Increasing the temperature gives energy to molecules, making them bombard the foulant more frequently – this increases the rate of reaction between the cleaning chemicals and the foulants. During soaking, warmer temperature increases the rate of diffusion of the cleaning chemicals into the deeper layers of the foulants. Additionally, a higher temperature ensures a higher rate of diffusion of the dissolved or disintegrated foulant away from the membrane surface and into the CIP solution. In other words, warmer temperature makes the chemical cleaning work faster. Activation energy is the minimum kinetic energy required to initiate a reaction, so in some cases, if the temperature isn’t warm enough, certain scales or foulants may not dissolve into the cleaning solution because there is insufficient energy to break the bonds.
Don’t wait until you reach the target solution temperature before you start your membrane cleaning. The solution in the membranes and piping will not be heated and will return to the CIP tank, cooling it back down.
Do turn on your heater and allow your membrane cleaning solution to warm up as you clean your membrane. In most cases, the CIP will still be at least partially effective at lower temperature, making use of the time until the target temperature is achieved. Additionally, waste heat from the circulation pump will help the solution warm up more quickly.
Do ensure to keep the heater submerged. Failing to do so can cause it to reach very high temperatures, igniting the plastic CIP tank and resulting in a fire.
See also:
What is the procedure for cleaning RO membranes? What CIP chemicals should be used?
Our RO plant doesn’t have a neutralization tank for our spent CIP solution. Can we just neutralize while circulating through the membrane system?
What is the relationship between pH and alkalinity? How are they different? How does temperature affect them?
What is the role of circulation in membrane cleaning?