors: Wei Zhou; Manuel Cardenas, David Moyeda
      Abstract: For combined cycle operations, especially during startup and shutdown, safety concerns have always been the top priority. Residual fuels can escape to and accumulate in the downstream heat recovery steam generator (HRSG) if appropriate purge is not taken, which may cause deflagration, an explosion at subsonic condition, during startup when heat source exists. Residual fuel deflagration will lead to pressure rise and therefore, structural and or tube damages depending on the level of pressure increase. Therefore, a careful study of the residual fuel distribution in HRSG and the pressure rise due to possible deflagration is wanted.Historically, thermodynamics relationships and chemical equilibrium calculations are used to estimate the pressure rise. These approaches either assume that all fuel energy is converted into heat, or make assumptions on the amount of fuel in chemical equilibrium that contributes to the pressure rise. These assumptions tend to overestimate the pressure rise. With the development of computational fluid dynamics (CFD) simulation, a more accurate prediction of the fuel concentration in HRSG during transient startup and/or shutdown process is possible. The local fuel concentrations can now be calculated and therefore, how much fuel that are within the explosion limits and contribute to the pressure rise can be detected readily.This article presents the transient CFD modeling results of residual fuel concentration in a typical HRSG configuration during a gas turbine/combined cycle startup failure process. The article then refines the adiabatic mixing model with the predicted local fuel concentrations to provide a better estimation of the pressure rise due to deflagration. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-03-09T01:46:35.814418-05:
      DOI: 10.1002/prs.11887
       
  • Process safety education and training academic education as a foundation
           for other process safety initiatives on education
    • Authors: Geert Boogaerts; Jan Degrève, Geert Vercruysse
      Abstract: Commitment to process safety is fundamental to the process industry. Governance, promotion, and participation in academic and related educational programs are testament to the industry's commitment and stakeholder reach. Process safety education and training is a very broad topic. Industry-academic collaboration is essential when developing high level education and training on process safety. This article looks at the development of educational and training programmes for students in Advanced Master programmes in the European master network and for experienced industry workers. The Advanced Master Safety Engineering developed at the University has a proven track record in realizing the intended learning outcomes along with a high level of academic and professional orientation as well as international orientation. The results related to the learning outcomes are very satisfying, which implies that there is a good relationship between the intended learning outcomes, the programme and the evaluation tests. The associated Advanced Master Class on process safety has a very satisfying overall trainee satisfaction (Level 1) and learning gains (Level 2) evaluation in the Kirkpatrick's Model. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-03-01T03:55:36.363538-05:
      DOI: 10.1002/prs.11885
       
  • Introduction to functional safety assessments of safety controls, alarms,
           and interlocks: How efficient are your functional safety projects'
    • Authors: Eloise Roche; Monica Hochleitner, Angela Summers
      Abstract: The return on investment (ROI) for safety controls, alarms, and interlocks (SCAI) can be significantly impacted by human error, which can occur during any lifecycle activity and be committed by competent workers. Design, installation, testing, maintenance, and operational practices are often repeated throughout a site, lowering the ROI with each flawed installation. A functional safety assessment (FSA) is a tool used to identify and correct defects before a simple human error allows an incident to propagate in spite of the capital spent on the installed SCAI equipment.Significant efficiency can be gained when FSAs are periodically conducted during the SCAI lifecycle, so that critical information is gathered when needed. This article will discuss the internationally endorsed five-stage approach to FSA. The purpose and content of each FSA stage is reviewed and execution timing is suggested that focuses project resources to maximize FSA benefit to project cost and schedule. Finally, a case study illustrates how lack of effective and timely FSA contributed to the occurrence of a costly and catastrophic loss event. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-03-01T03:55:34.665064-05:
      DOI: 10.1002/prs.11886
       
  • Instructions to Authors
    • PubDate: 2017-02-27T23:31:44.992698-05:
      DOI: 10.1002/prs.11888
       
  • Why DDT is the only way to explain some vapor cloud explosions
    • Authors: D.M. Johnson; V.H.Y. Tam
      Abstract: The possibility that Deflagration to Detonation Transition (DDT) occurs in vapor cloud explosions (VCEs) in industrial accidents has generally only been recognized for very reactive fuels such as hydrogen and ethylene. Assessment of the explosion hazards and risks associated with less reactive fuels such as propane and other alkanes has generally been based around the assumption that, in practice, only a deflagration can occur. This has the benefit that the magnitude of the maximum hazard to surrounding areas is defined by the physical parameters of any congested process region and not by the extent of the vapor cloud, as would be the case if there was a sustained detonation. However, following the Buncefield incident in the UK in 2005, a considerable amount of effort was expended in explaining the major VCE that occurred. This initially involved gathering and interpreting the evidence from the incident but then extended to experimental and theoretical research over two phases and lasting five years. Further research since showed that DDT can be achieved within dense vegetation and regions of pipework with a relatively small extent (of the order of a few meters). The results from this project will be summarized, indicating why the only explanation that is consistent with all of the evidence is a DDT soon after ignition of the cloud, with a sustained detonation then propagating through the majority of the cloud. Reference will be made to other incidents where similar evidence was observed. Awareness of the significance of such evidence will be important in the investigation of future VCEs. In addition, the possibility of DDT needs to be recognized in the methodologies used to assess VCE hazards. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-02-24T02:20:44.786149-05:
      DOI: 10.1002/prs.11874
       
  • Using social network theory to analyze the effectiveness of environment,
           safety and health management for two petrochemical companies
    • Authors: Jao-Jia Horng; Kuang-Yu Liao, Shun-Yeng Wang
      Abstract: The social network analysis theory was used to explore two domestic petrochemical companies on their environmental, safety, and health (ESH) management system and operation effectiveness. Both qualitative and quantitative analyses by NodeXL and statistical tools were applied through the survey questionnaires to observe the results of social network among two management systems. From the background information of those individuals, parameters and network diagrams, we could identify three kinds of specialized network personnel: Central persons, marginal men and information agents, in order to understand the organization work, and information flows and influence patterns. Two companies showed differences in their International Standard Organization (ISO) based management systems and actual functioning systems. The centrality parameter indicated that some managers lack network connections to others and some members' knowledge could not be adequately used owing to the faults in organization structures. These problems would lower the effectiveness of management systems. Our analysis also showed positive correlations between the trustworthiness among members as well as the recognition networks. This study showed that the network analysis could be a good reference for the high-level managers to understand their ESH system, to evaluate the organization efficiency and to analyze their future development and operation needs. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2017-02-22T01:00:34.587723-05:
      DOI: 10.1002/prs.11865
       
  • Atmospheric tank failures: Mechanisms and an unexpected case study
    • Authors: Michael S. Schmidt
      Abstract: The literature on catastrophic failures of low-pressure tanks focuses on the ignition of explosive mixtures in the vapor space of those tanks, and rightly so, because most catastrophic failures of atmospheric tanks involve explosions of such mixtures. Moreover, there is a general sense in the industry that other than explosions of flammable mixtures, the only other hazard associated with low-pressure tanks is the occasional dramatic implosion of a vessel that is inadequately protected against vacuum.In fact, there are a number of mechanisms that can lead to the catastrophic failure of a low-pressure tank that have nothing to do with combustion or unprotected vacuum. Under certain circumstances, even a tank equipped with an atmospheric vent and containing nothing other than salt water can explode, with disastrous impacts.This article reviews the mechanisms for catastrophic failure of low pressure tanks, both implosion and explosion, and serves as a reminder for experienced process safety practitioners and as a tutorial for new process safety practitioners of what to look for during a hazard review. It also includes a case study of an atmospheric caustic tank explosion that resulted from a previously unreported mechanism that involved neither combustion nor vacuum. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-02-06T04:35:52.316894-05:
      DOI: 10.1002/prs.11881
       
  • A technique to control major hazards of the coal gasification process
           developed from critical events and safety barriers
    • Authors: Feng Sun; Wei Xu, Guangjian Wang, Bing Sun
      Abstract: Many coal gasification related accidents happened in China recently. Investigations of the accidents show that the performance of safety barriers and the risk influence factors contributing to it plays an important role. Lack of attention on the performance of safety barriers and associated risk influence factors hinder the thorough understanding of these accidents and, therefore, needs to be addressed by providing a new analysis methodology. Herein, we developed an approach from critical events and safety barriers to control the major hazards during the coal gasification process. The method consists of process hazard identification based on critical events, barrier performance evaluation based on barrier diagrams, and quantification of risk influence factors based on Bayesian network. The application of the method indicates that it is suitable for controlling major hazards of the coal gasification process as well as other chemical processes. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-02-06T04:35:42.185681-05:
      DOI: 10.1002/prs.11880
       
  • Modeling and validation of dispersion following an instantaneous vapor or
           two-phase release from a pressurized vessel
    • Authors: Henk W.M. Witlox; Mike Harper, David Webber
      Abstract: This article presents a new model for the initial dispersion phase of energetic instantaneous expansion following a catastrophic vessel rupture. This model has been implemented as a new sub-model in the Phast dispersion model and is based on more sound physical principles than the old Phast sub-model. It allows for both vapor and two-phase releases. In the case of two-phase releases, droplets are assumed to expand radially, potentially leading to time-varying droplet rainout and the formation of a spreading evaporating liquid pool. For ground-level vapor or two-phase releases the correctness of the numerical predictions is confirmed against an analytical solution. The model has been validated against previously published experimental data for pressurized releases with and without rainout. This includes ground-level releases for nitrogen vapor and flashing liquid propylene, and elevated flashing liquid releases for Freon 11, Freon 12, propane and butane. Overall the old model tends to under-predict the cloud radius and cloud speed versus time, while the new model more closely agrees with small-scale experimental data. Therefore the new model produces smaller concentrations and doses, and is less conservative. For two-phase releases the new model predicts an increased amount of rainout, which is more in line with the experimental data. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-02-06T04:35:38.916611-05:
      DOI: 10.1002/prs.11876
       
  • Auditing management systems for safety controls, alarms, and interlocks:
           How effective are your instrumented protective systems'
    • Authors: Monica Hochleitner; Eloise Roche
      Abstract: Functional safety audits evaluate the performance of the management systems and procedures required to keep safety controls, alarms, and interlocks (SCAI) working effectively. Organizations invest thousands, sometimes millions, of dollars installing automation systems in safety applications to minimize the risk of their enterprise. Return on investment in SCAI systems, and the achieved degree of risk reduction, can be negatively impacted by human error, such as inadequate installation, testing, maintenance, or operation of the automation systems. Administrative controls and organizational discipline are needed to identify and correct these errors. This article will provide an introduction to the purpose, key content, and planning of a functional safety audit. The case studies presented will illustrate how safety system effectiveness could have been improved if a detailed audit of the implemented SCAI had been conducted and the findings addressed in a timely fashion. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2017-02-06T04:35:32.656454-05:
      DOI: 10.1002/prs.11875
       
  • One company's observations on the implementation of LOPA
    • Authors: Anne Bertelsmann
      Abstract: Layer of Protection Analysis (LOPA) has gained popularity as a semi-quantitative risk assessment tool, but often unexpected difficulties are encountered when rolling out LOPA. This article discusses the practical aspects of LOPA implementation in Marathon Petroleum Company LP's Refining Organization (MPC Refining). Specifically, it shows how scenarios are selected from a Hazard and Operability Study (HAZOP) and how they are organized for conducting LOPA efficiently, and it discusses whether to conduct LOPA concurrently or after the HAZOP. The article also compares the [cause consequence] or [consequence cause] methodology and addresses the implications of combining multiple causes in a single scenario.Another key aspect of LOPA implementation is the set of numerical values used for frequencies, modifiers and risk-reduction factors. The article shows how numerical values should be tied to the risk matrix and how internal consistency is achieved through the use of standardized values and restrictions on the use of frequency modifiers. It discusses potential solutions for cases where the LOPA outcome does not meet the risk target. Finally, the article shows how the use of application standards can supplement LOPA by defining minimum protections and providing standard LOPA scenarios. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-02-06T04:35:29.452056-05:
      DOI: 10.1002/prs.11873
       
