采空区煤层封存CO_2影响因素分析

Analysis on factors affecting sequestration of CO_2 in coal seam

为考察不同物理化学环境对采空区煤层封存电厂烟气中CO_2的影响,利用自行研制的煤大样量吸附装置,对常温常压条件下吸附体系中N_2、SO_2、H_2O及pH影响CO_2吸附的规律进行了实验研究。结果表明,改变物理化学环境可使CO_2的吸附量发生变化,由于吸附亲和性差异和竞争吸附作用,N_2使CO_2的吸附量降低1.4%~2.1%,SO_2气体使CO_2吸附量降低2.3%~3.3%,煤中水分使CO_2吸附量降低2.8%~3.7%;通过对煤样进行酸洗和碱洗处理发现,pH增大或减小后煤样对CO_2的吸附量可增加1.5%~3.8%,并且pH减小时煤样对CO_2的吸附量明显大于pH增大时煤样对CO_2的吸附量。这一结果为增大CO_2气体的封存量提供理论依据。

In order to study the influence of physical and chemical conditions on the adsorption of CO2 in a coal seam,an artificial experimental device was used for research on the influence of N2,SO2,H2O,and pH in the adsorption system,on the adsorption of CO2 at normal pressure and temperature. The results show that the capacity for adsorption of CO2 was changed with change in the physical and chemical conditions. Due to competitive adsorption,and differences in the affinity between gas molecules,N2 can reduce the capacity for adsorption of CO2 by 1. 4% to 2. 1%. The presence of SO2 can reduce the capacity for adsorption of CO2 by 2. 3% to 3. 3%and H2O in coal can reduce the capacity for adsorption of CO2 by 2. 8% to 3. 7%. Results from the study of the adsorption of acid-treated and alkali-treated coal samples indicate that,whether increasing or decreasing,the pH can increase the capacity for adsorption of CO2 by 1. 5% to 3. 8%. The capacity for adsorption of CO2 when pH is decreasing is obviously greater than the capacity when pH is increasing. These results provide a theoretical basis for increasing the capacity for adsorption of CO2.