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Biomass Feedstocks (biomass + feedstock)
Selected AbstractsImplications of system expansion for the assessment of well-to-wheel CO2 emissions from biomass-based transportationINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 13 2010Elisabeth Wetterlund Abstract In this paper we show the effects of expanding the system when evaluating well-to-wheel (WTW) CO2 emissions for biomass-based transportation, to include the systems surrounding the biomass conversion system. Four different cases are considered: DME via black liquor gasification (BLG), methanol via gasification of solid biomass, lignocellulosic ethanol and electricity from a biomass integrated gasification combined cycle (BIGCC) used in a battery-powered electric vehicle (BPEV). All four cases are considered with as well as without carbon capture and storage (CCS). System expansion is used consistently for all flows. The results are compared with results from a conventional WTW study that only uses system expansion for certain co-product flows. It is shown that when expanding the system, biomass-based transportation does not necessarily contribute to decreased CO2 emissions and the results from this study in general indicate considerably lower CO2 mitigation potential than do the results from the conventional study used for comparison. It is shown that of particular importance are assumptions regarding future biomass use, as by expanding the system, future competition for biomass feedstock can be taken into account by assuming an alternative biomass usage. Assumptions regarding other surrounding systems, such as the transportation and the electricity systems are also shown to be of significance. Of the four studied cases without CCS, BIGCC with the electricity used in a BPEV is the only case that consistently shows a potential for CO2 reduction when alternative use of biomass is considered. Inclusion of CCS is not a guarantee for achieving CO2 reduction, and in general the system effects are equivalent or larger than the effects of CCS. DME from BLG generally shows the highest CO2 emission reduction potential for the biofuel cases. However, neither of these options for biomass-based transportation can alone meet the needs of the transport sector. Therefore, a broader palette of solutions, including different production routes, different fuels and possibly also CCS, will be needed. Copyright © 2009 John Wiley & Sons, Ltd. [source] Fast pyrolysis technology developmentBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 2 2010RH Venderbosch Abstract While the intention of slow pyrolysis is to produce mainly charcoal, fast pyrolysis is meant to convert biomass to a maximum quantity of liquids (bio-oil). Both processes have in common that the biomass feedstock is densified to reduce storage space and transport costs. A comfortable, more stable and cleaner intermediate energy carrier is obtained, which is much more uniform and well defined. In this review, the principles of fast pyrolysis are discussed, and the main technologies reviewed (demo scale: fluid bed, rotating cone and vacuum pyrolysis; pilot plant: ablative and twin screw pyrolysis). Possible product applications are discussed in relation to the bio-oil properties. General mass and energy balance are provided as well, together with some remarks on the economics. Challenges for the coming years are (1) improvement of the reliability of pyrolysis reactors and processes; (2) the demonstration of the oil's utilization in boilers, engines and turbines; and (3) the development of technologies for the production of chemicals and biofuels from pyrolysis oils. One important conclusion in relation to biofuel production is that the type of oxygen functionalities (viz. as an alcohol, ketone, aldehyde, ether, or ester) in the oil should be controlled, rather then merely focusing on a reduction of just the oxygen content itself. Copyright © 2010 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Large-scale production, harvest and logistics of switchgrass (Panicum virgatum L.) , current technology and envisioning a mature technologyBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 2 2009Shahab Sokhansanj Abstract Switchgrass (Panicum virgatum L.) is a promising cellulosic biomass feedstock for biorefineries and biofuel production. This paper reviews current and future potential technologies for production, harvest, storage, and transportation of switchgrass. Our analysis indicates that for a yield of 10 Mg ha,1, the current cost of producing switchgrass (after establishment) is about $41.50 Mg,1. The costs may be reduced to about half this if the yield is increased to 30 Mg ha,1 through genetic improvement, intensive crop management, and/or optimized inputs. At a yield