  • Chinese process safety management core elements and control measures
    • Authors: Aitao Zhou; Lingpeng Fan, Mingfei Ma, Bo Tao
      Abstract: With the popularization and application of chemical process safety management (PSM) systems in the chemical industry, the use of such systems in China has become the focus of a large volume of research. In this article, 12 elements included in the current Chinese PSM system are divided into four stages from a structural point of view. This division will be helpful in the follow-up analysis. After a careful analysis of the evaluation results for one PSM pilot study in Nanjing, some correlations have been found between the results of the elemental evaluation. Small- and medium-sized chemical plants make up a large proportion of Chinese chemical plants and many chemical accidents take place in these plants, so a simplified PSM system in practical operation need to be found. Based on a previous PSM structural analysis, the secondary elements of the PSM system can be removed. This allows researchers to avoid the traditional method of analyzing PSM elements individually. In the concrete analysis process, a theoretical analysis of the correlation degree between elements can be combined with the results of accident investigations. The simplified Chinese PSM system consists of four core elements: Process safety information, process hazard analysis, training, and emergency management. Based on the current applications of these four core elements in China, a consideration of correlations between these elements is used to make several suggestions for improving China's PSM systems. © 2017 American Institute of Chemical Engineers Process Saf Prog, 2017
      PubDate: 2017-01-22T11:20:24.826483-05:
      DOI: 10.1002/prs.11878
       
  • Issue Information-TOC
    • Pages: 1 - 1
      PubDate: 2017-02-27T23:31:46.047825-05:
      DOI: 10.1002/prs.11843
       
  • Smartphones and process safety
    • Authors: Ronald J. Willey
      Pages: 3 - 3
      PubDate: 2017-02-06T04:35:40.051872-05:
      DOI: 10.1002/prs.11883
       
  • Smartphone use in process safety
    • Authors: Deborah Pano; Christina Baulch
      Pages: 4 - 9
      Abstract: Every development in technology brings the opportunity to build a safer future, in process safety and beyond. In the age of smartphones, this opportunity comes in the form of safety applications, education, and communication through social media. Because the majority of those in the workforce own smartphones, these devices may act as valuable tools for engineers, and are a possible medium for sending alerts and notifications. Because we live in the age of information, applications have been developed specifically to cater to the unmet needs of engineers. Technology has allowed us to have the information we need in the palm of our hand at a moment's notice, and access to this information will lead us to a safer tomorrow. Note that in some facilities, cell phones may be monitored or even prohibited. Always abide by the facility's rules to ensure everyone's safety, particularly in relation to cell phone use. © 2017 American Institute of Chemical Engineers Process Saf Prog 36: 4–9, 2017
      PubDate: 2017-02-08T01:21:10.970195-05:
      DOI: 10.1002/prs.11884
       
  • Practical Leadership Skills for Safety Professionals and Project
           Engineers, A Review (2016) By Gary L. Winn, PhD, CRC Press, Taylor &
           Francis Group, Boca Raton, FL 33487, 330 pages, $67.46, ISBN-9781498758222
           (Hardback)
    • Authors: John Murphy
      Pages: 109 - 109
      PubDate: 2017-01-17T03:37:16.666582-05:
      DOI: 10.1002/prs.11872
       
  • Safety & health news spring 2017
    • Authors: John F. Murphy
      Pages: 110 - 114
      PubDate: 2017-02-09T00:50:25.164063-05:
      DOI: 10.1002/prs.11879
       
  • Erratum: Dangerously close: The CSB's investigation into the fatal fire
           and explosion in west, Texas
    • Pages: 115 - 115
      PubDate: 2017-02-07T02:16:39.510015-05:
      DOI: 10.1002/prs.11882
       
  • Temporarily Withdrawn
    • Abstract: This article has been temporarily withdrawn. It was erroneously published prior to the license agreement process being completed.
      PubDate: 2016-12-29T00:35:23.835587-05:
      DOI: 10.1002/prs.11870
       
  • Think facility, act on integrity
    • Authors: Robert F. Wasileski
      Abstract: The Chemical Processing Industry (CPI) has witnessed growth in Mechanical Integrity (MI) programs, which have evolved from standards-based compliance, to continuous improvement programs, and on to risk-based programs. For instance, operators (i.e., manufacturers) have redesigned corporate standards, plant-level procedures and field practices to keep pace with incident learnings and recommended practices, such as those espoused by the American Institute of Chemical Engineers' (AIChE) Center for Chemical Process Safety (CCPS). Furthermore, the property insurance industry has duly taken note of this MI evolution, giving rise to a significantly greater focus on MI programs during insurance surveys and inspections. Meanwhile, incident investigators remain in demand as incidents with MI-related causes continue to occur in the CPI. This apparent disconnect naturally raises questions in regards to subjects such as “risk based inspection (RBI),” “reliability centered maintenance (RCM),” “industry best practice,” and “inspection, testing and preventive maintenance (ITPM).”MI programs play a considerably important role in the process safety lifecycle of equipment. The engineering design phase of a project may be on the order of just days, up to several years for a complete plant. Procurement and construction typically follow a similar timeline proportionate with the engineering design phase. However, once a facility becomes fully operational, the time devoted toward operation and maintenance will normally far out-weigh the engineering, procurement and construction (EPC) period, and may last for many decades. As such, the process safety equipment lifecycle (PSEL) may be largely governed by the MI program.The PSEL is explained in this article, with an examination of the central elements which should be embraced by a comprehensive MI program. While the article demonstrates the breadth and depth of MI, it aptly proposes a practical approach toward the management system that forms the foundation of a robust MI program. The proposed framework leverages the Onion Skin diagram in the context of the equipment lifecycle to create an intuitive approach to MI management. This management system framework is comprehensive, sound, and practical for implementation at facilities of most any size. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-12-26T10:35:24.993338-05:
      DOI: 10.1002/prs.11869
       
  • Hazards inherent to control systems: Case studies and lessons learned
    • Authors: Brenton L. Cox; Stephen W. Garner, Andrew R. Carpenter, Mark T. Fecke
      Abstract: Control systems are an integral part of almost all chemical processes, regardless of size or complexity. As the demands for performance and safety increase, control systems will only proliferate. With automation comes the ability to develop more complex and interrelated processes, and to respond more rapidly to disturbances. However, increased reliance on control systems, both discrete and continuous, requires increased diligence with respect to their development and testing, as well as the implementation of independent layers of protection.A control system that provides optimal product for typical feed conditions may behave poorly during abnormal conditions, such as idling or turnarounds. Similarly, independent control systems charged with safety instrumented functions may not be called upon to act until they become necessary to prevent or mitigate an emergency situation. To recognize and mitigate hazards associated with control systems, process design and process hazard assessment teams may need to consider these and other potential issues.Presented here is a brief overview of the hazards associated with control systems. Finally, case studies are used to highlight the need for considering the potential hazards associated with control systems, from the design stage, through startup, operation, and turnarounds. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-12-02T04:11:03.706557-05:
      DOI: 10.1002/prs.11868
       
  • Contribution of hydrogen peroxide to non-thermal atmospheric pressure
           plasma induced A549 lung cancer cell damage
    • Authors: Jie Ma; Hao Zhang, Cheng Cheng, Jie Shen, Lingzhi Bao, Wei Han
      Abstract: Non-thermal plasma (NTP) can induce cancer cell death which is supposed to be mediated by oxidative stress. In this work, the contribution of hydrogen peroxide (H2O2) in NTP induced lung cancer cell damage is quantitatively studied. Our results also show signification production of H2O2 in plasma activated medium (PAM). NTP treatment induce critical raising of cell death, apoptosis, and DNA double-strand breaks (DSBs) in A549 cell. NTP treatment also cause mitochondrial dysfunction and intracellular ROS production in A549 cells. Furthermore, catalase efficiently protect cells from NTP induced A549 cell damage. This work clarified the contribution of H2O2 to plasma induced cancer cell damage.Contribution of H2O2 in plasma induced decrease of cell viability: Plasma treatment induced significant production of H2O2 in plasma activated medium (PAM). It is calculated out that H2O2 contributed over 50% of decrease of A549 cell viability induced by non-thermal plasma. H2O2 plays important role in plasma induced cell damage.
      PubDate: 2016-11-10T05:25:31.039053-05:
      DOI: 10.1002/ppap.201600162
       
  • Deposition of homogeneous carbon-TiO2 composites by atmospheric pressure
           DBD
    • Authors: Paul Brunet; Rocío Rincón, Joëlle Margot, Françoise Massines, Mohamed Chaker
      Abstract: Atmospheric pressure Dielectric Barrier Discharge (AP-DBD) was used to deposit homogeneous carbon-TiO2 composites. Non-intrusive Laser Light Scattering was employed to study the transport of the nanoparticles across the plasma. The characteristics of the coating were found to depend on the gas flow and on the spray chamber used for introducing the nanoparticles (cyclonic and Scott spray chambers). According to the SEM images, higher gas flows favor the formation of more homogeneous coatings both in terms of thickness and NPs-aggregates distribution regardless of the spray chamber. The Scott spray chamber was shown to be more efficient for the deposition of uniform coatings even at low gas flows. It also yields the highest Ti concentration that reaches up to 18%. Furthermore, the light scattered by the nanoparticles was shown to be directly related to the coating thickness, hence to the density of nanoparticles in the plasma.The study of the deposition of TiO2-NPs with a Dielectric Barrier Discharge by means of Laser Light Scattering (LLS) has been performed to control the insertion of the NPs into the matrix and final characteristic of the composite. The key experimental conditions for the homogeneous deposition of c-TiO2 composite are shown in this work. Promising results, based on the good correlation between LLS and composite characteristics, are presented.
      PubDate: 2016-11-09T15:48:40.425978-05:
      DOI: 10.1002/ppap.201600075
       
  • Effect of electric fields on plasma catalytic hydrocarbon oxidation from
           atomistic simulations
    • Authors: Erik C. Neyts; Kristof M. Bal
      Abstract: The catalytic oxidative dehydrogenation of hydrocarbons is an industrially important process, in which selectivity is a key issue. We here investigate the conversion of methanol to formaldehyde on a vanadia surface employing long timescale simulations, reaching a time scale of seconds. In particular, we compare the thermal process to the case where an additional external electric field is applied, as would be the case in a direct plasma-catalysis setup. We find that the electric field influences the retention time of the molecules at the catalyst surface. These simulations provide an atomic scale insight in the thermal catalytic oxidative dehydrogenation process, and in how an external electric field may affect this process.Long time scale simulations, reaching a time scale of seconds, are employed to study methanol-to-formaldehyde conversion on a vanadia surface. An external electric field as present in a direct plasma-catalysis setup is added and compared to thermal conversion. The conversion mechanisms are discussed and the influence of the electric field on the surface retention time is demonstrated.
      PubDate: 2016-11-08T04:42:01.655201-05:
      DOI: 10.1002/ppap.201600158
       
  • Modeling of a Non-Thermal RF Plasma Jet at Atmospheric Pressure
    • Authors: Florian Sigeneger; Jan Schäfer, Klaus-Dieter Weltmann, Rüdiger Foest, Detlef Loffhagen
      Abstract: An RF driven non-thermal atmospheric pressure plasma jet used for plasma enhanced chemical vapor deposition is investigated by hydrodynamic modeling. The model describes the gas flow and heating, the plasma generation in the active zone, reactions of active plasma particles with precursor molecules in the effluent, and the transport of precursor fragments toward the substrate. Molecular argon ions are found to be the dominant active species transported into the effluent together with slow electrons. The radial profiles of the fluxes of precursor fragments onto the substrate depend sensitively on the flow conditions. Satisfactory agreement of the calculated gas temperature with measured profiles is obtained.The spatially two-dimensional hydrodynamic model of the plasma jet describes the gas flow and heating, the plasma generation in the active zone, reactions of active plasma particles with precursor molecules in the effluent and the transport of precursor fragments toward the substrate. The impact of flow conditions on the radial profiles of precursor fragments is analyzed.
      PubDate: 2016-11-07T07:32:08.960684-05:
      DOI: 10.1002/ppap.201600112
       
