Water hammer in steam heat exchangers

Where exactly does water hammer occur? Water hammer occurs due to the formation of a slug flow; measures can be taken regarding the condensate drainage to ensure smooth flow. If water hammer occurs in the condensate line, it is necessary to check whether a large amount of steam is entering the condensate system

The main cause of water hammer is still the poor drainage of condensate; the steam flow velocity is high while that of the condensed water is low.

It is likely caused by too slow drainage speed of the condensate water; adjust the steam flow to achieve a dynamic balance between heat supply and demand.

If the condensate water is not drained in a timely manner, installing a steam trap will solve the problem.

Installing a fully automatic regular drainage system at the lowest point of the equipment can solve this problem.

It is unknown where the liquid slugging is occurring. The reasons for liquid slugging are as follows: 1. Leaks in the heat exchanger lead to a mixture of vapor and liquid, which facilitates the occurrence of liquid slugging； 2. The vapor-phase valve is opened too wide, resulting in a low liquid-phase flow rate ； 3. If there is a steam trap, check whether it is unobstructed; if there is a bypass in the steam drain line, open it slightly to see if there is any change in the effect of water hammer. When putting heat exchange equipment into operation, it is necessary to first warm the pipes, remove condensate water, and then gradually supply steam to raise the temperature. During operation, to regulate the temperature, the steam valves must be operated smoothly to ensure a gradual increase or decrease in temperature.

First, check whether there is condensate in the steam; examine each trap sequentially from the source to rule out problems one by one. Looking for other reasons

It is necessary to determine where the water hammer occurs, whether it is front-end water hammer or back-end water hammer. If water hammer has not occurred before, check whether there is a malfunction in the steam trap of the heat exchanger. Replacing the steam trap with the same model will solve the problem. If this has happened before, it is due to an improper selection of the steam trap, which results in poor drainage of water; the steam flow rate is much higher than that of the condensate flow, and the steam carrying the condensate moves rapidly, causing water hammer. You can try opening a little of the bypass valve on the heat exchanger, drain the water, and see if the water hammer is reduced. It is also possible to check the source of the steam; the steam at the inlet may, due to long-distance transmission, cause some of it to condense and generate water. This water enters the heat exchanger along with the steam, which can also lead to water hammer. Given that the steam temperature you mentioned is around 200 degrees, the pressure is likely to be high as well, perhaps around 10 kilograms of pressure. If there is a large amount of wastewater and steam being discharged at the downstream end, you might want to consider the steam energy-saving equipment developed by our company. Built-in flash vapor extraction for pressurized reuse. It can also speed up the drainage of heat exchangers. Ensure that the heat exchanger is not filled with water, avoiding water hammer. It can be made as a steam return pipeline without a steam trap. Condensate water can be used to replenish water in boilers; it does not require softening or deoxygenation, and it can also be used for other purposes.

Water hammer is extremely destructive; in severe cases, it can break drainage pipes, leading to casualties and safety accidents. If water hammer is severe, the sooner it is resolved, the less damage will be done to the heat exchanger. Previously, at a client’s site in Binzhou, I saw that the heat exchanger in their air-flow drying tower had been damaged by water impact; there was severe leakage of hot water and high-temperature steam at the scene. Fortunately, no injuries were reported. Eliminating or reducing vapor in water under high pressure, or water in vapor, can both prevent water hammer phenomena.