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Model Biomass Feedstock National User Facility (BFNUF) to reduce cost and speed up the development to meet Bioenergy Technologies Office (BETO) 2030 mission. Model Based System Engineering (MBSE) detects problems early in the system which reduces cost and speeds up the development and is used for modeling BFNUF.
The microstructure of lignocellulosic biomass determines heat and mass transfer during conversion processes. We present a novel method for characterizing the transport properties of biomass using advanced imaging and computational techniques. The microstructure of two woody feedstocks, red oak and Douglas fir, before and after pyrolysis, is revealed using X-ray computed tomography (XCT). Transport properties are calculated from the XCT images, and principal permeability tensors are calculated using an immersed boundary-based finite volume solver to model gas flow through the geometries. We observe that the permeabilities of native biomass are distinctly anisotropic, however, this anisotropy is greatly reduced after pyrolysis.
Corn stover is a versatile feedstock for producing biofuels and other sustainable products. However, its diverse chemical and physical attributes can hinder the processes that convert it into these compounds. The composition of corn stover varies according to factors including corn plant variety, cultivation conditions and maturity at harvest. In essence, corn stover consists of the polymers cellulose, hemicellulose and lignin. The structural core of plant cell walls consists of elongated chains of glucose molecules arranged in bundles of cellulose. Additionally, lower concentrations of hemicellulose, a complex carbohydrate composed of various sugars, form part of the matrix surrounding cellulose bundles. Lignin is a complex aromatic polymer that reinforces plant cell walls. Corn stover generally comprises 40%-50% cellulose, 20%-30% hemicellulose, and 20%-30% lignin. The ratios of these components vary based on the specific type of corn plant and the growth conditions. For example, corn plants cultivated in drought conditions exhibit higher lignin levels than those grown under optimal conditions. The compositional diversity resulting from growth conditions is most pronounced among the different anatomical fractions of the corn plant. Understanding and accommodating the variation among the anatomical fractions of corn stover can enhance the effective utilization of this resource.
We report a method for fabricating optical quality silica and silica-titania glasses by additive manufacturing, or 3D printing. Key to this success was the combination of sol-gel derived silica and silica-titania colloidal feedstocks, 3D direct ink writing (DIW) technology, and conventional glass thermal processing methods. Printable silica and silica-titania sol inks were prepared directly from molecular precursors by a simple one-pot method, which was optimized to yield viscous, shear-thinning colloidal suspensions with tuned rheology ideal for DIW. After printing, the parts were dried and sintered under optimized thermal conditions to ensure complete organic removal and uniform densification without crystallization. Characterizations of the 3Dprinted pure silica and silica-titania glasses show that they are equivalent to commercial optical fused silica (Corning® 7980) and silica-titania glasses (Corning ULE® 7972). More specifically they exhibit comparable chemical composition, SiO2 network structure, refractive index, dispersion, optical transmission, and coefficient of thermal expansion. 3D printed silica and silica-titania glasses also exhibited comparable polished surface roughness and meet refractive index homogeneity standards within range of commercial optical grade glasses. This method establishes 3D printing as a viable tool to create optical glasses with compositional and geometric configurations that are inaccessible by conventional optical fabrication methods.
Here, in an effort to better understand the biomass recalcitrance, six natural poplar variants were selected as feedstocks based on previous sugar release analysis. Compositional analysis and physicochemical characterizations of these poplars were performed and the correlations between these physicochemical properties and enzymatic hydrolysis yield were investigated. Gel permeation chromatography (GPC) and 13 C solid state NMR were used to determine the degree of polymerization (DP) and crystallinity index (CrI) of cellulose, and the results along with the sugar release study indicated that cellulose DP likely played a more important role in enzymatic hydrolysis. Simons’ stain revealed that the accessible surface area of substrate significantly varied among these variants from 17.3 to 33.2 mg g$–1\atop{biomass}$ as reflected by dye adsorption, and cellulose accessibility was shown as one of the major factors governing substrates digestibility. HSQC and 31 P NMR analysis detailed the structural features of poplar lignin variants. Overall, cellulose relevant factors appeared to have a stronger correlation with glucose release, if any, than lignin structural features. Lignin structural features, such as a phenolic hydroxyl group and the ratio of syringyl and guaiacyl (S/G), were found to have a more convincing impact on xylose release. Low lignin content, low cellulose DP, and high cellulose accessibility generally favor enzymatic hydrolysis; however, recalcitrance cannot be simply judged on any single substrate factor.
