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1.
  • Abdelaziz, Omar, et al. (författare)
  • Continuous catalytic depolymerisation and conversion of industrial kraft lignin into low-molecular-weight aromatics
  • 2018
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6823 .- 2190-6815. ; 8:2, s. 455-470
  • Tidskriftsartikel (refereegranskat)abstract
    • Base-catalysed depolymerisation of lignin using sodium hydroxide has been shown to be an effective approach towards exploiting industrial (technical) lignins within the pulp and paper industry. In the present work, a pine kraft lignin (Indulin AT) which is precipitated from black liquor of linerboard-grade pulp was depolymerised via base catalysis to produce low-molecular-mass aromatics without any organic solvent/capping agent in a continuous-flow reactor setup for the first time. The catalytic conversion of lignin was performed/screened at temperatures varying from 170 to 250 °C, using NaOH/lignin weight ratio ≈ 1 with 5 wt% lignin solids loadings for residence times of 1, 2 and 4 min, respectively, with comprehensive characterisation of substrate and produced reaction mixtures. The products were characterised using size exclusion chromatography (SEC), nuclear magnetic resonance spectroscopy (NMR) and supercritical fluid chromatography-diode array detector-tandem mass spectrometry (SFC-MS). The optimum operating conditions for such depolymerisation appeared to be at 240 °C and 30 h−1, yielding the highest concentration of low-molecular-weight phenolics below the coking point. It was also found that the depolymerised lignin products exhibited better chemical stability during long-term storage at lower temperatures (~ 4 °C).
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2.
  • Belkheiri, Tallal, 1985, et al. (författare)
  • Hydrothermal liquefaction of kraft lignin in sub-critical water: the influence of the sodium and potassium fraction
  • 2018
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 8:3, s. 585-595
  • Tidskriftsartikel (refereegranskat)abstract
    • As a part of developing a hydrothermal liquefaction (HTL) process to valorise lignin, it is important to consider integration possibilities with existing infrastructures in order to obtain an overall positive economic impact. One obvious example is to integrate the HTL process with the kraft pulp mill: transport and storage costs is reduced, the temperature levels on process streams can be matched (energy integration) and the recovery/use of alkali can be made efficient. In this study, softwood kraft lignin was depolymerised using sub-critical water (623 K; 25 MPa) in a continuous, small pilot unit with a flow rate of 2 kg/h. ZrO2, K2CO3/KOH and Na2CO3/NaOH were used as catalytic system, and phenol as the capping agent. The influence of the ratio between sodium and potassium in the feed on the yield and composition of the product stream was investigated. The results showed that bio-oil, water-soluble organics (WSO) and char yields were not remarkably influenced by shifting the catalytic system from potassium to sodium. Moreover, the yields of most phenolic compounds did not change significantly when the sodium fraction was varied in the feed. The amounts of suspended solids in the bio-oil produced showed, however, a diminishing trend, (decrease from 10.8 to 3.8%) when the sodium fraction was increased in the feed, whilst the opposite trend was observed for the heavy oil, which increased from 24.6 to 37.6%.
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3.
  • Berguerand, Nicolas, 1978, et al. (författare)
  • Producer Gas Cleaning in a Dual Fluidized Bed - a Comparative Study of Performance with Ilmenite and a Manganese Oxide as Catalysts
  • 2012
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 2:3, s. 8-252
  • Tidskriftsartikel (refereegranskat)abstract
    • Secondary catalytic gas conditioning is one strategy to eliminate tars formed in a producer gas during biomass gasification. However, most catalysts tend to lose their tar reforming activity after short period of operation due to carbon formation. A novel technique for catalytic gas cleaning based on two interconnected fluidized beds has been investigated; this technique can be applied to all types of gasifiers. The idea is to reform the tar components into useful molecules - even at high tar contents - by means of a circulating catalyst. More precisely, the producer gas is cleaned with catalyst in one of the reactors, referred to as the fuel reactor (FR), while the catalyst is continuously regenerated in another reactor, the air reactor (AR). The system described here is coupled with the Chalmers 2-4 MWth biomass gasifier while the AR is fed with nitrogen-diluted air. The effect of different catalysts on both the tar content and the gas composition was investigated. Some of the tested materials do not only reform tars, they also influence the H2/CO-ratio in a beneficial manner; in particular, ratios closer to 3 in the reformed gas are favorable if subsequent methanation is implemented. In this paper, comparative results based on testing with manganese- and iron-based catalysts are presented. The former is a manufactured catalyst while the latter is a natural ore. Results suggest that both show satisfying ability for regeneration from carbon deposits. Higher temperature enhances tar decomposition during experiment with both catalysts. Moreover, the iron-based catalyst enhances water gas shift activity, which in turns impacts the total amount of produced gas. On the other hand, the manganese-based catalyst seems to display higher propensity for tar conversion.
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4.
  • Bilal, M., et al. (författare)
  • Bioprospecting lignin biomass into environmentally friendly polymers—Applied perspective to reconcile sustainable circular bioeconomy
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media Deutschland GmbH. - 2190-6815 .- 2190-6823.
  • Forskningsöversikt (refereegranskat)abstract
    • The valorization of lignin into biopolymers and other high-value products development is the most promising technology for sustainable development. This technology has gain importance for the development of kind of different biopolymers such as epoxies, polyesters, polyurethanes, phenol resins, polyhydroxyalkanoates, poly(lactic acids), and other useful biopolymers. However, lignin recalcitrance remains a potential problem for efficient lignin valorization, and therefore, several efforts have been made to develop high-efficiency bioprocesses for the synthesis of target polymer types, and other useful bioproducts. A comprehensive insight into lignin structure and properties will aid to understand the catalytic and metabolic deconstructive pathways for the efficient valorization of lignin. Due to the presence of multifunctional properties of lignin for the development of kinds of different biobased polymers, the review aims to highlight the biosynthesis and structure, potentialities of lignin and lignin-derivatives on polymers development, and future trends with outlook in lignin valorization have been systematically summarized. 
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5.
  • Birru, Eyerusalem, et al. (författare)
  • Assessing the potential of energy saving in a traditional sugar canemill during steady state and transient conditions : part I: basecase plant model
  • 2015
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6823 .- 2190-6815.
  • Tidskriftsartikel (refereegranskat)abstract
    • Sugar cane mills are energy intensive industries andalso have a large potential of providing surplus energy interms of heat or power. Identification of heat and mechanicallosses in sugar mills is one approach in indicating energysaving potential in sugar mills, especially in traditional mills.Such assessment of the energy flows in sugar mills needs to bedone both in steady state and transient conditions (where suddenstoppages occur). In this paper, such an approach is consideredwhere a base case plant is modeled for steady state andtransient state operations. For the transient state study, a typicalstoppage is chosen and three different scenarios aremodeled. Heat loss calculations are done for major cogenerationunits and for the amount accumulated of the surplus bagassewhen the steady state operation is estimated. The resultsof the models show that during steady state operation, thelosses related to mechanical prime movers is on the higherside as the mills and shredder are driven by steamand generatemechanical power higher than what is needed by the mills andthe shredder equipment themselves. In the transient statescenarios, where fuel oil is introduced during press mill stoppage,there is steam wasted (steam that could have been usedfor mechanical power generation) starting from the periodwhere the fuel oil is introduced until the power required duringthe stoppage is reached. The CO2 emission during the use offuel oil is also quite significant during the stoppage.
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6.
  • Birru, Eyerusalem, et al. (författare)
  • Energy performance comparisons and enhancements in the sugar cane industry
  • 2019
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Berlin/Heidelberg. - 2190-6815 .- 2190-6823. ; 9:2, s. 267-282
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, energy-related operational parameters for modern and traditional (conventional) sugar mills are analyzed, with the goals of identifying improvements in energy efficiency and potential for surplus electricity export. Results show that the power- to-heat ratio of modern and traditional mills is clearly distinct, lying in the ranges of 0.3–0.5 and 0.04–0.07, respectively. Modifications under consideration for the traditional mills include the following upgrades: electric drives and higher capacity back-pressure turbine (case 1); high-pressure boiler, condensing extraction steam turbine and electric drives (case 2); and improvements in case 2 plus bagasse drying (case 3). The thermodynamic impact of these modifications shows that more power is generated as the modification becomes more advanced. Case 1 exhibits a modest increase in cogeneration efficiency (4%) as compared to the base case, while the cogeneration efficiency increase is more marked for cases 2 and 3 (21% and 31%, respectively). Surplus power was studied in a regional context, where it was found that the contribution of 19 retrofitted sugar mills in nine Brazilian regions could supply 30% or more power as compared to current installed power capacity. The economic analysis showed that levelized cost of electricity (LCOE) was lowest for case 1 (11 USD/MWh) and highest for cases 2 and 3 (58 USD/kWh).
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7.
