鄂尔多斯盆地延川南区块煤炭地下气化产气潜力评价OA

Underground coal gasification(UCG)technology is an important part of realizing green mining of coal resources and fluidization mining of deep coal resources.UCG experimental research is helpful to promote its industrial application and provide theoretical support.In this paper,2#coal seam in Yanchuannan block of Ordos Basin is taken as the research object.Through UCG physical simulation experiments,the dynamic change characteristics of temperature and pressure and the composition characteristics of syngas in the process of lean coal gasification under different gasification agent ratios were explored.The DRYING,BURNING and DECOMP1 modules in Aspen Plus software were used to simulate the drying process,oxidation reaction and reduction reaction of coal samples,respectively.The effects of coal type and oxygen(O2)concentration on the effective components of UCG gas production were systematically analyzed,and the gas production in the study area was calculated.The results of physical simulation experiments show that with the increase of O2 concentration in the gasification agent,the average relative content of H2,CO,CH4 and CO2 and the calorific value of gas all show a trend of first decreasing and then increasing,while the average relative content of N2 increases first and then decreases.In addition,the increase of O2 concentration promotes the temperature rise in the gasifier,and the flow difference gradually expands,which indirectly indicates that the gas production capacity has been enhanced.Under the combined action of temperature and gas production capacity,the pressure in the furnace also continues to increase.The numerical simulation results show that the effective component yield of lean coal is the highest,followed by anthracite,lean coal and coking coal.When the O2 concentration in the gasification agent is 50%,60%,70%,80%,90%and 100%,the corresponding predicted gas production is 23509.44 billion Nm3,2162.519 billion Nm3,19793.20 billion Nm3,18015.02 billion Nm3,16289.81 billion Nm3 and 1461.414 billion Nm3,respectively.Furthermore,with the increase of O2 concentration,the proportion of effective components in the output gas continues to rise,but its growth rate shows a trend of increasing first and then decreasing,and the turning point is at 90%O2 concentration.Considering the economic factors,it is suggested that the oxygen concentration in the gasification agent should be set to 80%during underground coal gasification of the No.2#coal seam in the southern block of Yanchuan.Under these conditions,the production of H2,CO and CH4 accounted for 12.45%,35.20%and 3.33%,respectively.The combined proportion of these effective components exceeded 50%,indicative of favorable development benefits.