Circulating water cooling tower knowledge

① there is no evaporation loss of water, no wind blowing loss and no blowdown loss, so the dry cooling tower is suitable for water shortage areas, such as northern China Because there is no evaporation, there is no pollution caused by the air discharged from the outlet of the cooling tower ② The cooling limit of water is low efficiency of dry bulb temperature and high cooling water temperature ③ A large number of metal pipes (aluminum pipes or steel pipes) are required, so the cost is 4-6 times of that of wet tower with the same capacity Due to two disadvantages of dry cooling tower, wet tower should be used as far as possible in the area with conditions The dry tower can be naturally ventilated or mechanically ventilated Taking the dry cooling tower commonly used in thermal power plant as an example, it can be divided into indirect cooling and direct cooling Indirect cooling refers to the cooling water in the cooling tower is sent to the condenser to cool the exhaust steam from the turbine well Direct cooling refers to the direct cooling of the exhaust steam discharged from the steam turbine without using the condenser, which is led by the pipeline to the cooling tower to change into the condensate, and then sent back to the boiler for reuse by the water pump Heller system indirect air cooling dry natural ventilation cooling tower It is characterized by the use of jet condenser The exhaust steam from the turbine and the cold water from the cooling tower are directly mixed in the condenser, so the end difference is very small About 2% of the mixed water is sent back to the boiler and the rest to the cooling tower for cooling Because the cooling water and boiler water are the same kind of water, the water quality is required to be high Another feature is that the water cooled by the cooling tower still has a large residual pressure Before it is sent to the condenser, the small water turbine generator is used to collect energy Its radiator is placed outside the tower, similar to the wet cross flow tower The radiator can also be placed in the tower like the wet countercurrent tower, but in order to drain the water in the radiator, the radiator is not completely horizontal, but has a certain slope Another indirect air cooling tower uses a surface condenser, in which the exhaust steam and cooling water are not mixed with each other Fin tube or threaded tube for radiator, made of steel or aluminum The pipe section is oval or round The exhaust steam discharged from the steam turbine by the direct air cooling tower is directly sent to the cooling pipe in the cooling tower through the pipeline, and then cooled into condensate by fan ventilation instead of condenser, so it is called direct air cooling Because the steam is directly sent to the cooling pipe, rather than to the indirect air cooling tower, it is hot water Because the volume of steam is much larger than that of water, the steam pipe is particularly thick, with a diameter of more than three times that of indirect air cooling In addition, the steam transmission pipeline shall not leak, or it will directly affect the vacuum of the steam turbine and reduce the output Dry and wet cooling tower this kind of tower is the combination of wet tower and dry tower, with cadres at the top and wet part at the bottom There are also towers with wet ends on opposite sides and cadres on the other two sides The purpose of using this kind of tower is partly to save water, but most of it is to eliminate the condensation of saturated air discharged from the outlet of the tower, thus causing pollution around the tower After contacting with the cold air around the tower, the wet air discharged from the wet section at the bottom of the tower will become supersaturated air and condense, forming fog, causing pollution If the dry section is used at the upper part of the tower, the saturated wet air discharged from the wet section at the lower part of the tower will be heated to become unsaturated air when flowing through the dry section, so it will not condense after leaving the tower Jet cooling tower Designed by baitore aircraft, Inc Hot water is sprayed into the tower through pressure nozzle to become a dispersed jet body, and a large amount of air is brought into the tower at the same time Hot water transmits heat to air through evaporation and contact heat transfer The cooled water falls into the water collecting pool, and the air is discharged after passing through the water collector This tower does not use packing and fan, so there is no fan noise The treatment capacity can range from a few tons to several hundred tons per hour.