  • Birru, Eyerusalem, et al. (författare)
  • Upgrading of a traditional sugar cane mill to a modern milland assessing the potential of energy saving during steady stateand transient conditions : part II: models for a modifiedcogeneration unit
  • 2016
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6823 .- 2190-6815. ; 6:2, s. 233-245
  • Tidskriftsartikel (refereegranskat)abstract
    • It is known that there is a significant amount ofthermal energy used for the sugar cane industry for the purposeof power production and for use in the sugar or ethanolprocessing in cane sugar industries. Likewise, it is understoodthat there are substantial amounts of waste heat that is notbeing recovered, in particular for traditional sugar mills. Regardlessof this, energy conservation is given less considerationas compared to operational convenience due to the factthat sugar mills are self-sufficient in energy (heat and power).The identification of such potential heat loss areas (especiallyduring transient conditions) suggests the sugar mills play avital role in energy saving. In this study, a modified setup ofthe base case plant considered in part I of this paper is assessedfor its energy potential and possible major heat losses duringsteady state and transient conditions where 2-h stoppage of themill presses are considered to occur. For the modified setup,there are two major scenarios considered having two subscenarioseach. The result of the assessment showed that thesteady state assumption scenario of the modified plant (wherebagasse drying is not considered) indicated a 20 % reductionin the losses considered which resulted in a 57 % power generationincrease as compared to the steady state model of thebase case plant. It is also possible to save excess bagasse bydrying the bagasse for later use during unexpected stoppage.The carbon dioxide emission (amounting 29 t/day in case 2aof this study) that occurs during the use of fuel oil during suchstoppages will thus be avoided. The simple economic analysisshowed that it is only in case 2a where fuel oil cost is includedin the operation cost that resulted in a negative NPV. Since therest of the scenarios use bagasse as a fuel which is free, theNPV for all was positive. For the electricity price of 0.04 US$/kWh and discount rate of 15 %, the minimum paybackperiod attained is about 3 years (case 1b) where the bagassemoisture content is 30 % whereas the maximum payback periodis 6 years (case 1a) where there is no bagasse dryingconsidered.
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8.
  • Björnsson, Lovisa, et al. (författare)
  • Emerging technologies for the production of biojet fuels from wood—can greenhouse gas emission reductions meet policy requirements?
  • 2024
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • The transition from fossil jet fuel to biojet fuel is an important step towards reducing greenhouse gas (GHG) emissions from aviation. To enable such a fuel shift, the Swedish Government introduced a GHG emission reduction mandate of 27% by 2030 for aviation fuel sold in Sweden, forcing fuel suppliers to blend in biojet fuel in fossil jet fuel. A similar policy instrument is being discussed within the EU. Biojet fuels with life cycle GHG emissions 90% lower than those for fossil jet fuel are projected to be available by 2025, which by far exceeds the requirement of 65% lower emissions in the EU Renewable Energy Directive. The purpose of this study was to carry out life cycle assessments for a number of wood-fuel-based production chains near commercialization and to determine whether they meet the Swedish projection and the EU requirement. The study illustrates what can be achieved in a region with high availability of wood fuels and access to heat and power with low GHG emissions. The production chains studied include the production of hydrocarbon intermediates via (i) fast pyrolysis, (ii) hydrothermal liquefaction, (iii) thermal gasification followed by Fischer–Tropsch-synthesis, and (iv) cellulosic ethanol fermentation followed by upgrading of these four intermediates to biojet fuel and other liquid biofuels. The results show that all the production chains studied can deliver biojet fuels with 89–91% lower GHG emissions than fossil jet fuels. Non-fossil hydrogen is required to achieve low emissions in the upgrading of intermediates from fast pyrolysis and hydrothermal liquefaction.
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9.
  • Bär, Janosch, et al. (författare)
  • Deconstruction of hybrid poplar to monomeric sugars and aromatics using ethanol organosolv fractionation
  • 2018
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 8:4, s. 813-824
  • Tidskriftsartikel (refereegranskat)abstract
    • Acidic ethanol organosolv fractionation of hybrid poplar was investigated to determine the impact of pretreatment conditions on the resulting biomass and lignin properties and to assess the subsequent deconstruction of the cell wall biopolymers to monomeric sugars and aromatics. It was found that increasing reaction severity (i.e., time and temperature) during the organosolv fractionation increased the rate of delignification and xylan solubilization while the lignins recovered from the liquors were found to exhibit lower degrees of polymerization. Glucose hydrolysis yields > 75% at moderate enzyme loadings (30 mg/g glucan) could be obtained for the more severe pretreatment conditions. The lignins recovered from the pretreatment liquors were subjected to fractionation using a sequential extraction with solvents of increasing polarity. It was found that the low molar mass, low polydispersity lignins increased in pretreatment liquors with increasing time and temperature and were concentrated in the methanol fraction while a high molar mass fraction was extracted with the diethyl ether. We hypothesize that the extraction of the high molar mass fraction with diethyl ether is due to partial ethyl O-alkylation of lignin hydroxyl groups during pretreatment, rendering lignins more soluble in the non-polar solvent. Finally, depolymerization of unfractionated lignins by thioacidolysis resulted in mass yields of aromatic monomers ranging from 80 to 157 mg monomer per gram of lignin and that these yields exhibited strong positive correlations to the lignin β-O-4 content, molar mass, and strong negative correlations to the pretreatment temperature.
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10.
  • Caceres-Martinez, Louis Edwards, et al. (författare)
  • Significance of the particle physical properties and the Geldart group in the use of correlations for the prediction of minimum fluidization velocity of biomass–sand binary mixtures
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 13:2, s. 935-951
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study explores the relevance of the physical properties of biomass particles on the determination of the minimum fluidization velocity (U-mf) of binary mixtures. Fluidization experiments were performed in a cold flow unit with diverse biomasses mixed with sand in different mass fractions. Gas velocity and pressure drop across the bed were used to determine U-mf. Different correlations reported in the literature were evaluated on their ability to accurately predict U-mf of the mixtures. Results showed satisfactory predictions when appropriately identifying correlations according to the corresponding Geldart groups for the biomass particles. This perspective opens new possibilities toward the generalization of correlation factors and helps in improving the accuracy of the prediction for highly heterogeneous mixtures. The methodology also allows the analysis of mixtures for which the experimental approach is difficult, such as those including char particle, with the only requirement of carefully measuring the physical properties of the particles.
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11.
  • Caputo, Fabio, 1996, et al. (författare)
  • Understanding the impact of steam pretreatment severity on cellulose ultrastructure, recalcitrance, and hydrolyzability of Norway spruce
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; In Press
  • Tidskriftsartikel (refereegranskat)abstract
    • The efficient use of softwood in biorefineries requires harsh pretreatment conditions to overcome biomass recalcitrance. Following harsh pretreatments, the hemicellulose is solubilized. Here, we studied the material characteristics of Norway spruce following steam pretreatment at six different severities, relating chemical and structural information to the enzymatic hydrolyzability. Steam pretreatment conditions were defined by two different temperatures (180 °C and 210 °C), with and without the addition of various acids (CH3COOH, H3PO4, H2SO4, SO2). Structural knowledge of the streams is a cornerstone for developing an efficient saccharification process. This study combines advanced structural characterizations to gain fundamental understanding of the influence of severity of pretreatment on spruce. Structural knowledge is a cornerstone in developing an effective saccharification process by modulating pretreatment conditions and enzymes employed. Overall structural properties were assessed by scanning electron microscopy. The effect of stream pretreatment severity on lignin and lignin-carbohydrate bonds was investigated by two-dimensional heteronuclear single quantum correlation nuclear magnetic resonance. Finally, cellulose ultrastructure was studied by applying small/wide-angle X-ray scattering. The structural characteristics of the six pretreated softwood substrates were related to the enzymatic hydrolyzability. With increasing pretreatment severity, surface defibrillation, and lignin depolymeryzation were observed. Further, lignin-carbohydrate complexes signals were detected. Cellulose analysis revealed the rearrangement of microfibrils leading to the formation of larger microfibril aggregates. This microfibril rearrangement likely contributed to the observed increase in enzymatic hydrolysis yields as better enzyme accessibility resulted.
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12.
  • Cardozo Rocabado, Evelyn, et al. (författare)
  • Comparison of the thermal power availability of different agricultural residues using a residential boiler
  • 2016
  • Ingår i: BIOMASS CONVERSION AND BIOREFINERY. - : Springer. - 2190-6815 .- 2190-6823. ; 6:4, s. 435-447
  • Tidskriftsartikel (refereegranskat)abstract
    • This study presents a comparison of combustion performance, losses, and efficiency at steady-state and transient conditions for different biomass types in a residential boiler. The types of biomass used were 6 and 8 mm wood pellets, 6 mm sugarcane bagasse pellets, 6 mm sunflower husk pellets, and Brazil nut shells. The comparison in the development of the temperature in the combustion chamber during the start-up revealed that the 6 mm wood pellets ignite and propagate faster than the rest of the biomass fuels due to their smaller size compared with 8 mm wood pellets and lower ash content compared with the rest of the biomass sorts. Thermal power output and efficiencies under steady-state and transient conditions were calculated by the direct method, i.e., by measuring the heat recovery by the water boiler, and the indirect method, i.e., by measuring the heat losses. By using the indirect method, the availability of the flue gas thermal power during the start-up was seen more in detail than when the other method was applied. When comparing both methods as tools for boiler efficiency evaluation for different fuel types, the discrepancy of the resulting efficiencies between is larger when there are higher amounts of chemical losses in the boiler. Therefore, this method shows good agreement also for bagasse pellets but is, without modification, proposed not to be valid for fuels emitting higher amount of carbon monoxide (CO). Boiler efficiencies reached class 3 boilers according to EN 303-5 (> 74.8 %) for all biomass sorts.
