Isothermal adsorption model of coalbed methane

WU Yawen; PAN Jienan

doi:10.13225/j.cnki.jccs.2017.1267

Abstract：China is relatively rich in coalbed methane.A better estimation of maximum adsorption capacity and recovery ratio is based on a better understanding of isothermal adsorption curve.This paper is going to make a comparative study on Langmuir equation,the representative theory of monolayer adsorption theory,and DR equation,which is based on micropore filling theory on an attempt to find a more suitable model fitting equation.Data of the coal sample from four different coal ranks (R from 0.60％ to 3.18％) are fitted.The result shows that VL and PL would be more accurate in physical significance and the equation fitting would be more meaningful if the two parameters are calculated before fitted;the accuracy of other parameters is improved while Vo in DR equation is calculated;and Amankwah method is the most suitable method for calculating P0 after a comparison of five calculation methods by introducing the concept of virtual saturated vapor pressure.DR equation works better in fitting effect and comes nearer to the actual data after a comparison between Langmuir and DR equation.