关键词: 温和湿热条件, 碱性非碱溶液, 预处理, 玉米秸秆, 厌氧发酵, 沼气, 木质纤维素

Abstract: To provide an economic and effective preprocessiog method of corn straw,Dry yellow corn straw was used as feedstock.Four alkaline non-alkali solutions(Na₂CO₃,Na₂SO₃,K₂HPO₄,CaO₂,each had 3 gradients of 2%,4%,6%) were taken as pretreatment agents,no pretreatment as control,soaked in condition of TS content of 10% for 24 h,heated in 80℃ water bath kettle.The lignin,hemicellulose and cellulose content of straw,and COD(chemical oxygen demand)value and TVFA( total volatile fatty acid) content of aqueous extracts of straw and final biogas slurry after anaerobic fermentation,as well as the pH values of fermentation brothes, daily biogas yields and methane content of biogas during the anaerobic fermentation were analyzed.The results showed that,lignin,hemicellulose and cellulose content of corn straw decreased significantly after pretreament with alkaline non-aliki solutions under mild hydrothermal condition.For most pretreament groups,the biogas yields of unit solid and the peak methane content of biogas increased,pH values of fermentation brothes finally stabilized at 7.50—9.00.Among all groups,CaO₂ pretreament group could dissolve lignocellulose best,with the content of lignin,hemicellulose and cellulose decreasing by 59.75%, 69.61% and 47.09% respectively at most.For 2% CaO₂
pretreatment group,the best biogas production effect was got,with the biogas yield of unit solid reaching 291.8 mL/g and the peak of methane content of biogas increasing by 39.02%;COD value and TVFA content of the final biogas slurry of this group were also the lowest among all groups,decreasing by 56.25% and 61.45% compared with the control group respectively. Through analysis,it was found that types and concentrations of pretreatment solutions influenced the removal rates of lignocellulose of corn straw significantly,and both removal rates of lignocellulose and pretreament methods had influence on the anaerobic fermentation effect of corn straw,so comprehensive consideration should be conducted in the
actual production.

Key words: Mild hydrothermal condition, Alkaline non-alkai solution, Pretreatment, Corn straw, Anaerobic fermentation, Biogas, Lignocllulose