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 Biomass Conversion and Biorefinery   [10 followers]  Follow         Partially Free Journal    ISSN (Print) 2190-6815 - ISSN (Online) 2190-6823    Published by Springer-Verlag  [2355 journals]
• Optimizing GHG emission and energy-saving performance of miscanthus-based
value chains
• Authors: Florian Meyer; Moritz Wagner; Iris Lewandowski
Pages: 139 - 152
Abstract: Miscanthus is a high-yielding lignocellulosic crop providing up to 40 t of dry matter per hectare and year. Its biomass can be used in energetic or material utilization pathways. The goal of this study was the comparison of three different conversion techniques (combustion, second-generation bioethanol, and insulation material) for miscanthus biomass produced at five locations throughout Europe using a life cycle assessment approach. In particular, the interdependencies between the cropping location, the miscanthus genotypes, and the utilization pathways were investigated. The potential savings of greenhouse gas (GHG) emissions and fossil energy were analyzed through comparison with a corresponding substituted product system. The highest GHG savings of all scenarios investigated were achieved by heat and power production in Portugal (42.7 t CO2-eq ha−1 a−1). However, at the other four locations (Sweden, Denmark, Germany, England), bioethanol production gave the highest GHG savings. In contrast, the highest energy savings were achieved by combined heat and power generation via combustion at all five locations (up to 642 GJ ha−1 a−1). A high correlation was found between yield and both GHG-emission savings and energy savings. Biomass composition and quality showed a comparatively low impact on the results. However, the composition is assumed to have a high relevance for other impact categories not assessed within this study, such as acidification and eutrophication.
PubDate: 2017-06-01
DOI: 10.1007/s13399-016-0219-5
Issue No: Vol. 7, No. 2 (2017)

• Development and experimental validation of a water gas shift kinetic model
for Fe-/Cr-based catalysts processing product gas from biomass steam
gasification
• Authors: Michael Kraussler; Hermann Hofbauer
Pages: 153 - 165
Abstract: Abstract This paper introduces an improved kinetic model for the water gas shift reaction catalyzed by an Fe-/Cr-based catalyst. The improved model is based on a former model which was developed previously in order to consider the composition and the catalyst poisons (H2S) of product gas derived from dual fluidized bed biomass steam gasification. $$\begin{array}{c}r\left({\varphi}_i,T\right)=117.8\ \frac{\mathrm{mol}}{g\ {Pa}^{1.71}\ s}\cdot \mathit{\exp}\left(\frac{-126.6\ \frac{\mathrm{kJ}}{\mathrm{mol}}}{R\cdot T}\right)\cdot {p}_{CO}^{1.77}\cdot {p}_{\mathrm{H}2\mathrm{O}}^{0.23}\cdot {p}_{CO2}^{-0.17}\cdot {p}_{\mathrm{H}2}^{-0.12}\\ {}\left(1-\frac{K_{MAL}}{K_g}\right)\end{array}.$$ Furthermore, this improved model has been validated with experimental data. The data was generated by a WGS reactor which employed a commercial Fe-/Cr-based catalyst and which processed real product gas from the dual fluidized bed biomass steam gasification plant in Oberwart, Austria. Basically, the validation showed good agreement of the measured and the calculated values for the gas composition (absolute errors of the volumetric fractions of up to 1.5 %) and the temperature profile (absolute errors of up to 21 °C) of the WGS reactor. Of all considered gas components, the CO concentration showed the highest error. The results qualify the improved kinetic model for basic design and engineering of a WGS reactor employing a commercial Fe-/Cr-based catalyst which processes product gas from an industrial scale biomass steam gasification plant.
PubDate: 2017-06-01
DOI: 10.1007/s13399-016-0215-9
Issue No: Vol. 7, No. 2 (2017)

