Most heat exchangers used in industry are surface heat exchangers, in which heat is transferred from the hot medium to the cold medium through a separating wall. Over time, deposits build up on the heat transfer surfaces and must be removed regularly.
Deposits and why they are dangerous
The range of deposits on heat transfer surfaces is very wide. In some cases scale (mineral salts) forms on the walls; corrosion of the equipment material itself is also common. Heat transfer surfaces are often fouled by mechanical impurities and dirt contained in the heat transfer medium. Another widespread cause of fouling is biofouling. Where one of the media is an organic solvent or hydrocarbon gas in oil refining, deposits containing resinification products and coke often form.
Deposits on heat transfer surfaces sharply reduce heat transfer efficiency: the thermal conductivity of deposits is tens of times lower than that of metal. In practice this leads to:
- excessive consumption of fuel and heat;
- overheating of heat exchanger parts, up to burn-through and equipment failure;
- higher hydraulic resistance and lower throughput of the unit;
- deterioration of the process parameters of the entire system, up to going beyond the design values.
Timely cleaning extends the service life of heat exchange equipment and costs much less than replacement or repair.
Cleaning methods
- Chemical flushing — the main method for plate and shell-and-tube heat exchangers, including those with complex channel configurations.
- Hydrodynamic cleaning — using high-pressure units, channel-cleaning hoses and special nozzles; for the tubes of shell-and-tube heat exchangers and dense deposits.
- Mechanical cleaning — for heavy, fully blocked tube sides and individual components; requires disassembly.
- Dry ice blasting (cryoblasting) — gentle surface cleaning without chemicals, water or harsh mechanical action on the surfaces being cleaned; only for accessible surfaces and plates.
- Laser cleaning — non-contact removal of rust, carbon deposits and old coatings from external and accessible surfaces, without chemicals or abrasives.
Methods are often combined: for example, blocked tubes are first opened mechanically and then chemically flushed.
How the work is carried out
- Inspection. Examination of the equipment and, if necessary, video inspection (endoscopy) of internal surfaces. We determine the composition and thickness of deposits.
- Method selection. The method and mode are agreed with the customer for the specific equipment, material and deposits.
- Preparation. Any assembly and disassembly work required by the selected cleaning method.
- Cleaning. Cleaning by the selected method with control of the result.
- Protection. After chemical flushing — neutralisation of chemical residues, water rinsing and passivation of the metal surface against corrosion.
We work on a one-off basis or under a scheduled maintenance contract, with periodic inspections and preventive cleaning.
What we need for a quote
- type and model of the equipment, year of manufacture;
- dimensions, tube and shell material, heat transfer or working medium;
- what is known about the deposits: scale, rust, organics, petroleum products;
- photos and videos, equipment passport or diagram — if available;
- preferred timing: scheduled shutdown, off-season, urgent work.
Frequently asked questions
How do I know a heat exchanger needs cleaning?
Signs include a rising return temperature, lower capacity, a higher pressure drop across the unit and higher fuel consumption at the same load.
Which method should I choose — chemical flushing or mechanical cleaning?
It depends on the design and the deposits. Chemical flushing runs through the internal channels and does not require full disassembly; mechanical cleaning is used for dense and fully blocking deposits. We select the method after inspection and agree it with you.
How often should a heat exchanger be flushed?
The interval depends on the quality of the heat transfer medium and the operating mode. For equipment with regular fouling we offer scheduled maintenance with periodic inspections.
What should I send for a quote?
The type and model of the unit, its dimensions, the working medium, photos and the equipment passport, if available. A completed questionnaire can also be attached to the request.