Analysis And Utilization Study Of Flue Gas Residual Heat In Sintering Ring Cooler Of A Steel Company In Shanxi Province

The annual energy consumption of iron and steel enterprises accounts for about15%of the total energy consumption in China.The energy consumption in sinter process is relatively large in the overall ironmaking&steelmaking industry,among which the utilization potential of sintering ring cooler exhaust gas is high because of its high exhausting temperature.The recovery and reuse of the waste heat from the exhaust gas can not only effectively reduce the energy consumption of steel production,but also can reduce the pollution caused by the emission of flue gas to the environment.In this paper,a scheme to recover the power from the waste heat of the flue gas of sintering ring cooler is put forward based on the actual situation of the flue gas emission from a iron&steel enterprises sintering plant in Shanxi province.Firstly,the flue gas produced from the ring cooler during sintering process is tested and analyzed.Secondly,the material balance model and energy balance in the sintering process were established,analyzed and studied based on the investigation of the material balance data of last year,the potential of the waste heat recovery of the flue gas of the sintering ring refrigerator is also comprehensively evaluated.Thirdly,the thermodynamic research and comparison of dual pressure,single pressure and flash boiler system for flue gas generation of sintering ring cooler were conducted and the steam turbine thermal modeling and research is also carried out on the basis of the thermal modeling and analysis of the waste heat boiler in the flue gas power generation of the sintering ring cooler.Finally,the economic benefit analysis,environmental benefit analysis and social benefit analysis of the power generation system are carried out.The conclusions of this paper are as follows:?1?The composition of the flue gas is similar to the air,and the contents of each component are N₂=77.04%,CO₂=5.83%,H₂O=0.7%and O₂=16.43%,respectively.The recovery potential of the flue gas waste heat of the 1 and 2 sections of the sintering ring cooler is larger,The flow of flue gas in the first section of the ring cooler was 170,000Nm³/h,and the temperature was 390°C,the enthalpy value was 532.48 kJ/Nm³,and the flow rate of the flue gas in the second section of the ring cooler was 130000 Nm³/h,the flue gas temperature was 290°C and the enthalpy value was 391.35 kJ/Nm³.?2?The input and output material of the sintering process is basically balanced with error of 3.2%,the sinter are accounts for a larger proportion of the output material.The input and output energy of the sintering process keeps in balance,the proportion of heat energy consumed by the sintered heat is the largest among them,which can reach37.23%,and its value of waste heat recovery is the largest.?3?The double pressure waste heat boiler system of the waste heat generation of the sintering ring cooler is better than that of the single pressure and flash waste heat boiler system for its higher waste heat utilization rate,higher efficiency,higher steam output and better steam parameters.The waste heat utilization rate of the power generation system is 56%with generation efficiency of 77%,and the annual generating capacity is 44.568 million kW*h.?4?Annual profit of flue gas waste heat generation system of the sintering ring cooler is 11.2862 million yuan.The system will be profitable for the enterprise after the installation and use of the power generation system for about 3.37 years and its economic benefit is good.The annual generation capacity of the power generation system is 44.568 million kW*h and could save 14.40438 thousand tons of standard coal every year with significant environmental benefit.