Heat exchangers are used in many refrigeration, heating, ventilation, air conditioning (HVAC), and other processing systems in engineering to facilitate the heat transfer from one liquid or gas to another. However, fouling and aging can occur when heat exchangers are not maintained properly. This could result in increased operating costs caused by the rise of energy usage to compensate for the gap in the target temperature.
Therefore, cleaning and maintaining heat exchangers are essential for running smoothly and efficiently. In the long term, regularly maintaining your heat exchanger systems is a lot more cost-effective than repairing a heat exchanger in the event of an unexpected breakdown.
What Is Fouling?
Fouling is the accumulation of deposited materials such as insoluble salts, scales, suspended solids, and in some cases, algae. This significantly impacts the effectiveness of heat transfer and the overall performance of the heat exchange systems, as buildup restricts more of the cross-sectional area and increases the resistance to the fluid passing through tubes.
As a result, this causes the pressure to change across the heat exchanger, subsequently affecting the flow velocity and reducing the system’s efficiency. Over time, this could lead to high maintenance costs to remove large amounts of fouling deposits, loss in production by unscheduled shutdowns, and replacement costs of parts and components in the plugged equipment.
Factors Affecting Frequency and Extent of Fouling
There are a few factors that play significant roles in accelerating the occurrence of fouling; these include the chemical properties of the fluid, fluid temperature, and fluid velocity:
- Chemical Properties of Fluid: During the processing of fluids such as dairy products, certain components like sugar, protein, and fats can deposit and accumulate on heat exchangers.
- Fluid Temperature: Increasing temperature can cause water to produce scaling and biological growth in food processing.
- Fluid Velocity: High fluid velocity decreases fouling as it increases fluid shear stress and reduces the accumulation of deposits. However, this may be ineffective in heavier fouling deposits that may require maintenance or repair.
When Do You Need to Clean Your Heat Exchangers?
Heat exchangers are usually cleaned when it does not efficiently produce the intended temperature in the product during cooling and heating processes due to fouling. This is also usually accompanied by a decrease in pressure as fouling deposits constrict the channels and decrease heat transfer.
How Are Heat Exchangers Cleaned?
The most common way heat exchangers are cleaned is through Cleaning-In-Place (CIP), which provides mechanical and chemical cleaning by combining time, concentration, and temperature. The process agitates fluids and utilizes turbulent flow through channel passages such as piping and tubing. Therefore, this can effectively clean the heat exchanger without disassembling the equipment and is often used in many food processing, cosmetics, and pharmaceutical industries that need to maintain high levels of hygiene.
Overall, it is less labor-intensive, more efficient, and reaches components and parts inaccessible by mechanical cleaning. However, CIP may be incompatible with some systems that will require manual cleaning. The primary goal of this process is to remove lime deposits, neutralize cleaning agents and chemicals before draining, reduce the likelihood of corrosion. CIP usually involves four main steps:
- Alkaline cleaning to remove the accumulation of organic fouling deposits
- Rinsing with high flow water to agitate and dislodge debris from alkaline cleaning and remove accumulated deposits remaining.
- Acid cleaning to further dissolve and soften the fouling deposits
- Rinsing again with high water flow to remove remnants of acid.
Trust Torq N’ Seal® for Your Heat Exchanger Repair Supplies!
At Torq N’ Seal®, we have over three decades of experience in heat exchanger maintenance and repair. When cleaning is not enough and tubes must be removed from service, try the Torq N’ Seal ® Heat Exchanger Tube Plugs. We offer the latest range of high-pressure, condenser, and tapered tube plugs that are easy to install and help you quickly work on your repair needs on our online store. Our products are tried-and-tested and are trusted by many professionals in the industry. Additionally, we serve a wide range of domestic and international clients in many energy industries, bringing all the best of our products and services.