河北开滦矿区晚古生代煤对CH_4/CO_2二元气体等温吸附特性

Isothermal adsorption of CH_4/CO_2 mixed gas for the late Paleozoic coals from the Kailuan coalfield of Hebei Province

研究了开滦矿区不同变质程度煤对不同配比CH4/CO2二元气体等温吸附特性,用扩展Langmuir方程的推论计算了CH4/CO2二元气体各组分在吸附相中的浓度,并分析了其变化特征,表明:煤对CH4/CO2二元气体的吸附并不是对纯CH4和纯CO2的独立吸附,而是2种气体的竞争吸附,混合气体中CO2含量越高,总吸附量越大.在开滦矿区煤对CH4/CO2二元气体的吸附过程中,利于CO2吸附的条件是高CO2组分浓度和高压力;中等变质程度煤利于CH4吸附的条件是高CH4组分浓度和高压力,而低变质程度煤是相对的低CH4组分浓度和高压力.研究区低变质程度煤对CH4的竞争吸附大于其对CO2的竞争吸附,并不适合CO2-ECBM技术的实施;中等变质程度煤对CO2的竞争吸附优于对CH4的竞争吸附,适于CO2-ECBM技术的实施.

The characteristics for isothermal adsorption of CH4/CO2 for two coals of different rank （ the No. 11 coal from the Linnancang Mine and the No. 9 coal from the Majiagou Mine） from the Kailuan coalfield of Hebei Province were studied. The abundance and variation of each gas in the adsorption phase were analyzed using the extended- Langmuir equation. The results show that the adsorption of CH4/CO2 mixed gas is a competitive adsorption rather than an independent adsorption of pure CH4 and pure CO2. The more CO2 abundance in the CH4/CO2 miexed gas, the more the total amount of mixed gas being adsorbed. The favorable condition for the CO2 adsorption in the mixed gas is the relatively high CO2 abundance and high pressure. The favorable conditions for the CH4 adsorption in the mixed gas for the two coals with medium and low rank are relatively high and low CH4 abundance, respectively. The coal of low rank showed a stronger CH4 adsorption than that of CO2 and the coal of medium rank has a contrary adsorption of the mixed gas, indicating that the latter rather than the former is CO2 - ECBM suitable coal.