Study on Alkali-Metal Vapor Removal for High-Temperature Cleaning of Coal Gas

摘要

Six natural mineral sorbents and a series of self-made sorbents were used to remove alkali-metal vapor from high-temperature coal gas.Results indicate that the self-made sorbent GM6 is the best sorbent with the highest sodium compound content,under the conditions of 1173 K,a gas velocity of 16 L/min,a reaction time of 3 h,and a NaCl concentration of 0.13 mg/L.It is shown that the sodium compound content is dependent on the chemical constituents and the microporous structure of sorbent,based on the surface area data.Results of X-ray diffraction(XRD)analysis and the kinetics indicate that the adsorption process of GM6 is physical adsorption in an N2 atmosphere and it is controlled by the diffusion of a sodium resultant layer.The adsorption process in a N_2/H_2O(2%)atmosphere is mainly a chemical adsorption that is controlled by both the chemical control and the product-layer diffusion control.