What Are The Application Scenarios Of Dry Coolers in Thermal Power Plants?
What are the Application Scenarios of Dry Coolers in Thermal Power Plants?
Turbine Spent Steam Cooling
Direct air cooling system: The dry cooler is directly used to cool the spent steam discharged from the turbine. The spent steam is transported to the tube bundle of the dry cooler through the pipeline, where it exchanges heat with the air flowing outside the tube, is cooled and condensed into water, and then returned to the thermal system. This application scenario is more common in large thermal power generating units in water-scarce areas, such as some coal-fired power plants in Northwest China and North China, where the use of direct air-cooling technology can significantly reduce water consumption.
Indirect air-cooling system: In the indirect air-cooling system with surface condenser, the turbine spent steam is firstly cooled and condensed by the circulating water in the surface condenser, and then the circulating water is cooled by the dry cooler to realize the heat transfer and distribution. In the indirect air cooling system with jet condenser, jet pumps are used to mix the turbine spent steam with circulating water, and then the circulating water is cooled by the dry cooler, which is suitable for the occasions that require higher water quality or better control of cooling water temperature.
Auxiliary equipment cooling
Generator cooling: generators generate a lot of heat during operation and need to be cooled to ensure their normal operation and service life. Dry cooler can be used to cool the cooling medium of the generator, such as air or hydrogen, etc. The heat in the cooling medium is transferred to the outside air through heat exchange to maintain the proper temperature of the generator.
Turbine lubricating oil cooling: The lubricating oil of the turbine will increase in temperature due to the absorption of heat from the bearings and other parts during operation, and it needs to be cooled to ensure its good lubricating performance and heat dissipation effect. The dry cooler can cool the lubricating oil to ensure that the temperature of the lubricating oil is within the normal range, so as to ensure the safe and stable operation of the turbine.
Cooling of other auxiliary equipment: For other auxiliary equipment in thermal power plants, such as feed pumps, condensate pumps, supply fans, induced draft fans, etc., their motors or bearings and other parts will also generate heat during operation, and the dry cooler can be used as a part of the cooling system to cool the cooling medium of these auxiliary equipment to ensure the normal operation of the auxiliary equipment.
Other cooling links in the thermal system
Condensate re-cooling: After the initial cooling of the condensate, sometimes it is necessary to further reduce the temperature to meet the requirements of the thermal system, for example, in some of the lower temperature requirements of the condensate back to the heat system. The dry cooler can recool the condensate to improve the quality of the condensate and the efficiency of the heat system.
Cooling of circulating water in heat grids: In thermal power plants where heat grids are used for heat supply, the circulating water in the heat grids needs to be cooled for recycling as the temperature rises after absorbing some of the exhaust heat from the turbine. The dry cooler can be used to cool the circulating water of the heat network and reduce its temperature to a suitable range, so as to realize the effective transfer and recycling of heat.
