No cost/benefit analysis on the advantages to increasing or decreasing pretreatment severity exists Perform applied R&D on the mechanical front-end needs to focus on fractionation (i.e. clean lignin removal) and the production of a highly concentrated C5/C6 sugar stream Define the effects of increased xylan concentration in unit operations and associated cost impacts Develop new (fundamental) methods for species-selective adsorption during integrated cleanup Barrier Area 3: Enzyme Science & Biotechnology Research Activities The mechanistic basis underlying the action of most hydrolytic enzymes are still largely misunderstood Poor categorization and understanding of the natural diversity in hydrolytic enzymes The advantages and disadvantages of using lignolytic enzyme systems have received relatively little R&D focus The specific activity of hydrolytic enzymes are typically low Critical need for understanding applied processes (not basic science) End products (sugars and degradation products) inhibit enzymes, preventing high sugar concentrations Lignin derived species hinder enzyme efficiencies Cellulase enzyme loading with high solids (>20% w/w) is cost prohibitive Fulfill need for increased substrate structure chemistry R&D (characterize enzymes interaction and changes during digestion) Investigate integrating thermochemical/thermomechanical pretreatment with enzymatic saccharification Design new cellulase enzymes with enhanced thermostability and pH tolerance Perform fundamental studies to ascertain why glycans and C6 oligomers decrease cellulase activity Design new hydrolytic enzymes to work synergistically in mild pretreatment conditions Focus on applied R&D for enzyme reuse/recycle in industrial conditions
Barrier Area 1: Catalyst and catalytic process comprehension Research Activities Lack of understanding of how catalysts interact with the oxygen containing functional groups in the bio-oil or liquid matrix together with how the entities within bio-oil vapor and liquids react intermolecularly. Incomplete understanding of how to tune the optimal catalytic upgrading conditions for the molecular components of different bio-oils derived from different liquefaction processes and feedstocks in order to efficiently generate an optimal fuel blendstock. Current biomass/bio-oil catalysts have a short lifespan and are prone to deactivation. Catalyst selectivity, ability to regenerate, and stability are problematic. Lack of understanding of between species in the vapor stream and on the surface of catalysts for formation of bio-oil, and the relative ratios of components (acyclic molecules versus cyclic and aromatic molecules), and side products (char and volatile organics). Evaluate deoxygenation/decarboxylation catalyst interactions with multiple oxygenated species in order to develop catalyst active sites flexible to the broad classes of species present in bio-oil vapors (determine the benefits of catalysts). Develop effective catalysts that combine; high activity, optimal residence time, attrition resistance, and reactivation/regeneration. Conduct parametric testing to evaluate catalyst performance using real feedstocks in order to be representative for large-scale process design. Develop an understanding of thermal and catalytic deactivation mechanisms with the identification of key reactants. Ultimately facilitating the development of robust catalysts and accelerated aging protocols. Barrier Area 2: Hydroprocessing of Bio-Oils and Hydrogen Considerations Research Activities Process sustainability and economics are strongly influenced by the amount of hydrogen and flexibility of distribution that is needed to simultaneously achieve high carbon yields, and lower GHG emissions. Evaluate biomass-specific heat and mass transfer correlations for reactor systems. Evaluate carbon and hydrogen atom efficiency of processes. Develop an understanding of thermal and catalytic deactivation mechanisms with the identification of key reactants. Ultimately facilitating the development of robust catalysts and accelerated aging protocols. Evaluate use of H2, H2-donor molecules, and other reductants for in-situ bio-oil reduction, these technologies need to be identified, understood for optimal efficiency, and tested. Evaluate innovative processes for oxygen removal mechanisms, including robust catalytic and
electrochemical routes that limit the production of COx species. Evaluate the inorganic species identity and transport through the direct liquefaction and upgrading processes with a particular emphasis correlation of inorganic species with biogenic carbon usage efficiency. Barrier Area 3: Separation Systems and Selective Fractionation Research Activities Solvent recovery and recycle is difficult in many liquefaction processes. Better technologies are needed to improve the cost-competitiveness. Vapor phase filters: process optimization, robust high-temperature filter and gasket materials, catalytic removal/upgrading of specific process-stream components and permeable selective filters. The need better understand solids separation from condensable gas streams with the balance