In-situ catalytic reforming of converter gas in converter flue based on thermochemical energy storage: Kinetics and numerical simulation

Abstract

The converter gas, a major by-product of converter steelmaking, contains abundant and available physical heat. The reforming of converter gas with coke oven gas in a converter flue, which recycles the waste heat of the gas by a thermochemical energy storage technology, is an effective process to enhance the waste heat recovery rate and quality of the converter gas and reduce the direct emission of CO2. To obtain the reforming rate in the converter flue, the kinetics of the CH4–CO2 reaction, the main reaction in the reforming, catalyzed by converter dust was investigated through experiments. The reaction order, activation energy, and preexponential factor were determined. The partial order of CH4 was 1, while the partial order of CO2 was 0 in the reaction. The converter dust had a considerable catalytic effect on the reforming reaction. The adding amount of converter dust significantly affected the activation energy and preexponential factor. The reforming of the converter gas with the coke oven gas in the converter flue was then investigated through a numerical simulation. The waste heat recovery rate reached a peak of approximately 50%, and about 30% of the heat was converted into chemical energy when the ratio of the coke oven gas added into the converter flue was 31.3 to 37.5%. Under these conditions, the conversion rates of CH4 and CO2 were above 70% and 35%, respectively. The influence of the converter gas flow rate on the reforming was studied. The increases in the inner diameter and length of the converter flue are beneficial to improve the waste heat recovery rate as well as the conversion rates of CH4 and CO2.