  • Computing Different Modes on Cathodes of DC Glow and High-Pressure Arc
           Discharges: Time-Dependent Versus Stationary Solvers
    • Authors: Pedro G. C. Almeida; Mikhail S. Benilov, Mário D. Cunha, José G. L. Gomes
      Abstract: Complex behavior can appear in the modeling of gas discharges even in apparently simple steady-state situations. Time-dependent solvers may fail to deliver essential information in such cases. One of such cases considered in this work is the 1D DC discharge. The other case is represented by multiple multidimensional solutions existing in the theory of DC discharges and describing modes of current transfer with different patterns of spots on the cathodes. It is shown that, although some of the solutions, including those describing beautiful self-organized patterns, can be computed by means of a time-dependent solver, in most examples results of time-dependent modeling are at best incomplete. In most examples, numerical stability of the time-dependent solver was not equivalent to physical stability.It is shown in this work that time-dependent solvers may fail to deliver essential information when used in the modeling of DC gas discharges, particularly in the presence of complex behavior and/or multiple modes of current transfer to the cathode. Results of time-dependent modeling of complex behavior and different modes of are shown to be at best incomplete. In extreme situations, time-dependent solvers may produce patchy pictures of the pattern of different modes. In most cases numerical stability of time-dependent solvers was found to be not equivalent to physical stability.
      PubDate: 2016-11-04T05:38:18.193195-05:
      DOI: 10.1002/ppap.201600122
       
  • Characterization and comparison of N-, O-, and N+O-functionalized polymer
           surfaces for efficient (HUVEC) endothelial cell colonization
    • Authors: Gaël Boespflug; Marion Maire, Gregory De Crescenzo, Sophie Lerouge, Michael R. Wertheimer
      Abstract: Surface modifications are often required to enhance cell adhesion and growth around implanted biomaterials. This study compares various functionalization processes in their ability to create high densities of oxygen- and/or nitrogen-containing functional groups, mostly on a polymeric biomaterial, polyethylene terephthalate (PET). Primary amine (NH2)-rich surfaces were prepared by low-pressure plasma-polymerization (L-PPE:N), plasma modification (functionalized PET, “PETf”), chemical vapour deposition (Parylene diX AM), and grafting of polyallylamine (PAAm). Plasma polymerization was also used to obtain oxygen-rich (L-PPE:O) as well as hybrid (L-PPE:O,N) films, which were respectively compared to oxygen-rich tissue culture polystyrene (TCP) and hybrid (Primaria™) culture plates. Compositions and bond types were studied by X-ray photoelectron spectroscopy. Finally, the effect of each surface on cell adhesion and growth was assessed using human umbilical vein endothelial cells (HUVECs). Amine-containing surfaces manifested a wide [NH2] range, up to 8.9%. Hybrid surfaces, Primaria™ and L-PPE:O,N, showed lower [NH2] in spite of high [N], suggesting more varied and complex functionalities. Except for Parylene, all O- and NH2-rich surfaces promoted HUVEC adhesion and growth similarly, despite differing chemical compositions. Primaria™ showed the best cell behavior, but L-PPE:O,N did not reproduce this apparent synergistic effect. To conclude, both N- and O-rich surfaces displayed good cell-colonization properties, particularly plasma polymers, while “hybrid” surfaces appear somewhat ambiguous and call for further investigation.Various functionalized polymeric (PET) surfaces are compared in regard to their ability to enhance endothelial cell adhesion and proliferation. Most nitrogen-rich surfaces displayed excellent results, thanks to primary amine groups, and oxygen-bearing samples show a similar efficiency. Hybrid surfaces, containing both O- and N-bearing moieties, presented a great potential to induce even better endothelialization, but still need further improvement.
      PubDate: 2016-11-03T05:59:07.702539-05:
      DOI: 10.1002/ppap.201600139
       
  • Synergistic CO2 conversion by hybridization of dielectric barrier
           discharge and solid oxide electrolyser cell
    • Authors: Shinsuke Mori; Lin Lin Tun
      Abstract: Hybrid reactor of Dielectric Barrier Discharge (DBD) and Solid Oxide Electrolyser Cell (SOEC) was fabricated and CO2 decomposition characteristics were investigated. For the case of the DBD reactor alone, the CO2 conversion saturates with residence time. In contrast, the saturation is not observed for the case of the hybrid system where CO2 conversion increases monotonically with increasing residence time. This is because the reverse reaction to regenerate the CO2 in plasma is suppressed by the oxygen removal by SOEC in hybrid system and consequently CO2 decomposition reaction proceeds irreversibly. We have examined the experimental results by analytical modeling and reaction mechanism for the CO2 decomposition in the hybrid reactor of DBD and SOEC is deduced. The time-dependent CO2 conversion for the only plasma reactor and hybrid reactor can be reproduced by a reversible and irreversible first-order reaction model, respectively. The analytical model can also reproduce the dependence of CO2 conversion on the plasma input power very well. Interestingly, not only the reverse reaction rate but also the forward dissociation reaction rate is reduced by the SOEC in the case of hybrid reactor. The analytical modeling suggests that CO2 decomposition in the conventional DBD plasma reactor proceeds not merely by direct electron impact dissociation but also by reaction with reactive oxygen.Hybrid reactor of Dielectric Barrier Discharge (DBD) and Solid Oxide Electrolyser Cell (SOEC) was fabricated and CO2 decomposition characteristics were investigated. For the case of the DBD reactor alone, CO2 conversion saturates with increasing residence time. In contrast, the saturation is not observed for the case of the hybrid system. We have examined the experimental results by analytical modeling. Time-dependent CO2 conversion for the plasma reactor alone and hybrid reactor can be reproduced by a reversible and irreversible first-order reaction model, respectively. The analytical model can also reproduce the dependence of CO2 conversion on the plasma input power very well.
      PubDate: 2016-10-31T03:51:18.407891-05:
      DOI: 10.1002/ppap.201600153
       
  • Atmospheric-pressure nonthermal plasma synthesis of ammonia over ruthenium
           catalysts
    • Authors: Hyun-Ha Kim; Yoshiyuki Teramoto, Atsushi Ogata, Hideyuki Takagi, Tetsuya Nanba
      Abstract: Atmospheric-pressure nonthermal plasma was used to synthesize ammonia from nitrogen and hydrogen over ruthenium catalysts. Formation of NH3 in a N2-H2 mixture altered the plasma characteristics due to the low ionization potential of NH3 (10.15 eV). The optimum gas ratio was found at N2:H2 = 4:1 by volume (i.e., N2-rich conditions). When plasma was operated at a temperature below 250 °C, the NH3 concentration increased linearly with increasing specific input energy (SIE). For the Ru(2)-Mg(5)/γ-Al2O3 catalyst at 250 °C, pulse energization was four times more efficient than the AC energization case. The presence of RuO2 was found to be beneficial for the NH3 synthesis via plasma-catalysis. The addition of a small amount of O2 was found to be effective for the in situ regeneration of the deactivated catalyst. The effect of metal promoters was in the order of Mg > K > Cs > no promoter.Plasma-catalysis was studied to synthesis ammonia (NH3) at atmospheric pressure and temperatures near light-off of Ru-based catalysts. We found that the interaction of plasma and catalyst become significant when plasma-catalyst reactor is operated at light-off temperature of catalyst. Energy yield of NH3 synthesis was reached up to 36 g-NH3/kWh in this study, while it was less than about 2 g-NH3/kWh.
      PubDate: 2016-10-28T01:15:31.690998-05:
      DOI: 10.1002/ppap.201600157
       
  • A Simple Model for Ion Flux-Energy Distribution Functions in Capacitively
           Coupled Radio-Frequency Plasmas Driven by Arbitrary Voltage Waveforms
    • Authors: Edmund Schüngel; Zoltán Donkó, Julian Schulze
      Abstract: The ion flux-energy distribution function (IFEDF) is of crucial importance for surface processing applications of capacitively coupled radio-frequency (CCRF) plasmas. Here, we propose a model that allows for the determination of the IFEDF in such plasmas for various gases and pressures in both symmetric and asymmetric configurations. A simplified ion density profile and a quadratic charge voltage relation for the plasma sheaths are assumed in the model, of which the performance is evaluated for single- as well as multi-frequency voltage waveforms. The IFEDFs predicted by this model are compared to those obtained from PIC/MCC simulations and retarding field energy analyzer measurements. Furthermore, the development of the IFEDF shape and the ion dynamics in the plasma sheath region are discussed in detail based on the spatially and temporally resolved model data.The bombardment by energetic ions plays a key role in surface processing applications of capacitive discharges. We study the complex ion dynamics and the formation of the ion flux-energy distribution function (IFEDF) in the radio-frequency sheath. A simple model is introduced, which allows for the calculation of the IFEDF at various gas pressures, and voltage waveforms. It is validated in comparisons with PIC/MCC simulation results and measurements.
      PubDate: 2016-10-28T01:15:28.940577-05:
      DOI: 10.1002/ppap.201600117
       
  • Plasma-based liquefaction of methane: The road from hydrogen production to
           direct methane liquefaction
    • Authors: Ramses Snoeckx; Alexander Rabinovich, Danil Dobrynin, Annemie Bogaerts, Alexander Fridman
      Abstract: For the energy industry, a process that is able to transform methane—being the prime component of natural gas—efficiently into a liquid product would be equivalent to a goose with golden eggs. As such it is no surprise that research efforts in this field already date back to the nineteen hundreds. Plasma technology can be considered to be a novel player in this field, but nevertheless one with great potential. Over the past decades this technology has evolved from sole hydrogen production, over indirect methane liquefaction to eventually direct plasma-assisted methane liquefaction processes. An overview of this evolution and these processes is presented, from which it becomes clear that the near future probably lies with the direct two phase plasma-assisted methane liquefaction and the far future with the direct oxidative methane liquefaction.An overview of the efforts made to date in the field of plasma-based liquefaction of methane is given. Interest for transforming methane into more valuable liquid products dates back as far as the beginning of the 20th century, and it becomes clear that plasma technology can definitely play an important role in this field leading to a potential industrial implementation.
      PubDate: 2016-10-28T01:15:23.374802-05:
      DOI: 10.1002/ppap.201600115
       
  • Multiscale Modeling of Low Pressure Plasma Etching Processes: Linking the
           Operating Parameters of the Plasma Reactor with Surface Roughness
           Evolution
    • Authors: Sotiris Mouchtouris; George Kokkoris
      Abstract: Α multiscale modeling framework, linking the operating parameters of a low pressure plasma reactor with the surface roughness being formed on the etched substrate, is developed. It consists of a) a reactor scale model, which calculates densities, energies, and fields in the reactor, b) a Monte Carlo (MC) particle tracing model, which calculates the ion energy and angular distributions on the substrate, and c) a MC surface model, which calculates the evolution of the surface morphology during etching. The case study is etching of polymeric substrates with Ar plasma in the GEC reactor. Based on a generic surface model, the effects of the operating conditions (pressure, power) on the roughness are investigated. The potential for non-uniform and anisotropic roughness along the wafer radial direction is demonstrated.Plasma etching in low pressure reactors has been shown to “induce” surface roughness on polymeric substrates and thus affecting, e.g., the wetting properties of the surface or the surface – cell interactions. Aiming to process recipes delivering desired surface roughness, a multiscale modeling framework, linking the operating parameters of the plasma reactor with the evolution of surface roughness of the etched substrate, is developed.
      PubDate: 2016-10-28T01:11:03.479341-05:
      DOI: 10.1002/ppap.201600147
       
  • Understanding CO2 decomposition in microwave plasma by means of optical
           diagnostics
    • Authors: Tiago Silva; Nikolay Britun, Thomas Godfroid, Rony Snyders
      Abstract: The growing interest to plasma-based greenhouse gas decomposition requires the knowledge of the different kinetic mechanisms inherent in CO2 discharges and post-discharges. This automatically involves extensive plasma diagnostics research work. Among different types of plasma diagnostics, the ones based on optical spectroscopy are of particular relevance due to their non-intrusiveness. The recent progress in optical diagnostics of plasma-assisted CO2 decomposition process is discussed in this work. A microwave surfaguide discharge operating at 2.45 GHz in several CO2-containing mixtures was investigated. Optical emission spectroscopy is used to characterize the discharge area of the reactor in terms of fundamental plasma parameters. At the same time, two-photon absorption laser-induced fluorescence is applied for investigation of oxygen and carbon monoxide concentrations in the post-discharge.In this work, a microwave surfaguide discharge operating at 2.45 GHz in several CO2-containing mixtures is investigated. Among various useful applications, these sources are considered to be energy-efficient and powerful plasma-chemical systems in gas reforming. This subject is highly important nowadays due to the growing interest to plasma-based CO2 decomposition. We used optical emission spectroscopy and two-photon absorption laser-induced fluorescence to study plasma-assisted CO2 conversion in relation with plasma parameters, such as electron and gas temperature, etc. The current paper is targeted to demonstrate a potential for optimization of the pulsed microwave discharges for increasing the CO2 decomposition efficiency as well as to show an importance of the optical diagnostic methods for characterization of various physical and chemical mechanisms related to CO2 plasmas.
      PubDate: 2016-10-24T06:52:06.713014-05:
      DOI: 10.1002/ppap.201600103
       