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13.
  • Chen, Feng, et al. (författare)
  • Enabling efficient bioconversion of birch biomass by Lentinula edodes : regulatory roles of nitrogen and bark additions on mushroom production and cellulose saccharification
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 12:4, s. 1217-1227
  • Tidskriftsartikel (refereegranskat)abstract
    • Pretreatment with edible white-rot fungi has advantages in low inputs of energy and chemicals for reducing the recalcitrance of woody biomass for bioethanol production while harvesting protein-rich food. The effectiveness of fungal pretreatment may vary with substrate composition. In this study, birch with or without bark and nitrogen additives were experimentally studied for their effects on shiitake production, substrate lignocellulosic degradation and enzymatic convertibility with cellulolytic enzymes. Whey was added as protein nitrogen and led to successful outcomes, while non-protein nitrogen urea and ammonium-nitrate resulted in mortality of fungal mycelia. The mushroom yields of one harvest were generally comparable between the treatments, averaging 651 g fresh weight per kilogram dry substrate, and high enough as to be profitable. Nitrogen loading (0.5-0.8%, dry mass) negatively affected lignin degradation and enzymatic convertibility and prolonged cultivation/pretreatment time. The added bark (0-20%) showed quadratic correlation with degradation of lignin, xylan and glucan as well as enzymatic digestibility of glucan. Nitrogen loading of < 0.6% led to maximal mass degradation of xylan and lignin at bark ratios of 4-9% and 14-19%, respectively, peak saccharification of glucan at 6-12% and the shortest pretreatment time at 8-13% bark. The designed substrates resulted in 19-35% of glucan mass loss after fungal pretreatment, less than half of the previously reported values. Nitrogen and bark additions can regulate lignocellulose degradation and saccharification of birch-based substrates. The designed substrate composition could considerably reduce cellulose consumption during fungal pretreatment, thus improving bioconversion efficiency.
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14.
  • Cousins, Dylan S., et al. (författare)
  • Predictive models enhance feedstock quality of corn stover via air classification
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Nature. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • Feedstock heterogeneity is a fundamental obstacle to cost-competitive biobased products. Agricultural products like corn stover have anatomical components that vary in their chemical composition, mechanical properties, structure, and response to chemical and biological treatments. A technique that can enrich streams in select anatomical fractions would allow a tailored deconstruction approach to increase overall process efficiency. Air classification can be leveraged for such refining; however, fundamental characterization and understanding of the particle properties that underly the physics of air classification are only modestly documented. Here, we determine fundamental particle properties including mass-to-area ratio, drag coefficient, and partition velocity that describe how anatomical tissues of corn stover behave during air classification. Mass-to-area ratios of anatomical tissues vary by nearly two orders of magnitude from 2.3 mg/mm2 for cob to 0.04 mg/mm2 for leaf. Drag coefficients of longer, fibrous materials (i.e., rind, husk, and sheath) are shown to correlate with particle area (p-value < 0.001) whereas granular tissues (i.e., cob, pith, and leaf) correlate better with mass-to-area ratio (p-values < 0.001). When compared to experimental observations, a simulated two-stage air classification and size reduction scenario predicts the overall partitioning of anatomical tissues within 15% for pith, husk, rind, and cob tissues. The model predicts an air-classified fraction preferentially enriched in cob (purity = 20%), rind (purity = 74%), and pith (purity = 4.5%) with a mass yield of 47%. Empirical relations for these properties can be used to predict the partitioning of corn stover during air classification based on anatomical type and size.
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15.
  • Das, Atanu Kumar (författare)
  • Reducing sugars and bioethanol production from oil palm empty fruit bunch by applying a batch and continuous pretreatment process with low temperature and pressure
  • 2024
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 14, s. 11155–11164-
  • Tidskriftsartikel (refereegranskat)abstract
    • Exploring sustainable energy and chemical sources based on biomass has increased global interest. This study was focused on produce second-generation bioethanol using a new pretreatment process. The effectiveness of sodium hydroxide (NaOH) pretreatment on oil palm empty fruit bunch (OPEFB) for lignin removal, reducing sugar, and bioethanol production at low temperature and pressure was investigated using batch and continuous processes. Response surface methodology (RSM) was used to optimize the NaOH concentration and solid to liquor ratio (SL) at a maximum temperature of 100 degrees C and atmospheric pressure. The mathematical formula derived from RSM was based on 11 runs of the batch treatment. In the batch treatment process, 2 M NaOH, the temperature of 80 degrees C, and SL ratio of 8 have resulted in lignin removal of 38.7%, reducing sugars of 8.3%, and bioethanol concentration of 4.1%. The validation of formula has been calculated from calculation and experiment values. Moreover, at the same retention time, continuous pretreatment showed a reducing sugar content of 5.9% and a bioethanol concentration by 2.5%. The results show that the continuous process can be employed in effective bioethanol production from OPEFB.
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16.
  • Díaz, Sara, et al. (författare)
  • Oligosaccharides production by enzymatic hydrolysis of banana pseudostem pulp
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 13:12, s. 10677-10688
  • Tidskriftsartikel (refereegranskat)abstract
    • Banana production generates significant amounts of agricultural wastes, being fiber extraction one of the most relevant alternatives for their valorization. This process produces banana’s pseudostem pulp (BPP) as a byproduct, which shows an interesting composition for the biorefinery’s biochemical platform, with high polysaccharides (68%) and low lignin contents. This work deals with the enzymatic hydrolysis (EH) of raw and hydrothermally pre-treated BPP, focusing on the production of oligosaccharides (OS). Raw BPP hydrolysis with cellulase at different dosages rendered only 3.2% OS yields (OSY). Pectinase addition has not affected EH performance. On the other hand, EH of hydrothermally pre-treated BPP at 150 °C and 170 °C (P150 and P170) allowed to increase OSY up to 28% (P150, 1 FPU of cellulase/g dry biomass, 12 h), being 72% of the solubilized sugars in the form of cello-oligosaccharides. This last condition was subjected to a multi-stage EH strategy without improvements in OSY. An endo-glucanase was also tested, but obtained OSY were lower than cellulase results. Finally, obtained OS demonstrated to stimulate the growth of two Lactobacilli strains. The results show that BPP pre-treated under mild operational conditions is a good candidate for cello-oligosaccharides production by EH using 1 FPU/g DB of cellulase with a simple strategy.
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17.
  • dos Reis, Glaydson Simões, et al. (författare)
  • Application of design of experiments (DoE) for optimised production of micro- and mesoporous Norway spruce bark activated carbons
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 13:11, s. 10113-10131
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, Norway spruce (Picea abies (Karst) L.) bark was employed as a precursor to prepare activated carbon using zinc chloride (ZnCl2) as a chemical activator. The purpose of this study was to determine optimal activated carbon (AC) preparation variables by the response surface methodology using a Box–Behnken design (BBD) to obtain AC with high specific surface area (SBET), mesopore surface area (SMESO), and micropore surface area (SMICR). Variables and levels used in the design were pyrolysis temperature (700, 800, and 900 °C), holding time (1, 2, and 3 h), and bark/ZnCl2 impregnation ratio (1, 1.5, and 2). The optimal conditions for achieving the highest SBET were as follows: a pyrolysis temperature of 700 °C, a holding time of 1 h, and a spruce bark/ZnCl2 ratio of 1.5, which yielded an SBET value of 1374 m2 g−1. For maximised mesopore area, the optimal condition was at a pyrolysis temperature of 700 °C, a holding time of 2 h, and a bark/ZnCl2 ratio of 2, which yielded a SMESO area of 1311 m2 g−1, where mesopores (SMESO%) comprised 97.4% of total SBET. Correspondingly, for micropore formation, the highest micropore area was found at a pyrolysis temperature of 800 °C, a holding time of 3 h, and a bark/ZnCl2 ratio of 2, corresponding to 1117 m2 g−1, with 94.3% of the total SBET consisting of micropores (SMICRO%). The bark/ZnCl2 ratio and pyrolysis temperature had the strongest impact on the SBET, while the interaction between temperature and bark/ZnCl2 ratio was the most significant factor for SMESO. For the SMICRO, holding time was the most important factor. In general, the spruce bark AC showed predominantly mesoporous structures. All activated carbons had high carbon and low ash contents. Chemical characterisation indicated that the ACs presented disordered carbon structures with oxygen functional groups on the ACs’ surfaces. Well-developed porosity and a large surface area combined with favourable chemical composition render the activated carbons from Norway spruce bark with interesting physicochemical properties. The ACs were successfully tested to adsorb sodium diclofenac from aqueous solutions showing to be attractive products to use as adsorbents to tackle polluted waters. Graphical abstract: [Figure not available: see fulltext.].
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18.
  • Faisal, Abrar, et al. (författare)
  • Zeolite MFI adsorbent for recovery of butanol from ABE fermentation broths produced from an inexpensive black liquor-derived hydrolyzate
  • 2018
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 8:3, s. 679-687
  • Tidskriftsartikel (refereegranskat)abstract
    • In this work, high-silica MFI zeolite adsorbent was evaluated for selective recovery of butanol from a real ABE (acetone, butanol, and ethanol) fermentation broth by batch adsorption measurements. The fermentation broth was produced using a hydrolyzate originating from Kraft black liquor, an internal stream in pulp mills, i.e., a low-cost substrate. The adsorbent was very selective towards butanol and butyric acid and became nearly saturated with a mixture of butanol and butyric acid with relative amounts of butanol and butyric acid depending on the pH. The presence of phenolic compounds in significant amounts in the fermentation broths, originating from the black liquor hydrolyzate, did not affect the adsorption of butanol and butyric acid.
