Study of stand-support sintering to achieve high oxygen potential in iron ore sintering to enhance productivity and reduce CO content in exhaust gas

摘要

Coarse coke particles, thick combustion zone, and poor thermal permeability during sintering have been widely reported to lead to incomplete solid fuel combustion and low oxygen potential, which induces the formation of harmful gas and decreases the energy efficiency. To solve these problems, stand-support sintering with an ultrathick 1000 mm bed was first proposed in this paper. The influences of the stand height and coke size on the process parameters and sinter quality were studied through a series of experiments. The results showed that the average gas flow velocity increased from 0.24 m/s to 0.32 m/s and the maximum combustion zone thickness decreased from 202 mm to 140 mm, which indicated that stand-support sintering could substantially improve the thermal permeability and enhance the oxidizing atmosphere. The fuel consumption was reduced by 1.28 kg/t (2.25%), the generated CO in exhaust gas was reduced, and the production efficiency increased by 17.4% when the stand height increased from 0 to 500 mm. Moreover, a 3D high-energy X-ray computerized tomography (CT) scanner was first used to quantitatively confirm the effect of the stand on the distribution and size of the pores in the whole sinter cake. Research findings showed that the porosity increased by 7.1% when the height of the stand increased from 0 to 500 mm, which further illustrated the effect of stand-support sintering. The present study provided an effective way to optimize the energy efficiency and reduce the CO content in exhaust gas. (C) 2019 Elsevier Ltd. All rights reserved.