Abstract: In order to study factors influencing the volume of CO₂ adsorbed by coal under multi-factor coupling effect, the HCA high-pressure capacity method was used to determine the amount of CO₂ adsorbed by coal samples under different conditions, and the Langmuir volume was calculated. The coupling effect of temperature, particle size and water content on CO₂ adsorption of coal was analyzed. The Box Behnken test was designed by Design Expert software to construct a Langmuir volume quadratic regression response surface model for coal adsorption of CO₂. The results show that the adsorption amount decreases with the increase of temperature and particle size, and decreases first and then stabilizes with the increase of water content, that the single factors of temperature, particle size, and water content all have significant effects, that the order of influence degree under multi-factor coupling effect is as follows: particle size and water content> temperature and particle size> temperature and water content, and that the interaction between temperature and particle size, particle size and water content is significant, while the interaction between temperature and water content is not significant.

Key words: multi-factor coupling, adsorption capacity, influence factor, response surface, coal adsorbing CO₂, high pressure capacity method