of filter efficiency, and regeneration cycles for optimal performance while minimizing the loss of bio-oil. Liquid phase filters/membranes: process optimization and techniques to improve anti-fouling, aids to stabilize desired product, and process yields. Lack of knowledge about what fraction(s) do we want to separate (e.g., large oligomers, water, small organics, inorganics) and the trade-offs involved. Need for improved separation of aerosols and particulates from vapor phase Evaluate bio-oil quality and contaminant buildup over longer-term testing in recycle scenarios in continuous operation. Evaluate/develop optimal high-temperature membrane/filtration materials that are compatible with biomass-derived liquids, solids, and gases. Develop optimal pressure pulse to enable particulate removal from filters/membranes that are compatible with biomass-derived liquids and gases with minimal bio-oil loses. Demonstrate long-term solids filtration at high temperature. Evaluate catalytically active filters to balance optimal solid filter cake and upgrade bio-oils. Demonstrate high-temperature, high-pressure permeable, and selective filters/membranes to remove H2 from off gas, syngas, and recycled gas. Evaluate process economics for separating solids from bio-oils – compare hot-vapor separation and condensed phase separation Evaluate the fundamental aspects of degradation mechanisms for hydrocyclones in biomass separation systems. Evaluate which oxygenates are problematic and develop selective separation processes, e.g., adsorption, extraction, magnetic- and separations, etc. Develop/demonstrate energy efficient water removal processes.
Biochemical conversion allows the use of wet feedstocks. Are there comparable thermochemical conversion routes? Feedstock anatomy and fractionation is presumably different for thermochemical and biochemical processes are opportunities for a hybrid process? Generate process compatible feedstocks for hybrid processing. Modify feedstocks to take advantage of a hybrid process. Assess the techno-economic impact over the entire process for the use of wet feedstocks and the potential for energy savings. Barrier Area 4: Interdisciplinary Communication Research Activities The challenges of collaboration between biochemical and thermochemical conversion researchers Hold a multidisciplinary workshop on the hybrid concept with cross fertilization of presentations and breakout sessions Emphasize interesting hybrid research initiatives to encourage collaboration. Barrier Area 4: Integration Research Activities Energy integration. Thermochemical processes are generally higher temperature and potentially high pressure, while biochemical processes generally have milder conditions. Heat integration and temperature swings may be challenging. Balancing the Weight Hourly Space Velocity of thermochemical/thermocatalytic and biochemical processes. Publish more screening techno-economic analyses of different hybrid options and explore integration options. Energy “pinch” analysis to intelligently stage energy transfer. Counter current process flow concepts can potentially “conserve/transfer” thermal energy from thermocatalysts to thermogenic biocatalysts. TEA to enable rational evaluation of hybrid process options, including screening new hybrid options, assessing economics outlook, and determining potential operational ranges. Barrier Area 4: Risks/Unknown Research Activities Proliferation of unit operations. Use techno-economic analysis to address unit operation proliferation Techno-economic to enable rational evaluation of hybrid process options, including screening new
Barrier Area 1: Membrane/Filtration Separation Processes Research Activities Vapor Phase Filters: process optimization, filter and gasket materials, catalytic removal/upgrading of specific process-stream components, and permselective filters. Liquid Phase Membranes: process optimization and techniques to improve aids to stabilize desired product, and process yields. Demonstrate long-term char filtration. Develop optimal pressure to enable particulate removal from filters that are compatible with liquids and gases. Evaluate/develop optimal high-temperature filter materials compatible with biomass-derived liquids and gases. Evaluate/develop optimal high-temperature gasket materials compatible with biomass-derived liquids and Evaluate/develop catalytically active filters to remove solids and upgrade pyrolysis oils. (10 yrs) Develop high-temperature, high-pressure permselective filters to remove H2 from off gas, syngas, and recycled gas. Develop optimal pressure pulse process to enable particulate removal from membranes that are compatible with biomass-derived liquids. Evaluate/develop anti-fouling membranes compatible with biomass-derived liquids. on materials and system (e.g., flow pattern design to develop flow pattern; membrane surface chemistry to control wetting; magnetic- and electric-active separations). Evaluate/develop anti-bacterial membranes compatible with biomass-derived liquids. Evaluate/develop membrane process to remove char from bio-oil with low liquid organic losses.