The utilization of plants and other agricultural produce can partly offset petroleum dependency for energy requirements and can potentially provide sustainable solutions to global environmental problems. To this end, synthetic biology has shown great potential in developing transgenic bioenergy grasses such as sugarcane, sorghum, miscanthus, and energy cane that hyperaccumulate energy-rich lipid molecules in their vegetative tissues, such as leaves, stems, and roots. These perennial high-biomass transgenic C4 grasses are not targeted to grow on prime agricultural land and can be dedicatedly used to produce biofuels and other value-added bioproducts. Recently, sugarcane has been metabolically engineered to sequestrate carbon from juice towards biosynthesis of lipid molecules in the vegetative tissues. Transgenic sugarcane is referred to as “oilcane.” Transgenic sugarcane–oilcane has improved energy density due to an elevated lipid content in the vegetative tissues. Transgenic bioenergy crops cater to both cellulosic sugars and vegetative lipids, hence resulting in higher biofuel yield (biodiesel/renewable diesel and bioethanol) per unit area of cultivable land. In this book chapter, the genetic engineering of sugarcane and its bioprocessing are discussed to illustrate its development and use as an alternative feedstock for the production of biofuels (bio-jet fuel, biodiesel, and bioethanol) and value-added bioproducts.
Cellulose nanofibrils (CNFs) have attracted a great deal of research interest in recent years attributable to the low cost and abundance of lignocellulosic biomass from which they can be extracted. These materials have potential applications in a wide array of areas because of their unique properties such as ultra-high aspect ratios and specific strengths. However, the high energy required to extract CNFs from biomass through fibrillation often makes them prohibitively expensive or negates their inherent sustainability. As such, a variety of biomass treatments prior to fibrillation have been investigated by researchers to reduce the energy requirements of CNF extraction, improve the efficacy of biomass fibrillation and subsequent processes, and/or impart functionality in resulting nanofibrils. In this work, both widely used and emerging mechanical, chemical, and enzymatic pretreatments used prior to fibrillation of lignocellulosic biomass for CNF extraction are reviewed. Attention is given to the effect of these various pretreatments on the properties of the resulting CNFs. Finally, the energy consumption in fibrillation processes with and without the use of pretreatments is compared, and future perspectives on challenges and opportunities in lignocellulosic feedstock pretreatments are discussed.
Bacterial cellulose (BC), which is a hemicellulose- and lignin-free type of cellulose with unique properties, was produced by Komagataeibacter medellinensis, a new acid-resistant bacterial strain, using not suitable human consumption and sub-valorized food supply chain waste (FSCW) and agricultural by-products, namely, rotten banana, rotten mango and cheese whey. The BC was analyzed using Fourier transform infrared (ATR-FTIR) , tensile test, atomic absorption spectroscopy and thermogravimetric analysis. The properties of the BC obtained from each culture medium used were different, ranging from a material with high resistance and stiffness (280.6 MPa, 9.4 GPa) to a material with low resistance and less stiffness (17.7 MPa, 0.8 GPa). These properties provide considerable opportunities for obtaining different materials with multiple applications, such as composite reinforcements, wound dressings and edible films. The highest production of BC was achieved with rotten banana medium, and this BC also had the highest tensile properties. Meanwhile, the BC produced from cheese whey medium had the highest maximum rate of degradation temperature at 368 °C. This research demonstrated that FSCW and agrowaste by-products are advantageous alternative feedstocks in terms of economics and environmental concerns for producing BC with multiple properties and fields of application.
Thermo-mechanical processing was performed on two titanium alloy billets, a beta-titanium alloy (Ti1Al8V5Fe) and an alpha-beta titanium alloy (Ti6Al4V), which had been produced using a novel low-cost powder metallurgy process that relies on the use of TiH 2 powder as a feedstock material. The thermomechanical processing was performed in the beta region of the respective alloys to form 16-mm diameter bars. The hot working followed by the heat treatment processes not only eliminated the porosity within the materials but also developed the preferred microstructures. Tensile testing and rotating beam fatigue tests were conducted on the as-rolled and heat-treated materials to evaluate their mechanical properties. The mechanical properties of these alloys matched well with those produced by the conventional ingot processing route.
Properties of plasma-sprayed ceramic coatings can be improved significantly by reinforcing such coatings with carbon nanotube (CNT). However, it is difficult to disperse CNT in the plasma spray feedstock owing to its tendency to form agglomerate. A colloidal processing technique, namely heterocoagulation, is effective in bringing about unbundling of CNT, followed by its homogeneous dispersion in the ceramic powder. This report deals with the mixing of micro-sized crushed titania and agglomerated alumina powders with CNT using the heterocoagulation technique. Heterocoagulation of titania was attempted with both cationic and anionic surfactants, and the latter was found to be more effective. Mixing of the oxides and carbon nanotube was also accomplished in a ball mill either in a dry condition or in alcohol, and powders thus obtained were compared with the heterocoagulated powder. The heterocoagulated powder has shown a more homogeneous dispersion of CNT in the oxide. The coatings produced from the heterocoagulated powder demonstrated improvement in hardness, porosity, indentation fracture toughness and elastic modulus. This is attributed to CNT reinforcement.