• Comparative biochemical methane potential of some varieties of residual
banana biomass and renewable energy potential
• Authors: Florent Awedem Wobiwo; Thomas Happi Emaga; Elie Fokou; Maurice Boda; Sebastien Gillet; Magali Deleu; Aurore Richel; Patrick A. Gerin
Pages: 167 - 177
Abstract: The biochemical methane potential (BMP) of peduncles, bulbs, and peels of three banana varieties (Grande Naine (GN; export dessert banana), Pelipita (PPTA; locally used plantain), and CRBP969 (phytopathogen resistant hybrid-plantain)) was investigated as an assessment of the bioconversion potential of these residues to renewable energy or biorefined chemicals. Biogas production was monitored manometrically for 132 days and its composition was analyzed using gas chromatography. The BMP ranged from 162 to 257 ml_CH4/g_DM for peduncles, from 228 to 304 ml_CH4/g_DM for bulbs, and from 208 to 303 ml_CH4/g_DM for green peels, with methane content of the biogas in the range 56 to 60 %. Bulbs and green peels showed bioconversion yields of 95 % of the chemical oxygen demand (COD). The GN variety was generally more biodigestible than PPTA, which appeared richer in lignocellulosic fibres. The peels biodigestibility reduced with maturation and was already limited to 56 % of the COD at the yellow stage. The energy resource available in the residues of banana production is very significant, increasing by 91 % the energy resource offered by banana crop, which is generally limited to the nutritional value of the fruit pulp. In the study case of the African leading producer of bananas and plantains (Cameroon), the amount of available residues from the sole export variety GN could feed about 4 % of the annual electricity consumed by the country, i.e., a supply of electricity to an additional 9 × 105 people. Such valorization of the residual banana biomass could help banana-producing countries to become less dependent on fossil fuels and less prone to energy shortages.
PubDate: 2017-06-01
DOI: 10.1007/s13399-016-0222-x
Issue No: Vol. 7, No. 2 (2017)

• Bioethanol production from Eucalyptus grandis hemicellulose recovered
before kraft pulping using an integrated biorefinery concept
• Authors: Mairan D. Guigou; Florencia Cebreiros; María N. Cabrera; Mario D. Ferrari; Claudia Lareo
Pages: 191 - 197
Abstract: Pre-extraction of hemicelluloses prior to pulping and its conversion to other by-products can provide additional profits to traditional pulp and paper industry. In this study, hemicelluloses removed from Eucalyptus grandis with green liquor (2 %) at 155–160 °C for 150 min prior to kraft pulping were fermented by Scheffersomyces stipitis NBRC 10063 to produce bioethanol. These conditions were selected to obtain an extract rich in xylose without changing the quality of pulp produced: best xylose extraction yield and minor pulp viscosity degradation. Fermentation of hemicellulose hydrolysate containing 7.5 g/L xylose and 5.0 g/L acetic acid presented an ethanol yield of 0.19 g/g and sugar conversion of 89 %. However, the fermentation of hydrolyzates after concentration proved to be difficult or even impossible. Ethyl acetate extraction, used for removal of inhibitory compounds in concentrated hydrolyzates containing 19 g/L xylose, improved fermentability (final ethanol concentration of 5.0 g/L, ethanol yield of 0.21 g/g and 94 % sugar conversion, ethanol production of 4.4 Lethanol/t of dry wood) and made possible the recovery of a valuable product as acetic acid.
PubDate: 2017-06-01
DOI: 10.1007/s13399-016-0218-6
Issue No: Vol. 7, No. 2 (2017)

• Bioconversion of soybean and rice hull hydrolysates into ethanol and
xylitol by furaldehyde-tolerant strains of Saccharomyces cerevisiae ,
Wickerhamomyces anomalus , and their cofermentations
• Authors: Nicole Teixeira Sehnem; Lilian Raquel Hickert; Fernanda da Cunha-Pereira; Marcos Antonio de Morais; Marco Antônio Záchia Ayub
Pages: 199 - 206
Abstract: The aims of this work were to evaluate the ability of furaldehyde-tolerant yeast strains Saccharomyces cerevisiae P6H9 and Wickerhamomyces anomalus WA-HF5.5 and their cofermentations and to convert soybean and rice hull hydrolysates into ethanol and xylitol. In batch shaker cultures, the strains showed the ability to tolerate high osmotic pressure (1918 mOsmkg−1), completely depleting furaldehyde in the first 12 h of cultivations, while converting the hydrolysate sugars into ethanol. Highest ethanol yields of 0.37 g g−1 and productivity of 0.31 g L−1 h−1 were obtained in the cofermentation using rice hull hydrolysate as substrate. The concentration of sugars in soybean hull hydrolysate proved to be inadequate as substrate for the cultivation of these strains, showing a low ethanol productivity of 0.08 g L−1 h−1. Bioreactor cultivations of S. cerevisiae on rice hull hydrolysate under anaerobiosis showed a relatively high ethanol productivity of 6.7 g L−1 h−1, whereas the bioreactor cofermentation produced xylitol to yields of 0.86 g g−1 under conditions of oxygen limitation.
PubDate: 2017-06-01
DOI: 10.1007/s13399-016-0224-8
Issue No: Vol. 7, No. 2 (2017)