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19.
  • Furusjö, Erik, 1972-, et al. (författare)
  • Thermodynamic equilibrium analysis of entrained flow gasification of spent pulping liquors
  • 2018
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 8:1, s. 19-31
  • Tidskriftsartikel (refereegranskat)abstract
    • The main goal of this work is to investigate if thermodynamic equilibrium calculations can be useful for understanding and predicting process performance and product composition for entrained flow gasification of spent pulping liquors, such as black liquor. Model sensitivity to input data is studied and model results are compared to published pilot plant data. The high temperature and the catalytic activity of feedstock alkali make thermodynamic equilibrium a better predictor of product composition than for many other types of biomass and gasification technologies. Thermodynamic equilibrium calculations can predict the flows of the main syngas and slag products with high accuracy as shown by comparison with experimental data with small measurement errors. The main process deviations from equilibrium are methane formation and sulfur distribution between gas and slag. In order to study real process deviations from equilibrium, it is very important to use consistent experimental data. Relatively small errors in the model input, primarily related to fuel composition, can lead to grossly erroneous conclusions. The model sensitivity to fuel composition also shows that the gasification process is sensitive to naturally occurring feedstock variations. Simulations of a commercial-scale gasification process show that cold gas efficiency on sulfur-free basis can reach over 80 % and that greatly improved efficiency can be obtained by reducing ballast present in the form of water or inorganics.
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20.
  • Ghoreishi, Solmaz, et al. (författare)
  • Identification and quantification of valuable platform chemicals in aqueous product streams from a preliminary study of a large pilot-scale steam explosion of woody biomass using quantitative nuclear magnetic resonance spectroscopy
  • 2024
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media Deutschland GmbH. - 2190-6815 .- 2190-6823. ; 14, s. 3331-
  • Tidskriftsartikel (refereegranskat)abstract
    • Steam explosion breaks down the polymeric matrix and enables the recovery of valuable compounds from lignocellulosic feedstock. In the steam explosion process, biomass is treated with high-pressure steam which subsequently generates large quantities of a condensed aqueous liquid (process effluent) and a filtered aqueous liquid (filtrate) that contain furfural, 5-hydroxymethylfurfural, 5-methylfurfural, methanol, and acetic acid as major constituents. This study addresses the identification and quantification of value-added chemicals in the aqueous product streams using quantitative analytical nuclear magnetic resonance spectroscopy with water suppression. This work reports a screening study for two different types of sawdust (Norway spruce and birch) at two different scales (4 L and 10 L reactors) using different reaction temperatures (190–223 °C) and corresponding pressures (13–24 bar), with and without the addition of SO2 gas. The duration of all experiments was 8 min. The process effluents contained acetic acid, methanol, formic acid, 5-methylfurfural, and furfural. Acetic acid (0.5 g/kg dry input biomass) and furfural (1.0 g/kg dry input biomass) were more abundant than methanol, formic acid, and 5-methylfurfural for both feedstocks. The addition of SO2 increased the furfural yields, indicating more efficient hydrolysis of hemicelluloses under acidic conditions. Filtrate samples also contained 5-hydroxymethylfurfural, with the highest concentrations (5.7–6.0 g/kg dry input biomass) in the filtrates from spruce. The different feedstocks and steam explosion temperatures strongly influenced the overall yields of the target compounds, in some cases tripling the concentrations. The results can be used to improve the profit margins in a pellets and chemicals biorefinery, as demonstrated in the ArbaOne pellets plant. © 2022, The Author(s).
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21.
  • Grimm, Alejandro, et al. (författare)
  • Hardwood spent mushroom substrate–based activated biochar as a sustainable bioresource for removal of emerging pollutants from wastewater
  • 2024
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 14, s. 2293-2309
  • Tidskriftsartikel (refereegranskat)abstract
    • Hardwood spent mushroom substrate was employed as a carbon precursor to prepare activated biochars using phosphoric acid (H3PO4) as chemical activator. The activation process was carried out using an impregnation ratio of 1 precursor:2 H3PO4; pyrolysis temperatures of 700, 800, and 900 °C; heating rate of 10 °C min−1; and treatment time of 1 h. The specific surface area (SSA) of the biochars reached 975, 1031, and 1215 m2 g−1 for the samples pyrolyzed at 700, 800, and 900 °C, respectively. The percentage of mesopores in their structures was 75.4%, 78.5%, and 82.3% for the samples pyrolyzed at 700, 800, and 900 °C, respectively. Chemical characterization of the biochars indicated disordered carbon structures with the presence of oxygen and phosphorous functional groups on their surfaces. The biochars were successfully tested to adsorb acetaminophen and treat two simulated pharmaceutical effluents composed of organic and inorganic compounds. The kinetic data from adsorption of acetaminophen were fitted to the Avrami fractional-order model, and the equilibrium data was well represented by the Liu isotherm model, attaining a maximum adsorption capacity of 236.8 mg g−1 for the biochar produced at 900 °C. The adsorption process suggests that the pore-filling mechanism mainly dominates the acetaminophen removal, although van der Walls forces are also involved. The biochar produced at 900 °C removed up to 84.7% of the contaminants in the simulated effluents. Regeneration tests using 0.1 M NaOH + 20% EtOH as eluent showed that the biochars could be reused; however, the adsorption capacity was reduced by approximately 50% after three adsorption–desorption cycles.
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22.
  • Göransson, Kristina, et al. (författare)
  • Internal tar/CH4 reforming in a biomass dual fluidised bed gasifier.
  • 2015
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 5, s. 355-366
  • Tidskriftsartikel (refereegranskat)abstract
    • An internal reformer is developed for in situ catalyticreforming of tar and methane (CH4) in allothermal gasifiers.The study has been performed in the 150 kW dual fluidised bed (DFB) biomass gasifier at Mid Sweden University(MIUN). The MIUN gasifier is built for research onsynthetic fuel production. Reduction of tars and CH4 (exceptfor methanation application) in the syngas is a major challengefor commercialization of biomass fluidised-bed gasificationtechnology towards automotive fuel production. The MIUN gasifier has a unique design with an internal reformer, where intensive contact of gas and catalytic solids improves the reforming reactions. This paper presents an initial study on the internal reformer operated with and without Ni-catalytic pellets, by evaluation of the syngas composition and tar/CH4 content. A novel application of Ni-catalyst in DFB gasifiers is proposed and studied in this work. It can be concluded that the reformer with Ni-catalytic pellets clearly gives a higher H2 content together with lower CH4 and tar contents in the syngas than the reformer without Ni-catalytic pellets. The gravimetric tar content decreases down to 5 g/m3 and the CH4 content down below 6 % in the syngas. The tar content can be decreased further to lower levels, with increased gas contact to the specific surface area of the catalyst and increased catalyst surface-to-volume ratio. The new design in the MIUN gasifier increases the gasification efficiency, suppresses the tar generation and upgrades the syngas quality.
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23.
  • Hamzah, Wan Suzaini Wan, et al. (författare)
  • Microwave-assisted chemistry : parametric optimization for catalytic degradation of lignin model compounds in imidazolium-based ILs
  • 2021
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Berlin/Heidelberg. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • Lignin, a readily available form of biomass with a potential source of aromatic chemical compounds, has not been fully utilized due to its complex structure. Hence, this study aims to elaborate and optimize the effects of parametric microwave conditions for the catalytic degradation of lignin model compounds. In addition to that, 41 types of imidazolium-based Ionic liquids were employed for the conversion of lignin model compounds such as guaiacol and benzyl phenyl ether. The microwave-assisted conversion of lignin model compounds in imidazolium-based ionic liquids was performed at optimum applied microwave power 700 W and 30-min irradiation time. The percentages conversion and yield were quantified using high-performance liquid chromatography (HPLC) analysis. Results revealed that the chloride anion-based ionic liquids exhibited better nucleophilic behavior and catalyzed the cleavage of ether-based compounds efficiently under microwave irradiation. Among the imidazolium-based ionic liquids, 1H-methylimidazolium chloride ([1H-MIM][Cl]) exhibited better performance with guaiacol conversion and catechol yield of 99% and 81%, respectively. Therefore, the microwave-assisted technique was found to be more promising than conventional methods for the ionic liquid-based catalytic degradation of lignin model compounds.
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24.
