Study on Saturated Vapor Pressure Parameter k of Adsorption Potential Theory

Adsorption potential theory can be used to predict the adsorption isotherm of coal at different temperatur,but because the saturated vapor pressure parameter k and the adsorption phase density ρ_ad are not selected appropriately,it often leads to a large deviation in prediction.Because of this,the coal samples with the particle size of 0.18 mm to 0.25 mm were selected in this paper,isothermal adsorption experiments were carried out at 30 ℃,40 ℃and 50 ℃,and two types of adsorption characteristic curves of 30 ℃ and 30 ℃, 40 ℃, 50 ℃ have been derived and were used to predict the isothermal adsorption curve of 40 ℃and 50 ℃.The results showed that the saturated vapor pressure parameter k on the adsorption characteristic curve obtained from a single temperature has little effect, but a greater impact on the comprehensive adsorption characteristic curve at multiple temperature, the existence of the optimal saturated vapor pressure parameter k value is 3;the average deviation of single temperature adsorption characteristic curve prediction results is bigger than multiple temperature comprehensive adsorption characteristic curve prediction;the prediction accuracy of the latter is 2 times of the former in 40 ℃ and 2.5 times of the former in 50 ℃.Multiple temperature adsorption characteristic curve is sensitive to adsorbed phase density,predicting the isothermal adsorption curve of 40 ℃ and 50 ℃ should use adsorption phase density ρ_ad2 and ρ_ad1 respectively.