  • Synergy of DBD plasma and Fe-based catalyst in NH3 decomposition: Plasma
           enhancing adsorption step
    • Authors: Li Wang; Yanhui Yi, Yanjun Guo, Yue Zhao, Jialiang Zhang, Hongchen Guo
      Abstract: The synergy between catalyst and plasma has dramatically improved the efficiency of some plasma chemical processes. In this paper, the role of the electronically excited state NH3 (NH3*) in the synergy of a DBD plasma and a Fe-based catalyst for NH3 decomposition has been studied by in situ optical emission spectra diagnostics, as well as adsorption and desorption experiments. Results reveal that, the NH3* species could adsorb on the catalyst surface with higher adsorption capacity and stronger strength in comparison with ground-state NH3. The ammonia conversion increased by nearly 40% due to the contribution of NH3* species. Here, the acceleration of the surface adsorption step with excited reactants is proved to be another role of plasma in synergy with heterogeneous catalyst.The mechanism of synergy between plasma and catalyst is unclear. This paper provides a direct proof that the electronically excited state NH3 (NH3*) can adsorb on the Fe-based catalyst with higher adsorption capacity and stronger strength than that of the ground state NH3. Therefore, plasma-enhancing adsorption step as being observed herein should be one of the synergistic ways of plasma with heterogeneous catalyst.
      PubDate: 2016-10-21T05:05:41.387585-05:
      DOI: 10.1002/ppap.201600111
       
  • Temporarily Withdrawn
    • Abstract: This article has been temporarily withdrawn. It was erroneously published prior to the license agreement process being completed.
      PubDate: 2016-10-18T23:30:20.03365-05:0
      DOI: 10.1002/prs.11863
       
  • Micro-plasmoids in self organized filamentary dielectric barrier
           discharges
    • Authors: Max Engelhardt; Friederike Kogelheide, Katharina Stapelmann, Nikita Bibinov, Peter Awakowicz
      Abstract: A filamentary dielectric barrier discharge (DBD) is ignited on a silicon wafer under atmospheric pressure conditions in a mixture of argon and air (0.5/0.5) in two different modes, namely a stochastically ignited filamentary discharge and a self-organized filamentary discharge by the application of high voltage (HV) pulses at two repetition frequencies, 0.5 and 5 kHz. The discharge conditions are characterized by optical emission spectroscopy and current–voltage measurements. The silicon wafer surface treated with the DBD is studied with an electron microscope. The formation of a homogeneous silicon oxide layer is observed after treatment under a stochastically filamentary DBD. Whereas, in the self-organized filamentary DBD, etching tracks (thin channels) and blisters are produced on the silicon wafer surface, which are interpreted as tracks of plasmoids, namely plasma objects without any direct contact to a power supply. The transition between the different filamentary modes of the DBD plasma occurs in the presented study through an increase of the repetition frequency of HV pulses, but it can also be caused by small silicon splinters on the wafer surface. The splinters cause ignitions in stable positions, and therefore induce a combination of discharge modes, namely stochastically and self-organized DBD mode. In close proximity to the splinters, tracks of plasmoids are observed, even in the DBD at low frequency.An atmospheric pressure DBD is used to modify silicon wafer surfaces, on which etching tracks and silicon blisters can be observed. This is dependent on the DBD mode, in a diffuse mode no tracks are seen, whereas a self-organizing mode produces tracks.
      PubDate: 2016-10-18T03:31:11.357909-05:
      DOI: 10.1002/ppap.201600095
       
  • A Comprehensive Chemical Model for the Splitting of CO2 in Non-Equilibrium
           Plasmas
    • Authors: Peter Koelman; Stijn Heijkers, Samaneh Tadayon Mousavi, Wouter Graef, Diana Mihailova, Tomas Kozak, Annemie Bogaerts, Jan van Dijk
      Abstract: An extensive CO2 plasma model is presented that is relevant for the production of “solar fuels.” It is based on reaction rate coefficients from rigorously reviewed literature, and is augmented with reaction rate coefficients that are obtained from scaling laws. The input data set, which is suitable for usage with the plasma simulation software Plasimo (https://plasimo.phys.tue.nl/), is available via the Plasimo and publisher's websites. The cor­rectness of this model implementation has been established by indepen­dent ZDPlasKin implementation (http://www.zdplaskin.laplace.univ-tlse.fr/), to verify that the results agree. Results of these “global models” are presented for a DBD plasma reactor.A graphical overview of the complex CO2 chemistry, including the vibrational modes, which is implemented in the global models of Plasimo and ZDPlasKin. The reaction data set is obtained from literature and reviewed rigorously. The Plasimo compatible model, including the chemistry, is made available via the Plasimo (http://plasimo.phys.tue.nl/resources/index.html) and the publishers websites.
      PubDate: 2016-10-17T04:10:57.025718-05:
      DOI: 10.1002/ppap.201600155
       
  • Modeling of a Microwave Plasma Driven Biomass Pyrolitic Conversion for
           Energy Production
    • Authors: Dmitry L. Tsyganov; Neli Bundaleska, Elena Tatarova
      Abstract: The thermal decomposition of biomass particles in a microwave plasma operating at atmospheric pressure conditions has been theoretically investigated. The set of equations, including thermal balance equations for the gas and biomass particles and kinetic rate balance equations for stable and intermediate components of biomass decomposition was solved for two different assumptions: thermal equilibrium and non-equilibrium. The thermal equilibrium assumption is acceptable given the high temperature and high reaction rates achievable in the microwave plasma environment, and although it hides the evolution of the pyrolysis process, it allows the description of the detailed chemical composition of the stable pyrolysis by-products (H2, CO, C2H2, and C [solid]).The thermal decomposition of biomass particles in a microwave plasma operating at atmospheric pressure conditions is theoretically investigated. The equilibrium approach provides detailed chemical composition of the final products (CO, CO2, and H2), while the non-equilibrium presents the evolution of the pyrolysis process. A correlation between the two approaches is found.
      PubDate: 2016-10-17T02:56:00.738674-05:
      DOI: 10.1002/ppap.201600161
       
  • Bayesian network and bow tie to analyze the risk of fire and explosion of
           pipelines
    • Authors: Zerouali Bilal; Kara Mohammed, Hamaidi Brahim
      Abstract: As accidents were and still one of the main reasons standing behind the increasing rates of casualties such as death, injuries, and evacuations, the constant improvement of safety measures especially in the field of hydrocarbons remains a major concern. Therefore, in the work in hand, we attempt to shed the light on the ways of developing a method for the evaluation of risks of fire and explosions of pipelines. The causes of the latter and consequences are, in one hand, analyzed by means of fault tree and bow tie methods. On the other hand, a quantitative analysis implementing the Bayesian networks is used to estimate the probability of occurrence of the adverse event. Moreover, 72 basic events were found to be of the primary causes provoking the occurrence of undesirable events. However, some experts often find it difficult to precisely determine the probabilities of occurrence of basic events of the tree. For the purpose of evaluating the occurrence of each basic event, we used the fuzzy logic. Hence, at the end of the study, we were able to develop a model that could help us evaluate the risks accompanied the fires and pipelines explosion as well as the consequences. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-10-14T08:25:49.809962-05:
      DOI: 10.1002/prs.11860
       
  • Chemical Kinetics and Reactive Species in Normal Saline Activated by a
           Surface Air Discharge
    • Authors: Zhi Chao Liu; Li Guo, Ding Xin Liu, Ming Zhe Rong, Hai Lan Chen, Michael G. Kong
      Abstract: Normal saline is a common biological solution which provides much better living environment for Staphylococcus aureus than deionized water, but the plasma-activated normal saline is found to have a stronger bactericidal effect than the plasma-activated deionized water. A model is developed for the explanation, from which various kinds of reactive chlorine/oxy-chlorine species (RCS), such as HClO, are found to be generated in the plasma-activated normal saline. The production pathways of RCS are elucidated, in which O3 plays as an important intermediate species. Compared to the plasma-activated deionized water, the concentrations of reactive oxygen/nitrogen species are lower, but the bactericidal effect is higher, implying that the RCS play a crucial role for the sterilization.Plasma-activated normal saline is found to have a stronger bactericidal effect than the plasma-activated deionized water, which may be attributed to the production of reactive chlorine/oxy-chlorine species especially for HClO. A model is developed for the interaction between surface air plasmas and normal saline, from which the chemical profile of reactive chlorine/oxy-chlorine species is provided.
      PubDate: 2016-10-05T04:01:58.766822-05:
      DOI: 10.1002/ppap.201600113
       
  • Distinct modes in the evolution of interaction between polymer film and
           atmospheric pressure plasma jet
    • Authors: Tao Wang; Bin Yang, Xiang Chen, Xiaolin Wang, Chunsheng Yang, Jingquan Liu
      Abstract: Different modes are revealed and characterized in the evolution of interaction between an atmospheric pressure He/O2 plasma jet and the parylene-C film deposited on a silicon substrate. In the initial mode, the plasma jet spreads on the film surface with the etching process layer by layer from the top to the bottom of the polymer film. Transition mode occurs with sudden change of discharge and plasma characteristics . Then coupled mode dominated the interaction process with the plasma confined in the etched hole and advanced lap by lap from inner to outer domain in the radial direction. To copper substrate, the same distinct modes were also observed. However, to the glass substrate, only layer by layer etching process was observed.This manuscript reveals and characterizes distinct modes in the evolution of interaction between an atmospheric pressure He/O2 plasma jet and parylene-C film deposited on a substrate depending on discharge and plasma characteristics, as well as interaction direction.
      PubDate: 2016-10-04T07:06:05.328899-05:
      DOI: 10.1002/ppap.201600067
       
  • About the enhancement of chemical yield during the atmospheric plasma
           synthesis of ammonia in a ferroelectric packed bed reactor
    • Authors: Ana Gómez-Ramírez; Antonio M. Montoro-Damas, José Cotrino, Richard M. Lambert, Agustín R. González-Elipe
      Abstract: Plasma reactions offer an attractive alternative route for the synthesis of a variety of valuable chemical compounds. Here we investigate the parameters that determine the efficiency of ammonia synthesis in a ferroelectric packed bed dielectric barrier discharge (DBD) reactor. The effects of varying the operating frequency, the size of the ferroelectric pellets and the inter-electrode distance have been systematically studied. Under optimised conditions nitrogen conversions in excess of 7% were achieved, higher than those previously obtained using DBD reactors. These findings are discussed with respect to variations in the electrical characteristics of the reactor under operating conditions and in the light of emission spectra obtained as a function of reactant flow rates. These encouraging results signpost future developments that could very substantially improve the efficiency of ammonia synthesis by means of DBD technology.The direct synthesis of ammonia from N2 and H2 is carried out in a packed-bed ferroelectric barrier discharge reactor reaching nitrogen conversions as high as 7%, which was never achieved with plasma techniques. This outstanding efficiency is obtained thanks to the variation of operating parameters such as gas residence time, inter-electrode distance, pellet size and frequency of the input electrical signal.
      PubDate: 2016-10-04T07:06:02.891857-05:
      DOI: 10.1002/ppap.201600081
       
  • Quasi-Neutral Modeling of Gliding Arc Plasmas
    • Authors: Stanimir Kolev; Surong Sun, Georgi Trenchev, Weizong Wang, Haixing Wang, Annemie Bogaerts
      Abstract: The modelling of a gliding arc discharge (GAD) is studied by means of the quasineutral (QN) plasma modelling approach. The model is first evaluated for reliability and proper description of a gliding arc discharge at atmospheric pressure, by comparing with a more elaborate non-quasineutral (NQN) plasma model in two different geometries – a 2D axisymmetric and a Cartesian geometry. The NQN model is considered as a reference, since it provides a continuous self-consistent plasma description, including the near electrode regions. In general, the results of the QN model agree very well with those obtained from the NQN model. The small differences between both models are attributed to the approximations in the derivation of the QN model. The use of the QN model provides a substantial reduction of the computation time compared to the NQN model, which is crucial for the development of more complex models in three dimensions or with complicated chemistries. The latter is illustrated for (i) a reverse vortex flow (RVF) GAD in argon, and (ii) a GAD in CO2. The RVF discharge is modelled in three dimensions and the effect of the turbulent heat transport on the plasma and gas characteristics is discussed. The GAD model in CO2 is in a 1D geometry with axial symmetry and provides results for the time evolution of the electron, gas and vibrational temperature of CO2, as well as for the molar fractions of the different species.A gliding arc discharge (GAD) is studied by means of a quasineutral (QN) fluid plasma model. The model reliability is first evaluated against a more elaborate non-quasineutral discharge model at atmospheric pressure in argon. Subsequently, the QN approach is applied for a reverse vortex flow GAD in argon and a GAD in CO2.
      PubDate: 2016-10-04T06:40:25.649105-05:
      DOI: 10.1002/ppap.201600110
       
