What is the best way to clean the oil cooler?

- May 18, 2018-

What is the best way to clean the oil cooler?

There are two ways to clean the oil cooler: manual cleaning and in-place cleaning. If conditions are available, the in-place cleaning system should be used as much as possible, because the in-place cleaning system can pump water (or cleaning solution) into the device without having to dismantle the heat exchanger. If cleaning the system in place is not practical for your factory, you can clean the device by manual cleaning.

2. Plate cleaning precautions

(1) Do not wash the stainless steel plate with hydrochloric acid or water containing a chloride concentration exceeding 300×10-6.

(2) Do not use phosphoric acid or sulfuric acid to clean the titanium plate.

(3) The concentration of the cleaning solution should normally be 4% or less (except in special cases). The temperature of the cleaning solution should not exceed 60°C.

3. Backwash and Mesh Filters

In general, when there are fibrous and large particulate matter in the heat exchanger, the effect of backwashing the device is quite obvious. The purpose of backwashing can be achieved in one of two ways:

(1) Rinse the device in the opposite direction to normal operation with clean water.

(2) Arrange the pipe and set the valve on the pipe to work in the reverse mode at the product side for a fixed time. This special mode is particularly suitable for heat exchangers where the product is steam.

(3) When the water stream contains a considerable amount of solid or fibrous material, it is recommended to install a mesh filter on the water supply line in front of the heat exchanger. This reduces the number of back flushings.

4. Cleaning in Place (CIP)

Cleaning in place is the preferred method of cleaning the plate, especially when the process liquid in the SUPERCHANGER unit is corrosive. After completing a work cycle, the remaining liquid should be drained through the drain tube to prevent corrosion of the plate.

When cleaning the heat exchanger, follow the steps below.

(1) Exhaust the liquid from both sides of the heat exchanger into and out of the nozzle. If it does not drain, use water to force the process liquid out. 

(2) Rinse from both sides of the heat exchanger with warm water of approximately 43°C until the effluent water becomes clear and free of process fluid.

(3) Remove the flushed water from the heat exchanger and clean the pump in place. (See above "Plate Cleaning Considerations" for the selection of cleaning agents)

(4) To be thoroughly cleaned, the bottom of the in-situ cleaning solution must be flowed toward the top to ensure that all plate surfaces are wetted with the cleaning solution. When cleaning multi-process heat exchangers, the cleaning fluid must be allowed to flow in the opposite direction for a minimum of 1 to 2 cleaning time to ensure wetting of the surface of all the plates in the multi-process.

(5) After cleaning with the local cleaning solution, rinse thoroughly with clean water. If the heat exchanger uses brine as a cooling medium, the brine should be cleaned as much as possible before the cleaning operation is carried out, and then the heat exchanger should be flushed with cold water. If all parts of the brine side are flushed before cleaning the solution on both sides of the heat exchanger with heat, corrosion of the equipment will be minimal.

(6) The best cleaning solution is: use the in-place cleaning solution to wash at the maximum flow rate, or to clean the nozzle diameter in place to allow maximum flow rate cleaning (maximum flow rate of 260 GPM for nozzle diameter of 2 inches, maximum allowable flow rate of 67 GPM for nozzle diameter of 1 inch). If you can perform cleaning operations on site in accordance with the regular cleaning plan before thoroughly polluting, the cleaning effect will be better.

5. Principles of cleaning in place

(1) Never open the heat exchanger when the heat exchanger is still hot, pressurized, carrying fluid or is in operation.

(2) Always use clean water for flushing operations. (The water should be free from salt, sulfur, chlorine, or iron ions.)

(3) If steam is used as a sterilizing medium, the steam temperature of the nitrile gasket should not exceed 132°C, and the steam temperature of the EPDM gasket must not exceed 177°C.

(4) If a chlorine-containing solution is used as a cleaning medium, the smallest concentration of solution should be used at the lowest temperature possible. The time for cleaning the plate with this solution should be minimized as much as possible. The concentration of chlorine in the solution should not exceed 100×10-6, the temperature of the solution must be less than 37°C, and the contact time between the plate and the solution should not exceed 10 minutes. The following are recommendations for concentration, temperature, and cleaning time.

(5) The centrifugal pump must be used to keep the cleaning solution in circulation.

(6) Do not use hydrochloric acid to clean the plate.

(7) After cleaning the plate with any type of chemical solution, the plate must be thoroughly rinsed with water.

(8) A concentrated cleaning solution must be added before the water circulates through the device. Never inject these solutions while the water is circulating.