Research On Biogas Production Process Of Constant-temperatured Dry Anaerobic Fermentation With Mixed Biomass

Anaerobic fermentation is an effective way to realize energy recycling and recycling of organic agricultural and animal husbandry wastes such as straw,fruit and vegetable wastes and livestock manure.Dry anaerobic fermentation has attracted widespread attention due to its strong organic load handling capacity,low biogas slurry discharge,and flexible application.At present,there have been some studies on dry anaerobic fermentation of single raw material s at home and abroad.Mixed raw materials not only help to ensure the nutritional balance of anaerobic fermentation,but also conducive to engineering applications.However,there are few studies on the constant temperature dry fermentation of mixed raw ma terials at home and abroad.In this study,the mixed materials of cow manure and corn stover,cow manure and cabbage leaves were taken as the research object.Their dry anaerobic fermentation production under mesophile temperature（37±1°C）and thermophile temperature（52±1°C）was studied respectively.During the biogas process,the p H,ammonia nitrogen content,daily biogas production,methane content,cumulative gas production,and cumulative methane production parameters when the dry anaerobic fermentation at 0,10%,20%,30%,and 40%inoculation were studied.Combining the experimental results with the modified Gompertz model to analyze the biogas potential of the mixed raw materials.The main research contents and conclusions are as follows:（1）When cow manure was mixed with corn stover at mesophile temperature（37±1°C）,the inoculum amount had a significant effect on the start of anaerobic fermentation process,the peak of gas production,cumulative gas production,p H value and ammonia nitrogen content.The higher the inoculum amount,the faster the anaerobic fermentation starts and the sooner the peak of gas production comes,the higher the cumulative gas production,the higher the cumulative methane production,and the ammonia nitrogen content is more i n the normal range.When the inoculation volume was 40%,the TS and VS gas yields of dry fermentation of cow manure and corn stover under mesophile temperature were the highest,which were 203.4 m L·g^-1and 289.1 m L·g^-1,respectively.（2）When the cow manure was mixed with cabbage leaves under mesophile temperature（37±1°C）,the inoculation amount also had a significant effect on the initiation of anaerobic fermentation process,peak gas production,cumulative gas production,p H value and ammonia nitrogen co ntent.Unlike cow dung mixed with corn stovers,there is no obvious gas peak during dry fermentation of cow manure and cabbage leaves.When the inoculation amount is 30%,the dry fermentation of mixed raw materials starts at the fastest rate,and the cumul ative gas production and organic matter utilization rate are the highest.The p H value and ammonia nitrogen content were within the normal range.TS and VS had the highest gas yields,which were159.9 m L·g^-1 and 224.8 m L·g^-1,respectively.（3）Compared with the anaerobic fermentation process at mesophile temperature,the start-up speed of anaerobic fermentation of cow manure and corn stover or cow manure and cabbage leaves was faster at thermophile temperature（52±1°C）and the peak of gas production was advanced.The cumulative gas production was increased.And,the p H and ammonia nitrogen content are within the normal range.When the inoculum amount was 40%,the TS and VS produced by dry fermentation of cow dung and corn stover at the highest temperature were the highest,which were 257.4 m L·g^-1and 358.7 m L·g^-1,respectively.When the inoculation amount was 30%at thermophile temperature,TS and VS had the highest gas yields,which were 178.1 m L·g^-1 and250.3 m L·g^-1,respectively.（4）The temperature and inoculum amount had a certain influence on the TS/VS removal rate of each experimental group.For the dry fermentation of cow manure and corn stover,the higher the inoculum amounte,the higher the temperature,the higher the TS/VS removal rate,and the TS/VS removal rate at 40%inoculation amount at thermophile temperature was 61.20%and 60.07%.For the dry fermentation of cow manure and cabbage leaves,the highest TS/VS removal rate was 34.90%and 60.56%at 30%inoculation amount under thermophile temperature conditions.（5）The analysis results of the modified Gompertz model are consistent with the above experimental results.Therefore,thermophile temperature anaerobic fermentation is recommended for dry fermentation of cow manure and corn stover.For the dry fermentation of cow manure and cabbage leaves,from the perspective of energy conservation,since the experimental values under thermophile tempera ture conditions all reach the predicted value,it is recommended to use anaerobic fermentation at mesophile temperature.From the point of view of cumulative gas production and organic matter utilization rate,each test under thermophile temperature conditions has improved compared to the mesophile temperature control group,and high temperature anaerobic fermentation is recommended.The subject innovation points:It was revealed that during the dry anaerobic fermentation of cow manure and corn stover,cow manure and cabbage leaves under mesophile temperature（37±1°C）and thermophile temperature（52±1°C）conditions,the inoculum amount influenced the p H value,ammonia nitrogen content of the fermentation process,the methane content,cumulative gas production and cumulative methane production.According to the test results,it provides guidance for more efficient disposal of such wastes.