• Moisture effect on fluidization behavior of loblolly pine Wood grinds
• Authors: G Olatunde.; O Fasina.; T McDonald.; S Adhikari.; S Duke.
Pages: 207 - 220
Abstract: The impact of moisture content (MC of 8 to 27 % wet basis) on physical properties (particle size distribution, average size using Feret, chord, Martins, surface-volume, and area diameter measurement schemes, bulk density, and particle density), fluidization behavior, and minimum fluidization velocities (U mf) of loblolly pine wood grinds were studied. A new correlation for predicting the U mf of loblolly pine wood grinds at different moisture contents was also developed. Results showed that bulk density, particle density, and porosity of grinds were significantly affected by increase in MC (p < 0.05). Diameter of the grinds measured using Feret measurement scheme was consistently the highest while those measured by surface-volume scheme were consistently the lowest with the measured Feret-based diameter about three times the surface-volume based diameters. Particle size data showed that variations in sizes of particle within a sample reduced with increase in MC (coefficient of variation value was 90 at 8.45 % MC and 40 at 27.02 % MC). Generally, as MC increased, the minimum fluidization velocity values increased. The minimum fluidization velocity (Umf) was found to be 0.2 m/s for 8 % MC, 0.24 m/s at 14.86 % MC, 0.28 m/s at 19.86 % MC, and 0.32 m/s for 27.02 % MC. The correlation developed predicted the experimental data with mean relative deviation that was less than 10 %.
PubDate: 2017-06-01
DOI: 10.1007/s13399-016-0223-9
Issue No: Vol. 7, No. 2 (2017)

• The nutritional aspects of biorefined Saccharina latissima , Ascophyllum
nodosum and Palmaria palmata
• Authors: Peter Schiener; Sufen Zhao; Katerina Theodoridou; Manus Carey; Karen Mooney-McAuley; Chris Greenwell
Pages: 221 - 235
Abstract: The chemical profile of biorefined Saccharina latissima, Ascophyllum nodosum and Palmaria palmata after carbohydrate and polyphenol extraction was analysed with the aim to evaluate the nutritional aspects of biorefined seaweeds as a novel animal feed supplement. Optimised enzymatic saccharification has been used to show that the protein concentration in the residue of P. palmata and A. nodosum can be increased by more than 2-fold. Nutritional value of the residue was further enhanced through an increase in total amino acids and fatty acids. As a consequence of removal of inorganic elements such as sodium, potassium and chloride, the total solid and ash content of all three seaweeds was reduced by around 40%. In contrast, divalent metals such as iron and zinc, as well as silicon, accumulated in all three residues. Potentially harmful components such as arsenic and iodine were reduced only in brown biorefined seaweeds, whilst in biorefined P. palmata, iodine increased by 39% compared to a 24% decline of arsenic. Nutritional values such as total fatty acid and total amino acid content increased in all three seaweeds after enzymatic saccharification. Polyphenol removal in all three seaweeds was >80% using aqueous acetonitrile and, in combination with enzymatic saccharification, did not impact on protein recovery in A. nodosum. This highlights the potential of biorefinery concepts to generate multiple products from seaweed such as extracts enriched in polyphenols and carbohydrates and residue with higher protein and lipid content.
PubDate: 2017-06-01
DOI: 10.1007/s13399-016-0227-5
Issue No: Vol. 7, No. 2 (2017)