of 10 Mg ha,1, we estimate that harvesting costs range from $23.72 Mg,1 for current baling technology to less than $16 Mg,1 when using a loafing collection system. At yields of 20 and 30 Mg ha,1 with an improved loafing system, harvesting costs are even lower at $12.75 Mg,1 and $9.59 Mg,1, respectively. Transport costs vary depending upon yield and fraction of land under switchgrass, bulk density of biomass, and total annual demand of a biorefinery. For a 2000 Mg d,1 plant and an annual yield of 10 Mg ha,1, the transport cost is an estimated $15.42 Mg,1, assuming 25% of the land is under switchgrass production. Total delivered cost of switchgrass using current baling technology is $80.64 Mg,1, requiring an energy input of 8.5% of the feedstock higher heating value (HHV). With mature technology, for example, a large, loaf-collection system, the total delivered cost is reduced to about $71.16 Mg,1 with 7.8% of the feedstock HHV required as input. Further cost reduction can be achieved by combining mature technology with increased crop productivity. Delivered cost and energy input do not vary significantly as biorefinery capacity increases from 2000 Mg d,1 to 5000 Mg d,1 because the cost of increased distance to access a larger volume feedstock offsets the gains in increased biorefinery capacity. This paper outlines possible scenarios for the expansion of switchgrass handling to 30 Tg (million Mg) in 2015 and 100 Tg in 2030 based on predicted growth of the biorefinery industry in the USA. The value of switchgrass collection operations is estimated at more than $0.6 billion in 2015 and more than $2.1 billion in 2030. The estimated value of post-harvest operations is $0.6,$2.0 billion in 2015, and $2.0,$6.5 billion in 2030, depending on the degree of preprocessing. The need for power equipment (tractors) will increase from 100 MW in 2015 to 666 MW in 2030, with corresponding annual values of $150 and $520 million, respectively. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Standard assays do not predict the efficiency of commercial cellulase preparations towards plant materialsBIOTECHNOLOGY & BIOENGINEERING, Issue 1 2006Mirjam A. Kabel Abstract Commercial cellulase preparations are potentially effective for processing biomass feedstocks in order to obtain bioethanol. In plant cell walls, cellulose fibrils occur in close association with xylans (monocotyls) or xyloglucans (dicotyls). The enzymatic conversion of cellulose/xylans is a complex process involving the concerted action of exo/endocellulases and cellobiases yielding glucose and xylanases yielding xylooligomers and xylose. An overview of commonly measured cellulase-, cellobiase-, and xylanase-activity, using respectively filter paper, cellobiose, and AZCL-dyed xylan as a substrate of 14 commercially available enzyme preparations from several suppliers is presented. In addition to these standardized tests, the enzyme-efficiency of degrading native substrates was studied. Grass and wheat bran were fractionated into a water unsoluble fraction (WUS), which was free of oligosaccharides and starch. Additionally, cellulose- and xylan-rich fractions were prepared by alkaline extraction of the WUS and were enzymatically digested. Hereby, the capability of cellulose and xylan conversion of the commercial enzyme preparations tested was measured. The results obtained showed that there was a large difference in the performance of the fourteen enzyme samples. Comparing all results, it was concluded that the choice of an enzyme preparation is more dependent on the characteristics of the substrate rather than on standard enzyme-activities measured. © 2005 Wiley Periodicals, Inc. [source] An economic comparison of different fermentation configurations to convert corn stover to ethanol using Z. mobilis and SaccharomycesBIOTECHNOLOGY PROGRESS, Issue 1 2010Abhijit Dutta Abstract Numerous routes are being explored to lower the cost of cellulosic ethanol production and enable large-scale production. One critical area is the development of robust cofermentative organisms to convert the multiple, mixed sugars found in biomass feedstocks to ethanol at high yields and titers without the need for processing to remove inhibitors. Until such microorganisms are commercialized, the challenge is to design processes that exploit the current microorganisms' strengths. This study explored various process configurations tailored to take advantage of the specific capabilities of three microorganisms, Z. mobilis 8b, S. cerevisiae, and S. pastorianus. A technoeconomic study, based on bench-scale experimental data generated by integrated process testing, was completed to understand the resulting costs of the different process configurations. The configurations included whole slurry fermentation with a coculture, and