Study And Application Of Q-g Prediction Method Of Surplus Gas In Iron And Steel Enterprise

A lot of secondary energy sources including coal gas are produced in the steel production process which constantly consumes resource and energy. According to statistics, gas consumption accounts for about40%of the total energy consumption in iron and steel enterprises, and gas surplus rate is about30%with the energy conservation. Therefore, reduction of gas resource and recycle of surplus gas are becoming the vital technologies for enterprises which plan to improve competitive force and take a new road to industrialization.For a long time, researchers focus on reduction of gas consumption in each equipment or each process, while the amount of surplus gas is ignored. According to the principle of system energy saving, this paper wants to realize the maximum recycling of both quantity and quality of coal gas, the reduction and reasonable use of consumed gas, and the maximum value of surplus gas.With reference to e-p analysis method, q-g prediction method of surplus gas is proposed in this paper. In order to find out factors affecting the amount of surplus gas per ton, the mathematical expression of q-g prediction method is decomposed into the q-p prediction method of gas yield per ton and the g-p prediction method of gas consumption per ton. It can be seen from analysis that the main factors affecting supply and demand balance of gas system include steel ratio, process gas yield and process gas consumption. Considering the problem of evaluation index of gas utilization existed in iron and steel enterprises, index of gas consumption per ton which includes process gas consumption and gas emission quantity per ton is proposed in this paper.In order to resolve the problem of much low-heat value gas discharging, blast-furnace gas is mingled with coke oven gas before using. But with the development of new technology such as HTAC, blast-furnace gas can be used to process heating alone, so the necessity of mixed gas is discussed. According to the second law of thermodynamics, calculation formula of exergy loss in gas mixed process is deduced, and the conclusion that quality of gas will decrease during mixture of different gas is concluded. On account of the condition that mixed gas is widely used in real production, the impact of gas pressurization and mixture on energy consumption is researched, and it is indicated that the mode of pressurization followed by mixture can save25%energy than the mode of mixture followed by pressurization. The principle of selection of gas type is provided in comprehensive consideration of gas energy matching and different requirements of gas heat value.Considering the application of advanced energy conservation technology, gas production, gas consumption and the amount of surplus gas of Nanjing steel, when10million ton development plan is implemented, are predicted and analyzed in this paper based on q-g prediction method of surplus gas, besides, the programs of surplus gas recycling use include gas fired boiler-steam turbine power generation, coke oven gas hydrogen-electricity generation and coke oven gas methanol-electricity generation are compared.