Study On Gas Control Technology Of The Storage Of Wheat Straw Based On Anaerobic Fermentation

As a traditional agricultural producer,a large number of wheat straw was produced each year in China.The utilization of these straw resources can not only solve the air pollution caused by straw burning and random stacking such non-point source pollution and other environmental problems.The utilization of straw and livestock manure together anaerobic fermentation to produce methane can effectively alleviate the energy problems facing today.The comprehensive utilization of straw resources should first solve the collection,storage and transportation of straw.In this paper,wheat straw is selected as the experimental material,and study how to store wheat straw effectively and promote the methane production of wheat straw anaerobic fermentation at later stage.Under the sealed condition,the gas in the wheat straw and the environment is replaced by the carbon dioxide gas.The oxygen content in the air of the wheat straw is reduced,resulting in an anaerobic environment,reducing the number of aerobic respiratory saprophytic bacteria and avoiding the aerobic respiration.The production of low temperature create the conditions inhibit the growth of other microorganisms,in the end,achieve the purpose of wheat straw preservation.The experiment is in the indoor circumstance,gas replacement method was studied in water content of 45%,55%,65%,75%of wheat straw,the influence of different gas oxygen partial pressure of 5%,9%,13%,17%for 30 days.60 days,90 days of wheat straw storage,mainly analyses the lost of straw weight during the process of storage and the lost rate of cellulose and hemicelluloses,studying the pH,DOC,DN,SCOD,the quantity of bacteria,actinomycetes and fungi changes of physicochemical properties of water extract.And the physical structure of wheat straw was analyzed by Fourier transform infrared spectroscopy,scanning electron microscopy,XRD diffraction and thermogravimetric analysis.The main results are as follows:1.Under the same moisture content,the dry matter lost of wheat straw can be effectively reduced by gas-regulated storage.The dry matter lost ratio of CK wheat straw is 36.73%for one month.In contrast,oxygen partial pressure of 13%and 17%,he dry matter weight lost was only 13%and 11%,respectively compared with the control decreased by 25.15%and 26.67%;also effectively reduce the loss of cellulose and hemicellulose,for the final anaerobic fermentation to ensure adequate nutritional conditions.The more times of carbon dioxide gas regulation,the lower the oxygen partial pressure in the storage environment,the less the organic loss of wheat straw,the more beneficial to the storage of wheat straw.Under the same gas regulation times,the higher the water content,the more wheat straw lost,the lower the cellulose and hemicellulose content.And as the time goes on,the wheat straw rotten degree will increase,the wheat straw preserved best was stored for 30 days.2.Compared with the wheat straw without gas regulation,the amount of bacteria,fungi and actinomycetes contained in the wheat straw treated by gas regulation was obviously reduced,which indicated that the wheat straw had better storage effect.Through the analysis of physicochemical properties of water extract of different treatment of wheat straw,also shows that the carbon dioxide gas regulated storage of wheat straw to get more organic carbon and organic nitrogen,is conducive to the anaerobic fermentation.The more times of carbon dioxide gas regulation is,the more beneficial for the storage of wheat straw.3.Dealing the different treatment wheat straw with Fourier infrared transform,scanning electron microscope,XRD diffraction and thermogravimetric analysis found that the wheat straw with the carbon dioxide gas regulated shows the best storage effect,and the lower oxygen environment could effectively prevent the straw from degrading and save more,and it was found that can save more fiber structures.The more times of carbon dioxide gas regulation is,the more lost of the wheat straw is.4.The biogas of wheat straw with different treatment was produced by anaerobic fermentation.The gas-regulated wheat straw produced a higher methane production potential,and the lower the oxygen partial pressure in the storage environment,the higher the gas production efficiency.The gas production of wheat straw contained 75%water under the conditions the 13%oxygen partial pressure than the 17%oxygen partial pressure increased by 11.9%.In summary,compared with the wheat straw without gas conditioning storage,the gas regulation can effectively store the straw,reduce the organic loss of straw,save most of the active ingredients such as cellulose and hemicellulose,and preserve the organic carbon source for the final anaerobic fermentation.The more times of carbon dioxide gas regulation,the more beneficial for the storage of wheat straw,and the gas production of anaerobic fermentation also increase.