Assessment of hydrothermal pretreatment of various lignocellulosic biomass with CO2 catalyst for enhanced methane and hydrogen production. (1st September 2017)

• Record Type: Journal Article
• Authors: Eskicioglu, Cigdem; Monlau, Florian; Barakat, Abdellatif; Ferrer, Ivet; Kaparaju, Prasad; Trably, Eric; Carrère, Hélène
• Is Part Of: Water research. Volume 120(2017)
• Page Start: 32
• Page End: 42
• Publication Date: 2017-09-01
• Subjects: Anaerobic digestion -- Dark fermentation -- Straw -- Sorghum -- Corn stover -- Douglas fir bark; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2017.04.068
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Hydrothermal pretreatment of five lignocellulosic substrates (i.e. wheat straw, rice straw, biomass sorghum, corn stover and Douglas fir bark) were conducted in the presence of CO2 as a catalyst. To maximize disintegration and conversion into bioenergy (methane and hydrogen), pretreatment temperatures and subsequent pressures varied with a range of 26–175 °C, and 25–102 bars, respectively. Among lignin, cellulose and hemicelluloses, hydrothermal pretreatment caused the highest reduction (23–42%) in hemicelluloses while delignification was limited to only 0–12%. These reductions in structural integrity resulted in 20–30% faster hydrolysis rates during anaerobic digestion for the pretreated substrates of straws, sorghum, and corn stover while Douglas fir bark yielded 172% faster hydrolysis/digestion due to its highly refractory nature in the control. Furans and phenolic compounds formed in the pretreated hydrolyzates were below the inhibitory levels for methane and hydrogen production which had a range of 98–340 ml CH4 /g volatile solids (VS) and 5–26 ml H2 /g VS, respectively. Results indicated that hydrothermal pretreatment is able to accelerate the rate of biodegradation without generating high levels of inhibitory compounds while showing no discernible effect on ultimate biodegradation. Highlights: Hydrothermal pretreatment of lignocellulosic biomass for CH4 /H2 with CO2 catalyst. At 26–175 °C/25–102 bars, hemicellulose and lignin were reduced up to 42 and 12%. Rate of biomethane production was enhanced by 20–172% (substrate specific). Furans/phenolic by-products of pretreatment below the inhibitory levels for CH4 /H2 . No discernable effect on extent of biodegradation for straws, sorghum, corn stover.