Optimal resource allocation in integrated steelmaking with biomass as auxiliary reductant in the blast furnace

Abstract

An integrated steel plant with two blast furnaces with the option to use biomass to partially substitute fossil reductants was simulated. A thermodynamic blast furnace model was used, combined with simpler models of the other unit processes (sintermaking, cokemaking, basic oxygen furnace, hot stoves and power plant) and a nonlinear model of the biomass conversion with respect to the processing temperature. Given an aim steel production rate for the plant, the economics of the plant was optimized by minimizing the specific costs of liquid steel, considering costs of raw materials, energy and CO 2 emissions. Limited supply of sinter and coke was optimally allocated to the two blast furnaces and the effects of restrictions in the biomass, oxygen and oil supply on the operating states were studied. An analysis was also undertaken to study how the production rate of the plant would affect the optimal state. The results demonstrate that a non-uniform distribution of the resources can be economically justified, in particular for cases where the blast furnaces operate under different constraints. © 2012 ISIJ.