煤中CO₂吸附相密度不同获取方法对比分析

Comparative Analysis of Different Methods for Obtaining CO₂ Adsorption Phase Density in Coal

摘要: 碳捕集、利用与封存(CCUS)技术中，明确煤中CO₂吸附相密度对掌握煤层中CO₂吸附机理和评估封存潜力至关重要。本研究选取淮北矿区祁东矿气煤煤样，依据相关标准开展不同温度(36℃、42℃、48℃)下的高压等温吸附实验。采用吸附模型拟合法(优化后的Langmuir、BET、DA模型)和截距法对实验数据进行处理，对比分析两种方法获取的CO₂吸附相密度。结果表明，吸附模型拟合法中Langmuir和DA模型对煤样48℃下CO₂吸附过程拟合效果良好，校正后的Langmuir模型拟合得到的CO₂吸附相密度为1.16 g/ml，DA模型为1.07 g/ml，BET模型不适用；截距法得到的CO₂吸附相密度随温度升高从36℃的2.22 g/ml下降到48℃的1.19 g/ml。两种方法各有优劣，吸附模型拟合法利于深入研究吸附机理，截距法能快速获取数据和反映变化趋势，实际应用中应按需选择。本研究为获取煤中CO₂吸附相密度提供了方法参考，对CCUS技术在煤层封存领域的发展具有重要意义。

Abstract: In carbon capture, utilization, and storage (CCUS) technology, it is crucial to understand the density of CO₂ adsorption phases in coal to grasp the mechanism of CO₂ adsorption in coal seams and evaluate the potential for storage. This study selected gas-coal samples from Qidong Mine in the Huabei mining area and conducted high-pressure isothermal adsorption experiments at different temperatures (36˚C, 42˚C, 48˚C) according to relevant standards. The experimental data were processed using the adsorption model fitting method (optimized Langmuir, BET, and DA models) and the intercept method, and the CO₂ adsorption phase densities obtained by both methods were compared. The results showed that the Langmuir and DA models performed well in fitting the CO₂ adsorption process at 48˚C for the coal sample. The corrected Langmuir model yielded a CO₂ adsorption phase density of 1.16 g/ml, while the DA model gave 1.07 g/ml; the BET model was not applicable. The intercept method resulted in a CO₂ adsorption phase density that decreased from 2.22 g/ml at 36˚C to 1.19 g/ml at 48˚C. Each method has its advantages and disadvantages; the adsorption model fitting method facilitates in-depth research on adsorption mechanisms, while the intercept method can quickly obtain data and reflect trends. In practical applications, the choice should be made based on specific needs. This study provides a methodological reference for obtaining CO₂ adsorption phase densities in coal and is of significant importance for the development of CCUS technology in coal seam storage.