• Pyrolysis kinetics of Sal ( Shorea robusta ) seeds
• Authors: Ranjan R. Pradhan; Pragyan P. Garnaik; Bharat Regmi; Bandita Dash; Animesh Dutta
Pages: 237 - 246
Abstract: Thermal kinetics of Sal seeds during pyrolysis process was investigated as feedstocks for chemical, material, and bioenergy industries. The physicochemical properties of the seeds were examined. Results showed that Sal seed can be characterized as high calorific values, low ash, and high volatile content biomass to suit pyrolysis applications. Kinetic analysis for thermal degradation of this biomass was given particular attention. Two major degradation zones were identified with T max at about 321 and 405 °C, and activation energy was evaluated using various methods. Model-free pyrolysis kinetic approach was verified to be appropriate and indicated that unprocessed Sal seed biomass can directly become potential renewable feedstock of energy, chemicals, and biochar.
PubDate: 2017-06-01
DOI: 10.1007/s13399-017-0240-3
Issue No: Vol. 7, No. 2 (2017)

• Characteristics of hydrochar and hydrothermal liquid products from
hydrothermal carbonization of corncob
• Authors: Kamonwat Nakason; Bunyarit Panyapinyopol; Vorapot Kanokkantapong; Nawin Viriya-empikul; Wasawat Kraithong; Prasert Pavasant
Abstract: Corncob (CC) was converted to renewable fuel resource by hydrothermal carbonization (HTC). HTC was performed by varying process temperature (160–200 °C), residence time (1–3 h), and biomass to water ratio (BTW) (1:5 to 1:15). The properties of hydrochar were significantly enhanced where the fixed carbon and carbon content of hydrochar increased at about 24.9 and 83.7% from original contents in CC, respectively. The calorific values and yield of hydrochar were between 19.3–23.5 MJ/kg and 50.1–58.6%. The optimal condition for the production of hydrochar as solid fuel was determined at 200 °C, 3 h residence time, and BTW of 1:5 with maximum energy yield of 68.74%. In addition, hydrothermal liquid was characterized where volatile fatty acid, furfural, furfuryl alcohol, and hydroxymethylfurfural were the most abundant compositions with their highest yields of 17.3, 11.5, 7.9, and 5.1%, respectively. Process temperature was the most influencing variable on product properties and characteristics. The results suggested that corncob has high potential as a source for solid fuel and valuable platform chemicals.
PubDate: 2017-07-22
DOI: 10.1007/s13399-017-0279-1

• Exploring the stability and reactivity of Ni 2 P and Mo 2 C catalysts
using ab initio atomistic thermodynamics and conceptual DFT approaches
• Authors: Ángel Morales-García; Junjie He; Pengbo Lyu; Petr Nachtigall
Abstract: The stability and reactivity of Mo2C and Ni2P surfaces with different terminations are systematically investigated by means of ab initio atomistic thermodynamics and conceptual DFT approaches as a function of the chemical potential (μ). Five surfaces labeled as (001)-Mo-1, (110)-Mo/C, (001)-Ni3P2, (001)-Ni3P2-P, and (001)-Ni3P1 emerge as the most stable ones for Mo2C and Ni2P catalysts depending on μ C and μ P, respectively. The Fukui function, a reactivity descriptor, reveals that the metal atoms interact preferentially with nucleophilic adsorbates such as H2S. Here, our study predicts that a high concentration of C and P atoms on the surface reduces the catalytic activity where nucleophilic species are involved. The qualitative agreement between the nucleophilic Fukui function (f +) and the adsorption energies indicates that the Ni2P catalyst is, in general, more reactive than Mo2C catalyst. This study may help to improve and optimize the catalytic processes, such as the hydrogenations HDO and HDS, where Mo2C and Ni2P catalysts are involved.
PubDate: 2017-07-12
DOI: 10.1007/s13399-017-0278-2

• Alkaline hydrogen peroxide pretreatment of lignocellulosic biomass: status
and perspectives
• Authors: Emmanuel Damilano Dutra; Fernando Almeida Santos; Bárbara Ribeiro Alves Alencar; Alexandre Libanio Silva Reis; Raquel de Fatima Rodrigues de Souza; Katia Aparecida da Silva Aquino; Marcos Antônio Morais Jr; Rômulo Simões Cezar Menezes
Abstract: Lignocellulosic biomass is a renewable and abundant resource that is suitable for the production of bio-based materials such as biofuels and chemical products. However, owing to its complex chemical composition, it requires a process that enhances the release of sugars. Pretreatment is an essential stage in increasing the efficiency of enzymatic hydrolysis of lignocellulosic biomass. The most widely used pretreatment methods operate at high temperatures (160–290 °C) and pressures (0.69 to 4.9 MPa) and generate biological growth inhibitors such as furfural and hydroxymethylfurfural (HMF). Thus, there has been a growing need to adopt new approaches for an effective pretreatment that operates at ambient temperature and pressure and reduces the generation of inhibitors. Among these methods, alkaline hydrogen peroxide (AHP) is notable because it is effective for a wide range of lignocellulosic biomass concentrations, and can provide a high degree of enzymatic hydrolysis efficiency. However, few results have been discussed in the literature. Given this, the aim of this study was to investigate the use of alkaline hydrogen peroxide (AHP) as an oxidative pretreatment agent to improve the efficiency of enzymatic hydrolysis for different types of biomass and examine the key areas of the pretreatment. Finally, there is a discussion of the challenges facing a large-scale application of this method.
PubDate: 2017-07-06
DOI: 10.1007/s13399-017-0277-3