  • Hannl, Thomas Karl, M.Sc. 1993-, et al. (författare)
  • Thermochemical equilibrium study of ash transformation during combustion and gasification of sewage sludge mixtures with agricultural residues with focus on the phosphorus speciation
  • 2021
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 11:1, s. 57-68
  • Tidskriftsartikel (refereegranskat)abstract
    • The necessity of recycling anthropogenically used phosphorus to prevent aquatic eutrophication and decrease the economic dependency on mined phosphate ores encouraged recent research to identify potential alternative resource pools. One of these resource pools is the ash derived from the thermochemical conversion of sewage sludge. This ash is rich in phosphorus, although most of it is chemically associated in a way where it is not plant available. The aim of this work was to identify the P recovery potential of ashes from sewage sludge co-conversion processes with two types of agricultural residues, namely wheat straw (rich in K and Si) and sunflower husks (rich in K), employing thermodynamic equilibrium calculations. The results indicate that both the melting behavior and the formation of plant available phosphates can be enhanced by using these fuel blends in comparison with pure sewage sludge. This enhanced bioavailability of phosphates was mostly due to the predicted formation of K-bearing phosphates in the mixtures instead of Ca/Fe/Al phosphates in the pure sewage sludge ash. According to the calculations, gasification conditions could increase the degree of slag formation and enhance the volatilization of K in comparison with combustion conditions. Furthermore, the possibility of precipitating phosphates from ash melts could be shown. It is emphasized that the results of this theoretical study represent an idealized system since in practice, non-equilibrium influences such as kinetic limitations and formation of amorphous structures may be significant. However, applicability of thermodynamic calculations in the prediction of molten and solid phases may still guide experimental research to investigate the actual phosphate formation in the future.
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25.
  •  
26.
  • Hermundsgård, Dag Helge, et al. (författare)
  • Investigating solids present in the aqueous stream during STEX condensate upgrading—a case study
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media Deutschland GmbH. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • Steam explosion (STEX) of woody biomass is an efficient pretreatment method in the production of water-resistant wood pellets. The STEX process also generates an aqueous condensate stream containing dissolved organic compounds, with furfural as the most abundant and valuable component. An industrial-scale recovery process for furfural and other organic by-products is therefore in the process of being developed and built. One challenge in the process has turned out to be the formation of solid particulate matter that can clog filters in the process unit. We have analyzed both the solid deposits and the fluids present at different points in the process unit to try to identify the origin of the particles using spectroscopic and chromatographic analysis, elemental analysis, and scanning electron microscopy. The aqueous fluids deriving from condensed steam contain furfural and other small organic molecules, with a separate low-density organic layer occurring at some points. This layer largely consists of wood extractives, typically terpenoids. In addition, a heavy organic phase comprising mostly furfural was found at one sampling point. The particles comprise a black, largely insoluble material with a H/C ratio of 0.88 and an O/C ratio of 0.26 and a very low ash content. IR spectra show a low content of C–H functional groups, and chromatographic analysis supports an interpretation that the particles are dominantly furfural-sourced humin-like polymers with adsorbed or co-polymerized terpenoids. Particle formation has been reproduced in a laboratory setting with conditions similar to those in the full-scale process. © 2022, The Author(s).
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27.
  • Heyne, Stefan, 1979, et al. (författare)
  • Exergy-based comparison of indirect and direct biomass gasification technologies within the framework of bio-SNG production
  • 2013
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 3:4, s. 337-352
  • Tidskriftsartikel (refereegranskat)abstract
    • Atmospheric indirect steam-blown and pressurised direct oxygen-blown gasification are the two major technologies discussed for large-scale production of synthetic natural gas from biomass (bio-SNG) by thermochemical conversion. Published system studies of bio-SNG production concepts draw different conclusions about which gasification technology performs best. In this paper, an exergy-based comparison of the two gasification technologies is performed using a simplified gasification reactor model. This approach aims at comparing the two technologies on a common basis without possible bias due to model regression on specific reactor data. The system boundaries include the gasification and gas cleaning step to generate a product gas ready for subsequent synthesis. The major parameter investigated is the delivery pressure of the product gas. Other model parameters include the air-to-fuel ratio for gasification as well as the H2/CO ratio in the product gas. In order to illustrate the thermodynamic limits and sources of efficiency loss, an ideal modelling approach is contrasted with a model accounting for losses in, e.g. the heat recovery and compression operations. The resulting cold-gas efficiencies of the processes are in the range of 0.66–0.84 on a lower heating value basis. Exergy efficiencies for the ideal systems are from 0.79 to 0.84 and in the range of 0.7 to 0.79 for the systems including losses. Pressurised direct gasification benefits from higher delivery pressure of the finished gas product and results in the highest exergy efficiency values. Regarding bio-SNG synthesis however, a higher energetic and exergetic penalty for CO2 removal results in direct gasification exergy efficiency values that are below values for indirect gasification. No significant difference in performance between the technologies can be observed based on the model results, but a challenge identified for process design is efficient heat recovery and cogeneration of electricity for both technologies. Furthermore, direct gasification performance is penalised by incomplete carbon conversion in contrast to performance of indirect gasification concepts.
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28.
  • Hu, Xiao, et al. (författare)
  • Product gas biomethanation with inoculum enrichment and grinding
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • The use of cheap product gas from biomass air gasification to produce methane via anaerobic digestion is a novel and potential pathway for the large-scale production of biomass-based substitute natural gas (BioSNG). In this experimental work, the product gas biomethanation (PGB) was studied with respect to the biosludge enrichment and inoculum partial grinding as well as the mesophilic and thermophilic conditions. The results show that the biosludge enrichment can effectively stop methanogenesis inhibition from the product gas, particularly CO, thus increase the biomethanation reaction rate and shorten the reaction start-up time. The inoculum partial grinding treatment can clearly change the microorganism composition and effectively reduce the diversity of microorganisms in the mixed bacterium system for the mesophilic biomethanation, thereby improving the product gas biomethanation efficiency, which is limited for the thermophilic biomethanation.
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29.
  • Isam, Mubeen, et al. (författare)
  • Optimization and modelling of Pb (II) and Cu (II) adsorption onto red algae (Gracilaria changii)-based activated carbon by using response surface methodology
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Nature. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • Activated carbon obtained from red algae Gracilaria changii was used as an adsorbent to remove Pb (II) and Cu (II) from an aqueous solution. The raw red algae were first impregnated with phosphoric acid, followed by thermal activation. The Box–Behnken design was used to optimize the activation process. The optimum activation parameters were 84%, 650 °C, and 175 min for acid concentration, activation temperature, and activation time, respectively. The obtained activated carbon had a high surface area of 867 m2/g. The removal of Pb (II) and Cu (II) was evaluated using a batch adsorption study. The effect of solution pH on the removal of metal ions was investigated within the range of 2–7. The effect of three important adsorption parameters (initial metal ion concentration, adsorbent dosage, and contact time) was analyzed using central composite design. The optimum removal of Pb (II) and Cu (II) was 76% and 36%, respectively. The adsorption kinetics obeyed the pseudo-second-order model, while the adsorption isotherm obeyed the Langmuir model.
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30.
  • Jafri, Yawer, et al. (författare)
  • A study of black liquor and pyrolysis oil co-gasification in pilot scale
  • 2018
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 8:1, s. 113-124
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of the blend ratio and reactor temperature on the gasification characteristics of pyrolysis oil (PO) and black liquor (BL) blends with up to 20 wt% PO was studied in a pilot-scale entrained-flow gasifier. In addition to unblended BL, three blends with PO/BL ratios of 10/90, 15/85, and 20/80 wt% were gasified at a constant load of 2.75 MWth. The 15/85 PO/BL blend was used to investigate the effect of temperature in the range 1000–1100 °C. The decrease in fuel inorganic content with increasing PO fraction resulted in more dilute green liquor (GL), and a greater portion of the feedstock carbon ended up in syngas as CO. As a consequence, the cold gas efficiency increased by about 5%-units. Carbon conversion was in the range 98.8–99.5% and did not vary systematically with either fuel composition or temperature. Although the measured reactor temperatures increased slightly with increasing PO fraction, both unblended BL and the 15% PO blend exhibited largely similar behavior in response to temperature variations. The results from this study show that blending BL with the more energy-rich PO can increase the cold gas efficiency and improve the process carbon distribution without adversely affecting either carbon conversion or the general process performance.
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31.
  • Jonsdottir Glaser, Sara, et al. (författare)
  • Fractionation of sugar beet pulp polysaccharides into component sugars and pre-feasibility analysis for further valorisation
  • 2024
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • Sugar beet pulp (SBP) is a by-product formed in large amounts during the production of refined sugar and is currently used as a low-cost feed for livestock. The dry SBP comprises largely three polysaccharides (75–85%), cellulose, hemicellulose and pectin, whose component sugars constitute potential valuable feedstock for producing building blocks for chemicals and materials. In the present study, a simple and integrated process for the fractionation of SBP polysaccharides into streams enriched with corresponding sugars is developed. Initial screening of several pectinase preparations (from Novozymes) for the treatment of dry SBP (at initial pH 4.0, 50 °C) showed Pectinase ME to release the maximum amount of galacturonic acid (GalU) along with high amounts of arabinose (Ara). On the other hand, subjecting the SBP to acid hydrolysis using 0.64 M sulphuric acid at 80 °C was relatively selective in solubilising mainly Ara (71.3% of the initial content), and the subsequent treatment with Pectinase ME solubilised 68.5% of the initial GalU content. Treatment of the residual solid fraction with cellulases released 81.9% of the original glucose content. Size-exclusion chromatography revealed the presence of oligomers ranging from dimers to pentamers in the acid and pectinase hydrolysates. Mass-balance based process analysis of 1000 kgdry/h SBP biorefinery using the three-stage fractionation of sugars and further valorization to arabitol, mucic acid and levulinic acid, respectively, indicated the potential economic feasibility and value addition of SBP, which is currently sold at 200 US$/t as animal feed. Recycling of water and catalysts would be important for reducing waste generation and improving environmental performance.
