Study On Anaerobic Digestion Characteristics Of Several Straws

Straw is mainly composed of cellulose,hemicellulose and lignin.The complicated structure of lignocellulose leads to a more complicated anaerobic digestion and degradation process of straw,and the raw material gas production rate is not high.At the same time,the amount of cellulose,hemicellulose and lignin contained in different straws is also different,resulting in a large difference in digestion effect and biogas production performance,which has become a limiting factor for the large-scale production of biogas using straw.Therefore,exploring the relationship between straw anaerobic digestion characteristics and the relationship between lignocellulose composition and anaerobic digestion performance is the basis for scientific utilization of straw bioenergy.In this paper,corn stalks are used as the research object to study the effects of fermentation concentration,temperature,raw material particle size,and inoculation amount on the anaerobic digestion of corn stalks,to obtain the best process conditions for anaerobic digestion of corn stalks;Corn stalks,reed stalks,and cotton stalks are the research objects.The relationship between the lignocellulose composition of different straws and anaerobic digestion is studied to provide a basis for the rational development of anaerobic digestion of crop straws.The research results are as follows:（1）The optimal fermentation concentration for anaerobic digestion of corn stover is 6%.The greater the fermentation concentration,the lower the methanogenic efficiency,and the HRT will be extended.The fermentation temperature of corn stover anaerobic digestion is in the range of 25℃³8℃,and the optimal methanogenic temperature is 35℃.Increasing the fermentation temperature is beneficial to the anaerobic digestion of straw,but the fermentation temperature is38℃.Gas production efficiency is low.（2）When anaerobic digestion of corn stover has a particle size of 5-15mm,the cumulative gas production,VS methane production rate and average methane content are the highest,and the gas production effect is the best,so 5-15mm can be used as the recommended particle size.The optimal inoculation volume of corn stover anaerobic digestion is 35%.Increasing the inoculation volume is beneficial to the anaerobic digestion of corn stover.However,as the increase of inoculation volume affects the enrichment of methane bacteria,the inoculation volume is 40%average,the content is not high.（3）Anaerobic digestion experiments were carried out on rapeseed straw,ryegrass straw,corn straw,reed straw,and cotton straw under the same fermentation conditions.The experiment found that:ryegrass had the best gas production effect,and the TS gas production rate was 613mL·g^-1.The cotton straw has the worst gas production effect,and the TS gas production rate is 161mL·g^-1.According to the determination of the lignocellulose content of the five straws,the gas production efficiency of the straw is positively correlated with hemicellulose and negatively correlated with lignin;the higher lignin of the straw is not conducive to the biodegradation of the straw,but the hemicellulose of the straw is more Gaoyue is beneficial to the energy conversion of straw.