Open classification: industry, production
1, cooling tower
In industry, a device for cooling hot water. Water is transported to the tower to exchange heat with air or heat and mass, thus reducing the water temperature.
2. Wet cooling tower
A cooling tower in which water and air directly contact and exchange heat and mass at the same time.
3. Dry cooling tower
There is no direct contact between water and air, only the cooling tower exchanges heat.
4. Dry and wet cooling tower
A cooling tower consisting of dry and wet parts.
5. Natural ventilation cooling tower with natural ventilation
A cooling tower that uses air convection ventilation formed by air density difference inside and outside the tower or natural wind.
6. Mechanical ventilation cooling tower with mechanical ventilation
A cooling tower ventilated by wind.
7. Chimney cooling tower of air duct cooling tower
The cooling tower has hyperbola, cylinder, polygon and other geometric lines and a certain height of air duct.
8. Open cooling tower
There is no air duct, the cooling tower is ventilated by natural wind, and the louver cooling tower is set around the water spraying filler.
9. Mechanical cooling tower of induced draft fan
The fan is installed in the cooling tower at the air outlet of the cooling tower.
10, forced ventilation mechanical cooling tower with forced mechanical ventilation
The fan is installed in the cooling tower at the air inlet of the cooling tower.
1 1, cross-flow cooling tower
Water flows vertically from the upper part of the tower, air flows horizontally through the packing, and the air flow is orthogonal to the water flow in the cooling tower.
12 countercurrent cooling tower
A cooling tower in which the water flows vertically in the tower and the air flow direction is opposite to the water flow direction.
13, closed cooling tower of closed cooling tower
Use the self-circulating water in the cooling tower to cool the circulating water in the copper tube. The water quality of circulating water in copper tube can be well guaranteed.
Working principle of cooling tower
Cooling tower is a kind of equipment that uses the contact between water and air to dissipate the waste heat generated in industry or refrigeration and air conditioning through evaporation. The basic principle is that dry (low enthalpy) air enters the cooling tower from the air inlet network after being twitched by the fan; High temperature water molecules with high partial pressure of saturated steam flow to the air with low pressure, and hot and humid (high enthalpy) water is sprinkled into the tower from the water seeding system. When water drops contact with air, on the one hand, due to the direct heat transfer between air and air, on the other hand, due to the pressure difference between the surface of water vapor and air, evaporation occurs under the action of pressure, taking away the latent heat of evaporation at present and the heat in water, that is, evaporation heat transfer, so as to achieve the purpose of cooling down. Working process of cooling tower: Take the working process of circulating countercurrent cooling tower as an example: the hot water main room pumps the circulating water into the water sowing system of the cooling tower through pipes, horizontal throats, curved throats and central throats at a certain pressure, and evenly sprinkles the water on the filler through small holes in the water sowing pipe; Dry air with low Han value enters the tower from the bottom through the air net under the action of the fan, hot water flows through the surface of the packing to form a water film to exchange heat with the air, hot air with high humidity and high Han value is pumped out from the top, and cooling water drips into the bottom basin and flows into the main engine through the water outlet pipe. Under normal circumstances, the air entering the tower is dry air with low wet bulb temperature, and there is obvious concentration and kinetic energy pressure difference between water and air. When the fan is running, under the action of static pressure in the tower, water molecules continuously evaporate into the air and become water vapor molecules, and the average kinetic energy of the remaining water molecules will decrease, thus reducing the temperature of circulating water. From the above analysis, it can be seen that evaporative cooling has nothing to do with whether the air temperature (usually called dry bulb temperature) is lower than or higher than the water temperature. As long as water molecules can continuously evaporate into the air, the water temperature will drop. However, the evaporation of water into the air will not go on endlessly. When the air in contact with water is not saturated, water molecules evaporate into the air continuously, but when the air in contact with water and gas is saturated, water molecules cannot evaporate, but are in a dynamic equilibrium state. The number of water molecules evaporated is equal to the number of water molecules returned from the air to the water, and the water temperature remains unchanged. It can be seen that the drier the air in contact with water, the easier it is to evaporate and the easier it is to lower the water temperature.
Classification of cooling towers
First, according to the ventilation mode, there are natural ventilation cooling towers, mechanical ventilation cooling towers and mixed ventilation cooling towers.
Second, according to the contact mode between hot water and air, there are wet cooling towers, dry cooling towers and dry-wet cooling towers.
Three, according to the flow direction of hot water and air, there are countercurrent cooling towers, cross-flow (AC) cooling towers and mixed-flow cooling towers.
Four, according to the use of general air conditioning cooling tower, industrial cooling tower, high temperature cooling tower.
