Heat is a crucial subject to grasp in a variety of engineering domains. Because heat transfer is important in material selection, equipment efficiency, and reaction kinetics, it is especially important for civil, mechanical, and chemical engineers.
What are Heat Exchangers?
Heat exchangers are devices that allow heat to be transferred from one medium to another. These media might be in the form of a gas, a liquid, or a mix of the two. To prevent mixing, the media may be separated by a solid wall or maybe in direct touch.
Cleaning of Heat Exchangers
There are three basic forms of heat exchanger cleaning, each with its own set of benefits and drawbacks based on your process and plant configuration
Cleaning with chemicals– It commonly includes flushing with liquids to remove or dissolve soil
Mechanical cleaning– It is the process of physically removing debris from tubes.
Vibronic cleaning- Cleaning methods that include parts of both.
Chemical Cleaning of Heat Exchanger Tubes
Chemical cleaning has the benefit of not requiring the unit to be dismantled from the process if it is taken offline and cleaning connections are provided. To keep the cleaning fluid contained, the unit is normally separated.
The downsides are that cleaning fluids are sometimes hazardous, and disposal is frequently a challenge. Some chemicals might also cause corrosion if they are not properly controlled.
Depending on the cleaning chemicals, the physical technique of applying them differs.
- Temperature: elevated or ambient
- Type of fluid filling
- Chemicals in the form of liquids, vapors, foams, or emulsions are used.
The rate of foulant elimination will improve if cleaning fluid is circulated.
In chemical cleaning of heat exchanger tubes, if the cleaning connections are tiny or the heat exchanger is obstructed, a high circulation rate may be difficult to obtain. To induce agitation without circulation, air sparging can be utilized.
To accomplish a comprehensive cleaning, chemical cleaning is frequently done in phases. The following factors, as well as lab testing against specific fouling deposits, determine the appropriate type or combination of fluids or gases to utilize. The final advice will be to utilize acids, alkalis, oxidants, or solvents.
Cleaning acids come in a wide variety of strengths. Hydrochloric, nitric, sulphuric, and other acids are examples. Inhibitors are frequently added to prevent the acid from damaging the heat exchanger’s surface.
Organic foulants such as fats and greases are frequently removed using cleaning alkalis such as caustic soda and ammonia.
Potassium permanganate, sodium bromate, and sodium nitrite generate a persistent oxide layer on the cleaned surface, forming a corrosion-resistant shell. Passivation is the term for this process of cleaning.
Solvents such as aromatic hydrocarbons, aliphatic hydrocarbons, and chlorinated hydrocarbons are utilized to dissolve certain deposits. However, they are strictly controlled.
Biocides, surfactants, inhibitors, antifoams, and dispersants can all be added to help in the cleaning process.
Cleaning advice will be included in a thorough design process that has taken your procedure into account. Your heat exchanger servicing professionals should be able to advise you on the optimal chemical and additive combinations to obtain the outcomes you want.
Mechanical cleaning is another option for keeping heat exchangers in good working order, but it necessitates access concerns and, in many cases, needs the unit to be withdrawn from the process totally so that the maintenance crew can reach all areas of the bundles.
Access to the inside of tubes is normally straightforward on Shell and Tube type exchangers. However, U tubes might present some obstacles, according to our experience. Therefore, if the original designer considered cleaning and maintenance, detachable bundles, square, or huge pitches might have been incorporated to make access simpler.
There are approximate as many different types of cleaning equipment as there are different types of exchangers to clean. Service crews will use brushes, scrapers, and drills to remove soft deposits (manual or motor-driven, with or without water flushing).
Mechanical cleaning can be done on either the tube or the shell, but care must be given to ensure that the instruments are handled appropriately to avoid damage.
High-pressure water jetting, with pressure ranges of 200 to 3000 Bar, is a frequent mechanical cleaning procedure for brittle and hard deposits. Water seeps into the fouling’s fissures, pushing the fracture to spread and shattering the deposit, allowing it to be flushed away.
Hydro jetting is a particularly effective mechanical cleaning process. It is frequently employed on a large number of exchanges at the same time during a refinery turnaround.
There are additional cleaning procedures that combine the two forms of cleaning. For instance, employing mechanical ways to boost the efficacy of a cleansing chemical mix. This is shown by Serck’s vibronic cleaning service.
Vibrasonic cleaning uses pneumatically powered turbines to generate sinusoidal wave patterns via a specially prepared cleaning fluid, combining the advantages of mechanical agitation with chemical dissolution to deliver a deep, thorough, and quick cleaning that is also very cost-effective.
How Often Should I Clean My Heat Exchanger?
So, how often should your heat exchangers be cleaned? Frequent cleaning has been shown to save energy and reduce unexpected downtime, but this must be balanced against any lost productivity from even the most meticulously planned shutdowns.
Site maintenance engineers can use historical data from extensive maintenance records to create an effective cleaning program. In this area, we also see advancements in Industrial Internet of Things technology, where condition-based monitoring may warn to lower performance before critical maintenance is required and without overscheduling process-limiting service before it’s genuinely required.
Contact Heat Exchanger Industry
IF you are looking for installation, repair, maintenance, or cleanliness of your heat exchanger, instead of waiting long, contact the experts. You need to hire experts so that you do not have to deal with any consequences later.
Experts are licensed and certified professionals with years of experience. They know how to do their job. Contacting them can be both time and money-saving. Search online, and you will find some of the best companies.