how to clean shell and tube heat exchanger?

How to Clean the Heat Exchanger Tube Bundle

Heat exchanger cleaning

Due to the corrosion, erosion and fouling of the medium, the heat exchanger must be cleaned. Several common cleaning processes are listed below, and the specific implementation is as follows:

Mechanical descaling

When the tube bundle of the shell-and-tube heat exchanger is slightly blocked or slag is accumulated, stainless steel bars or low-carbon copper discs can be passed in from one end and pulled out from the other end to remove the slight blockage or slag accumulation.

For light and thin fouling, you can choose a special pigging brush according to the size of the pipe diameter, put a thick iron wire on one end, pull the pigging brush out of the heat exchange tube, and repeat it several times to remove the scale that is not tightly combined with the heat exchange tube or Accumulation of foreign matter.

When the scale inside the pipe is serious or completely blocked, it can be cleaned with a soft metal poke. When the nozzle of the pipe is blocked by scale or foreign matter, it can be handled manually by shoveling, chipping, scraping, brushing, etc.

High pressure water cleaning

High-pressure water flushing is to use the high-pressure water pumped by the high-pressure water pump to directly pump the high-pressure water to the parts to be cleaned through a special cleaning gun. Its pressure adjustment range is 0~100MPa.

When the scaling is not too tight, the pressure can be selected to be around 40MPa. When the structure is hard and tight, the high-alloy nozzle can also be inserted into the tube to use higher pressure cleaning. Generally, this method is mainly used to clean the scale layer in the tube of the shell-and-tube heat exchanger, or to flush the heat exchanger equipment that can extract the tube bundle. Scaling and foreign matter on the surface of shell and tube bundle, such as the cleaning process of U-shaped tube heat exchanger:

(1) Cleaning personnel should wear labor protection equipment;

(2) Reasonably adjust the water pressure according to the condition of the equipment itself, and pay attention to the safety of personal and equipment;

(3) Trial water gun;

(4) Clean the heat exchanger tube and shell side. If the head of the equipment has been disassembled, a warning range should be set up in the direction of the water gun spraying water during the cleaning process, and a special person should be sent to warn.

Chemical descaling

First of all, chemical analysis should be carried out on the fouling substances, and then decide what solvent to use for cleaning.

Generally, alkali washing is used for sulfate and silicate scales, acid washing is used for carbonate scales, and sodium hydroxide, sodium carbonate, washing powder, detergent, etc. can be used to prepare and wash oily scales in a certain proportion with water.

The addition of corrosion inhibitors must be considered when chemical cleaning is used. After chemical cleaning, add clean water to rinse several times until the water is neutral. In addition to the above cleaning methods, the sponge ball automatic cleaning method can also be used.