Performance Analysis And Optimization Of Coke Dry Quenching Waste Heat Power Generation System

As a waste heat recovery process,CDQ(Coke Dry Quenching)waste heat power generation system can effectively recover and utilize the high-temperature sensible heat carried by red coke.As the main coke producer,domestic independent coking enterprises have low popularization rate of CDQ and immature waste heat recovery technology.Taking the CDQ waste heat power generation system of independent coking enterprises as the research object,this paper qualitatively analyzes the production process of CDQ waste heat power generation system and the mechanism of waste heat generation from both field and theoretical aspects,and quantitatively calculates the position and distribution proportion of waste heat in the CDQ waste heat power generation system.Key discussions focus on CDQ furnace and waste heat boilers..The main contents are as follows:(1)The Aspen Plus CDQ technology simulation process is established,and the heat exchange of CDQ furnace is qualitatively analyzed.Controlling the amount of circulating gas has little effect on adjusting the temperature of cold coke and boiler inlet gas,while adjusting the amount of coke discharge can effectively change the temperature of boiler inlet gas and cold coke.When the carbon dioxide concentration of circulating gas increases by 1%,the gas temperature at the boiler inlet decreases by3℃and the temperature of cold coke decreases by 2℃.When the circulating gas-to-coke ratio is 1450 Nm~3/t,the heat transfer is the best.The law of heat transfer points out the optimization direction for improving the heat transfer efficiency in CDQ furnace.(2)Based on the law of heat transfer of CDQ furnace,the thermal exergy analysis model is used to calculate and analyze the CDQ waste heat power generation system.The analysis shows that the condenser is the most serious heat loss of CDQ waste heat power generation system in full condensation state,accounting for 52.54%,followed by cold coke,accounting for 16.98%.At the same time,the exergy loss is mainly concentrated inside the equipment.The steam turbine accounts for 24.28%of the exergy of the system,the waste heat boiler accounts for 23.42%of the exergy of the system,and the CDQ accounts for 5.29%of the exergy of the system.In actual operation,the burning loss of coke is a major factor affecting the efficiency of the exergy of the system of CDQ system.The lower the burning loss rate of coke,the greater the efficiency of exergy.When the circulating gas-coke-ratio is 1450 Nm~3/t,the exergy carried by the boiler inlet gas is the largest,which is 126.3 GJ/h.At this time,the exergy efficiency of dry quenching furnace is increased by 0.74%.Increasing the main steam pressure and temperature can improve the working capacity of the system,and the temperature has a great impact on the working capacity of the steam.The main steam parameters can be adjusted purposefully according to the production needs.(3)The energy-saving benefit of CDQ waste heat power generation system is calculated and analyzed.Dry quenching one ton of red coke saves 0.41 t steam and25.29 kg standard coal.The biggest factor affecting energy saving is the burning loss of coke,including burning loss inside and outside furnace.After the red coke transportation situation is improved,the energy saving of each ton of red coke will increase by 2.14 kg of standard coal.After the system parameters are optimized,an additional 100,560 KW·h will be generated in the whole year.