Five, according to the noise level is divided into ordinary cooling tower, low noise cooling tower, ultra-low noise cooling tower, ultra-quiet cooling tower.
Six, others such as jet cooling tower, fan-less cooling tower, hyperbolic cooling tower, etc.
Scope of application of cooling tower
Waste heat generated in industrial production or refrigeration is generally taken away by cooling water. The function of cooling tower is to exchange heat between cooling water with waste heat and the air in the tower, so that the waste heat can be transferred to the air and emitted to the atmosphere. For example, in thermal power plants, the boiler heats water into high-temperature and high-pressure steam, which drives the steam turbine to do work and makes the generator generate electricity. The waste steam after the steam turbine does work is discharged into the condenser, which exchanges heat with cooling water and condenses into water, and then is pumped back to the boiler for recycling. In this process, the waste heat of exhaust steam is transferred to cooling water, which makes the water temperature rise. The cooling water with waste heat is transferred to the air in the cooling tower and discharged into the atmosphere from the air duct. Application scope of cooling tower: it is mainly used in air conditioning cooling system, refrigeration series, injection molding, leather making, foaming, power generation, steam turbine, aluminum profile processing, air compressor, industrial water cooling and other fields, and the most widely used are air conditioning cooling, refrigeration and plastic chemical industry.
structural style
In order to save energy, large-scale cooling towers mostly adopt natural ventilation cooling towers, which are composed of ventilation pipes, herringbone columns, ring bases, water spraying devices and tower core materials.
Most ventilators are reinforced concrete hyperbolic rotating shells, which have good structural mechanics and hydrodynamic characteristics. The lower edge of the shell is supported on V-shaped or X-shaped inclined columns with equal distance to form the air inlet of the cooling tower. The load of the shell is transferred to the foundation through the inclined column. The foundation is often made into a circular foundation with an inclined plane to bear part of the circumferential tension from the inclined column, or it can be made into an independent single foundation or pile foundation.
The throat diameter of the ventilation pipe is the smallest, and when the shell is stable under pressure, the shell wall is the thinnest, so the upward diameter gradually increases, forming the diffusion section of the airflow outlet. A rigid ring is arranged at the top of the tower, which gradually expands in a hyperbolic shape below the throat, and the shell wall of the lower section is correspondingly thickened, forming a lower ring beam with certain rigidity. The ventilation pipe can also be made into a truncated cone shell or a combined cone shell, or a polygonal tower tube with a steel frame wrapped with a wooden fender or an asbestos cement fender. A dry-type cooling tower with a height of1.46m in Schmeihausen nuclear power station, Germany, adopts a tower with a net cable structure, and is covered with aluminum fender and aluminum fender, which has good seismic and wind resistance.
Function of cooling tower
1. Thermal power plants generally have cooling towers, cooling towers, cooling towers, cooling towers, cooling towers and cooling towers. After water is heated, high-pressure gas is generated to drive the turbine to generate electricity, and the remaining gas needs to be cooled. Its working principle is as follows: the water on the cooling tower of the power plant is pumped up by a pump and evenly dispersed and dripped through the water distributor. Generally, the height of a cooling tower is tens of meters, like a huge chimney, which can draw air up from below and take away heat in the process of contact between air and water droplets, thus playing the role of cooling water.
2. The central air conditioner also has the function of cooling tower to cool the circulating liquid.
3. There are also glass fiber reinforced plastic cooling towers, commonly known as cooling towers, cold water towers, cooling towers, glass fiber reinforced plastic towers, water towers and so on. , mainly including square, round, cross-flow, counter-flow and non-packing spray series cooling towers.
Compared with the traditional packing cooling tower, the automatic rotary atomizing cooling tower also has the following incomparable advantages:
1. Because there is no packing, the tower is basically in a hollow state, with small fan resistance and low noise.
2. The efficient water collector produced by our company's patented technology can effectively reduce floating water and save water obviously.
3. The tower adopts streamlined design, with small gap between the fan and the air duct, large air volume, fast wind speed and good cooling effect.
4. The automatic rotary atomizer is made of polymer wear-resistant material, which is corrosion-resistant and has long service life.
5. Modular design is adopted to facilitate transportation, installation and debugging.
6, no jam, no maintenance, stable and reliable operation. A series of phenomena that affect the performance of packed tower and process system equipment are completely eliminated, such as packing being blocked by impurities in circulating water, aging, deformation, brittle cracking of packing, blocking and falling of water distribution nozzle, and packing debris blocking pipelines, pumps, heat exchangers, etc. The trouble of frequent cleaning and replacement of fillers and water distribution nozzles is completely eliminated.