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32.
  • Joseph, Prajin, et al. (författare)
  • The O-factor : using the H-factor concept to predict the outcome of organosolv pretreatment
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media Deutschland GmbH. - 2190-6815 .- 2190-6823. ; 13, s. 6727-
  • Tidskriftsartikel (refereegranskat)abstract
    • The H-factor, a parameter used extensively to analyze and predict the outcome of kraft pulping, is applied to organosolv pretreatment. The total solid yield after organosolv pretreatment fits well with the H-factor. The concept has been extended to apply to the individual biomass polymers using unique values for the activation energy for the depolymerization of the individual biomass polymers, giving the O-factor concept analogous to the P factor used for analyzing prehydrolysis kinetics. The results showed a linear relationship between ln(L0/L) and O-factor at an activation energy of 96 kJ/mol. The best linear fit for mannan and xylan degradation was obtained at O-factor activation energies of 104 kJ/mol and 142 kJ/mol, respectively, and the formation of furfural and 5-HMF gave a good linear fit using an O-factor activation energy of 150 kJ/mol. The O-factor is thus a useful concept for analyzing organosolv pretreatment when the temperature during pretreatment is not constant. © 2021, The Author(s).
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33.
  • Kirtania, Kawnish, et al. (författare)
  • CO2 gasification behavior of biomass chars in an entrained flow reactor
  • 2016
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 6:1, s. 49-59
  • Tidskriftsartikel (refereegranskat)abstract
    • Chars of different particle sizes (150–250, 500–600 μm) from two different biomass species (spruce and coconut shell) were gasified under entrained flow condition in the presence of CO2 at different temperatures (800, 900 and 1000 °C). The concentration of CO2 was also varied between 5 and 20 % to determine its effect. It was found that significant improvement in gasification efficiency is possible by lowering the particle size below 0.5 mm. This finding was attributed to the spruce char as it showed the highest (≈50 %) conversion for the lowest particle size. It was also revealed that less reactive chars (coconut shell) were insensitive to the particle size and temperature variation for CO2 as a gasifying agent. Generally, pyrolysis process dominates the conversion process during raw biomass gasification. No tar component was observed during gasification at 1000 °C. As a whole, this study provides useful insight about the entrained flow gasification process of biomass chars with CO2.
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34.
  • Konwar, Lakhya Jyoti, 1987-, et al. (författare)
  • Efficient hydrothermal deoxygenation of tall oil fatty acids into n-paraffinic hydrocarbons and alcohols in the presence of aqueous formic acid
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 12:1, s. 51-62
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrothermal deoxygenation of tall oil fatty acids (TOFA) was investigated in the presence of aqueous formic acid (0.5–7.5 wt%) as a H2 donor in the presence of subcritical H2O pressure (569–599 K). Pd and Ru nanoparticles supported on carbon (5% Pd/CSigma, 5% Ru/CSigma, 10% Pd/CO850_DP, and 5% Ru/COPcomm_DP) were found to be efficient catalysts for deoxygenation of TOFA. The reaction pathway was mainly influenced by the concentration of formic acid and the catalyst. In case of Pd catalysts, in the presence of 0–2.5 wt% formic acid, decarboxylation was the dominant pathway producing n-paraffinic hydrocarbons with one less carbon atom (heptadecane yield up to 94 wt%), while with 5–7.5% formic acid, a hydrodeoxygenation/hydrogenation mechanism was favored producing C18 deoxygenation products octadecanol and octadecane as the main products (yields up to 70 wt%). In contrast, Ru catalysts produced a mixture of C5-C20 (n-and iso-paraffinic) hydrocarbons via decarboxylation, cracking and isomerization (up to 58 wt% C17 yield and total hydrocarbon yield up to 95 wt%) irrespective of formic acid concentration. Kinetic studies showed that the rates of deoxygenation displayed Arrhenius type behavior with apparent activation energies of 134.44 ± 31.36 kJ/mol and 148.92 ± 3.66 kJ/mol, for the 5% Pd/CSigma and 5% Ru/CSigma catalyst, respectively. Furthermore, the experiments with glycerol tristearate, rapeseed oil, sunflower oil, rapeseed biodiesel, and hydrolyzed rapeseed oil produced identical products confirming the versatility of the aforementioned catalytic systems for deoxygenation of C18 feedstocks.
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35.
  • Kuba, Matthias, et al. (författare)
  • Surface characterization of ash-layered olivine from fluidized bed biomass gasification
  • 2021
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 11:1, s. 29-38
  • Tidskriftsartikel (refereegranskat)abstract
    • The present study aims to present a comprehensive characterization of the surface of ash-layered olivine bed particles from dual fluidized bed gasification. It is well known from operation experience at industrial gasification plants that the bed material is activated during operation concerning its positive influence on gasification reactions. This is due to the built up of ash layers on the bed material particles; however, the chemical mechanisms are not well understood yet. Olivine samples from long-term operation in an industrial-scale gasification plant were investigated in comparison to fresh unused olivine. Changes of the surface morphology due to Ca-enrichment showed a significant increase of their surface area. Furthermore, the Ca-enrichment on the ash layer surface was distinctively associated to CaO being present. The presence of CaO on the surface was proven by adsorption tests of carbon monoxide as model compound. The detailed characterization contributes to a deeper understanding of the surface properties of ash layers and forms the basis for further investigations into their influence on gasification reactions.
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36.
  • Lind, Fredrik, 1978, et al. (författare)
  • Manganese oxide as catalyst for tar cleaning of biomass-derived gas
  • 2012
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 2:2, s. 133 - 140
  • Tidskriftsartikel (refereegranskat)abstract
    • The possibilities to upgrade raw gas with the use of a manganese oxide have been investigated in an application for secondary tar cleaning of biomass derived gas. Experiments were conducted in a reactor system where a novel technique that combines tar cleaning with catalyst regeneration is applied. Raw gas from the Chalmers non-catalytic steam biomass gasifier - containing roughly 32 gtar/Nm3gas - was fed to the tar cleaning reactor. The tar reforming qualities of the manganese oxide were evaluated in the reactor system using a mixture of 23 wt% catalysts in silica sand at the temperatures 700 and 800°C. Experiments showed that the catalyst was continuously regenerated from carbon deposits and that the total amount of tars was decreased by as much as 44,5% at a gas residence time of 0.4 s in the bed. The catalyst showed activity in water-gas shift reaction and the H2/CO-ratio increased from 0.6 in the raw gas to a peak value of 1 in the reformed gas at 800°C. Only a slight decrease in methane and acetylene content was observed for both operating temperatures.
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37.
  • Malek, Laura, et al. (författare)
  • Scrubber liquid recovery in biomass gasification plants: centrifugation as a method for tar separation
  • 2016
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 6:3, s. 261-269
  • Tidskriftsartikel (refereegranskat)abstract
    • Many gasification plants use scrubber systems for the removal of tars from producer gas. The cost of the scrubber liquid represents a considerable part of the operating cost, which could be decreased by regenerating the spent scrubber liquid by separating it from ash residues and heavy tars. In this study, different types of spent scrubber liquids were regenerated using a centrifuge. The effect of centrifugation time (1.5–10 min) and sample temperature (50–90 °C) on the separation efficiency was studied. Based on the results, the separation of tars from the scrubber liquids can be ranked as follows: diesel > RME > linoleic acid > linseed oil > rapeseed oil > motor oil. This ranking correlates to the viscosity of the different scrubber liquids, with the separation efficiency increasing with decreasing scrubber liquid viscosity. The best separation efficiency was achieved for scrubber liquids with low viscosity at 90 °C and 10 min of centrifugation time. The results obtained indicate that centrifugation can be used for the regeneration of spent scrubber liquid.
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38.
  • Mandviwala, Chahat, 1995, et al. (författare)
  • Fluidized bed steam cracking of rapeseed oil: exploring the direct production of the molecular building blocks for the plastics industry
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 13, s. 14511-14522
  • Tidskriftsartikel (refereegranskat)abstract
    • Fossil-based production of plastics represents a serious sustainability challenge. The use of renewable and biogenic resources as feedstocks in the plastic industry is imminent. Thermochemical conversion enables the production of the molecular building blocks of plastic materials from widely available biogenic resources. Waste cooking oil (WCO) represents a significant fraction of these resources. This work provides insights into the thermochemical conversion of the fatty acids present in WCO, where rapeseed oil is used as the source of fatty acids. The experimental results reveal that fluidized bed steam cracking of rapeseed oil in the temperature range of 650-750 degrees C yields a product distribution rich in light olefins and mono aromatics. Up to 51% of light olefins, 15% of mono aromatics, and 13% of light paraffins were recovered through steam cracking. This means that up to 70% of the carbon in rapeseed oil was converted into molecular building blocks in a single step. The main conclusion from this study is that WCO and vegetable oils represent viable biogenic feedstocks for the direct production of the molecular building blocks, where the conversion is achieved through steam cracking in fluidized beds.
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39.
