Jeehoon Han

Nonenzymatic Sugar Production from Biomass Using Biomass-Derived γ-Valerolactone

Renewable Breakdown Routine In order to transform cellulose-containing biomass into liquid fuels such as ethanol, it is first necessary to break down the cellulose into its constituent sugars. Efforts toward this end have focused on chemical protocols using concentrated acid or ionic liquid solvents, and on biochemical protocols using cellulase enzymes. Luterbacher et al. (p. 277) now show that γ-valerolactone, a small molecule solvent that can itself be sourced renewably from biomass, promotes efficient and selective thermal breakdown of cellulose in the presence of dilute aqueous acid. A solvent sourced from biomass may offer a cost-effective means of breaking down cellulose for biofuels production. Widespread production of biomass-derived fuels and chemicals will require cost-effective processes for breaking down cellulose and hemicellulose into their constituent sugars. Here, we report laboratory-scale production of soluble carbohydrates from corn stover, hardwood, and softwood at high yields (70 to 90%) in a solvent mixture of biomass-derived γ-valerolactone (GVL), water, and dilute acid (0.05 weight percent H2SO4). GVL promotes thermocatalytic saccharification through complete solubilization of the biomass, including the lignin fraction. The carbohydrates can be recovered and concentrated (up to 127 grams per liter) by extraction from GVL into an aqueous phase by addition of NaCl or liquid CO2. This strategy is well suited for catalytic upgrading to furans or fermentative upgrading to ethanol at high titers and near theoretical yield. We estimate through preliminary techno-economic modeling that the overall process could be cost-competitive for ethanol production, with biomass pretreatment followed by enzymatic hydrolysis.

A strategy for the simultaneous catalytic conversion of hemicellulose and cellulose from lignocellulosic biomass to liquid transportation fuels

We develop and evaluate an integrated catalytic conversion strategy, which utilizes both the hemicellulose and cellulose fractions of lignocellulosic biomass to produce liquid hydrocarbon fuels (butene oligomers). In this strategy, the cellulose and hemicellulose fractions are simultaneously converted to levulinic acid (LA), using LA-derived γ-valerolactone (GVL) as a solvent. The LA is then converted to GVL, which is subsequently converted to butene, and then to butene oligomers. To generate the integrated strategy, we develop separation subsystems to achieve experimentally optimized feed concentrations for the catalytic conversion steps. Importantly, to minimize the utility requirements of the overall process, we perform heat integration, which allows us to satisfy all heating requirements from combustion of biomass residues, which are also used to produce steam for electricity generation. In addition, we develop an alternative design in which there is no electricity generation, study alternative feedstocks, and perform sensitivity analyses. Our technoeconomic analysis shows that the integrated strategy using hybrid poplar feedstock leads to a minimum selling price of

A lignocellulosic ethanol strategy via nonenzymatic sugar production: Process synthesis and analysis

4.01 per gallon of gasoline equivalent for butene oligomers if biomass residues are sold as low quality fuel.

Process systems engineering studies for the synthesis of catalytic biomass-to-fuels strategies

The work develops a strategy for the production of ethanol from lignocellulosic biomass. In this strategy, the cellulose and hemicellulose fractions are simultaneously converted to sugars using a γ-valerolactone (GVL) solvent containing a dilute acid catalyst. To effectively recover GVL for reuse as solvent and biomass-derived lignin for heat and power generation, separation subsystems, including a novel CO2-based extraction for the separation of sugars from GVL, lignin and humins have been designed. The sugars are co-fermented by yeast to produce ethanol. Furthermore, heat integration to reduce utility requirements is performed. It is shown that this strategy leads to high ethanol yields and the total energy requirements could be satisfied by burning the lignin. The integrated strategy using corn stover feedstock leads to a minimum selling price of

A catalytic biofuel production strategy involving separate conversion of hemicellulose and cellulose using 2-sec-butylphenol (SBP) and lignin-derived (LD) alkylphenol solvents.

5 per gallon of gasoline equivalent, which suggests that it is a promising alternative to current biofuels production approaches.

Catalytic production of biofuels (butene oligomers) and biochemicals (tetrahydrofurfuryl alcohol) from corn stover

The goal of this paper is to show how chemical process synthesis and analysis studies can be coupled with experimental heterogeneous catalysis studies to identify promising research directions for the development of strategies for the production of renewable fuels. We study five catalytic biomass-to-fuels strategies that rely on production of platform chemicals, such as levulinic acid and fermentable sugars. We first integrate catalytic conversion subsystems with separation subsystems to generate complete conversion strategies, and we then develop the corresponding process simulation models based on experimental results. Our analyses suggest that catalytic biomass-to-fuel conversion strategies could become economically competitive alternatives to current biofuel production approaches as a result of iterative experimental and computational efforts.

Optimal strategy for carbon capture and storage infrastructure: A review

A strategy in which the hemicellulose and cellulose fractions of lignocellulosic biomass are converted separately to jet fuel-range liquid hydrocarbon fuels (butene oligomers) through catalytic processes is developed. Dilute sulfuric acid (SA)-catalyzed pretreatment fractionates the first biomass into cellulose and hemicellulose-derived xylose, and these are then converted separately to levulinic acid (LA) using 2-sec-butylphenol (SBP) and lignin-derived (LD) alkylphenol solvents, respectively. LA is upgraded catalytically to butene oligomers via γ-valerolactone (GVL) and butene intermediates. Separation subsystems are designed to recover the alkylphenol solvents and biomass-derived intermediates (LA and GVL) for combination with the catalytic conversion subsystems of hemicellulose, cellulose, and lignin. In addition, a heat exchanger network (HEN) design is presented to satisfy the energy requirements of the integrated process from combustion of biomass residues (degradation products). Finally, a technoeconomic analysis shows that the proposed process (

Catalytic production of 1,4-pentanediol from corn stover

3.37/gallon of gasoline) is an economically competitive alternative to current biofuel production approaches.

An integrated strategy for catalytic co-production of jet fuel range alkenes, tetrahydrofurfuryl alcohol, and 1,2-pentanediol from lignocellulosic biomass

A strategy is presented that produces liquid hydrocarbon fuels (butene oligomers (BO)) from cellulose (C6) fraction and commodity chemicals (tetrahydrofurfuryl alcohol (THFA)) from hemicellulose (C5) of corn stover based on catalytic conversion technologies using 2-sec-butylphenol (SBP) solvents. This strategy integrates the conversion subsystems based on experimental studies and separation subsystems for recovery of biomass derivatives and SBP solvents. Moreover, a heat exchanger network is designed to reduce total heating requirements to the lowest level, which is satisfied from combustion of biomass residues (lignin and humins). Based on the strategy, this work offers two possible process designs (design A: generating electricity internally vs. design B: purchasing electricity externally), and performs an economic feasibility study for both the designs based on a comparison of the minimum selling price (MSP) of THFA. This strategy with the design B leads to a better MSP of

Operating Optimization and Economic Evaluation of Multicomponent Gas Separation Process using Pressure Swing Adsorption and Membrane Process

1.93 per kg THFA.