Study Of Characteristics And Prediction Of CH₄,CO₂,N₂ And Binary GAS Adsorption On Coals And CO₂/CH₄ Replacement

Adsorption characteristics and adsorbed amount prediction of CH₄,C0₂, N₂ single and binary gas on coals have been studied comprehensively on the basis of experiments and literature data with computer program from the point of view of Physical Chemistry, Interface Chemistry, Coal Chemistry, Coal Quality, Coal Petrology and so on in the paper. Finally, the properties of adsorbed methane displacement with carbon dioxide and enhanced coalbed methane recovery and C0₂ sequestration in China' s coal have been investigated primarily in the paper.First of all, adsorption/desorption characteristics of CH₄, C0₂, N₂ pure and binary gas adsorption on Jincheng coal and Luan coal has been studied, and then, the eight different models viz. Langmuir, BET, DA, DR, Toth, Freundlich, Expended-Langmuir, Langmuir-Freundlich and three curvilinear equations viz. quadratic equation, cubic equation and logarithmic equation were used to fit the experimental and literature data of CH₄, C0₂, N₂ adsorption on coals by SPSS software, linear regression and iterative method. Expended Langmuir, Ideal adsorption Solution Theory and Real adsorption Solution Theory combined with pure gas absorption isotherms equation viz. Langmuir, DA, DR, BET were employed to predict the adsorbed amount of C0₂/CH₄ adsorption on coals on the conditions of known and unknown compositions concentration in the free phase. The linear regression relation between the Langmuir adsorption constants and adsorption ratio of CO₂/CH₄ or CH4/N2 and coal quality indexes were studied with SPSS software. The primary experimental study about enhanced coalbed methane recovery with C0₂ injection with the founded experimental equipment simulating C0₂-ECBM technology, and the interaction between C0₂ injected into coal and mineral matter in coal was studied primarily in the paper.In the light of the adsorption isotherms and predicted results of CH₄, C0₂, N₂ and their mixtures, the coal micropore structure and gases adsorption characteristics on coal can be known on the whole. The studied results in the paper improve gases adsorption theory on coal, and provide the theoretical basis and prediction method for CO₂-ECBM, and supply the technique or method for ECBM and C0₂ sequestration with C0₂-ECBM.