Experimental Study on Influencing Factors and Thermal Effects of CO(2) Adsorption by Coal

[Image: see text] The utilization of CO(2) is extremely important to solve the environmental problems and coal spontaneous combustion in goaf. There are three kinds of CO(2) utilization in goaf: adsorption, diffusion, and seepage. Since adsorption will consume CO(2) in goaf, the optimization of CO(2) injection amount is very critical. A self-developed adsorption experimental device was used to determine the CO(2) adsorption capacity of three different particle sizes of lignite coal samples at 30–60 °C and 0.1–0.7 MPa. The factors affecting CO(2) adsorption by coal and its thermal effect were studied. In the coal and CO(2) system, the CO(2) adsorption characteristic curve is not affected by temperature, but there are differences in that with different particle sizes. The adsorption capacity increases with the increase of pressure, while it decreases with the increase of temperature and particle size. Under atmospheric pressure, the adsorption capacity of coal is a logistic function relationship with temperature. Furthermore, the average adsorption heat of CO(2) on lignite shows that the interaction force between CO(2) molecules has a stronger effect on CO(2) adsorption than the effect of heterogeneity and anisotropy on the coal surface. Finally, the existing gas injection equation is improved theoretically with CO(2) dissipation, which provides a new idea for the work of CO(2) prevention and fire suppression in goaf.