Maximizing the liquid fuel yield in a biorefining process

Abstract

Biorefining strives to recover the maximum value from each fraction, at minimum energy cost. In order to seek an unbiased and thorough assessment of the alleged opportunity offered by biomass fuels, the direct conversion of various lignocellulosic biomass was studied: aspen pulp wood (Populus tremuloides), aspen wood pretreated with dilute acid, aspen lignin, aspen logging residues, corn stalk, corn spathe, corn cob, corn stover, corn stover pellet, corn stover pretreated with dilute acid, and lignin extracted from corn stover. Besides the heating rate, the yield of liquid products was found to be dependent on the final liquefaction temperature and the length of liquefaction time. The major compounds of the liquid products from various origins were identified by GC-MS. The lignin was found to be a good candidate for the liquefaction process, and biomass fractionation was necessary to maximize the yield of the liquid bio-fuel. The results suggest a biorefinery process accompanying pretreatment, fermentation to ethanol, liquefaction to bio-crude oil, and other thermo-conversion technologies, such as gasification. Other biorefinery options, including supercritical water gasification and the effectual utilization of the bio-crude oil, are also addressed.

Selected Process Alternatives for Biomass Refining: A Review

“…[27] by pyrolysis, liquefaction and gasification, including the postprocessing of synthesis gas to yield methanol and Fischer-Tropsch liquid fuels [3]. Fast pyrolysis of LCM leads to renewable solvents, monomers suitable as building blocks for polymers and other industrial chemicals [23]; whereas liquefaction leads to crude oils [28] which can yield chemicals upon refining.…”

“…For example, certain types of lignin can be good substrates for liquefaction [28], whereas the production of higher alcohols can be achieved from both methanol (see Fig. 1) and ethanol (see Fig.…”

“…-decrease of the overall energy intensity of the biorefinery's unit operations, for example by using energyefficient separation technologies such as membranes [38,39], -management of the environmental challenges, particularly the decrease of greenhouse gas emissions [19] and mitigation of global warming [9], -recovery of maximum value from each fraction of the feedstock at a minimum cost [28], -increasing the potential to achieve even lower costs in the longer term,…”

“…This latter possibility is specially interesting because in terms of energy recovery from pulping liquors, lignin has a relatively high heating value (27.0 MJ/kg), but the heating value of hemicelluloses is just about one half of this value, and extracting hemicelluloses prior to pulping could potentially boost the industry [52], b. possibility of producing monomeric sugars that can be fermented into ethanol [2], and producing bioethanol, biohydrogen and biogas from waste streams or hydrolyzates [30,53], c. possibility of converting the lignin-rich fermentation residues and low quality biomass residues into syngas that can be used to produce liquid fuels [2], d. utilization of lignin for producing chemicals such as organic acids [54], e. gasifying the biomass or lignin-rich spent pulping liquors for the production of liquid fuels [28], f. incorporation of new technologies for processing, reaction and separations [55,56], alternatives to classical solvents like supercritical fluids, near-critical and supercritical water and water systems (ionic liquids, biphasic and bio-sourced solvents), microwave treatment, sonochemistry, electrochemistry and photochemistry, g. recovery of valuable compounds (such as vanillin, syringol, and syringaldehyde) from pulping liquors by new technologies [20,40] or direct production of selected chemicals (levulinic acid, lactic acid), h. manufacture of chemicals such as by means of depolymerization and dehydration reactions (for example, in nearcritical water) [40], i. manufacture of advanced materials by fermentation (for example, bioplastics), from cellulose-enriched materials [57] and/or lignin (composites) or cellulose nanocrystals for nanotechnology applications.…”

Hot-water pretreatment of cattails for extraction of cellulose

“…Consequently, a serious interest in alternative energy sources is now being fostered for reducing dependence on non-renewable foreign energy sources. One such measure is the conversion of under-utilized lignocellulosic biomass sources, such as corn stover, bagasse, pulp and paper waste, switchgrass and the like, into liquid fuels and chemicals that can partially replace petroleum and petrochemicals [2][3][4][5][6][7].…”