The Exergy Analysis And Process Parameters Optimization In The Blast Furnace

Steel industry is the pillar industry of national economy, and its energy consumption accounts for13%to14%of total energy consumption. In the energy consumption of the steel enterprises, the energy consumption of iron-making system (sintering、coking、blast furnace process) takes the first place, which accounts for70%of total energy consumption, and the blast furnace accounts for50%. Therefore, the energy saving of the blast furnace process becomes the primary task of the steel enterprises implementing energy saving policies. In this paper, based on the second law of thermodynamics, exergy analysis method is used to make a detailed energy analysis on the blast furnace process, which provides an important reference for the blast furnace to reduce energy and cost.Exergy analysis models contain white-box and black-box model, and the white-box model is a fine model. In this paper, the white-box model is used to analyze all the energy consumption processes of the blast furnace one by one. According to the basic knowledge of iron-making, based on the blast furnace ingredients calculation and material balance calculation, the reaction exergy and the irreversible exergy loss of the chemical reaction processes were solved in detail, as well as the heat transfer irreversible exergy loss inside the furnace, the combustion irreversible exergy loss, etc. The white-box model of the blast furnace was built. According to the built exergy analysis model, the link and factors of exergy loss were analyzed in detail. It is shown that the exergy efficiency of the blast furnace was33.2%. Besides, the internal exergy loss were42.62%(mainly the combustion irreversible loss and the reaction irreversible loss), and the external exergy loss were16.81%; The influence of the ore grade, blast temperature, humidity, coke ratio and coal ratio on the exergy loss was analyzed.According to the actual production data of Anshan Steel No.11blast furnace, based on the white-box model of the blast furnace, to set the minimal exergy loss of the blast furnace as the target, to take the material balance, exergy balance, slag balance and operation line of blast furnace as the constraints, single objective optimization model of Anshan steel No.11blast furnace was established. Lingo was used to optimize the model, and the best ingredients, coke ratio, coal ratio and other parameters were got; compared with the actual production data, the correctness of the white-box model and the optimization model was testified.