Research Of Interchageability Of The Mixture Of Biogas And Natural Gas

With the speeding up of urbanization process in China, natural gas users and usageis also increasing. On the other hand, with the development of large and medium scalefarms spring up, livestock waste and industrial waste water are difficult to deal with. Ifwe make use of human and animal waste, or industrial waste water for making biogas,mixing with other gases, used as a load of gas source, not only can increase a town gassource, also implements the waste utilization, response to the national sustainabledevelopment strategy of national policy. Compared to other gases, biogas havesignificant advantages such as rich material sources, huge decelopment potential, can berecycled, and so on. So, if use biogas mixed with other gases, we can make up for theconsumption of natural gas gap, as a means of gas peak shaving gripper and realizeurban and rural plan as a whole.Use different ways such as wobbe index method, combustion index method, A.G.Aindex method, and weaver index method, to study the interchangeability problem ofmixtures of biogas mixed with ChongQing natural gas, and biogas mixed with AustraliaLNG. Simplify the biogas components as60%CH4+40%CO₂, gradually increase theproportion of biogas in the mixtures, and use the mixtures as replacement gas, carryon the interchangeabilitial theoretical calculation with12T natural gas （benchmarkgas）. When a certain mixing propotion under the interchangeability of judge indexbeyond the allowable range, that biogas mixing ratio has reached to allow mixinglimit. The research results show that wobbe index method, combustion index method,A.G.A index method, and weaver index method allowed limits of biogas mixingrespectively21.6%,12.8%,6.68%and6%. On the basis of the theoretical calculation,make a calculation software of gas interchangeability to solve other gases’sinterchangeabilty computational problems.Based on the theoretical calculation, conduct an experiment to study the combus-tion flame characteristics, thermal efficiency, heat load and flue gas composition etc. ofthe mixtures of biogas and ChongQing natural gas. The results show that when biogasmixing ratio is less than16%, the indicators are within the scope of the nationalstandards allowment.Conduct laminar flame propagation velocity experiment on a Bunsen burner, tostudy the changes of flame height and flame propagation speed when mixed natural gas with biogas. The results show that the flame propagation speed of mixture （84%ChongQing natural gas+16%biogas） is reduced by about9%than100%ChongQingnatural gas under the condition of the primary air coefficient is the same.Take a biogas comprehensive utilization engineering as an example, whick locatedat a cow farm which has1200cow every year, analyzed its economic benefit,environmental benefit and social benefit. The results show that the project can get aprofit of163300yuan every year, the biogas slurry is a high-quality crop fertilizer, andis beneficial to the environment.