Research On Efficient Power Generation Of Sintering Waste Heat Energy

Energy-efficient and emission-reducing has been taken as one of the important research targets in iron and steel industry in China, and efficient recovery and full use of the waste heat in iron and steel industry will be as the breakthrough of deep-level energy conservation in iron and steel production. With project selection of major iron and steel project and urgent demand in energy-efficient and emission-reducing in China, efficient recovery and power generation of sensible heat of flue gas from sintering machine tail bellows and sinter ore in sintering process is an urgent problem to overcome. In this dissertation, the sintering process in iron and steel industry is taken as the research object. And based on field synergy principle and energy cascade utilization method, lots of work including theoretical study on efficient recovery of sintering waste heat, experimental study on sensible heat cascade recovery of sinter, development of efficient recovery device and process about sintering waste heat and optimal selection and scheduling of sintering waste heat power station is done. Above four parts, they are independent of each other, support each other and prove each other. The major scientific issues involved are as follows:1. Heat transfer model of two processes including sinter conveying and sinter cooling is established. Based on the sintering energy flow diagram, thermomass transport effect on transport pathways and in cooler is revealed. According to field synergy principle of convective heat transfer optimization, the mechanism of sinter gas-solid heat transfer is analyzed, vertical sinter cooler and double-helix sinter cooler are developed, and the scientific essence of improvement of medium-low temperature waste heat grade is revealed.2. Combined with orthogonal experimental method, the experiment of sinter sensible heat cascade recovery is done. Heat transfer characteristic in different particle size, material thickness, cooling air volume and air temperature of the cooler inlet is discussed. The influence of sinter operation process and equipment parameters and other factors on cooling rate of cooler exhaust gas and heat source parameters is revealed. Above work can provide basis for the optimization operation, design and improvement of the cooler.3. According to the method of collaborative heat recovery and cascade utilization, the three-inlet HRSG and dual-source HRSG are developed to enhance comprehensively the performance and efficiency of the sintering waste heat recovery device, and to achieve the goal of minimizing the sintering waste heat dissipation. The dissertation researches scientific basis and circulation collaborative law of convertion from heat to mechanical energy among sintering machine and cooler, waste heat boiler and steam turbine, then puts forward advanced progress program about sintering double waste heat source integrated power generation and helical cooler cascade power generation.4. Net power output is taken as the optimization target. According to the method of cascade utilization, this dissertation builds thermodynamic calculation and optimization model of sintering waste heat power station, and makes optimized selection of thermal system and equipment, at the same time, researches coupling mechanism of exhaust system and steam-water system and response strategy of cooler adapting to sintering mechanism change, then provides the optimal dispatch method about unit sinter waste heat power generation indicators to achieve optimized scheduling to sintering waste heat power station operation.At the view of heat transfer and conversion, this dissertation carries out applied basic research on efficient power generation of sintering waste heat, and develops four key technologies includes the technology of cooler heat transfer enhancement, technology of sinter sensible heat extraction, technology of cascade recovery of sintering waste heat, technology of optimizated selection of sintering waste heat power station. The research results provide theoretical reference for basic science problem research about low-medium grade industrial waste heat efficient recovery, and also offer technical assurance for energy-efficient and emission-reducing in the iron and steel industry.