Laser powder bed fusion (L-PBF) is an additive manufacturing process in which a 3D part is fabricated by fusing metal powder together layer by layer. L-PBF has many variables which contribute to part performance, which include powder properties, process parameters, and machine condition. L-PBF is a relatively expensive process compared to traditional manufacturing. Feedstock material and build time are two major factors which contribute to the cost of the L-PBF process. Various methods were explored as ways to reduce the cost of 4340 steel parts manufactured by L-PBF, including fabricating the parts with thicker powder layers and expanding the allowable powder particle size range. In addition, the effects of powder porosity and recoater condition on producing consistent material properties in the manufactured part were also explored. The experimental results showed that allowing a larger powder particle size range and thicker powder layers was a possible method for reducing the cost of L-PBF-fabricated 4340 steel parts without significantly degrading the mechanical properties. Methods for measuring the allowable loose particle porosity will be emphasized in this report. Furthermore, the study also revealed the importance of the recoater condition because variation in the machine condition can negatively influence the part quality.
Light oil from pyrolysis, which accounts for ~10 % carbon yield of the starting biomass, is a complex aqueous product that is difficult to utilize and usually discarded. This work presents the feasibility of light oil as a sole carbon source to support the growth of Rhodococcus opacus (R. opacus) that in turn accumulate triacylglycerols as biodiesel feedstock. Two types of bacteria (R. opacus PD630 and DSM 1069) were selected in this study. Research results showed that after short adaption periods both strains can grow well on this complex carbon source, as proved by the consumption of oligomers and monomers in light oil. Lipid content by R. opacus PD630 and DSM 1069 was observed up to 25.8 % and 22.0 % of cell dry weight, respectively. Palmitic and stearic acids were found to be the predominant fatty acids in these bacterial cells. In addition, the light oil-based lipid production can be enhanced by reducing the pH value from 7 to 4, especially in case of DSM 1069.
In this study, terrestrial lignocellulosic biomass has the potential to be a carbon neutral and domestic source of fuels and chemicals. However, the innate variability of biomass resources, such as herbaceous and woody materials, and the inconsistency within a single resource due to disparate growth and harvesting conditions, presents challenges for downstream processes which often require materials that are physically and chemically consistent. Intrinsic biomass characteristics, including moisture content, carbohydrate and ash compositions, bulk density, and particle size/shape distributions are highly variable and can impact the economics of transforming biomass into value-added products. For instance, ash content increases by an order of magnitude between woody and herbaceous feedstocks (from ~0.5 to 5 %, respectively) while lignin content drops by a factor of two (from ~30 to 15 %, respectively). This increase in ash and reduction in lignin leads to biofuel conversion consequences, such as reduced pyrolysis oil yields for herbaceous products as compared to woody material. In this review, the sources of variability for key biomass characteristics are presented for multiple types of biomass. Additionally, this review investigates the major impacts of the variability in biomass composition on four conversion processes: fermentation, hydrothermal liquefaction, pyrolysis, and direct combustion. Finally, future research processes aimed at reducing the detrimental impacts of biomass variability on conversion to fuels and chemicals are proposed.
AlSi10Mg tensile bars were additively manufactured using the powder-bed selective laser melting process. Samples were subjected to stress relief annealing and hot isostatic pressing. Tensile samples built using fresh, stored, and reused powder feedstock were characterized for microstructure, porosity, and mechanical properties. Fresh powder exhibited the best mechanical properties and lowest porosity while stored and reused powder exhibited inferior mechanical properties and higher porosity. The microstructure of stress relieved samples was fine and exhibited (001) texture in the z-build direction. Microstructure for hot isostatic pressed samples was coarsened with fainter (001) texture. To investigate surface and interior defects, scanning electron microscopy, optical fractography, and laser scanning microscopy techniques were employed. Hot isostatic pressing eliminated internal pores and reduced the size of surface porosity associated with the selective laser melting process. Hot isostatic pressing tended to increase ductility at the expense of decreasing strength. Furthermore, scatter in ductility of hot isostatic pressed parts suggests that the presence of unclosed surface porosity facilitated fracture with crack propagation inward from the surface of the part.
