Frequency of CIP is once a year per plate heat exchanger. However, when any of the plate heat exchanger performance has deteriorated, the CIP need to be carried out immediately.
Drain out the remnant oil from the plate heat exchanger that is scheduled for cleaning.
Dismantle the flanges that are connected to the plate heat exchanger for fixing flexible hose of CIP line.
Fill in fresh water into the CIP tank until the marked level and heat the water to 70 to 90°C.
Circulate the hot water from CIP tank to plate heat exchanger and back to CIP tank for 4 to 6 hours.
After 4 to 6 hours drain out the water from the Plate Heat Exchanger, CIP line and CIP tank.
Prepare 8 % of caustic solution by pouring 6 bags X 25 kgs of caustic soda pearls and fill water into CIP tank.
Note: Wear personal protective equipment (PPE) like goggles, rubber glove and dust mask when preparing lye solution.
Heat the caustic solution to 70 to 80°C.
Circulate the caustic solution from CIP tank to plate heat exchanger and back to CIP tank for 4 to 5 days.
Record the flow rate of the initial caustic flow and take a sample of the circulated water (for reference).
After 1 day of caustic circulation, stop the CIP pump for 10-15 minutes. Then run it again. Repeat this step in a space of every six hours. This is to aggressively loosen any stubborn scale sticking on the plate surface.
After 2 or 3 days of caustic circulation, stop the CIP pump and reverse the flow. The flexible hose connection needs to be changed.
Repeat the steps.
After circulating for 4 to 5 days take the flow rate reading and water sample of the circulated caustic solution.
Drain out the used caustic solution from the plate heat exchanger, CIP line and CIP tank and clean the CIP tank.
Drained Lye solution will be pumped to Effluent Plant for further treatment.
Fill in water into the CIP tank and heat the water to 70 to 80°C.
Circulate the hot water from CIP tank to Plate Heat Exchanger and back to CIP tank for 4 to 6 hours.
Repeat this exercise for 3 times.
After 3 times of washing with hot water check the PH of hot water.
If the PH is 7 which is neutral, drain out the water from the plate heat exchanger, CIP line and CIP tank.
Record down the CIP of plate heat exchanger in weekly cleaning checklist.
