2021 年 61 巻 1 号 p. 129-137
Reduction shaft furnace is an effective process to produce Direct Reduced Iron (DRI), in which natural gas is used as reducing agent and heat source. Recently, in some countries lacking natural gas resources, Coke Oven Gas (COG) was proposed to be used in shaft furnace process instead of natural gas. In the present work, the effect of COG consumption on the yield of metallic Fe in shaft furnace was thermodynamically calculated. Both the chemical equilibrium and heat balance were considered. The main findings include, in shaft furnace process, the COG consumption as heat source is more than that as reducing agent. In the case of directly supplying reformed COG, the yield of metallic Fe decreases with increasing formation temperature of metallic Fe. For a coke oven with capacity of 600000 tons, as the formation temperature are 850°C and 900°C, the corresponding annual yields of shaft furnace are 253.58 × 103 tons/year and 249.48 × 103 tons/year. In the case of ZR technology followed by supplying extra COG, the yield of metallic Fe first increases and then decreases, and there is a peak value. For a coke oven with capacity of 600000 tons, as the formation temperature are 845°C and 900°C, the corresponding annual yields of shaft furnace are 283.44 × 103 tons/year (maximum value) and 278.38 × 103 tons/year. The findings from this work may provide guidelines for choosing optimal parameters for an actual shaft furnace process.
