| Converter steelmaking is the key process of iron and steel metallurgy.The residual heat and energy recovery from the converter process,especially the recovery of converter flue gas,is the core of“negative energy steelmaking”.Due to the unfriendly interface,uncoordinated operation and unclear coupling rules,the current production process of converter has high converter gas discharge and low sensible heat recovery.In this paper,the 250t converter?LT system?is taken as the research object,and the influences of converter operating parameters,raw material conditions and steel species on sensible heat and latent heat recovery of flue gas were studied.Based on these,the evaluation indicator and model of residual heat and energy recovery of converter process were proposed,and the evaluation system was established.The main research conclusions are as follows:The characteristic model of converter flue gas composition of the 250t converter was established by mathematical statistics method.The model was verified by three indicators,the volume and the average CO concentration of recovered converter gas,and the gas recovery volume of standard calorific value.It shows that the single furnace error is within±15%,and the average error of the hundred furnaces is within±2%.The effects of CO distribution ratio,air combustion coefficient and limiting CO concentration on the recovery volume of converter gas,the calorific value of recovered gas and the limit recovery volume of steam were studied.The recovery volume of converter gas is proportional to the CO distribution ratio,inversely proportional to the air combustion coefficient and limiting CO concentration;calorific value of recovered gas is inversely proportional to air combustion coefficient,proportional to CO distribution ratio and limiting CO concentration;limit recovery volume of steam is inversely proportional to CO distribution ratio,proportional to air combustion coefficient and limiting CO concentration.When CO distribution ratio,air combustion coefficient and limiting CO concentration increased by 1%respectively,the recovery volume of converter gas increased by 1.59m3/t-steel,-1.52m3/t-steel and-0.61m3/t-steel respectively,the calorific value of recovered gas increased by 20.21×4.187kJ/m3,-39.54×4.187kJ/m3 and 12.83×4.187kJ/m3 respectively,and the limit recovery volume of steam increased by-0.017 kg/t-steel and 5.65 kg/t-steel,2.16 kg/t-steel respectively.The effects of the carbon content of molten iron and molten steel,the ratio of molten iron on the recovery volume of converter gas and the limit recovery volume of steam were studied.The recovery volume of converter gas is proportional to the carbon content of molten iron and the ratio of molten iron,and inversely proportional to carbon content of molten steel.The limit recovery volume of steam is proportional to the carbon content of molten iron and the ratio of molten iron,and inversely proportional to carbon content of molten steel.When carbon content of molten iron and molten steel,the ratio of molten iron increased by 0.1%?0.01%and 1%,the recovery volume of converter gas increased by 2.33m3/t-steel,-0.24m3/t-steel and 1.15m3/t-steel respectively,the limit recovery volume of steam increased by 5.75 kg/t-steel,-0.59 kg/t-steel and 2.84 kg/t-steel,respectively.The reasonable recovery concentration of converter gas is determined.The limiting CO concentration?24%and the limiting O2 concentration?1%.Under this condition,the recovery volume of converter gas increased by 5.55m3/t-steel,and the calorific value of recovered gas is decreased by 6.2%.The feasibility of full recovery of flue gas energy in the early and final stages of converter blowing is demonstrated.The reasonable recovery concentration of converter gas in the early and final stages is CO concentration?15%,CO concentration?35%and the limiting O2 concentration?3%.Under this condition,the recovery volume of converter gas is 11.11 m3/t-steel,and the average calorific value of recovered gas is about 728×4.187kJ/m3.Taking a converter steelmaking system as a research object,the evaluation indicator and mathematical model of the residual heat and energy recovery of the converter process were established,including 9 indicators such as the recovery volume of converter gas per ton of steel,the recovery volume of steam per ton of steel and oxygen consumption per ton of steel,etc.A converter energy recovery evaluation system was developed,including production data display interface,evaluation interface for recovery of residual heat and energy in steelmaking plant,evaluation interface for recovery of residual heat and energy in different enterprises and feature time statistical interface. |
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