• One-vessel saccharification and fermentation of pretreated sugarcane
bagasse using a helical impeller bioreactor
• Authors: Raul Alves de Oliveira; Leda Maria Fortes Gottschalk; Suely Pereira Freitas; Elba Pinto da Silva Bon
Abstract: The effect of Tween® 80 and the cellulase load, on the enzymatic hydrolysis of hydrothermally pretreated sugarcane bagasse (HPSB), was evaluated in shake flask experiments, using experimental design. The optimized conditions were further applied in a second set of shake flask experiments to study the effect of the biomass load. The overall optimum parameters, e.g., 6.9% Tween® 80, 15 FPU/g glucan, and 150 g/L (dry HPSB), were used in hydrolysis experiments carried out in a laboratory-scale bioreactor equipped with a helical impeller. After a 48 h reaction time, 60% of the HPSB glucan content was hydrolyzed into glucose. The same bioreactor and hydrolysis conditions were used for one-vessel saccharification and fermentation experiments as follows: 150 g/L (dry HPSB) was hydrolyzed at 50 °C and 150 rpm for either 24 or 48 h, followed by the bioreactor’s temperature and mixing decrease to 30 °C and 90 rpm for ethanol fermentation by Saccharomyces cerevisiae. Experiments resulted in ethanol yields of 48 or 52%, for hydrolysis time of 24 or 48 h, respectively, taking into account the HPSB glucan content. The best ethanol productivity, for the overall process of 0.51 g/L.h, was achieved for the 24 h hydrolysis time.
PubDate: 2017-06-29
DOI: 10.1007/s13399-017-0272-8

• Hydrothermal carbonization of food waste: simplified process simulation
model based on experimental results
• Authors: Kyle McGaughy; M. Toufiq Reza
Abstract: Hydrothermal carbonization (HTC) was performed on homogenized food waste (FW) in a batch reactor at 200, 230, and 260 °C for 30 min. Solid product, called hydrochar, was characterized by means of ultimate analysis, proximate analysis, higher heating value (HHV), and ash content. On the other hand, liquid products were analyzed by inductively coupled plasma (ICP), total carbon, and pH. HHV of FW was increased from 25.1 to 33.1 MJ kg−1 by HTC. Ash content is less than 3% for hydrochars as well as the raw FW. Fixed carbon increased from 18.8 to 22.4% with the increase of HTC temperature. Fuel characteristics indicate hydrochar as a potential solid fuel and carbon storage. Therefore, a simplified simulation model was created for a continuous process that performs HTC of 1 t of FW per day. It was determined that HTC of food waste has potential to be a viable process for the production of solid fuel, primarily due to ease of drying product char.
PubDate: 2017-06-28
DOI: 10.1007/s13399-017-0276-4

