Preliminary Study Of Concentrating Coalbed Methane By Adsorption

Concentrating coalbed methane becomes a tough problem because of the rich reserves and low usage percentage in our country. By far, pressure swing adsorption (PSA) is the most economical and reasonable method to separate methane and nitrogen. This thesis reports some basic study on concentrating coalbed methane by PSA.We used the super active carbon (surface area 2097m2) as adsorbent and simulative coalbed methane (methane 31.1%,nitrogen 68.9%) as feed gas to the dynamic measurement of adsorption and desorption. In condition of the same temperature and flux, the trend of methane concentration with the change of time and desorption pressure was investigated through several adsorption pressure and two desorption process. The results showed that in the same condition cocurrent desorption process gave higher methane concentration in contrast with countercurrent desorption process. Inflecxions ocurred in almost the same location of all desorption curves. The desorption gases which are above this pressure can be used to equalize with other tower and the rest can be collected as products. We also reviewed the effect of adsorption pressure and desorption process on methane concentration during two-tower rotative operation. In the optimal condition (adsorption pressure 0.6MPa, equalization pressure 0.3MPa, equalization time 10s and vacuum time 50s) the concentration of desorption methane can be kept steady after several cycles.