以晋城无烟煤为研究对象,进行了30℃时煤对甲烷和氮气的吸附解吸试验。基于吸附特性曲线的唯一性特点,根据30℃甲烷的吸附解吸数据,以吸附势理论为依据,预测了50℃时甲烷的等温吸附曲线,结果表明预测曲线与实测曲线吻合良好,其预测值平均绝对误差为0.5 cm3/g,平均相对误差为3.12%。同时依据30℃时氮气和甲烷的吸附特性曲线,发现氮气和甲烷的吸附势对应压力在0.61 MPa时存在交点,表明压力低于0.61 MPa时氮气的吸附势高于甲烷的吸附势,此时注入氮气对提高煤层气的增产具有促进作用,这为煤储层在N2-ECBM(注氮增产法)过程中确定氮气的注气压力范围提供了初步的理论依据。

Taking the Jincheng anthracite coal as the study object, the methane and nitrogen adsorption and desorption experiments were conducted at 30 °C. Base d on the uniqueness of adsorption characteristic curve, according to the adsorption and desorption data of 30。C, with the adsorption potential theory as the basis, the methane isothermal adsorption curve at 50。C was predicted.The results showed that the predicted curve and the site measured curve could be well fitted, the average absolute error of the predicted vaule was 0.5 cm3/g and the average relative error was 3.12% .Meanwhile according to the adsorption feature curves of nitrogen and met hane at 30。C, there would be a cross point at the corresponding pressure of 0.61 MPa between the nitrogen and methane adsorption characteristic curves.Thus when t he pressure was lower than 0.61 MPa, the adsorption potential of nitrogen would be higher than the adsorption potential of the methane.The nitrogen injection would pl ay a promotion role to improve the production of the coal bed methane.Therefore, a preliminary theoretical basis could be provided to determine the nitrogen injection p ressure range during the N2-ECBM process of the coal reservoir.

国家重点基础研究发展规划(973计划)资助项目(2009CB219605)；国家科技重大专项资助项目(2008ZX05034)；国家自然科学基金重点资助项目(40730422)；国家自然科学基金青年科学基金资助项目(40802032)；