separate cellulose simultaneous saccharification and fermentation (SSF) and xylose fermentations with none, some or all of the water to the SSF replaced with the fermented liquor from the xylose fermentation. The difference between the highest and lowest ethanol cost for the different experimental process configurations studied was $0.27 per gallon ethanol. Separate fermentation of solid and liquor streams with recycle of fermented liquor to dilute the solids gave the lowest ethanol cost, primarily because this option achieved the highest concentrations of ethanol after fermentation. Further studies, using methods similar to ones employed here, can help understand and improve the performance and hence the economics of integrated processes involving enzymes and fermentative microorganisms. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Evaluation of Minimal Trichoderma reesei Cellulase Mixtures on Differently Pretreated Barley Straw SubstratesBIOTECHNOLOGY PROGRESS, Issue 6 2007Lisa Rosgaard The commercial cellulase product Celluclast 1.5, derived from Trichoderma reesei (Novozymes A/S, Bagsværd, Denmark), is widely employed for hydrolysis of lignocellulosic biomass feedstocks. This enzyme preparation contains a broad spectrum of cellulolytic enzyme activities, most notably cellobiohydrolases (CBHs) and endo-1,4-,-glucanases (EGs). Since the original T. reesei strain was isolated from decaying canvas, the T. reesei CBH and EG activities might be present in suboptimal ratios for hydrolysis of pretreated lignocellulosic substrates. We employed statistically designed combinations of the four main activities of Celluclast 1.5, CBHI, CBHII, EGI, and EGII, to identify the optimal glucose-releasing combination of these four enzymes to degrade barley straw substrates subjected to three different pretreatments. The data signified that EGII activity is not required for efficient lignocellulose hydrolysis when addition of this activity occurs at the expense of the remaining three activities. The optimal ratios of the remaining three enzymes were similar for the two pretreated barley samples that had been subjeced to different hot water pretreatments, but the relative levels of EGI and CBHII activities required in the enzyme mixture for optimal hydrolysis of the acid-impregnated, steam-exploded barley straw substrate were somewhat different from those required for the other two substrates. The optimal ratios of the cellulolytic activities in all cases differed from that of the cellulases secreted by T. reesei. Hence, the data indicate the feasibility of designing minimal enzyme mixtures for pretreated lignocellulosic biomass by careful combination of monocomponent enzymes. This strategy can promote both a more efficient enzymatic hydrolysis of (ligno)cellulose and a more rational utilization of enzymes. [source] Effects of Pressing Lignocellulosic Biomass on Sugar Yield in Two-Stage Dilute-Acid Hydrolysis ProcessBIOTECHNOLOGY PROGRESS, Issue 3 2002Kyoung Heon Kim Dilute sulfuric acid catalyzed hydrolysis of biomass such as wood chips often involves pressing the wood particles in a dewatering step (e.g., after acid impregnation) or in compression screw feeders commonly used in continuous hydrolysis reactors. This study addresses the effects of pressing biomass feedstocks using a hydraulic press on soluble sugar yield obtained from two-stage dilute-acid hydrolysis of softwood. The pressed acid-impregnated feedstock gave significantly lower soluble sugar yields than the never-pressed (i.e., partially air-dried or filtered) feedstock. Pressing acid-impregnated feedstocks before pretreatment resulted in a soluble hemicellulosic sugar yield of 76.9% from first-stage hydrolysis and a soluble glucose yield of 33.7% from second-stage hydrolysis. The dilute-acid hydrolysis of partially air-dried feedstocks having total solids and acid concentrations similar to those of pressed feedstocks gave yields of 87.0% hemicellulosic sugar and 46.9% glucose in the first and second stages, respectively. Microscopic examination of wood structures showed that pressing acid-impregnated wood chips from 34 to 54% total solids (TS) did not cause the wood structure to collapse. However, pressing first-stage pretreated wood chips (i.e., feedstock for second-stage hydrolysis) from approximately 30 to 43% TS caused the porous wood matrix to almost completely collapse. It is hypothesized that pressing alters the wood structure and distribution of acid within the cell cavities, leading to uneven heat and mass transfer during pretreatment using direct steam injection. Consequently, lower hydrolysis yield of soluble sugars results. Dewatering of corn stover by pressing did not impact negatively on the sugar yield from single-stage dilute-acid pretreatment. [source] | ||||||||||