Fundamental Study On The Integrated Process Of Smelting Reduction With Coal Gasification Using A Static Model

At present,the problems of physical energy waste of high-temperature gas and low gas chemical energy are common in the smelting reduction process.At the same time,the process of coal gasification faces the status quo of single technology and high consumption of water.In recent years,the integrated process of smelting reduction with coal gasification has received more and more attention because it just makes up for the shortcomings of the two single processes.Therefore,on the basis of the related integrated process of smelting reduction with coal gasification proposed in the literature,this study was aimed to build a static model including three calculation modules of the direct reduction furnace(DRF),smelting reduction vessel(SRV)and gas reforming furnace(GRF).In particular,DRF mainly performs pre-reduction of pellets,SRV mainly performs melting,slagging and reduction of metalized pellets,and the SRV gas is reformed in GRF to produce high-quality gas for pre-reduction and external output.The static model,which can be used to understand the material and energy consumption in each reactor,was established according to the principle of material balance and heat balance.Using the static model,the integrated process was firstly studied under the condition where ironmaking is taken as the main purpose.The effects of gas temperature,metallization degree of pellet and post combustion ratio on material and energy consumptions were investigated.After that,the integrated process was assessed under the condition where coal gasification is taken as the main purpose.The effects of different parameters on the gas production and the overall material and energy consumptions were investigated.Finally,the multi-objective optimization of the integrated process of smelting reduction with coal gasification was achieved.The main conclusions of this study are given as follows.(1)Taking ironmaking as the main purpose,the optimal operating parameters of the integrated process are,the inlet gas temperature of DRF is 850℃,the metallization degree of pellet is 90%,and the post combustion ratio of the upper free space in the SRV is 15%.In addition,the post combustion ratio of the middle layer in the SRV is 10%,and is 0 in the lower layer.(2)Taking coal gasification as the main purpose,it is recommended that there is no post combustion in SRV.For the process of DRF smelting reduction with coal gasification,reforming DRF’s off-gas by GRF to increase quantities of gas.For the process of smelting reduction with coal gasification excluding a DRF,the quantity and temperature of gas are 10994.0 kg/tHM and 1500℃,respectively.It should be pointed out that the physical energy of the high temperature gas can be used to preheat materials such as pellets and oxygen.