Thermal Characteristics Simulation And Energy-saving For Cold End System Of Direct Air-cooling Unit

The direct air-cooling technology has become an effective solution for power supply in coal-rich and water scarce areas, and it has got swift and vigorous development. However, the problems of hot-air recirculation and the constant speed adjustment of axial fan cluster which causes poor efficient performance of operation have always existed. Therefore, researching on the operation characteristics of cold end system means a great deal to the direct air-cooling unit.The operation characteristics of the condenser unit and air-cooled island have been simulated with Fluent for #5 supercritical direct air-cooling unit in Shang,an Power Plant. The influences of operating condition on state of air-cooling island have been found. The analyses show that the simulation results have significant reference value for the main plant layout. According to engineering theory, the optimum dispatching module of axial fans can be built and its strategy of fan has been carried out upon the condition that no wind blows or wind blows from the boiler house. A reasonable allocation including four parts of fan module improves the average heat transfer efficiency by 11% to 12%. The practical calculation shows that the dispatching strategy of modularization partitioning is valuable to the application of engineering. The thermal performance simulation programs are written in VB which are validated on design parameter. The high-pressure heaters removal condition and TRL are compared, and the results show that the regenerative system performance also directly affects the economy of cold end system.The study results show that the economic dispatching method can be realized by using condenser pressure as target function and considering two factors of external environment wind field and internal regenerative system parameters. This dispatching way can effectively response the variation of the unit loads. The research results provide a theoretical basis and a technology support for the optical operation of the direct air-cooling units in variable operating conditions.