Due to the corrosion, erosion and scaling of the medium, the heat exchanger must be cleaned. Several common cleaning processes are listed below, as follows.
Mechanical descaling method
When the heat exchanger tube bundle has a slight blockage or scaling, stainless steel rods or low-carbon copper discs can be inserted from one end and pulled out from the other end to exclude minor blockage or scumming and fouling. For light scaling, a special pipe cleaning brush can be selected according to the size of the pipe, and a thick wire is worn at one end to pull the cleaning brush out of the heat exchanger tube.
When the scaling in the pipe is serious or completely blocked, soft metal poke pipe cleaning is available. When the pipe orifice is blocked by scale or foreign matter, manual methods such as shoveling, cutting, scraping and brushing can be used to deal with it.
High-pressure water cleaning
High-pressure water cleaning is the use of high-pressure water pump generated by high-pressure water flow, through a special cleaning gun will be high-pressure water directly to the parts to be cleaned, its pressure adjustment range is 0 ~ 100MPa, when the scale is not too firm, the pressure can be selected in about 40MPa.
When the structure is hard and tight, the high alloy nozzle can also be inserted into the tube for higher pressure cleaning. Generally this method is mainly used to clean the scale layer inside the shell and tube heat exchanger tube, or flush the heat exchange equipment that can be extracted from the tube bundle. Tube and shell surface scaling and foreign matter, such as U-tube heat exchanger cleaning process.
- Cleaning personnel wearing labor protective equipment.
- Rational adjustment of water pressure according to the equipment itself, pay attention to the safety of personnel and equipment.
- try the water gun.
- Clean the heat exchanger tube and shell process.
If the head of the equipment has been disassembled, the cleaning process should be set up in the direction of the water gun spray alert range, and a person to remind.
Chemical descaling
Chemical analysis of the scaling material should be carried out first, and then decide on the solvent used for cleaning. General sulfate, silicate scale with alkali cleaning, carbonate scale with acid cleaning, oil scale coking available sodium hydroxide, sodium carbonate, washing powder, detergent, etc., with water to prepare a certain ratio. When using chemical cleaning, must consider adding corrosion inhibitor.
After chemical cleaning, add water to rinse several times until the water is neutral. In addition to the above cleaning methods, you can also use the sponge ball automatic cleaning method.