燃煤机组烟气余热和水协同回收系统多参数优化及运行策略

To enhance energy saving, emission reduction and economic performance of waste heat and water co-recovery system of boiler exhaust fluegas, and to guarantee the system safe operation, the multi-parameter optimization and off-design characteristics analysis model of the system are developed. With a 330MW power plant as the reference case, the optimized parameters, water-saving and energy-saving potentials of the system were obtained. According to the off-design characteristics of the system, the control strategy of the system under all operating conditions was proposed. The optimization results of the benchmark conditions show that the comprehensive water saving rate of the system is 15.34 kg•s^-1, and the comprehensive coal saving rate of the system reaches 4.12g•(kW•h)^-1. The research on the system off-design characteristics shows that the working fluid temperature and coal saving rate of the system decrease with the ambient temperature. When the ambient temperature drops to -20℃, the compressive coal saving rate of the system decreases by 38.7%, and the inlet circulating water temperature of the low-temperature fluegas cooler decreases below 70℃, threatening the safety of system operation. Therefore, an optimal operation strategy of the system under all working conditions was proposed. This strategy can not only maintain the inlet circulating water temperature of the low-temperature fluegas cooler above 70℃ to ensure the safety of the system, but also realize the effective utilization of the waste heat of the fluegas condensation process.