The Optimal Design Of Gas Turbine Heat Recovery Steam Generator And Flue Gas Waste Heat Refrigeration Cogeneration System

Gas turbine is popular due to its advantages of low capital cost, high flexibility, reliability and environment friendly, which promotes the technology of gas turbine combined cycle(GTCC) greatly.The cogeneration system which includes the gas turbine, the heat recovery steam generator and the flue gas waste heat absorption refrigeration unit receives so much attendtion in academic and engineering fields because of its ability to maximize the recovery of waste heat of exhaust gas of combustion engine with high efficiency.In this article,the cogeneration system which satisfies the fixed demand of heat(65t/h 1.0Mpa steam),power(44MW) and cooling(2000k W) need of one refinery includes the gas turbine,the single pressure heat recovery steam generator and the separated heat pipe Li Br absorption refrigeration unit is used as the research object. Considering the condition of the equipments and the temperature of the heat recovery steam generator is 150~200°C, the cogeration system is divided into three sub systems which include the gas turbine+heat recovery sub system, the single effect Li Br absorption refrigeration sub sytem and the separated heat pipe generator sub system, the optimization design of three sub systems are conducted. First, the mechanism model of the above three sub systems are established. Then the degree of freedom of each sub system is condu cted, finding that the degree of freedom of them are 4,8 and 9. The optimization variables are selected according to the engineering constraints and the convenience of design and the objective functions of each sub sytem are the total annual operation cost(TAC), the thermal coefficient of unit area(A/COP)and the overall heat transfer coefficient(UH). The corresponding programs of the three sub systems are coding in MATLAB and then the genetic algorithm is used for optimization.After the optimization, corresponding to the optimal design parameters of each system, the minimum TAC is 1283×104﹩ of the first sub system,the optimal A/COP is 729.32(COP=0.7252, A=528.9 m2) of the second sub system, the maximumHUis232.0 W/(m °C) of the third sub system.