A sulfuric acid management strategy for the production of liquid hydrocarbon fuels via catalytic conversion of biomass-derived levulinic acid

Abstract

In this study, we first develop an integrated strategy for the catalytic conversion of lignocellulose into liquid fuels based on the production of levulinic acid (LA) followed by its hydrogenation to gvalerolactone (GVL). Our integrated strategy involves a novel catalytic conversion process employing alkylphenol-based separation to extract LA from the sulfuric acid containing aqueous solution following the sulfuric acid catalyzed deconstruction of cellulose. To minimize utility consumption, we perform heat integration, while the remaining heating requirement is satisfied by the combustion of residual biomass. Hot combustion gases are also used to generate electricity, which meets the electricity requirement of the process, while the excess electricity is sold to the grid. We perform a technoeconomic analysis for the alkylphenol-based strategy and compare its economics with a previously reported strategy, in which butyl acetate was used as an extractive solvent to separate GVL from sulfuric acid following the LA hydrogenation step. With some improvements in the process configuration, the alkylphenol strategy leads to a minimum selling price (MSP) of $4.40 per gallon of gasoline equivalent (GGE) for compatible biofuel components, whereas the butyl acetate strategy leads to a MSP of $4.68 per GGE. We show that the alkylphenol strategy becomes a significantly better choice when the catalyst lifetime for the hydrogenation of LA becomes less than 6 months.

Process synthesis and analysis for catalytic conversion of lignocellulosic biomass to fuels: Separate conversion of cellulose and hemicellulose using 2-sec-butylphenol (SBP) solvent

“…We used an integrated method for the catalytic conversion of cellulose to butene oligomers (developed by Sen et al [38], Section 2.1) and developed an integrated method for the catalytic conversion of hemicellulose to butene oligomers (Section 2.2).…”

“…The cellulose-to-fuel conversion strategy [38] combines three catalytic conversion subsystems for the (i) conversion of cellulose to LA [48], (ii) LA reduction to GVL [42], and (iii) conversion of GVL to butene oligomer [32].…”

“…The catalytic process has advantages such as less expensive processing (than biochemical requiring significantly (32-40%) higher operating cost mainly due to high enzyme costs, 15-20% of the total production cost [8,34], despite slightly (3-4%) higher capital cost burden [35,36]) with high biofuels yields under milder processing conditions (than thermochemical operating at >573 K [37]). Sen et al [12,38,39] carried out studies for the synthesis and analysis of the liquid hydrocarbon fuel (butene oligomers) production from the catalytic conversion of the cellulose fraction of lignocellulosic biomass via sulfuric acid (SA) catalyzed hydrolysis of cellulose to levulinic acid (LA) followed by progressive catalytic upgrading to c-valerolactone (GVL) and butene oligomers. One key step in these processes was the removal of the hemicellulose fraction from lignocellulosic biomass using dilute SA pretreatment.…”

“…Moreover, the main challenge is separation of SA from the biomass-derived intermediates (LA and GVL) at low concentrations to prevent its negative effects on downstream catalytic conversion processes. They developed one method using an alkylphenol solvent (2-sec-butyl phenol (SBP)) that effectively extracts biomass-derived intermediates from the SA-containing aqueous phase [38], thus it can lead to an economically competitive alternative of downstream catalytic conversion despite the major potential drawbacks. To overcome these drawbacks, an integrated process was developed for the simultaneous catalytic conversion of hemicellulose and cellulose to butene oligomers [35].…”

Catalytic routes towards acrylic acid, adipic acid and ε-caprolactam starting from biorenewables

“…The technical improvements in levulinic acid production are increasing interest in the production of γ-valerolactone (GVL). For producing levulinic acid, a versatile platform chemical 116,117 and potential biofuel feedstock, 118 there are currently two main routes. One relies on the conversion of maleic anhydride and another is based on the hydrolysis of furfural derivatives.…”