Biofuel demand is on the rise, yet there is limited information available about the likely implications of increased planting of cellulosic biofuel crops on water and nutrient fluxes. To help address this gap, this study quantifies subsurface water, nitrate, and dissolved phosphorus fluxes below feedstock crops managed for biofuel production on naturally well drained soils in southern Wisconsin. Automated equilibrium tension lysimeters were used to measure subsurface (below root zone) fluxes of water and nutrients below continuous corn (CC), monoculture switchgrass (SG), and hybrid poplar (HP) cropping systems for three years. Average water fluxes below SG were nearly double those below CC and HP. Most of this difference can be linked to seasonal events, particularly during late winter and early spring when subsurface water fluxes and increased soil moisture were observed below SG plots, likely due to enhanced macropore flow. Nitrate fluxes were approximately 14 times higher below CC than the 37.4 kg NO 3 -N/ha three year annual average observed for SG; the nitrate fluxes were negligible below HP despite similar nitrogen application rates. The high flux in one of the two CC plots is likely due to excessive manure applications prior to the study period; however, the nitrate loss potential from CC is much higher than the perennial crops. Dissolved reactive phosphorus (DRP) concentrations were very low below all three cropping systems (average of 0.076, 0.083, 0.034 mg/L in SG, CC, and HP respectively). For the cropping systems evaluated, nitrate fluxes were driven by concentration differences in leachate and not influenced by nominal differences in N fertilizer inputs, whereas DRP fluxes were mainly driven by water fluxes and therefore independent of phosphorus inputs and soil test phosphorus. The data in this paper provide a foundation to better understand differences in fluxes below different biofuel cropping systems.
There has been substantial technical progress in developing algae-based bioenergy in recent years and a large part of industry and academic research and deployment projects have pivoted away from a pure biofuels strategy. This letter summarizes the findings of a recently completed, comprehensive report, that represents a collaborative effort of at least 20 co-authors, where we analyzed the prospects for using microalgae and macroalgae as feedstocks for biofuels and bioenergy production. The scope of this report includes a discussion of international activities advancing bioenergy and non-energy bioproducts from algae, progress on the use of macroalgae (both cast and cultivated seaweeds) for biogas applications, distinct biochemical and thermochemical conversion pathways, multi-product biorefining opportunities, as well as a thorough review of process economics and sustainability considerations. It is envisioned that a higher value algal biomass-based bioproducts industry will provide the additional revenue needed to reduce the net cost of producing algae-based biofuels. As such, a biorefinery approach that generates multiple high-value products from algae will be essential to fully valorize algal biomass and enable economically viable coproduction of bioenergy. Furthermore, to accelerate the implementation of algae-based production, minimizing energy, water, nutrients and land use footprints of integrated algae-based operations needs to be a primary objective of larger scale demonstrations and future research and development.
Minimum production cost and optimum plant size are determined for pellet plants for three types of biomass feedstock e forest residue, agricultural residue, and energy crops. The life cycle cost from harvesting to the delivery of the pellets to the co-firing facility is evaluated. The cost varies from 95 to 105 t -1 for regular pellets and 146–156 t -1 for steam pretreated pellets. The difference in the cost of producing regular and steam pretreated pellets per unit energy is in the range of 2e3 GJ -1 . The economic optimum plant size (i.e., the size at which pellet production cost is minimum) is found to be 190 kt for regular pellet production and 250 kt for steam pretreated pellet. Furthermore, sensitivity and uncertainty analyses were carried out to identify sensitivity parameters and effects of model error.
Here, we report here on an experimental study to produce refinery-ready fuel blendstocks via catalytic hydrodeoxygenation (upgrading) of pyrolysis oil using several biomass feedstocks and various blends. Blends were tested along with the pure materials to determine the effect of blending on product yields and qualities. Within experimental error, oil yields from fast pyrolysis and upgrading are shown to be linear functions of the blend components. Switchgrass exhibited lower fast pyrolysis and upgrading yields than the woody samples, which included clean pine, oriented strand board (OSB), and a mix of pinon and juniper (PJ). The notable exception was PJ, for which the poor upgrading yield of 18% was likely associated with the very high viscosity of the PJ fast pyrolysis oil (947 cp). The highest fast pyrolysis yield (54% dry basis) was obtained from clean pine, while the highest upgrading yield (50%) was obtained from a blend of 80% clean pine and 20% OSB (CP 8 OSB 2 ). For switchgrass, reducing the fast pyrolysis temperature to 450 degrees C resulted in a significant increase to the pyrolysis oil yield and reduced hydrogen consumption during hydrotreating, but did not directly affect the hydrotreating oil yield. The water content of fast pyrolysis oils was also observed to increase linearly with the summed content of potassium and sodium, ranging from 21% for clean pine to 37% for switchgrass. Multiple linear regression models demonstrate that fast pyrolysis is strongly dependent upon the contents lignin and volatile matter as well as the sum of potassium and sodium.