Study On The Influence Of Anaerobic Microbial Conversion Of Syngas On High Value Utilization

With the development of society,the global energy demand is also increasing,and the more efficient use of various energy sources has become an urgent hope.China is a typical resource structure with multiple coals,lean oil and less gas.How to use synthetic gas efficiently is of great significance to China's reasonable energy layout.This study focused on the high-efficiency and high-value utilization of syngas anaerobic fermentation.The main experimental conclusions are as follows:(1)The effects of temperature,pH,operating load,etc.on the acid production of anaerobic microorganisms using syngas were investigated.Under the fermentation conditions of room temperature,low load and constant pH 9,the amount of TVFA reached 1003.7 mg/L when the amount of syngas was 5 L/d,and the acetic acid was in TVFA at each stage after the introduction of syngas.The proportion has reached more than 80%.Under the fermentation conditions of medium temperature and low load and constant pH 9,there is a large amount of methane in the system,which is good for synthesizing gas to produce acid.When the amount of syngas is 5L/d,the amount of TVFA is only 385.8 mg/L..The experimental results show that the fermentation conditions with room temperature,low load and constant pH 9 are more suitable for the microbial utilization of syngas to produce acetic acid.Under this condition,the microbial conversion of synthesis gas to produce acetic acid with high efficiency has the feasibility of long-term stable operation.(2)The addition of decyl alcohol slag pyrolysis carbon,wood chip pyrolytic carbon,zeolite powder,bentonite,magnet powder,zero-valent iron,granular activated carbon,suspended bio-filler,polyurethane bio-filler and brown mineral was investigated.Oxygen fermentation conversion efficiency,product and microbial community structure.Among them,the addition of magnet powder,brown mineral,wood pyrolysis carbon and zeolite powder significantly promoted the system to absorb CO and methane,which increased the yield of methane by 99.0%,90.8%,54.6%and 44.4%,respectively.The addition of suspended bio-filler and polyurethane bio-filler significantly inhibited the system's methanogenesis,and promoted the acid production of the system.Compared with the blank group,the acid yield increased by 130.0%and 192.9%,respectively.The pyrolysis of carbon,bentonite,zero-valent iron and granular activated carbon of decyl alcohol residue did not have a significant effect on the anaerobic fermentation system.Analysis of archaea by high-throughput sequencing revealed that Methanosarcina was dominant in all samples,indicating that it can survive well in an anaerobic environment with CO.Analysis of the bacterial flora showed that the proportion of Actinobacteria and Proteobacteria increased significantly after the introduction of CO,indicating that these bacteria can survive well in the anaerobic environment in which CO is introduced compared to other bacteria.(3)The feasibility and efficiency of co-fermentation of methane by syngas and kitchen waste under medium temperature and high temperature conditions were investigated,and the effects of different fermentation conditions on microbial community structure were studied.The study found that the H2 and CO absorption rates were higher than 96%at each stage after the introduction of syngas,and the TS decreased from 2.60(medium temperature)and 1.69(high temperature)to 1.24 and 1.22,respectively,indicating that it can be used in the anaerobic reactor.At the same time,two processes of bio-methanation of syngas and kitchen waste are realized,and the addition of syngas accelerates the hydrolysis and acid production stages.In addition,when the syngas feed rate is 3L/d under high temperature conditions,the methane production reaches 7143.5 mL,which is 17.9%higher than the methanogenic amount under the medium temperature condition,indicating that the high temperature condition is more suitable for the synthesis gas fermentation.Methane.The microbial community was analyzed by high-throughput sequencing technology.The results showed that the high-temperature archaea group was dominated by Methanosarcina,while the mesophilic archaea was dominated by Methanosaeta.Because Methanosarcina produces methane mainly through hydrogen-consuming pathways,Methanosaeta produces methane mainly through the acetic acid-consuming pathway,which indicates that in high-temperature environment,the process of anaerobic fermentation of methane by the kitchen is dominated by hydrogen-consuming methanogenesis,while in the medium-temperature environment.The next step is to use acetic acid to produce methane.