Study On The Influence Of Gas Injection On The Synergistic Variation Of Gas Pressure And Concentration

Aerobic-ventilation is the primaly way to rapidly degrade garbage landfills site,which is usually completed by injecting air into the garbage soil through gas wells.Affected by the storage condition of garbage soil,the multi-component gas in the garbage soil will undergo migration and chemical reactions during the process of gas injection.Therefore,The research on the pattern is the coordinated change between the pressure and concentration of the multi-component gas in the garbage soil during the gas injection process,has important practical significance for the efficient operation and management of aerobic-ventilation projects.Based on the aerobic-ventilated indoor and on-site tests of garbage soil,the paper carried out the monitoring test of multi-component gas pressure and concentration during the process of gas injection,which analyzed the quantitative characterization models between gas pressure and concentration during the process.Through the indoor test,the research was done about the monitoring test of the pressure and concentration of the multi-component gas in the anaerobic and aerobic phase;In the gas injection test,it was done about a monitoring test of the pressure and concentration changes of multi-component gases in the garbage soil during the process of gas injection of single well.The main findings are as follows:(1)The indoor test used the aerobic-ventilation simulation test system for garbage soil to carry out study on the characterization relationship between the pressure and concentration of each component gas in the aerobic and aerobic degradation environment,that is developed by the Wuhan Institute of Rock and Soil Mechanics,Chinese Academy of Sciences-Hong Kong Poly U Joint Laboratory on Solid Waste Science(IRSM-CAS/HK Poly U Joint Laboratory on Solid Waste Science),The test results of groups Ⅰ and Ⅱ show that the pressure value and concentration of each component gas will be obtained in both the anaerobic stage and the aerobic stage.The characterization relationship is linear,and it is obtained about the modified equation of state(MES).(2)Field tests were done at the Chibi Landfill(Group A)and Beiyangqiao Landfill(Group B),which is about gas injection tests under different strength conditions,and analyzed the pressure and concentration synergy of multiple component gases.The changing relationship is got on the comparative analysis of the ES model and the MES model,that is based on the results of two sets of on-site gas injection experiments.The gas pressure values calculated by the ES model are all higher;Simultaneously,it preliminarily verify that is reliable about the revised gas state equation proposed in the paper.(3)Comsol Multiphysics software was used to carry out numerical simulations on two sets of on-site gas injection experiments.The simulation results showed,with the continuous gas injection,the gas pressure in the garbage showed a law of increasing-gradually slowing down-tending to be stab.In simulating the field test of Group A,when the landfill depth is about 11 m,and the model length is about 30 m,the simulation results are closer to the field monitoring results.The pressure at 6 m obtained by field test and simulation is 101396 Pa and101777 Pa,respectively,about 6～7 h.In simulating the field test of Group B,when the landfill depth is about 10 m,and the model length is about 80 m,the simulation results are closer to the field monitoring results.The pressure at 6 m obtained from the field test and simulation is101540 Pa and 101853 Pa,respectively,about 33～34 h.