375 / 2018-07-31 01:02:27

Can hydrothermal pretreatment improve anaerobic digestion for biogas from lignocellulosic biomass?

全体主题 > 生物质燃气

In order to elucidate the feasibility of hydrothermal pretreatment in anaerobic digestion of lignocellulosic biomass, hydrothermally-pretreated rice straw (HPRS) from various pretreatment temperatures (90, 150, 180 and 210℃, respectively; retention time was 15 min) was anaerobically-digested in whole slurry. Biogas yield, system stability and the effect of soluble fractions on methane yield were investigated. Results indicated promoting pretreatment temperature significantly deconstructed rice straw, and facilitated the conversion of insoluble fractions to soluble fractions. Although 306.6 mL/g TS biogas was maximally yielded in HPRS-90 and HPRS-180 at organic loading of 35 g TS/L, respectively, via digestion in whole slurry, it was only 3% promotion compared to the unpretreated rice straw. HPRS-210 yielded 208.5 mL/g TS biogas, which was 30% reduction with longer lag period of 19.8 d, suggesting serious inhibitions happened. Through slightly increasing organic loading to 50 g TS/L, more serious acidification and reduction on biogas yield could be observed, especially at higher pretreatment temperatures, indicated the soluble fractions controlled digestion performances. Pearson correlation analysis suggested negative relationship existed between methane yield and the soluble fractions including soluble carbohydrates, formic acid and furfural. Hydrothermal pretreatment, especially at higher temperature, did not improve anaerobic digestion performance, thereby, was not recommended, however, lower temperature can be considered potentially.