Research of a bidisperse diffusion model based on adsorption hysteresis

A new model of adsorption hysteresis was put forward for describing the sorption quantity and speed variation characteristics of coal adsorption hysteresis process.According to the coal adsorption hysteresis analysis and combined with the theory of ink bottle, a sorption model was put forward by introducingα named hysteresis factor, which revealing the mechanism of the coal quality change in the process of sorption, then α was verified reasonable by fitted with the four types of domestic and foreign data of isothermal adsorption experiments and the fitting data showed that the bigger the α value, the greater the degree of sorption hysteresis.By comparing the velocity of adsorption process, a diffusion equation considering the change of coal matrix porosity was put forward, which the equation of diffusion coefficient can directly reflect the problem of asynchronous time in the process of sorption.Based on Comsol computing platform, the numerical simulation of the diffusion equations had realized.Numerical simulation results showed that the tendency of the diffusion coefficient in the process of adsorption was on the contrary, for instance, the diffusion coefficients decreased with time in the process of adsorption, the adsorption rate decreased with time and the process of adsorption was on the contrary, this result was consistent with the laboratory result which could prove the rationality of the parameters and further be used to analyze the change trend of adsorption hysteresis phenomenon on the time.