Numerical Simulation of Combustion Characteristics in the Dome Zone of the COREX Melter-Gasifier: The Effect of Rising Gas

Abstract

The dome zone is one of the most significant areas of the COREX melter-gasifier. The coupled fields in the dome vary with the transport phenomena, which is one of the key factors that impact the smooth operation of the reactor. In this work, a three-dimensional steady-state mathematical model was developed to study the inner characteristics of the dome zone. First, the model was validated by comparing the simulated and experimental results. Then, the effects of key operating parameters of rising gas (e.g., flow rate, component, and temperature) on the hydrodynamics and thermochemical behaviors in the dome zone were analyzed. The results show that the main reaction zone can be divided into three parts, which are controlled by homogeneous reaction, heterogeneous reaction, and diffusion effect in turn. Due to the adequate reaction zone and long residence time, the burnout rate of the dust particle can reach more than 99.9%. Increasing the flow rate of rising gas leads to the increase of CO and H2 in the gas yields. When the proportion of (CO + H2) increases from 80 to 95%, the average temperature of the dome first increases and then decreases, attributed to the heat consumption of excessive H2. The temperature of rising gas insignificantly affects the component of the generator gas at the outlet.