Winter antifreeze solution of closed cooling tower and evaporative condenser

The evaporative condenser (closed cooling tower) is widely used in metallurgy, electric power, petroleum, chemical and other industries, it has the advantages of water-saving, energy-saving, high heat exchange efficiency and so on.

The temperature is usually below zero in winter, and the problem of frost prevention in the operation of closed cooling tower has become increasingly prominent. If it is not solved well, the heat exchange tubes or other parts of the cooling tower may be damaged by freezing. So, it is necessary to consider the issue of winter  antifreeze solution of closed cooling tower. There are several solution for different operation condition.

1. )The closed cooling tower is barely used in winter

 If the closed cooling tower does not need to be operated in winter, the spray water and circulating water inside the heat exchange tube must be drained when it is shut down.

  Specific operation sequence:

       ① Turn off the power of the axial flow fan and spray water pump successively;

       ② Close the equipment inlet valve, open the tube bundle vent and drain sealing cover, connect the DN32 water pipe to the tube bundle drain pipe to introduce the water in the tube bundle into the water tank, then close the water tank replenishment valve, open the drain valve to empty the water tank, and turn on the spray water pump The drain outlet drains the water in the pump body;

       ③ Open the bottom line plug of each pipe pass, and use high-pressure air to drain the residual water in the pipe;

       ④ Install the wire plug to the equipment, and cover the tube bundle to vent and drain.

       (For a closed cooling tower with a flexible coil structure, when it is out of service, open the inlet and outlet valves of the equipment to drain the medium in the pipe)

2. )The closed cooling is occasionally used in winter

In winter, the evaporative cooling equipment has a large heat dissipation capacity. For a system with multiple equipment running in parallel, some spraying water and fans can be stopped to reduce the heat dissipation of the equipment to achieve the purpose of antifreeze. For equipment with water tanks, it should be installed as far as the water storage tank or underground drainage pool. When the spray water temperature is lower than 10℃, the water in the water collection tank should be emptied.

For the antifreeze of a small circulating water system, consider adding glycol and then air-cooling operation; adding antifreeze can solve the problem at one time. Ethylene glycol solution is the main component of most antifreeze liquids. The disadvantage is that the price is higher (≈$1400/ton).

Ethylene glycol solution is the main component of most antifreeze liquids. Refer to the following table for antifreeze formula:

3. )The closed cooling toweryear-round operation  

① When the ambient temperature is 0°C ~ -5°C, anti-freezing measures must be taken when the machine stops for more than 10 hours;

② When the ambient temperature is  -5°C ~ -10°C, anti-freezing measures must be taken when the machine stops for more than 5 hours;

③ When the ambient temperature is lower than -10℃, anti-freezing measures must be taken when the machine stops for more than 1 hour.