Numerical simulation of smelting characteristics around raceway in melter gasifier

In comparison with blast furnace, pure oxygen instead of air is injected into melter gasifier. Thus, there is a great difference between melter gasifier and blast furnace in the mass, momentum, heat transfer and gas distribution. A two-dimensional mathematical model at steady state was developed to describe the gas velocity, temperature and species distribution around raceway in melter gasifier. The results show that the gas temperature reaches above 3 500 K rapidly, due to the heat exchange with the burden and the heat release of combustion reaction with coke or semi-coke formed by lump coal. In addition, a small-scale gas circulation flow phenomenon is observed in front of tuyere. Thus, there is a serious damage in the front of tuyere which results in a higher unplanned blowing-down percentage. In order to decrease the gas temperature in the raceway to prevent the blowing-down, the appropriate hydrogen-rich fuel gas, including natural gas, coke oven gas, can be fed through the tuyere. Furthermore, it also reduces the solid fuel ratio and improves the reduction advantage of H₂ in the high temperature to enhance the smelting efficiency of melter gasifier.