Exergy Analysis And Thermoeconomic Analysis Of Energy-saving Technology In Iron And Steel Enterprises

The iron and steel industry is an energy-intense industry in china, and it is one of the greatest potential industries of energy saving due to its high energy consumption. So, energy-saving technologies should be adopted in order to reduce the energy consumption per unit product and the production cost. Besides, the technologies should be feasible in technology, reasonable in economy and acceptable for the environment and society. Then the competitiveness of steel enterprises is enhanced.Exergy analysis integrates the first and the second law of thermodynamics. From the point of view of combining the "quantity" and "quality" of the energy, It reveals the situation about exergy’s conversion, transmission, use and loss from the point of energy’s "quantity" and "quality", so this method is more scientific and more reasonable to evaluat the energy use status. Thermoeconomic analysis integrates the thermodynamic analysis and economical factors which takes into account of the "quality" and "quantity" in energy, and prices the exergy flow to maximize the benefit. In this paper, exergy analysis and thermoeconomic analysis were applied to the steel production system, and thermodynamic and economic analyses were made on the energy-saving technologies of steel enterprises. The direction for the enterprise to save energy and reduce consumption was pointed out.Steel production system mainly contains eight processes which are coking, pelletizing, sintering, blast furnace, converter, refining, continuous casting and rolling. In this paper, black-box models of exergy analysis were established in each process, exergy loss coefficients of each process were calculated, and the exergy loss weights of each process were got. According to those above, it was found that the weak links in energy utilization of the steel production system were blast furnace, rolling and sintering. The exergy analysis was made on the main energy-saving technologies of steel enterprises (CDQ, TRT, sensible heat recovery of each process, etc.). What’s more, the influence of various energy-saving technologies on the total exergy efficiency was analyzed.This paper constructs the thermoeconomic cost analysis models process by matrix model thermoeconomic analysis according to steel production system and supplementary equations to sort out the thermoeconomic cost. By using this model, various energy-saving technologies were evaluated on the thermoeconomic cost, and the influence of the various energy-saving technologies on the product cost was got.Through the exergy analysis and thermoeconomic analysis on each process and energy-saving technologies of steel system, the energy utilization of the system was got, as well as the result brought by the energy-saving technologies. It has an important reference for the steel enterprises to save energy and reduce cost.