  • Plasma afterglow treatment of polymer powders: Process parameters,
           wettability improvement, and aging effects
    • Authors: Gina Oberbossel; Christian Probst, Vito Roberto Giampietro, Philipp Rudolf von Rohr
      Abstract: Polyethylene powder is treated in an atmospheric pressure circulating fluidized bed plasma reactor, in which powder particles pass the afterglow of 64 discharge channels multiple times. Contact angle drops with increasing treatment time and powder gradually becomes wettable with liquids of higher surface tensions. X-ray photoelectron spectroscopy is used to prove particle surface functionalization induced by the afterglow process. Two different channel arrangements and geometries are studied and the influence of applied voltage and frequency on activation efficiency is investigated. Minimal surface aging is observed when samples are stored in air. However, when dispersed in water, particles maintain the engineered wettability.Polymer powder is activated in the afterglow of 64 dielectric barrier discharges. With increasing treatment time powders gradually become wettable with liquids of higher surface tensions and XPS measurements confirm oxygen incorporation onto particle surface. Influence of reactor geometry, applied voltage and frequency as well as storage time on measured powder contact angles is discussed.
      PubDate: 2016-10-04T06:40:21.579515-05:
      DOI: 10.1002/ppap.201600144
       
  • Study of the Stability and Hydrophilicity of Plasma-Modified Microfluidic
           Materials
    • Authors: Bradley Da Silva; Mengxue Zhang, Guillaume Schelcher, Lea Winter, Cédric Guyon, Patrick Tabeling, Daniel Bonn, Michael Tatoulian
      Abstract: Polymers among new classes of materials such as polydimethylsiloxane (PDMS), cyclic olefin copolymer (COC), Norland optical adhesive (NOA), and THV (fluoropolymer) were evaluated as surface-modified microfluidic materials, including investigating the incorporation of silica-like functional groups onto these surfaces. The functionalization of these materials was performed using a hybrid reactor equipped with magnetron sputtering using a silica target and with a PECVD apparatus starting from hexamethyldisiloxane as a chemical precursor. Coated microfluidic materials were then evaluated in terms of wettability, stability, composition, and structure. The deposited coatings were proved to be stable up to 2 month in air and water storage for these materials, with COC providing the most stable substrate.Evolution of water contact angles of PDMS with SiO2-like coatings deposited by PECVD and by sputtering in air and water storage (PECVD: 150 W plasma discharge power, 4 min deposition time, 150 sccm oxygen flow rate, and 0.3 mbar precursor pressure. Sputtering: 150 W plasma discharge power, 60 min deposition time, 30 sccm Ar flow rate, and 150 sccm O2 flow rate).
      PubDate: 2016-10-04T04:01:19.164419-05:
      DOI: 10.1002/ppap.201600034
       
  • Comparison of Helical and Helicon Antennas as Sources of Plasma Excitation
           Using a Full Wave 3D Electromagnetic Analysis in Vacuum
    • Authors: Yorgos Stratakos; Angelos Zeniou, Evangelos Gogolides
      Abstract: Helical and Helicon antennas are routinely used to generate inductively coupled plasmas, but there are only a few simulations or experimental data with comparisons among them. Thus, selection of the appropriate number of turns, or the type of helical or helicon antenna to use is empirical. In this paper, a comparison via simulation of various helixes and helicon antennas is presented. Full wave 3D electromagnetic analysis is performed in vacuum using a commercial software, and the electric/magnetic field component is calculated and compared for four cases of helixes, namely N = 1–4 where N is the number of turns that each helix has, as well as two helicon antennas (half and full Nagoya type). In order to reduce the capacitive coupling of these antennas an electromagnetic shield is also applied. Simulation and comparison of the shielded and unshielded antennas is given. We show that via such simulations electric and magnetic field components can be compared in order to select the appropriate antenna type for a plasma source.Electric field distributions on the surface of the dielectric cylinder generated by helical and helicon plasma antennas with and without electrostatic shielding.
      PubDate: 2016-09-30T08:31:55.561961-05:
      DOI: 10.1002/ppap.201600107
       
  • Atmospheric pressure non-equilibrium plasma cleaning of 19th century
           daguerreotypes
    • Authors: Marco Boselli; Cristina Chiavari, Vittorio Colombo, Matteo Gherardi, Carla Martini, Fabio Rotundo
      Abstract: In the work, the feasibility of using atmospheric pressure non-equilibrium plasmas to clean the surface of a deteriorated 19th century daguerreotype has been examined and a proof-of-principle demonstration is given. The daguerreotype was treated by means of both a commercial plasma jet source (kINPen 09, Neoplas Tools GmbH) and a specially designed Dielectric Barrier Discharge (DBD) plasma source operated within a controlled volume at atmospheric pressure, by using a argon-hydrogen gas mixture (H2 content: 35% vol.) to remove corrosion products, without immersion of the substrate in solvents or chemicals. The effectiveness of plasma treatment in removing tarnishing products while preventing damage to the fragile image has been evaluated analysing the surface by means of scanning electron microscopy (SEM) with energy dispersive microprobe (EDS) for localized elemental analysis, micro-Raman and ATR-FTIR spectroscopy for phase identification.Two different atmospheric pressure non-thermal plasmas have been used to clean the surface of a corroded 19th century daguerreotype. The influence of the plasma treatment on the image quality, surface composition and its effectiveness in removing tarnishing products has been evaluated by means SEM with EDS for localized elemental analysis, micro-Raman and ATR-FTIR spectroscopy for phase identification.
      PubDate: 2016-09-29T04:37:39.648711-05:
      DOI: 10.1002/ppap.201600027
       
  • Plasma-driven dissociation of CO2 for fuel synthesis
    • Authors: Waldo Bongers; Henny Bouwmeester, Bram Wolf, Floran Peeters, Stefan Welzel, Dirk van den Bekerom, Niek den Harder, Adelbert Goede, Martijn Graswinckel, Pieter Willem Groen, Jochen Kopecki, Martina Leins, Gerard van Rooij, Andreas Schulz, Matthias Walker, Richard van de Sanden
      Abstract: Power-to-gas is a storage technology aiming to convert surplus electricity from renewable energy sources like wind and solar power into gaseous fuels compatible with the current network infrastructure. Results of CO2 dissociation in a vortex-stabilized microwave plasma reactor are presented. The microwave field, residence time, quenching, and vortex configuration were varied to investigate their influence on energy- and conversion efficiency of CO2 dissociation. Significant deterioration of the energy efficiency is observed at forward vortex plasmas upon increasing pressure in the range of 100 mbar towards atmospheric pressure, which is mitigated by using a reverse vortex flow configuration of the plasma reactor. Data from optical emission shows that under all conditions covered by the experiments the gas temperature is in excess of 4000 K, suggesting a predominant thermal dissociation. Different strategies are proposed to enhance energy and conversion efficiencies of plasma-driven dissociation of CO2.CO2 dissociation experiments in two setups of a vortex-stabilized microwave plasma reactor are presented. The microwave field, residence time, quenching, and vortex configurations are varied. Data of optical emission indicate that under all experimental conditions the plasma is in thermal equilibrium due to a high gas temperature (Tg). Different strategies are proposed to create a non-thermal plasma in order to increase energy and conversion efficiencies.
      PubDate: 2016-09-28T10:13:09.906622-05:
      DOI: 10.1002/ppap.201600126
       
  • Observations of Surface Mode Influence on Plasma Uniformity in PIC/MCC
           Simulations of Large Capacitive Discharges
    • Authors: Denis Eremin; Ralf Peter Brinkmann, Thomas Mussenbrock
      Abstract: Capacitively coupled plasmas with large electrodes, driven at high frequencies, exhibit new physics compared to small scale CCP devices or at low frequencies. This is due to excitation of two types of surface modes which arise as a result of interaction between the bulk plasma and the plasma sheaths separating the plasma from electrodes. Based on the physical effects that these modes cause, they are labeled as “self-bias” (SB) and “plasma-series resonance” (PSR) modes. Results of electrostatic 2d3v PIC/MCC simulations for a model geometry are used to selectively study the SB modes and demonstrate that they lead to non-uniformities of the plasma density profile owing to the influence of the SB modes on the heating of high- and low-energy electrons.2D electrostatic PIC simulations of a large CCP discharge demonstrate non-uniformities in plasma density profile. A suggested explanation is based on excitation of surface modes, for which a new physics-based terminology is suggested. The surface mode studied in the present work interacts differently with low-energy and high-energy electrons.
      PubDate: 2016-09-28T10:12:55.886779-05:
      DOI: 10.1002/ppap.201600164
       
  • Advanced analysis to supplement HAZOP/LOPA for effective process design
    • Authors: William R. Banick; Cindy Wei
      Abstract: The HAZOP and LOPA methods are commonly used for qualitative hazard identification and semi-quantitative assessment of risk in the process industries. Integration of HAZOP and LOPA techniques into a single study has provided the practical advantage of utilizing the same team of subject matter experts to complete evaluation of hazard scenarios, identify needs for further risk reduction, recommend specific safeguards required and confirm resulting residual risk is acceptable. While practical and efficient, the one-step comprehensive integrated HAZOP/LOPA method can have pitfalls. In particular, use of LOPA alone to confirm risk acceptability can lead to complex solutions to meet order-of-magnitude threshold requirements for risk reduction and restrictive requirements for independent protection layers (IPLs). Quantitative methods are sometimes required beyond HAZOP/LOPA to obtain a more precise evaluation of identified hazards and benefits of the associated safeguards. This article presents a risk assessment approach incorporating advanced analysis, including human factors task, fault tree and cost-benefit analysis, following HAZOP/LOPA analysis. To illustrate this approach, an example is shown on the selection of appropriate engineering design options for cyclic regeneration of dense phase ethylene treaters, which have unique safety concerns. Using advanced analysis, a cost effective design solution is developed and is shown to reduce risk to as low as reasonably practicable (ALARP). © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-09-28T04:56:17.589372-05:
      DOI: 10.1002/prs.11855
       
  • A network based approach to envisage potential accidents in offshore
           process facilities
    • Authors: Al-Amin Baksh; Rouzbeh Abbassi, Vikram Garaniya, Faisal Khan
      Abstract: Envisaging potential accidents in large scale offshore process facilities such as Floating Liquefied Natural Gas (FLNG) is complex and could be best characterized through evolving scenarios. In the present work, a new methodology is developed to incorporate evolving scenarios in a single model and predicts the likelihood of accident. The methodology comprises; (a) evolving scenario identification, (b) accident consequence framework development, (c) accident scenario likelihood estimation, and (d) ranking of the scenarios. Resulting events in the present work are modeled using a Bayesian network approach, which represents accident scenarios as cause-consequences networks. The methodology developed in this article is compared with case studies of ammonia and Liquefied Natural Gas from chemical and offshore process facility, respectively. The proposed method is able to differentiate the consequence of specific events and predict probabilities for such events along with continual updating of consequence probabilities of fire and explosion scenarios taking into account. The developed methodology can be used to envisage evolving scenarios that occur in the offshore oil and gas process industry; however, with further modification it can be applied to different sections of marine industry to predict the likelihood of such accidents. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-09-28T04:56:08.703581-05:
      DOI: 10.1002/prs.11854
       
