Simulation on the combustion in the raceway zone of COREX melter gasifier

Two dimensional numerical simulation of the particle motion and combustion behavior in the raceway has been done to analyze the gas flow field, pressure field, temperature field, distribution of gas composition, as well as the effect of coke mass flow rate and blowing gas temperature on the maximum temperature in the raceway zone. The results show that the temperature in the cavity reaches the maximum in the upper part of the cavity region, and the maximum value is above 3000 K. During the combustion process, the concentration of O2 decreases, and the concentration of CO increases. The highest CO content in the gas leaving the raceway zone and entering the coke bed is about 0.95, while the lowest O2 content is 0.05.

Numerical Simulation of the Raceway Zone in Melter Gasifier of COREX Process

The physical and chemical processes in the raceway zone of the COREX melter–gasifier express are similar to those inside the blast furnace. Based on the research achievements on blast furnaces, the unsteady numerical simulation of a gas-solid two-phase in the raceway was carried out by using computational fluid software. The formation process of the raceway in the COREX melter–gasifier was simulated. The shape and size of the raceway were obtained. Then, the effect of gas flow on the depth and height of the raceway was analyzed in this paper.

Analysis of Coke Oven Gas Injection from Dome in COREX Melter Gasifier for Adjusting Dome Temperature

Coke oven gas (COG) injection from the dome in a COREX melter gasifier is a good method to not only reduce the amount of solid fuel used for gasification, but also to adjust the freeboard temperature that should be maintained within a certain range. In this paper, the characteristics of COG injection used to adjust dome temperature are studied through a static model. The results show that an increase in melting rate causes a decrease in dome temperature and generator gas volume. However, with an increase in coke rate, dome temperature increases, while generator gas volume decreases. For low coke rate conditions, the dome temperature is generally found to be lower than 1050 °C, and COG is blasted for combustion and heat releasing. For high coke rates, the dome temperature is generally higher than 1050 °C. Under the premise that oxygen reduction cannot meet the demand, COG is used for decomposition. After the COG injection, the amount and reduction capacity of the generator gas can meet the needs of reduction in shaft furnace. The findings of this work can be used as a theoretical basis to guide plant operations for COG injection.