Research On The Inlfuence Of Mixed Material On Biogas Production By Anaerobic Fermentation

Compared with anaerobic ferment of single material, regionalism and seasonality ofmaterial influence mix anaerobic ferment little and remedy the incomplete defect of singlenutritional materials, so mix anaerobic ferment is recently one hot spot in the research field.Cow dung is common material in the process of fermenting methane, its carbon and nitrogensuit anaerobic fermentation and microbial population is rich, but the number of crude fibre ishuge, easily degradable material is little, available nutrient is not huge. Mix the cow dungkitchen waste and maize straw into anaerobic fermentation can increase the productivity ofbiogas production, reduce the pollution of the environment, and provide a way of reclamationand minimization for the kitchen waste at the same time.This thesis analyses three kinds of materials in physicochemical property. Include theexperiment of mixing two kinds material and three material, Analysing the influence of gas production rate in different mixing proportion to get a suitable technological conditions. Thefollowing conclusion according to the tests:(1) In the fermentation condition of constant temperature anaerobic of35±1℃. TS adjustmentof8%,inoculum size of25%, cow dung and maize straw can both product gas normally. Disposekitchen waste by anaerobic fermentation,especially it can cause the accumulation of volatile fattyacids with single-phase reactor.(2) crude fibre of cow dung and maize straw is huge, and available nutrient is low, but ithas stationary, temperament, buffer ability stable system in this process. It influence the stablesystem when we put maize straw in it, microbial flora needs time to adapt, the gas productionrate of TS does not improve remarkable. Organics of kitchen waste is high, it is biodegradableand can produce more CH4.It can produce more gas of mixture in the suitable environment.(3)The influence of mixed concentration and double-factor to the gas production rate.When the concentration of fermentation is certain, gas production rate is close to the mixingratio. When the purity of kitchen waste is between0.1and0.2, gas production rate increasesaccording to the increase of concentration of fermentation; When the purity of kitchen waste is between0.2and0.4, gas production rate fall according to the increase of concentration of thefermentation.(4)According to the total volume, to make multiple regression fitting by using responsesurface optimization and then get a equation of linear regression of three material.The parameteris: raw material ratio(content of kitchen)=1:0.6:0.4(22%)；concentration of TS=9.9%. The bestgas production rate is87.18L. To check the result,the authentication value is less than1%,theresult is reasonable.