Removing CO_2 and H_2S from the Gas Produced during Underground Coal Gasification (UCG)

摘要

The new method of simultaneous disposal of CO_2 and H_2S in coal gas generated during underground coal gasification (UCG) using industrial waste alkali liquor is put forward and studied for the first time. The rationale of absorption of CO_2 and H_2S by the alkali liquor is analyzed, and the mass transfer model for the above process is established. The impact of the existence of H_2S on absorbing CO_2 by the alkali liquor is studied on the basis of the model experiment. Research shows that as the velocity of coal gas increases, the selection coefficient of H_2S improves, the temperature rises, the selection coefficient of H_2S deceases, but the removal rate of CO_2 increases. By means of study, it can be found that the removal rate of CO_2 can reach more than 60% under the conditions of the suitable concentration of the alkali liquor and the ratio of liquid to gas, the heat value of underground coal gas can heighten by 12.3%, 17.7%, and over 20%, respectively, when the removal rate of CO_2 is 58%, 80%, and greater than 90%.