| Energy is the foundation of human development,steel materials in the human social progress plays an important role,is also the symbol of human civilization,iron and steel enterprises is also a large energy consumption at the same time,in the process of production will produce a lot of waste heat resources,how to make good use of this part of resources is not only the requirement of energy conservation and emissions reduction but also reduce the energy consumption of per ton steel important way to improve enterprise competitiveness.In the Outline of the 13 th Five-Year Plan for National Economic and Social Development,it is proposed to further reduce the energy consumption per unit of GDP.As industries with high energy consumption and high pollution,iron and steel enterprises are naturally the first to take the lead.In the Plan for The Adjustment and Upgrading of the Iron and Steel Industry,it is proposed that by 2020,the energy consumption per ton of steel will be reduced from 572 kg to 560 kg standard coal,and the total energy consumption will be reduced by more than 10%.Based on the conventional energy saving technology of sintering waste heat power generation,this paper compares the flash-evaporation process,sintering double pressure waste heat boiler,sintering waste heat power generation process with and without flue gas,and concludes that double pressure waste heat boiler is the most efficient way.However,the thermal balance analysis method can only analyze the quantity of energy,and the results are often one-sided and unscientific.Exergy analysis since the 1970 s can be evaluated not only in terms of quantity but also in terms of quality.Exergy analysis method is used in the fourth chapter to calculate the exergy loss and exergy efficiency of Plant A and Plant B respectively.Plant A is A conventional sintering double pressure waste heat boiler plant B is A double pressure superheated steam furnace combined system.Results: The exergic efficiency of Plant A was 49.76%;Exergic efficiency of Plant B is 31.16%,combined exergic efficiency is 44.6%.From the exergy loss,the exergy loss inside waste heat boiler in Plant B and Plant A was 33.49% and 11.96% respectively.The partial heat loss of superheated steam furnace accounts for85.28%.It can be seen from the calculation results that Plant B has energy saving potential in waste heat boiler and superheated steam furnace.The weak link of energy use is found out through calculation,and the direction of energy saving in the future is pointed out.The steam source stability of steelmaking converter is poor and storage is difficult.A large area of leakage occurred in the high-temperature superheater tube of Plant B after the superheated steam furnace had been operating for about three years,and the service time was far less than the design life.In Chapter 5 of this paper,the study was carried out.The famous Larson-Miller formula was used to analyze the hightemperature superheater tube with 15 Cr Mog as the material.If the failure time is about 3 years,the wall temperature of the tube will be around 1000?,which is consistent with the operation data.When replacing the superheater tube,black oxide was found on the inner side of the tube wall,especially on the fire side.Therefore,the cause of low service life was the combined effect of creep failure and high-temperature steam corrosion in the tube.The operation suggestion is to control the furnace temperature strictly and set a minimum security flow.And can run according to the data of superheater tube replacement time is given. |
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