Co2-ecbm developments in experiments
In order to understand CO2-ECBM, sorption, diffusion, wettability and swelling results from experiments on the coal-CO2-CH2-H2O systems are compared and explained. Variation in sorption methods and procedures make comparison of results complex to compare. To improve experimental precision, for CO2 sorption in particular, accurate pressure and temperature measurements under super critical conditions are essential. Additionally, swelling behavior of coal can change volumes. Ash content, maceral type, degree of coalification and pressure variations change the wettability of coal. Hence, wettability experiments at scales varying from nanometer- to centimeter-range, and three different methods of swelling measurements, are discussed. The swelling experiments are also used to determine swelling induced cleat permeability and associated stress built-up. Since the experiments take months and are very expensive, institutes must find agreement how to regulate measurements and results. The results are valuable input parameters for modeling.