  • Maric, Jelena, 1983, et al. (författare)
  • Using a manganese ore as catalyst for upgrading biomass derived gas
  • 2015
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 5:1, s. 75-83
  • Tidskriftsartikel (refereegranskat)abstract
    • Secondary catalytic tar cleaning has been evidencedas a promising technology for upgrading gas derivedfrom biomass gasification. When applying this technologydownstream a biomass gasifier, the tar fraction in the rawgas can potentially be reduced and the content of hydrogenbe increased. In this work, experiments have been conductedin a chemical-looping reforming (CLR) reactor. The presentreactor system features a circulating fluidized bed as thereformer section, which offers a higher gas-solid contact timethan a bubbling bed configuration previously tested. All experimentswere performed using raw gas from the Chalmers2–4MWth biomass gasifier as feedstock to the reactor system.The catalyst inventory consisted of a natural manganese ore,and its activity was evaluated at three different temperaturelevels—800, 850, and 880 °C—andwith an oxygen content of2.2 %, corresponding to a theoretical air-to-fuel ratio of 0.06.Experimental results showed that the manganese ore exhibitscatalytic activity with respect to tar conversion, and a tarreduction of as much as 72 % was achieved at 880 °C.Moreover, this material showed high activity towards hydrogenproduction and overall, an interesting upgrading capacitytoward this producer gas. An H2/CO ratio of nearly 3 in theproduced gas can make this material potentially interesting forapplication in an SNG system. Regarding the analysis of thephysicochemical characteristics, the material showed signs ofagglomeration with traces of sand most likely resulting fromprevious sieving during particle preparation. Though, a positiveaspect is that this occurred without impacting the catalystactivity.
  •  
40.
  • Maryana, Roni, et al. (författare)
  • Reducing sugars and bioethanol production from oil palm empty fruit bunch by applying a batch and continuous pretreatment process with low temperature and pressure
  • 2024
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Nature. - 2190-6815 .- 2190-6823. ; 14:10, s. 11155-11164
  • Tidskriftsartikel (refereegranskat)abstract
    • Exploring sustainable energy and chemical sources based on biomass has increased global interest. This study was focused on produce second-generation bioethanol using a new pretreatment process. The effectiveness of sodium hydroxide (NaOH) pretreatment on oil palm empty fruit bunch (OPEFB) for lignin removal, reducing sugar, and bioethanol production at low temperature and pressure was investigated using batch and continuous processes. Response surface methodology (RSM) was used to optimize the NaOH concentration and solid to liquor ratio (SL) at a maximum temperature of 100 degrees C and atmospheric pressure. The mathematical formula derived from RSM was based on 11 runs of the batch treatment. In the batch treatment process, 2 M NaOH, the temperature of 80 degrees C, and SL ratio of 8 have resulted in lignin removal of 38.7%, reducing sugars of 8.3%, and bioethanol concentration of 4.1%. The validation of formula has been calculated from calculation and experiment values. Moreover, at the same retention time, continuous pretreatment showed a reducing sugar content of 5.9% and a bioethanol concentration by 2.5%. The results show that the continuous process can be employed in effective bioethanol production from OPEFB.
  •  
41.
  • Menya, E, et al. (författare)
  • Optimization of pyrolysis conditions for char production from rice husks and its characterization as a precursor for production of activated carbon
  • 2020
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 10, s. 57-72
  • Tidskriftsartikel (refereegranskat)abstract
    • Response surface methodology was employed to optimize pyrolysis conditions for production of char with maximumyield, fixedcarbon content, and with minimum ash content from Uganda’s New Rice for Africa (NERICA) 1 rice husk variety. The aim wasto obtain rice husk char with more suitable properties as an activated carbon precursor. Mathematical models were developed toexplain the relationships between the experimental responses and the pyrolysis parameters of temperature (400–600 °C), heating rate (10–25 °C min−1), and heating period (60–120 min). The optimized rice husk char was further characterized for elementaland proximate compositions, thermal behavior, specific surface area, as well as surface functional groups. Results from theanalysis of variance (ANOVA) revealed that the quadratic model best fits each of the responses. Pyrolysis temperature had thegreatest influence on each of the responses, followed by heating period, and lastly heating rate. Optimum pyrolysis conditionswere found to be temperature (406 °C), heating rate (10 °C min−1), and heating period (60 min), resulting in char yield, fixedcarbon, and ash contents of 35.26, 55.39, and 35.01% dry basis, respectively. Compared to raw rice husk, the resulting rice huskchar was found more suited as activated carbon precursor, due to its enriched carbon content (60.35%) and specific surface area (123.9 m2 g−1). Thermogravimetric analysis of the rice husk char revealed that thermal activation temperatures higher than 400 °C may be required to considerably devolatilize the char, forming a more porous activated carbon.
  •  
42.
  • Menya, E., et al. (författare)
  • Synthesis and evaluation of activated carbon from rice husks for removal of humic acid from water
  • 2022
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Nature. - 2190-6815 .- 2190-6823. ; 12:8, s. 3229-3248
  • Tidskriftsartikel (refereegranskat)abstract
    • Activated carbon was synthesized from the New Rice for Africa (NERICA) rice husk variety, followed by its evaluation for removal of humic acid from water. Product values of carbon yield, C and total specific surface area, as,BET were employed as the performance criterion. The best physically activated carbon resulted from char activation at 800 °C for 10 min, leading to as,BET and C×as,BET values of 756.8 and 402.7 m2 g−1, respectively. The best chemically activated carbon resulted from 30 wt% H3PO4 activation of rice husk at 400 °C for 30 min, leading to as,BET and C×as,BET values of 2258.4 and 1058.7 m2 g−1, respectively. Despite the higher as,BET value, the maximum adsorption capacity of the best chemically activated carbon (5.3 mg g−1) was found lower than 8.9 and 27.2 mg g−1 exhibited by the chemically activated carbons prepared at 500 and 600 °C, respectively. The best adsorption conditions included carbon dose of 0.5 g, solution pH of 2, and contact time of 60 min. The adsorption capacity of the prepared activated carbons (27.2 mg g−1) was comparable to that of the commercial activated carbon (30.40 mg g−1). The analyses of the adsorption isotherms and kinetics revealed that the experimental data fits well the Langmuir isotherm model, as well as the pseudo-second-order kinetic model. The latter suggests that the adsorption of humic acid onto the activated carbon was controlled by the chemisorption process. Overall, the study revealed that the NERICA rice husk variety has good prospects for preparation of activated carbons for humic acid adsorption.
  •  
43.
  • Michel, Julie, et al. (författare)
  • Fate of biomass inorganic elements during hydrothermal carbonization : an experimental study on agro-food waste
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • The distribution of inorganic elements between solid and liquid phases during biomass hydrothermal carbonization (HTC) is a poorly investigated topic despite its importance for process optimization. To fill in this gap, the distribution of inorganic elements and their forms were determined for three agro-food waste feedstocks converted at HTC temperatures of 180, 220, and 260 °C in 12 h. Satisfactory balances were achieved, with values between 80 and 92% for C and N, and 80 and 110% for most inorganic elements. At 180 °C, over 90% of P, Mg, Ca, K, Na, and Mn were removed from hydrochars whatever feedstock. At higher temperatures, P, Mg, Ca, and Mn were partly reincorporated into hydrochars (between 7 and 53%), possibly due to the formation of insoluble precipitates, while K and Na remained in the liquid. On the opposite, some minor elements, Cu and Al, remained in the hydrochars, whatever temperature. Si showed different removal behaviors according to feedstock and temperature. These results show the possibility of optimizing the removal of inorganic elements from hydrochars using different temperatures.
  •  
44.
  • Muryanto, Muryanto, et al. (författare)
  • Characterization of solid waste biomass of agar processing plants and scale-up production of bioethanol
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Nature. - 2190-6815 .- 2190-6823.
  • Tidskriftsartikel (refereegranskat)abstract
    • Seaweed industries are producing solid waste composting of about 60-70% w/w fiber, which is rich in cellulose. Conversion of cellulose-rich waste into sugar and ethanol can provide a zero-waste industry. The objectives of this study were to characterize the solid waste biomass (SWBS) of agar processing industries and convert it into sugar and ethanol. The chemical composition and morphology of SWBS samples from three agar extraction plants (SWBS EP1, SWBS EP2, and SWBS EP3) were examined. Results showed that the SWBS had 3.01-16.4% cellulose, hemicellulose of 3.41-11.53%, lignin of 5.49-6.45%, agar of 7.28-17.03%, and ash content of 59.18-78.75%. X-ray diffraction (XRD) analysis supported the Fourier transform infrared ( FTIR) result while revealing that the filter aid of the SWBS EP3 sample was not the same with the two others. SWBS EP3 sample contained more biomass and less filter aid, and it was selected to convert into sugar and ethanol in a 250-L tank. The concentration biosugar reached 21.45 g/L with the addition of the cellulase after the agarase (A24S24), and 15 g/L when the cellulase was mixed together with the agarase (AS24). The highest ethanol production was obtained when agarase and cellulase were added simultaneously for 24-h saccharification followed by yeast fermentation.
  •  
45.
