Evaluation of by-product-gas utilization options for carbon reduction at an integrated iron and steel mill.

The comprehensive utilization of steel mill by-product gases is an important method for achieving climate goals. In this study, a comprehensive model is proposed for analyzing carbon-emission reduction strategies of by-product gases comprehensive utilization system at an integrated iron and steel mill. The model is used to explore carbon-emission reduction performance applying blast furnace with top-gas recycling (TGR-BF) and carbon capture and storage (CCS) applications, as well as consequent influence on steam and power cogeneration system (SPCS) operation. Carbon-emission intensity, total emission reduction and unit reduction cost are used to evaluate the carbon reduction result of by-product gases comprehensive utilization system. The results of the study indicate that the upgrade of SPCS can achieve an emission reduction of 311,200 tCO 2 , and the carbon-emission intensity of the power and heat supply can be reduced by 0.14 tCO 2 /104 kWh and 0.02 tCO 2 /GJ, respectively. After TGR-BF technology is applied, the total emission reduction peaks at the top-gas recovery rate of 6%, which is 85,100 tCO 2. The unit reduction cost is also minimized at the top-gas recovery rate of 6%. Sensitivity analysis indicates that the reduction of power price significantly reduces the unit reduction cost. • Carbon-reduction technology affects steam and power cogeneration system scheduling. • Multi-indicators provide a comprehensive assessment of carbon reduction result. • Carbon emission reduction peaks at 85100 tCO 2 when top-gas recovery rate is 6%. • Unit reduction cost is the lowest (6441 CNY/tCO 2) when top-gas recovery rate is 6%. [ABSTRACT FROM AUTHOR]