• Catalytic hydroprocessing of lignin β-O-4 ether bond model compound
phenethyl phenyl ether over ruthenium catalysts
• Authors: B. Gomez-Monedero; J. Faria; F. Bimbela; M. P. Ruiz
Abstract: The catalytic hydroprocessing of phenethyl phenyl ether (PPE), a model compound of one of the most significant ether linkages within lignin structure, β-O-4, has been studied. Reactions were carried out using two ruthenium-based catalysts, supported on different materials: 3.8 wt.% Ru/C and 3.9 wt.% Ru/Al2O3. Aiming at studying the reaction mechanism, experiments were carried out at 150 °C and 25 bar in H2 atmosphere, with varying feed to catalyst mass ratios and reaction time. Differences between the relative importance of the steps of the mechanism were observed when using those two catalysts. The most significant finding was the predominance of the cleavage of Cβ-O bonds compared to the cleavage of the Caryl-O when using Ru/Al2O3 as catalyst; whereas with Ru/C, the two routes were nearly equivalent. It has been observed that the kinetic model describes the general tendencies of consumption and formation of the different products, but some over/under estimation of concentrations occurs. Finally, the effect of temperature was also explored by carrying out reactions at 100 and 125 °C, observing that decreasing temperature from 150 to 125 or 100 °C favored the dimer hydrogenation route versus the hydrogenolysis of the ether bonds.
PubDate: 2017-06-24
DOI: 10.1007/s13399-017-0275-5

• Effect of additives on thermochemical conversion of solid biofuel blends
from wheat straw, corn stover, and corn cob
• Authors: Natasa Dragutinovic; Isabel Höfer; Martin Kaltschmitt
Abstract: To investigate the effect of fuel blending and additives on ash melting behavior and the formation behavior of particulate matter (PM) emissions from combustion of crop residues, corn stover, corn cobs, and wheat straw as well as selected blends without and with 2 wt% additive have been examined by determining ash melting behavior in laboratory muffle furnace, ash elemental composition using ion chromatography (IC) and atomic absorption spectrometer (AAS), thermogravimetric properties of ashes using thermogravimetric analysis (TGA), and crystalline phases using powder X-ray diffraction (XRD). The results show that wheat straw starts sintering above 800 °C, corn cobs at 900 °C, whereas corn stover above 1000 °C. Fuel blending can influence the ash characteristics, but the influence is not sufficient to prevent ash sintering during typical combustion temperatures. All three additives (kaolinite (Al2Si2O5(OH)4), magnesium oxide (MgO), and calcite (CaCO3)) are successful in preventing ash sintering up to 1100 °C. At 1000 °C, K, Ca, Mg, and SO4 2− remain in decreased concentrations only partly in the ashes (i.e., a certain share of these components is transferred into the gas phase forming particulate matter emissions). However, Cl− is completely released into the gas phase. After heating 550 °C ashes to 1000 °C using TGA, mass losses of ~15 wt% were observed in most fuels and fuel blends with and without additives. An exception in the TGA was the blends with CaCO3; the samples show a mass loss higher than 25 wt%, which at the same time leads to an increased release of components into gas phase. Kaolinite and MgO are good K sorbents, forming new silicates in the ash such as K-Al silicates, K-Mg silicates, Ca-Mg silicates, and K-Al silicates, whereas CaCO3 facilitated K release and formation of Ca silicates, Ca-Na silicates, and Ca-Mg-Al silicates. Furthermore, MgO and CaCO3 can bind SO4 2− in the ashes.
PubDate: 2017-06-23
DOI: 10.1007/s13399-017-0273-7

• Study of time reaction on alkaline pretreatment applied to rice husk on
biomass component extraction
• Authors: Lara Soares Monte; Viviane Alves Escócio; Ana Maria Furtado de Sousa; Cristina Russi Guimarães Furtado; Marcia Christina Amorim Moreira Leite; Leila Lea Yuan Visconte; Elen Beatriz Acordi Vasquez Pacheco
Abstract: Rice husk (RH) residue was submitted to a sequence of experimental procedures, specifically to investigate the reaction time influence of NaOH pretreatment on the extraction of silica, hemicellulose, and lignin components. In order to follow the extraction of each non-cellulosic components of rice husk, techniques such as Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction analysis, and scanning electron microscopy were performed on untreated RH and samples collected from the NaOH reaction media at several different reaction times, as well as the sample after alkaline-peroxide treatment. Under the process parameters used in the present study, the results showed that a great part of hemicellulose and silica contents was removed during the first 30 min of reaction time in NaOH pretreatment. Although there is evidence that NaOH pretreatment also removed some lignin content, the complete delignification process was more effective just after alkaline-peroxide reaction, which produced material rich in type I cellulose.
PubDate: 2017-06-20
DOI: 10.1007/s13399-017-0271-9