  • Atmospheric pressure roll-to-roll plasma enhanced CVD of high quality
           silica-like bilayer encapsulation films
    • Authors: Fiona M. Elam; Sergey A. Starostin, Anna S. Meshkova, Bernadette C. A. M. van der Velden-Schuermans, Jan B. Bouwstra, Mauritius C. M. van de Sanden, Hindrik W. de Vries
      Abstract: A glow like atmospheric pressure dielectric barrier discharge in a roll-to-roll setup was used to synthesize 90 nm silica-like bilayer encapsulation films composed of a 30 nm dense “barrier layer” and a comparatively less dense 60 nm “buffer layer” onto a polyethylene 2,6 naphthalate substrate by means of plasma enhanced chemical vapor deposition. Tetraethyl orthosilicate was used as the precursor gas, together with a mixture of nitrogen, oxygen, and argon. The microstructure, chemical composition, morphology, and permeation properties of the films were studied as a function of the specific energy delivered per precursor molecule, and oxygen concentration in the gas mixture, during the deposition of the barrier layer. The presence of the buffer layer within the bilayer architecture critically enhanced the encapsulation performance of the bilayer films, and this in conjunction with increasing the specific energy delivered per precursor molecule during the barrier layer deposition to a value of 20 keV, enabled an effective water vapor transmission rate as low as 6.9 × 10−4 g m−2 d−1 (at 40 °C, 90% relative humidity (RH)) to be achieved. Furthermore, the bilayer film structure has given rise to a remarkable 50% reduction in deposition energy consumption per barrier area with respect to single layer silica-like films of equivalent encapsulation performance and thickness.Flexible bilayer silica-like thin films deposited using roll-to-roll AP-PECVD onto a polymeric substrate are presented as a remarkable alternative to single layer encapsulation films. They demonstrate both a notable effective water vapor transmission rate of 6.9 × 10−4 g m−2 d−1 (at 40 °C, 90% relative humidity) and a 50% reduction in deposition energy consumption per barrier area.
      PubDate: 2016-09-27T01:55:38.185493-05:
      DOI: 10.1002/ppap.201600143
       
  • Modeling of Single and Dual Frequency Capacitive Discharge in Argon
           Hydrogen Mixture − Dynamic Effects and Ion Energy Distribution Functions
           
    • Authors: Dmitry G. Voloshin; Yuri A. Mankelevich, Olga V. Proshina, Tatyana V. Rakhimova
      Abstract: Single (SF) and dual frequency capacitively coupled plasma (DF CCP) in (0–50%) H2/Ar mixtures was studied numerically with 1D hybrid (Particle-in-cell with Monte Carlo Collision + fluid) model. In SF (81 MHz) discharge the effect of hydrogen dilution is studied for the fixed discharge input power. Mechanisms of the plasma density decrease and variation of ions composition with H2 percentage are discussed. The effect of low-frequency voltage on plasma density, ions composition, ions fluxes, and ions energy was studied in DF CCP (1.76–81 MHz) discharge in 5% H2/Ar gas mixture at low (20 mTorr) and high (100 mTorr) pressures.The single and dual frequency capacitively coupled plasma discharges in argon hydrogen mixtures are studied numerically with Particle-in-cell with Monte Carlo Collision method. In single frequency 81 MHz discharge the effect of hydrogen addition from 1 to 50% is shown. In dual frequency 1.76–81 MHz discharge the effect of low-frequency voltage is studied for 20 and 100 mTorr.
      PubDate: 2016-09-26T06:15:32.871072-05:
      DOI: 10.1002/ppap.201600119
       
  • Hybrid and Fluid Modeling of Ion Activation Energy and Reactive Fluxes to
           Particulates Suspended in Air and Residing on Surfaces
    • Authors: Natalia Yu. Babaeva
      Abstract: We report on a computational study of the intersection of plasma filaments in a dielectric barrier discharge with small particulates suspended in air or residing on surfaces. The relative location of the particle with respect to the streamer axis is important on plasma time scale considered in the paper. The particulates residing on the substrate surface are partially enveloped by the sheath formed beneath the filament and the substrate. Ion energies and fluxes incident on the particulate depend on dielectric properties of the underlying substrate materials.Intersection of plasma filaments with small particulates-bacteria suspended in air or residing on surfaces results in different scenario of their surface treatment. The particulates residing on the substrate can be partially or totally immersed in the sheath formed beneath the filament and the substrate. Ion energies and fluxes to particulates are determined by the sheath properties and the dielectric constant of the substrate.
      PubDate: 2016-09-22T07:36:22.470685-05:
      DOI: 10.1002/ppap.201600165
       
  • Influence of Gap Size and Dielectric Constant of the Packing Material on
           
    • Authors: Koen Van Laer; Annemie Bogaerts
      Abstract: A packed bed dielectric barrier discharge (DBD) was studied by means of fluid modelling, to investigate the influence of the dielectric constant of the packing on the plasma characteristics, for two different gap sizes. The electric field strength and electron temperature are much more enhanced in a microgap reactor than in a mm-gap reactor, leading to more current peaks per half-cycle, but also to non-quasineutral plasma. Increasing the dielectric constant enhances the electric field further, but only up to a certain value of dielectric constant, being 9 for a microgap and 100 for a mm-gap reactor. The enhanced electric field results in a higher electron temperature, but also lower electron density. This last one strongly affects the reaction rate.By reducing the size of the gap or by increasing the dielectric constant of the packing, the electric field in the dielectric barrier discharge reactor is significantly enhanced. The electron temperature also increases, but the electron density drops, which can have a negative effect on the rate of CO2 dissociation.
      PubDate: 2016-09-19T08:25:33.820278-05:
      DOI: 10.1002/ppap.201600129
       
  • A Comparison of Continuum and Kinetic Simulations of Moderate pd
           Microplasmas Integrated With High Secondary Yield Cathodes
    • Authors: Abhishek Kumar Verma; Arghavan Alamatsaz, Ayyaswamy Venkattraman
      Abstract: The computational techniques commonly used for low-temperature plasma simulations are compared in the context of modeling microplasmas driven by cathodes with high secondary electron emission coefficient. Simulations of 100 µm argon microplasmas operating at pressures of 100 Torr and secondary electron emission coefficient of 0.1 are performed using particle-in-cell with Monte Carlo collisions (PIC-MCC), and fluid model using the full-momentum equations for both electrons and ions. Results obtained for plasma density, potential, electric field, and electron temperature using continuum simulations are compared with the PIC-MCC simulations as benchmark. The comparison demonstrates significant discrepancies and a need to calibrate continuum simulation parameters based on kinetic simulations.Continuum and kinetic simulations of low-temperature moderate pd microplasmas driven by cathodes with high secondary emission are compared and contrasted with each other. One-dimensional simulations of a 100 μm argon microplasma performed using the momentum equation for both ions and electrons are compared with particle-in-cell with Monte Carlo collision simulations. The discrepancies between the results obtained from the two methods are highlighted.
      PubDate: 2016-09-16T07:05:37.671076-05:
      DOI: 10.1002/ppap.201600130
       
  • Temporarily Withdrawn
    • Abstract: This article has been temporarily withdrawn. It was erroneously published prior to the license agreement process being completed.
      PubDate: 2016-09-16T04:06:31.821829-05:
      DOI: 10.1002/prs.11852
       
  • Coating of carbon fibers with adhesion-promoting thin polymer layers using
           
    • Authors: Jörg Friedrich; Korinna Altmann, Sascha Wettmarshausen, Gundula Hidde
      Abstract: Plasma polymers and electrospray-ionization (ESI) polymer layers are compared for most efficient adhesion promotion in carbon fiber-epoxy resin composites. The ultra-thin ESI layers (2–30 nm) of commercial poly(acrylic acid) and poly(hydroxyethylmethacrylate) produce an significant increase of adhesion measured by single-fiber pull out tests. However, plasma treatment has also advantages, such as simultaneous activation of the fiber substrate. Chemical structure and composition are rather far from the regular structure of commercial polymers as deposited by ESI processing.Plasma polymers and electrospray-ionization (ESI) polymer layers are compared for most efficient adhesion promotion in carbon fiber-epoxy resin composites. Differences in chemical structure and composition of polymer layers are discussed as well as the surface topography of these nanometer thick films.
      PubDate: 2016-09-09T09:31:43.84085-05:0
      DOI: 10.1002/ppap.201600074
       
  • Effect of Substrate Temperature on Thermal Properties and Deposition
           Kinetics of Atmospheric Plasma Deposited Methyl(methacrylate) Films
    • Authors: Gill Scheltjens; Guy Van Assche, Bruno Van Mele
      Abstract: The first part of this paper focuses on the chemical and thermal properties of pdMMA films, which are evaluated as a function of Tsubstrate. Thermogravimetric analysis reveals a decreased low molecular weight fraction and enhanced cross-link density with increasing Tsubstrate. In accordance, an enhanced glass transition is observed with differential scanning calorimetry. In a second part, a new Arrhenius-type empirical model is presented for the specific plasma deposition rate k0, i.e., k0(Yf,T)=Aapp(Yf)⋅exp(−Eapp/(R⋅T)), with input plasma power and precursor feed rate (by means of the Yasuda factor, Yf) and T of the substrate as variables of the plasma deposition process. A simplified plasma deposition mechanism is suggested based on adsorption, desorption, and surface plasma polymerization of activated species, justifying the experimental findings and empirical model.In this work, the effect of Tsubstrate on the plasma deposition kinetics and thermal properties of pdMMA films is assessed. A plasma deposition mechanism is proposed, based on the adsorption/desorption equilibrium of activated species, followed by a surface plasma polymerization. A decreased volatile fraction and enhanced cross-link density with increasing Tsubstrate is shown by TG analysis. In accordance, DSC analysis confirms an increasing glass transition.
      PubDate: 2016-08-17T01:40:27.901599-05:
      DOI: 10.1002/ppap.201500213
       
  • Application of a liquid nitrogen direct jet system to the extinguishment
           of oil pool fires in open space
    • Authors: Bobo Shi; Fubao Zhou
      Abstract: Liquid fuel fires occurring during industrial processes are serious safety concerns around the world due to their devastating impact on lives, the environment and property. In this study, a liquid nitrogen delivery system was set up to extinguish the oil pool fires in open space. Effects of liquid nitrogen flow rate, pipe diameter, and liquid nitrogen release distance on the suppression process were analyzed according to the mass loss, burning rate and temperature variations. When liquid nitrogen release distance was 0.50 m and pipe diameter was 0.04 m, fire extinguishing time was the shortest 1.6 s and the temperature decrease rate above the liquid fuel surface reached 275°C/s. Fuel surface cooling and blow off process were revealed through the experiments as two kinds of fire extinguishing mechanisms. Based on the flame images captured by high speed camera, the flame expansion phenomenon might occur early in liquid nitrogen injection, especially the situation of the higher flow rate of liquid nitrogen. Three approaches (ground fixed system, moving transportation, and directional transportation of liquid nitrogen) are provided for fire extinguishment of large scale fires. The results obtained provide important reference for the conduct of fire extinguishment for fires. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-08-16T02:36:38.239568-05:
      DOI: 10.1002/prs.11840
       
  • Continuous-Wave RF Plasma Polymerization of Furfuryl Methacrylate:
           Correlation Between Plasma and Surface Chemistry
    • Authors: Solmaz Saboohi; Sameer A. Al-Bataineh, Hanieh Safizadeh Shirazi, Andrew Michelmore, Jason D. Whittle
      Abstract: The plasma phase of furfuryl methacrylate (FMA) and its relationship to the surface chemistry of the generated plasma coatings was investigated utilizing mass spectrometry. Positive ion mass spectra from plasma phase and plasma coatings of FMA revealed that furanylmethyl fragment (FM, 81 m/z) has high stability and form oligomers with itself and other species in the plasma phase and on the surface. Combined with ion flux and deposition rate data, the correlation between the normalized intensities of positive fragments from the mass spectra of the neutrals and plasma coatings suggests that neutrals were a major contributor to the plasma film growth. These findings highlight the potential of plasma phase diagnostic tools to predict the chemistry of neutral and positive species, and their role in thin film deposition.The relationship between the chemistry of the plasma phase of furfuryl methacrylate and the generated plasma coatings is investigated using mass spectrometry. The study found that furanylmethyl fragment (FM, 81 m/z) is highly stable and form oligomers with itself and with other species in the plasma phase and on the surface. It also found that neutrals are a major contributor to the plasma film growth.
      PubDate: 2016-08-09T07:52:29.918462-05:
      DOI: 10.1002/ppap.201600054
       
