Design And Application Of Low-pressure Feedwater Heater For 30MW Condensing Steam Turbine

The feedwater heater is mainly arranged between the condensate pump and boiler while the low pressure heater is arranged between the condensate pump and deaerator to enhance the condensation of water temperature through the heat exchange of hot and cold medium,reduce the steam turbine directly discharged into the condenser and the actual amount of steam still has potential,improve the heat exchange efficiency of thermal system.The high pressure heater is arranged between the water supply pump and the boiler,and the water supply is heated by the extraction of the steam from the high-pressure cylinder of the steam turbine.In theory,the more heat recovery series,the better the thermal economy of the generator group,but the investment of the equipment will increase,and the system becomes more complicated.The setting of the feedwater heater is determined by the comparison of the equal enthalpy distribution and the comprehensive technical and economic analysis of the investment cost of the power plant,so it has the best economy.It is proved by practice that if the heater is not used in a turbo generator set,the net heat consumption and coal consumption of the unit will be multiplied and the output will be reduced.In the same way,the change of a suitable feedwater heater is also affected by the parameters of the whole unit.This paper takes ShanDong QingNeng power co.,LTD production of "ShenMu Power Generation Company Limited,JiuYe complementary energy recycling power project N30-8.83 high temperature and high pressure,single cylinder,direct air-cooled steam turbine generator" as the main body,designs and develops a suitable heat temperature higher than 130?(i.e.,high pressure deaerator)low pressure heater unit,according to the design conditions and special conditions,in accordance with the unit needs and customer specific requirements and the actual situation of the company.This paper completed the design and calculation process,the low-pressure heater mainly includes:how to determine the heat exchanger area and suitable structure size;optimal optimization of heat transfer coefficient;design and selection of heat exchangers;flow structure design of pipe and shell;optimization of pipe and shell inlet and outlet;optimization of related components.In addition,the low in the field at outage,working state monitoring and frequent fault handling related issues are discussed.This article from the product design versatility and interchangeability of components,the main products include bundle,shell,water chamber and related accessories were optimized design,can reduce the time of development,product inventory and the operating risk of manufacturing enterprises.The design of the low base,straighten out the high pressure(low water side)and the development process,such as the design of heat exchanger steam seal heater to provide reference for other types of the company after the low and other exchangers,have great help to the company's future products to broaden and improve the competitiveness.