• Miscanthus as biogas feedstock: influence of harvest time and stand age on
the biochemical methane potential (BMP) of two different growing seasons
• Authors: Axel Schmidt; Sébastien Lemaigre; Thorsten Ruf; Philippe Delfosse; Christoph Emmerling
Abstract: The use of perennial crops instead of maize as feedstock in biogas plants can be associated with multiple environmental and economic benefits. One promising species in this domain is the C4-grass Miscanthus × giganteus. The use of its biomass can mitigate carbon dioxide emissions by substitution of fossil fuels, sequestration of carbon in soils and reduced fertilizing. We compared Miscanthus from two different old fields (established 1995 and 2008) at three different harvest dates over 2 years. While the harvest in spring, like usual for combustion purposes, led to relatively low methane yields per hectare, the harvest in autumn, when the biomass is still green, exceeded the average methane yields per hectare of maize. The comparison of different old Miscanthus fields showed that there is no significant difference in terms of biomass yield, specific BMP and BMP per hectare. Only the influence of repeated autumn harvest showed differences in the methane production per hectare between both stand ages. The methane yield of the younger stand did not change considerable, while in the older stand, the productivity decreased about 15% after 1 year.
PubDate: 2017-06-20
DOI: 10.1007/s13399-017-0274-6

• Editorial thematic issue BCAB
• Authors: Frédéric Vogel
PubDate: 2017-06-16
DOI: 10.1007/s13399-017-0270-x

• Updates on the pretreatment of lignocellulosic feedstocks for bioenergy
production–a review
• Authors: Karthik Rajendran; Edward Drielak; V. Sudarshan Varma; Shanmugaprakash Muthusamy; Gopalakrishnan Kumar
Abstract: Lignocellulosic biomass is the most abundant renewable energy bioresources available today. Due to its recalcitrant structure, lignocellulosic feedstocks cannot be directly converted into fermentable sugars. Thus, an additional step known as the pretreatment is needed for efficient enzyme hydrolysis for the release of sugars. Various pretreatment technologies have been developed and examined for different biomass feedstocks. One of the major concerns of pretreatments is the degradation of sugars and formation of inhibitors during pretreatment. The inhibitor formation affects in the following steps after pretreatments such as enzymatic hydrolysis and fermentation for the release of different bioenergy products. The sugar degradation and formation of inhibitors depend on the types and conditions of pretreatment and types of biomass. This review covers the structure of lignocellulose, followed by the factors affecting pretreatment and challenges of pretreatment. This review further discusses diverse types of pretreatment technologies and different applications of pretreatment for producing biogas, biohydrogen, ethanol, and butanol.
PubDate: 2017-06-06
DOI: 10.1007/s13399-017-0269-3

• Mono-, bi-, and tri-metallic Ni-based catalysts for the catalytic
hydrotreatment of pyrolysis liquids
• Authors: Wang Yin; Robbie H. Venderbosch; Songbo He; Maria V. Bykova; Sofia A. Khromova; Vadim A. Yakovlev; Hero J. Heeres
Abstract: Catalytic hydrotreatment is a promising technology to convert pyrolysis liquids into intermediates with improved properties. Here, we report a catalyst screening study on the catalytic hydrotreatment of pyrolysis liquids using bi- and tri-metallic nickel-based catalysts in a batch autoclave (initial hydrogen pressure of 140 bar, 350 °C, 4 h). The catalysts are characterized by a high nickel metal loading (41 to 57 wt%), promoted by Cu, Pd, Mo, and/or combination thereof, in a SiO2, SiO2-ZrO2, or SiO2-Al2O3 matrix. The hydrotreatment results were compared with a benchmark Ru/C catalyst. The results revealed that the monometallic Ni catalyst is the least active and that particularly the use of Mo as the promoter is favored when considering activity and product properties. For Mo promotion, a product oil with improved properties viz. the highest H/C molar ratio and the lowest coking tendency was obtained. A drawback when using Mo as the promoter is the relatively high methane yield, which is close to that for Ru/C. 1H, 13C-NMR, heteronuclear single quantum coherence (HSQC), and two-dimensional gas chromatography (GC × GC) of the product oils reveal that representative component classes of the sugar fraction of pyrolysis liquids like carbonyl compounds (aldehydes and ketones and carbohydrates) are converted to a large extent. The pyrolytic lignin fraction is less reactive, though some degree of hydrocracking is observed.
PubDate: 2017-06-03
DOI: 10.1007/s13399-017-0267-5

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