  • Effects of Non-Thermal Atmospheric Pressure Plasma and Sodium Hypochlorite
           Solution on Enterococcus faecalis Biofilm: An Investigation in Extracted
           Teeth
    • Authors: Alexander Hüfner; Heike Steffen, Birte Holtfreter, Rabea Schlüter, Kathrin Duske, Rutger Matthes, Thomas von Woedtke, Klaus-Dieter Weltmann, Thomas Kocher, Lukasz Jablonowski
      Abstract: The aim of this study was to compare the effect of atmospheric pressure plasma (APP) with sodium hypochlorite (NaOCl) or the combination of APP and NaOCl on Enterococcus faecalis biofilm in root canals of extracted human teeth. The disinfection efficiency was determined as the logarithm of the number of colony-forming units (CFU). Additionally, scanning electron microscopy (SEM) was used to visualize the treatment effect on biofilm. The adjunctive treatment with Plasma + O2 has a small additive, albeit statistically not significant effect in the CFU reduction of an E. faecalis biofilm compared to the 12 min monotherapy with NaOCl. The effectiveness of Plasma + O2 could be significantly increased by longer treatment time.Non-thermal atmospheric pressure plasma provides numerous opportunities for applications in dentistry. For example, plasma treatment has great potential on root canal disinfection. In this in vitro study, plasma is investigated as an adjuvant antiseptic option for endodontic treatment in extracted human teeth.
      PubDate: 2016-08-04T07:45:56.007484-05:
      DOI: 10.1002/ppap.201600064
       
  • Synthesis of Micro- and Nanomaterials in CO2 and CO Dielectric Barrier
           Discharges
    • Authors: Igor Belov; Jens Vanneste, Morteza Aghaee, Sabine Paulussen, Annemie Bogaerts
      Abstract: Dielectric Barrier Discharges operating in CO and CO2 form solid products at atmospheric pressure. The main differences between both plasmas and their deposits were analyzed, at similar energy input. GC measurements revealed a mixture of CO2, CO, and O2 in the CO2 DBD exhaust, while no O2 was found in the CO plasma. A coating of nanoparticles composed of Fe, O, and C was produced by the CO2 discharge, whereas, a microscopic dendrite-like carbon structure was formed in the CO plasma. Fe3O4 and Fe crystalline phases were found in the CO2 sample. The CO deposition was characterized as an amorphous structure, close to polymeric CO (p-CO). Interestingly, p-CO is not formed in the CO2 plasma, in spite of the significant amounts of CO produced (up to 30% in the reactor exhaust).Dielectric Barrier Discharges operating in CO and CO2 form solid products at atmospheric pressure. The main differences between both plasmas and their deposits are analyzed keeping similar energy input.
      PubDate: 2016-07-29T01:05:34.669232-05:
      DOI: 10.1002/ppap.201600065
       
  • Superhydrophobic Paper by Facile and Fast Atmospheric Pressure Plasma
           Etching
    • Authors: Panagiotis Dimitrakellis; Anastasios Travlos, Vassilios P. Psycharis, Evangelos Gogolides
      Abstract: Superhydrophobic and to some extent oleophobic paper surfaces are prepared using atmospheric pressure plasma etching. A novel dielectric barrier discharge operating in helium–oxygen mixture is used to rapidly etch organic material from paper surface and create hierarchical topography and subsequently a thin fluorocarbon film is deposited to modify the surface energy. The enhancement of surface topography is achieved via the selective removal of organic matter over inorganic calcium carbonate (calcite) fillers that co-exist in paper. The process led to the fabrication of roll-off superhydrophobic paper with water contact angles >150° and hysteresis
      PubDate: 2016-07-27T02:30:50.521974-05:
      DOI: 10.1002/ppap.201600069
       
  • Plasma Polymers Containing Sulfur and Their Co-Polymers With
           1,7-Octadiene: Chemical and Structural Analysis
    • Authors: Kim S. Siow; Leanne Britcher, Sunil Kumar, Hans J. Griesser
      Abstract: In comparison with other chemistries, little has been reported on sulfur-containing plasma polymers; reasons include low volatility or high toxicity of monomers. Here, we report on plasma polymerization of dimethyl sulfoxide, by itself and its co-polymerization with 1,7-octadiene to generate S-containing plasma polymers. Results show dominance of SS, SH, and SC with small percentages of SO and SO2. Upon storage in air there were no observable changes to the oxidation states of the S atoms in these plasma polymers, whereas the hydrocarbon component underwent oxidative changes. Methods were studied to oxidize the initial sulfur-containing surface groups, but approaches such as H2O2 treatment post-deposition and electrical biasing during deposition did not affect the oxidation states of the incorporated S.Plasma polymerization of DMSO or DMSO with 1,7-octadiene produces coatings containing S in low oxidation states. Bias potentials during polymerization has no effect on 1,7-octadiene-DMSO plasma co-polymers. DMSO plasma polymers are resistant to further modification by hydrogen peroxide. While there are some changes in the composition of DMSO plasma polymer, the S does not oxidize further during air aging over 129 days.
      PubDate: 2016-07-27T02:30:39.362452-05:
      DOI: 10.1002/ppap.201600044
       
  • The eye opener: Preparing for and performing facility siting to best
           communicate with upper management
    • Authors: Michael James
      Abstract: Upon completion of a facility siting study, a major step in the critical path for implementation is acceptance from upper management on the remediation plan. Communicating with upper management occurs at the end of several steps which can be strategically mapped in order to maximize upper management's understanding of the needs of a site's remediation requirements.Using an example chemical plant, this paper will detail the process of initiating a facility siting study, provide a novel approach to prioritizing building remediation requirements, and discuss how the resulting information can best be framed and communicated to upper management. In addition to discussing strategies for effective communication with upper management on proposed facility siting strategies, the paper also details an online system that could be used for keeping facility siting data evergreen after the study is completed. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-07-17T23:25:41.39118-05:0
      DOI: 10.1002/prs.11835
       
  • Experimental investigation of the innovative foaming device using gas as
           the sole power for firefighting
    • Authors: Zhilin Xi
      Abstract: Foam is used as an efficient means of firefighting. The innovative foaming device using gas as the sole power is designed to replace the previous foam generating system using two or three power sources, and appropriate size of the new foaming device can be made to control dust and fire in households or companies based on the actual need. The results of the experimental investigation on the new device in three cases are as follows: in the first case, the minimum working pressure is 0.4 MPa and the working flow range is: 8.0858 m3/h ≤ qa ≤ 48.45 m3/h and qL ≤ 0.4532 m3/h. In the second case, the maximum working time of the new foaming device is 109 s and the minimum working pressure of the storage tank II is 0.26 Mpa. In the third case, the maximum working time of the new device is 205 s and the minimum working pressure values of the storage tanks I and II are 0.26 Mpa and 0.3 Mpa respectively. The fire extinguishing experiment is explained in this article, and the results show that the foam generated by the new foaming device is more effective and efficient than the ABC powder fire extinguisher. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-07-15T05:31:12.815552-05:
      DOI: 10.1002/prs.11834
       
  • Parametric generation of explosion scenarios for quantitative risk
           assessment of gas explosion in offshore plants
    • Authors: YeongAe Heo; Inwon Lee
      Abstract: In this study, probabilistic risk assessment has been carried out for the prediction of gas explosion loads due to hydrocarbon leaks and subsequent explosions in the topside of offshore platforms. In the initial phase of the risk assessment, the effect of various scenario parameters on the annual probability of gas explosion was quantified via a MATLAB code. For calculating the gas explosion frequency, the hydrocarbon leak frequencies and the ignition probabilities were derived from the HCR (HydroCarbon Release) database from the Health & Safety Executive (HSE, UK), and the IP (Ignition Probability) report from UKOOA (UK Offshore Operators Association), respectively. The MATLAB code has the algorithm to cope with the varying design practice in either Front End Engineering Design phase or detailed design phase. User-definable parameter setup and spreadsheet data input provide the user with the flexibility in selecting relevant level of elaboration for such design parameters as the leak size distribution, the hydrocarbon composition, etc. These features of the code enable controlling the number of explosion scenarios without any parameter range remaining unaccounted for. The present MATLAB code has been applied to generate hydrocarbon leak scenarios and corresponding explosion probability for the topside process modules of a specific oil Floating Production, Storage and Offloading. Varying the number of cases for each parameter leads to the variation of the number of explosion scenarios selected, which are either 48 or 24 in the particular case. For each explosion scenario, the gas leak and explosion simulation was carried out using the FLame Acceleration Simulator (FLACS) commercial S/W package, giving rise to the annual probability of exceedance for the explosion overpressure. Discussion of the influence of explosion scenario selection method on the change of the overpressure exceedance curves is made. © 2016 American Institute of Chemical Engineers Process Saf Prog, 2016
      PubDate: 2016-07-04T06:21:04.534931-05:
      DOI: 10.1002/prs.11832
       
  • Used, classic, or antique; solving the enigma of disciplined adherence to
           standards for existing equipment
    • Authors: Jack McCavit; Todd Aukerman, Jeff Fox, Rukyah Hennessey
      Pages: 10 - 13
      Abstract: What do you consider when buying a used car' Do you have minimum safety requirements for your used car' Similarly, do you have minimum safety requirements for existing equipment in your plant' One of the CCPS Vision 20/20 Industry Tenets is Disciplined Adherence to Standards. In this tenet, Vision 20/20 puts special emphasis on application of standards for existing equipment. Companies with great process safety performance recognize that having minimum standards for existing equipment is as important as having them for new projects. However, identifying and applying relevant standards to equipment that may have been installed decades ago can be challenging. This article will describe how to establish minimum standards for existing equipment and will provide a suggested approach for the implementation of these internal or common industry standards. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 10–13, 2017
      PubDate: 2016-09-16T04:06:29.64825-05:0
      DOI: 10.1002/prs.11851
       
  • Process safety: A wicked problem'
    • Authors: James Moseman
      Pages: 14 - 17
      Abstract: The nature of process accidents is discussed, and the relevant definition of Horst Rittel's social phenomenon, “wicked problems,” is examined. Existing accident models are reviewed for inclusion of social drivers thought to dominate process accidents. A suggested method, new to process safety and termed morphological analysis, is offered to uncover unacknowledged drivers. Give the purported fit of process safety as a wicked problem, an assessment of the US Chemical Safety Board's “Most Wanted” is made doubting its potential reduction in accidents. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 14–17, 2017
      PubDate: 2016-04-15T04:15:39.086593-05:
      DOI: 10.1002/prs.11826
       
  • RAGAGEP considerations for relief and flare systems
    • Authors: Georges A. Melhem; Casey Houston
      Pages: 18 - 23
      Abstract: Recent emphasis on Recognized and Generally Accepted Good Engineering Practices (RAGAGEP) increased the scope of relief systems risk factors that require evaluation to develop complete and compliant Pressure Relief and Flare Systems documentation. Failure to comply with RAGAGEP ((d)(3)(ii)) is the most cited element of the Process Safety Management requirements.This paper discusses how RAGAGEP considerations now require evaluation and proper documentation of risk factors that are often overlooked including but not limited to: dispersion analysis, thermal radiation, noise, vibration risk, reaction forces and structural supports, metal cold temperatures due to expansion cooling and two phase flow, hot temperatures due to fire exposure and/or runaway reactions, PRV stability, chemical reaction systems, and loss of high pressure/low pressure interface.Important RAGAGEP considerations for these additional risk factors are highlighted and discussed. Recommendations are provided on how to best address these factors in the evaluation and documentation of design basis. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 18–23, 2017
      PubDate: 2016-08-11T05:00:37.871146-05:
      DOI: 10.1002/prs.11839
       
  • Expanded Chemical Reactivity Worksheet (CRW4) for determining chemical
           compatibility, past, present, and future
    • Authors: James Farr; Dave Gorman, Dan Sliva, Al Hielscher, Trong Nguyen, George Baran, Brenton Drake, Emory Ford, Dave Frurip, Kirk Mulligan, John W. Ryan, Dalina Viveros
      Pages: 24 - 29
      Abstract: Chemical compatibility is a key consideration throughout the chemical industry wherever two or more chemicals have the potential to mix, either inadvertently or by design. One of the most comprehensive tools available for determining chemical compatibility, the NOAA Chemical Reactivity Worksheet (CRW), has gained significant traction since the release of the third version (CRW3) in 2012. In 3 years, this free software has been downloaded >200,000 times and has become the chemical compatibility tool of choice at many organizations. As a result of an ongoing partnership between the National Oceanic and Atmospheric Administration (NOAA), The Dow Chemical Company, The Center for Chemical Process Safety (CCPS), Materials Technology Institute (MTI) and other industrial/academic/government volunteers, a fourth version of the CRW (CRW4) has been developed. The expanded capabilities of this new version include a materials of construction section, improved import/exporting/data sharing capabilities, additional reactive groups to aid in determining compatibility decisions, several user interface enhancements, along with the correction of minor issues found in the CRW3. This article will describe past development, the new features included in the CRW4, followed by a brief discussion of future development plans for the software tool. Such developments should solidify this tool's position as the gold standard within the chemical industry for determining chemical hazards. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 24–29, 2017
      PubDate: 2016-07-17T23:25:33.181123-05:
      DOI: 10.1002/prs.11833
       
