Abstract
A simple model was proposed for char capture by molten slag surface under high-temperature gasification conditions. In this model, char particles were pneumatically carried to the molten slag surface. It was assumed that the char particles were captured if they reach the molten slag surface whereas they were repelled if they reach the part that is covered by the unreacted char particles. Thus the probability of char capture was given by the balance of char feed rate per unit surface area of the slag and the rate of char consumption by the gasification reaction. Experiments were carried out to evaluate the probability of char capture by molten slag surface at 1400℃. A ceramic tube whose bottom was closed was vertically placed in an electric furnace. Slag (mixture of coal ash and limestone) was placed at the bottom of the reactor. Char particles were conveyed by CO_2-N_2 mixture stream to the molten slag surface. CO was produced by gasification reaction at the molten slag at the bottom. The effect of char properties such as particle size, density, and gasification rate, on the conversion of carbon to CO was evaluated. The theoretical results agreed well with the experimental results.
