An Experimental Study On Straw Pretreatment Technology And The Characteristics Of Biogas Production

Straw takes an important part in biomass and is one of the main sources of biomass. Straw resources are very rich in our country,but most are open-air burned,thus not only cause air pollution,but also make the source of biomass serious waste. The effluent from anaerobic digestion was used in this experiment for the straw pretreatment.An orthogonal experiment program was carried out to use a method of chemical and biological which pretreats straw to degradate lignocellulose of straw, and use the straw which has pretreated by the method of chemical and biological to produce biogas with the new method.After the straw has pretreated by the method of chemical and biological, the straw for lignin content, the fiber content and hemicellulose content and so on are measured, the results show that biological pretreatment and chemical pretreatment can degrade the straw of internal parts of lignin, hemicellulose, cellulose and lignin degradation rates is the highest;The straw which has pretreated by the method of chemical and biological can destroy a certain extent, the bond between lignin and carbohydrates and lignin structure, and generate more small molecules or soluble carbohydrate.The subject for straw anaerobic digestion producing biogas technology is investigated. First,the topic has studied by the efficiency of straw in anaerobic digestion and the impact of biogas production which straw had pretreated by biological pretreatment with biological pretreatment time, straw longth and anaerobic digestion temperature not at the same time; Then, the topic has studied by the efficiency of straw in anaerobic digestion and the impact of biogas production which straw had pretreated by chemical pretreatment with the concentration of NaOH pretreatment, straw longth and anaerobic digestion temperature not at the same time, the optimum conditions for anaerobic digestion.Through research, this paper draws the following conclusion:(1) After straw had been pretreated by biological pretreatment and chemical pretreatment which has been anaerobic digestion in different particle longth,2-3cm diameter of straw under the cumulative biogas production of anaerobic digestion is better than 10-12cm,8-10cm and 5-7cm diameter under the cumulative biogas production of anaerobic digestion.(2) Straw by biological pretreatment and chemical pretreatment has been anaerobic digestion experiment in ambient temperature and mesophilict temperature, the results show that:the condition of anaerobic digestion accumulation biogas production in mesophilict temperature is superior to the condition of anaerobic digestion accumulation biogas production in ambient temperature, and the biggest increase rate is 103.9%.(3) Learning from two of the pre-tanaka natural dried straw and rotten straw which have been pretreated by biological pretreatment in 15d,30d,45d and 60d have been anaerobic digestion experiment, the results show that:in ambient temperature and mesophilict temperature, pre-tanaka natural dried straw is always the highest cumulative gas production by biological pretreatment 15d; In ambient temperature, rotten straw is always the highest cumulative biogas production by biological pretreatment 30d;Then in mesophilict temperature,rotten straw is always the highest cumulative biogas production by biological pretreatment 15d.(4) Straw by quality score 2.5%,5.0%,7.5% and 10% NaOH pretreatment has been anaerobic digestion experiment, the results show that:in ambient temperature,straw by NaOH pretreatment in quality score 5.0% is always the highest cumulative biogas production, then in mesophilict temperature, straw by NaOH pretreatment in quality score 7.5% is always the highest cumulative biogas production.Straw by biological pretreatment carried out a feasibility analysis biogas production of anaerobic digestion from the feasibility of operation costs, operating income, saving energy expenditure, and environmental benefit and environment economic benefit,the analysis shows that: straw as main raw materials through biological pretreatment used in large-scale production of biological biogas is economical and feasible method, and has good realistic significance for popularization.