  • Revisions to FM Global Property Loss Prevention Data Sheet 7-14, Fire
           Protection for Chemical Plants
    • Authors: Matthew Daelhousen; Henry L. Febo, Benjamin Ditch
      Pages: 30 - 37
      Abstract: For nearly two centuries, businesses around the world have relied on FM Global and its property loss prevention data sheets to reduce risk at their facilities. Data Sheet 7-14, Fire Protection for Chemical Plants, addresses fire and explosion hazards at chemical manufacturing plants and similar processing facilities, particularly those associated with ignitable liquid, flammable gas, and liquefied flammable gas where a release could result in a fire of long duration. In 2014, FM Global assigned a team of engineers to update the data sheet, which had not undergone a major revision in over 15 years.A primary focus of the revision was to reduce reliance on prescriptive guidelines when designing fire protection systems at chemical plants. Renewed emphasis was placed on identifying potential fire/explosion scenarios, and designing fire protection systems appropriate for the anticipated loss scenario. Additionally, safeguards to minimize the volume of the potential liquid or gas release were developed, such as accidental release control systems, siting guidance, and other passive methods to mitigate damage in the event of a release. This new guidance is based on a mixture of scientific research, loss history, and engineering experience. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 30–37, 2017
      PubDate: 2016-11-10T01:16:29.714121-05:
      DOI: 10.1002/prs.11864
       
  • Beyond HAZOP and LOPA: Four different company approaches
    • Authors: Jerry Wayne Chastain; Paul Delanoy, Chris Devlin, Thomas Mueller, Karen Study
      Pages: 38 - 53
      Abstract: For operations where application of standards, regulations, and/or Recognized and Generally Accepted Good Engineering Practices may not be sufficient to address a particular company's risk, several options exist. For qualitative assessment of process hazards, Hazard and Operability Studies (HAZOP) and What-If reviews are two of the most common petrochemical industry methods used. Up to 80% of a company's process hazard analysis (PHA) may consist of HAZOP and What-If reviews (Nolan, Application of HAZOP and What-If Safety Reviews to the Petroleum, Petrochemical and Chemical Industries, William Andrew Publishing/Noyes, 1994, p. 1). After the PHA, Layer of Protection Analysis (LOPA) is commonly used throughout industry to evaluate the required safety integrity level for instrumented protection layers in a semiquantitative manner (Dowell, International Conference and Workshop on Risk Analysis in Process Safety, CCPS/AIChE, 1997). HAZOP, What-If, and LOPA are all straightforward methods and are relatively easy to perform. However, much like a hammer, they are not always the best or most appropriate tool for a given job. At times, more advanced methodologies such as Fault Tree Analysis, Quantitative Risk Assessment, Event Tree, Failure Mode, and Effects Analysis and Human Reliability Analysis are necessary to properly assess risk. However, these more advanced tools come with a price. They are often more expensive, time consuming, and require a higher level of expertise. The decision to use these higher level methodologies is not taken lightly and different companies use different criteria for determining when to take this next step. This article will present approaches by four companies, BASF, Celanese, The Dow Chemical Company, and Eastman Chemical Company. Each company will outline criteria used to determine when to go beyond HAZOP, What-If, and LOPA and will present examples where more advanced techniques were used. The intent of this article is to provide readers with real world examples that demonstrate the appropriate application of the “right” tool and to illustrate what criteria can be used to make informed decisions regarding selection of a PHA methodology. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 38–53, 2017
      PubDate: 2016-06-21T06:15:32.067724-05:
      DOI: 10.1002/prs.11831
       
  • Suppression of overpressure during a vapor cloud explosion — A new
           approach
    • Authors: Norbert Baron; Chris R. Buchwald
      Pages: 54 - 61
      Abstract: In this article, a new concept is presented with the intent to suppress the generation of damaging overpressures during a vapor cloud explosion via triggering ignitions at additional locations within the vapor cloud immediately after the primary ignition has occurred. The resulting lower explosion overpressures would then be less damaging to buildings and their occupants. The results of early experimental work support the hypothesis underlying this new concept. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 54–61, 2017
      PubDate: 2016-11-07T05:47:55.642361-05:
      DOI: 10.1002/prs.11807
       
  • Simultaneous Operation (SIMOP) Review: An Important Hazard Analysis Tool
    • Authors: Paul Baybutt
      Pages: 62 - 66
      Abstract: Simultaneous operations (SIMOPs) occur within process facilities when two or more activities occur at the same time and place. They may involve risks that are not identified when each activity is considered by itself. A SIMOP review identifies possible interactions between activities that may adversely impact people, property, or the environment. SIMOP reviews are an important adjunct to the performance of process hazard analyses such as hazard and operability studies. A number of major process industry accidents have involved SIMOPs. Several examples are described. A procedure for conducting a SIMOP review and an example are provided. The development of a plan to address the performance of SIMOPs using the results of SIMOP reviews is discussed and plan contents are identified. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 62–66, 2017
      PubDate: 2016-11-11T00:35:32.188863-05:
      DOI: 10.1002/prs.11866
       
  • The effect of an obstacle on methane-air explosions in a spherical vessel
           connected to a pipeline
    • Authors: Qingqing Zuo; Zhirong Wang, Yaya Zhen, Shangfeng Zhang, Yiqing Cui, Juncheng Jiang
      Pages: 67 - 73
      Abstract: A series of experiments are carried out to reveal the effect of an obstacle on the explosion intensity of a methane-air mixture in a spherical vessel connected to a pipeline. Results show that obstacle presence, blockage ratio, and position play significant roles in explosion intensity. The oscillation amplitude of pressure both in the vessel and at the pipeline terminus weakens when an obstacle exists in the pipeline. The effects of the blockage ratio on explosion intensity are different when obstacle position changes. Explosive intensity decreases with blockage ratio when the obstacle is set at the intersection of the spherical vessel and the pipeline and in the middle section of the pipeline. Moreover, when the blockage ratio is ∼56%, the minimum explosion intensity is obtained when the obstacle is set at the middle section of the pipeline. Explosion intensity increases with blockage ratio when the obstacle is positioned near the pipeline terminus. The most dangerous case is when the obstacle is positioned near the pipeline terminus, especially when the blockage ratio is 75% or greater. The maximum pressure and the rate of pressure increase at the point of intersection of the spherical vessel and the pipeline are higher than at the middle section. The conclusions provide an important reference for designing explosion venting safety systems and explosion-resistant designs. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 67–73, 2017
      PubDate: 2016-03-31T06:25:59.078642-05:
      DOI: 10.1002/prs.11823
       
  • Interrelations between process safety management elements
    • Authors: Hanida Abdul Aziz; Azmi Mohd Shariff, Risza Rusli
      Pages: 74 - 80
      Abstract: OSHA PSM standard has been established with 14 elements that define the management principles to control process hazards and protect the workplace. One of the key factors to the success of Process Safety Management (PSM) implementation is that each element comes as a component in an integrated PSM program. Although various kind of integrated safety management systems have been introduced, direct integration system between PSM elements was not extensively studied due to vague concept on interrelation between PSM elements. This also hampers efforts in designing and developing integrated system for PSM. In this study, the interrelation of critical PSM elements was analyzed based on objectives and information functional of the elements stipulated in OSHA PSM regulations. From the conducted analysis, all the critical elements are interrelated at least with other seven PSM elements. Among the elements, Process Hazard Analysis and Mechanical Integrity were identified to have the highest interrelations comprising of 12 interrelated PSM elements. The developed PSM matrix has systematically showed the interrelation of critical PSM elements that useful for the development of Integrated PSM system. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 74–80, 2017
      PubDate: 2016-04-01T02:16:49.613016-05:
      DOI: 10.1002/prs.11824
       
  • Lower explosion limit/minimum explosible concentration testing for hybrid
           mixtures in the Godbert-Greenwald furnace
    • Authors: Emmanuel Kwasi Addai; Dieter Gabel, Ulrich Krause
      Pages: 81 - 94
      Abstract: Experimental investigations of the lower explosion limits (LEL) of three-component hybrid mixtures of six combustible dusts, three gases, and four solvents were performed in the modified Godbert-Greenwald furnace. The test protocol was in accordance with European standard EN 50281-2-1 which is originally used to determine the minimum ignition temperature of dusts. Modification was done on the equipment to test for the explosion limits for dusts, gases, solvents, and hybrid mixtures. In order to prove the validity of our experimental procedure, the LEL for pure gases were initially tested and the results were compared with values found in literature obtained from the standard procedure which show very good agreement. The experimental results demonstrated a significant decrease of the explosion limits of gas, solvent, or dust and an increase in the likelihood of explosion when a small amount of dust was mixed with gas or solvent and vice versa. For example, the minimum explosible concentration (MEC) of high density polyethylene (HDPE) of 174 g/m3 decreased to 130 g/m3 upon addition of methane the concentration of which itself was below the LEL. The MEC of HDPE further decreased to 65 g/m3 when a nonexplosible concentration of hexane was added. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 81–94, 2017
      PubDate: 2016-04-01T02:16:31.061074-05:
      DOI: 10.1002/prs.11825
       
  • Risk assessment on chemical plants by the method of safety checklist
           analysis
    • Authors: Zhang Xiaoliang; Shen Qian, Zhao Daoliang, Zhang Zhikai, He Rui, Song Huijuan
      Pages: 95 - 101
      Abstract: In this article, 46 chemical plants were investigated and assessed by Safety Department of Shanghai Institute of Technology in China. The safety management and technology ability and level were evaluated by the method of Safety Checklist Analysis (SCA) under the perspective of Safety Specialty Engineer. The risk levels of the overall of 46 plants were got. The SCA assessment presents the visible and invisible risks of the plants quantitatively and plainly. The results show that a majority of the plants have not fully implemented either on the good safety management or the reliable safety practice technology. The level of the overall risk indicate that about 35% of the plants reach the level of A (Scores ≥90), and others both lower than A, even 2 plants in the level of E, with total disregard for their health, safety, and well-being. Otherwise, 23 items were surveyed and judged one by one in safety assessment by SCA, and put forward suggestions for rectify and reform, which helps the plants recognize the reality of the situation and make better in the future. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 95–101, 2017
      PubDate: 2016-04-20T04:18:03.998042-05:
      DOI: 10.1002/prs.11827
       
  • Learning from incidents at a Norwegian and a Polish refinery
    • Authors: Kirsti Russell Vastveit; Monika Orszak, Ove Njå, Andrzej Kraslawski
      Pages: 102 - 108
      Abstract: Today companies are expected to learn from incidents in the form of accidents and near misses to improve safety at their facilities. In this article, we examine how two refineries located in Poland and Norway work to learn from incidents. We address the nature of their classification systems and how they select incidents for particularly thorough analysis or investigation, methods for analysis of less severe and severe incidents as well as participation in activities, the nature of follow up activities at the refineries and who these are directed at, as well as learning among contractors who carry out maintenance and projects at the refineries. For each of the stages of incident treatment, we consider the similarities and differences between the refineries and how the practices that are used may affect learning. © 2016 American Institute of Chemical Engineers Process Saf Prog 36: 102–108, 2017
      PubDate: 2016-03-21T01:46:01.5195-05:00
      DOI: 10.1002/prs.11822
       
  • Safety improvements in a Methanation reactor
    • Authors: Mike Walton; Tony Southerton, Paul Sharp
      Abstract: A 35-year-old Methanator vessel required replacement due to High Temperature Hydrogen Attack (HTHA). The opportunity was taken to upgrade the over temperature protection system to meet the requirements of IEC 61511. An additional Layer of Protection was added to reduce demand on the High Temperature Trip system. © 2009 American Institute of Chemical Engineers Process Saf Prog 2009
      PubDate: 2009-05-06T00:00:00-05:00
      DOI: 10.1002/prs.10325
       
 
 
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