  • Nguyen Lyckeskog, Huyen, 1985, et al. (författare)
  • Thermal stability of low and high Mw fractions of bio-oil derived from lignin conversion in subcritical water
  • 2017
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 7:4, s. 401-414
  • Tidskriftsartikel (refereegranskat)abstract
    • The thermal stability of bio-oil influences its application in industry and is, therefore, a very important factor that must be taken into consideration. In this study, the stability of low and high molecular weight (Mw) fractions of bio-oil obtained from the hydrothermal liquefaction (HTL) of lignin in subcritical water was studied at an elevated temperature (80 °C) for a period of 1 h, 1 day and 1 week. The changes in molecular weight (gel permeation chromatography (GPC)) and chemical composition (gas chromatography–mass spectrometry (GC–MS) and 2D heteronuclear single quantum correlation (HSQC) NMR (18.8 T, DMSO-d6)) of low and high Mw fractions of the HTL bio-oil (i.e. light oil (LO) and heavy oil (HO)) were evaluated before and after ageing. It was found that only a slight formation of high Mw insoluble structures was obtained during ageing at elevated temperature for 1 week: 0.5% for the LO and 3.1% for the HO. These higher Mw moieties might be formed from different polymerisation/condensation reactions of the reactive compounds (i.e. anisoles, guaiacols, phenols, methylene (–CH2–) groups in phenolic dimers and xanthene). The high Mw insolubles in both the LO and the HO were analysed for structural composition using 2D HSQC NMR to obtain a better understanding of the changes in the composition of bio-oil fractions during the accelerated ageing process. In addition, a chemical shift database in DMSO-d6 was analysed for a subset of phenolic model compounds to simplify the interpretation of the 2D HSQC NMR spectra.
  •  
46.
  • Nielsen, Fredrik, et al. (författare)
  • The effect of mixed agricultural feedstocks on steam pretreatment, enzymatic hydrolysis, and cofermentation in the lignocellulose-to-ethanol process
  • 2020
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 10:2, s. 253-266
  • Tidskriftsartikel (refereegranskat)abstract
    • Second-generation fuel ethanol is typically researched using one type of raw material as feedstock. However, the variability in the supply and quality of biomass calls for an expansion of the feedstock base to ensure sufficient supply for commercial-scale production. By expanding the feedstock base and using mixtures in the conversion process, the biomass supply can be improved and associated economic risks can be hedged. However, the heterogeneity of feedstock mixtures requires conversion processes that can accommodate mixtures with no or minimal reduction in conversion efficiency compared to processing single feedstocks. In this study, the effects of using mixtures of wheat straw and corn stover on conversion efficiency and ethanol yield were investigated. The feedstocks and mixtures thereof were pretreated with dilute acid–catalysed steam pretreatment, and saccharified and cofermented using different simultaneous saccharification and cofermentation (SSCF) configurations, employing commercial cellulolytic enzymes and a xylose-fermenting strain of Saccharomyces cerevisiae. Process ethanol yields, based on total glucose and xylose in the raw material, were maximised by SSCF configurations that emphasise the saccharification efficiency over cofermentation efficiency. Ethanol concentrations exceeding 50 g L−1 and process ethanol yields of 74–78% of the theoretical maximum were achieved across the range of feedstocks and feedstock mixtures studied. The narrow range of the ethanol yields suggests that wheat straw and corn stover can be used interchangeably and mixed in the proposed lignocellulose-to-ethanol process without significant negative effects on conversion efficiency and process economics.
  •  
47.
  • Niero, Luisa, et al. (författare)
  • The effect of pH, temperature, and inoculum on the fermentation of pulp and paper biosludge: increasing the nutrient availability for rearing of black soldier fly larvae
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Nature. - 2190-6815 .- 2190-6823. ; 13:18, s. 16685-16693
  • Tidskriftsartikel (refereegranskat)abstract
    • Pulp and paper production is one of the largest global industries producing annually 400 million metric tons of pulp and paper products and 6 million tons of pulp and paper biosludge (PPBS). From a resource efficiency and sustainability perspective, there is a need for improving PPBS management. This study assessed fermentation of PPBS as pretreatment to improve PPBS feasibility as feed for black soldier fly larvae. The impact of temperature, pH, and inoculum on the concentration of soluble chemical oxygen demand (sCOD) and volatile fatty acids (VFA) was assessed. An initial pH of 10 and the addition of inoculum from an anaerobic digester substantially increased the concentration of sCOD. The obtained concentration of VFA was low compared to the VFA concentration needed to improve the growth of Black Soldier Fly Larvae (BSFL). The PPBS is recalcitrant to fermentation because of the high content of lignocellulose. Fermentation as done in this study does not convert PPBS to a feasible feed for black soldier fly larvae; thus, further research on improved fermentation is needed. However, fermentation at alkaline pH and addition of inoculum do increase the final pH of PPBS which improves its feasibility as feed for BSFL. Future studies should explore pH > 10 and temperatures > 55 °C to increase sCOD and improving generation of VFA by removal of inhibiting substances, testing other types of inoculum (rumen microorganisms) and co-fermentation.
  •  
48.
  • Nilsson, Patrik, et al. (författare)
  • Laboratory evaluation of a gasifier particle sampling system using model compounds of different particle morphology
  • 2011
  • Ingår i: Biomass Conversion & Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 1:2
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this work was to design and evaluate an experimental setup to be used for field studies of particle formation in biomass gasification processes. The setup includes a high-temperature dilution probe and a denuder to separate solid particles from condensable volatile material. The efficiency of the setup to remove volatile material from the sampled stream and the influence from condensation on particles with different morphologies is presented. In order to study the sampling setup model, aerosols were created with a nebulizer to produce compact and solid KCl particles and a diffusion flame burner to produce agglomerated and irregular soot particles. The nebulizer and soot generator was followed by an evaporation–condensation section where volatile material, dioctylsebacete (DOS), was added to the system as a tar model compound. The model aerosol particles were heated to 200°C to create a system containing both solid particles and volatile organic material in gas phase. The heated aerosol particles were sampled and diluted at the same temperature with the dilution probe. Downstream the probe, the DOS was adsorbed in the denuder. This was achieved by slowly decreasing the temperature of the diluted sample towards ambient level in the denuder. Thereby the supersaturation of organic vapors was reduced which decreased the probability for tar condensation and nucleation of new particles. Both the generation system and the sampling technique gave reproducible results. A DOS collection efficiency of >99% was achieved if the denuder inlet concentration was diluted to less than 1–6 mg/m3 depending on the denuder flow rate. Concentrations higher than that lead to significant impact on the resulting KCl size distribution. The choice of model compounds was done to study the effect from the particle morphology on the achieved particle characteristics after the sampling setup. When similar amounts of volatile material condensed on soot agglomerates and compact particles, a substantially smaller growth in mobility diameter was found for soot compared with compact KCl.
  •  
49.
  • Norgren, Robert, et al. (författare)
  • Fermented pulp and paper bio-sludge as feed for black soldier fly larvae
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer. - 2190-6815 .- 2190-6823. ; 13:7, s. 5625-5632
  • Tidskriftsartikel (refereegranskat)abstract
    • This study evaluates the use of fermentation to increase nutrient availability in pulp and paper bio-sludge (PPBS) as feed for black soldier fly larvae (BSFL). Rearing of BSFL on fermented PPBS was carried out in a climate chamber in order to assess nutrient availability and larvae survival and growth. The PPBS used came from a chemo-thermomechanical pulp/groundwood pulp mill. The PPBS was fermented at 35 °C and 55 °C, respectively, at initial pH of 10. The effects of sediment and liquid from fermented PPBS on larvae dry weight, survival rate until the prepupae stage, bioconversion, and reduction rate of PPBS were measured. The bioconversion of the liquids (4.1–6.6%) was substantially higher than for both the sediments and untreated PPBS (≤ 0.4%). The survival rate, on the other hand, was substantially lower (26.3–30.9 %) than for the sediments and untreated PPBS (49.5–52.6%). Neither the sediments nor the liquids had significant effects on the larvae weight or on the PPBS reduction rate. The sediments had no significant effect on the survival rate or the bioconversion. This study demonstrates that fermentation dissolves a part of the PPBS and that dissolved substances in the fermentation liquid readily convert to larvae biomass. However, the bulk of the lignocellulose is not dissolved, and most of PPBS nutrients remain unavailable for growth of the larvae. Further research should focus on improved pretreatment of PPBS to increase availability of nutrients and thereby improve the feasibility of BSFL as a recycling method for PPBS.
  •  
50.
  • Olsson, Johanna, et al. (författare)
  • An extensive parameter study of hydrotropic extraction of steam-pretreated birch
  • 2023
  • Ingår i: Biomass Conversion and Biorefinery. - : Springer Science and Business Media LLC. - 2190-6815 .- 2190-6823. ; 13:5, s. 4001-4009
  • Tidskriftsartikel (refereegranskat)abstract
    • Efficient fractionation of lignocellulosic biomass is an important step toward the replacement of fossil-based products. However, the utilisation of all of the components in biomass requires various fractionation techniques. One promising process configuration is to apply steam explosion for the recovery of hemicelluloses and a subsequent hydrotropic extraction step for the delignification of the remaining solids. In this work, the influence of residence time, temperature and biomass loading on lignin recovery from birch using sodium xylene sulphonate as a hydrotrope was investigated. Our results show that residence time, temperature and biomass loading correlate positively with lignin extraction, but the effects of these parameters were limited. Furthermore, when steam explosion was implemented as the initial step, hydrotropic extraction could be performed even at room temperature, yielding a lignin extraction of 50%. Also, hydrothermal degradation of the material was necessary for efficient delignification with sodium xylene sulphonate, regardless of whether it occurs during steam explosion pretreatment or is achieved at high temperatures during the hydrotropic extraction.
  •  
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