Theoretical And Experimentai Study On Jet Type Condenser Used In Peak Cooling Of Air Cooling Unit

Direct air-cooled unit is the main type of thermal power units in northern China.However,with the change of natural factors such as ambient temperature and wind speed,problems such as insufficient heat radiating area and undercapacity of units are exposed.Especially at high temperature period in summer,the units are in peak period of electricity consumption and can not be fully operated due to the obvious increase of back pressure.Aiming at the problem of undercapacity of air-cooled units in summer,the main solution is to install peak cooling system on the original units.At present,the widely used peak cooling technology needs to consume a large amount of water resources in exchange for the increase of power generation,which is extremely scarce in northern areas,especially in Northwest areas,and also contrary to the original intention of saving water for air-cooled units.It is imperative to research zero water consumption peak cooling technology.A new type of indirect air peak cooling system is proposed in this paper.Jet-type condenser is used as the condensing equipment of extracting steam and forced ventilation cooler is used as the cooling equipment of circulating water.The whole system is closed-cycle and does not consume water resources.Taking a 600 MW air-cooled unit as an example,establishe the mathematical model of back pressure calculation of the original unit and indirect air peak cooling system,through optimal calculation determine parameter of peak system,get the reduction values of back pressure under different ambient temperatures,and analyse the influence of natural factors on the peak system.According to the determined system parameters,the design and calculation of the jet-type condenser are carried out,its hydraulic calculation model is established,the distribution ratio of circulating cooling water in the cooling zone before and after the jet-type condenser is obtained.The thermodynamic calculation model is established to analyze the change of heat transfer coefficient of water film at different locations.The rationality of the designed jet-type condenser is verified,and the terminal temperature difference of the condenser under different working conditions was calculated to be within the allowable range.The effects of air volume,water film height,circulating water temperature and steam volume on heat transfer performance are studied.The performance experimental Platform of jet-type condenser is built,and the factors such as recirculating water flow,recirculating water temperature and air in-leakage of the system are experimentally studied.The specific influence rules are obtained,which provided a reference for the actual operation.