NaOH - CIP (solution 1.5%)

[Shanzon]

I use to run CIP using Caustic solution 1.5%, I am intending to decrease this concentration...maybe 0.5 to 1%, I suppose will be enough to clean pipes (concentrate orange juice pipes). Caustic solution temperature 60ºC..is there some kind of limitation about temperature...I am thinking about reduce concentration and increase temperature...75ºC.
Technically, what is limitations of NaOH uses in CIP?

Araujo

 

[orch]

You shouldn't have a problem at 75C subject to what chemicals are blended with the caustic, We've used 85C without issue. Increasing temp will help your washes, But watch out for dangers of burns etc as temp is increased.

I'd generally suggest you dont drop below 1% solution.

The criteria you can change are generally temperature, strength, time and mechanical effect (turbulance), If you need to decrease 1 the others can be increased to compensate, it's a matter of finding the right balance for your application

 

[Shanzon]

Thank you, Orch

I undestand if we change a parameter as concentration it is necessary to adjust others, so I have a question, do you know what is the maximum temperature to NaOH solution, I am not sure if there is some kind of decomposition because temperature...
What kind of problem can I have is concentration is less than 1%?

Araujo

 

[orch]

I've used Caustic at 85C without problem, and I'm not aware of any limiting factor up to boiling, though above 85C there is a lot of steam to contend with which can lead to changes in concentration over a period of time.

Most detergents have other chemicals blended in- surfacants wetting agents etc, These may have different propoerties to the caustic base, but I'm sure your chemical supplier can probably provide any info on limitations for your specific blend.

We tend not to drop below 1% purely from experience, a few years ago We'd typically use 2%, but as chemical blends have improved along with the design of plant, we've found that 1% blends provide a reasonable compromise of wash time against chemical cost. I do not recall any client wanting the level reduced further.

This level also still gives a reasonable conductivity difference to monitor when sensing changes from water / detergent on automatic systems or for automatic dosing systems.

It's all down to setting a system up that is repeatable. if you can acheive the wash standard you need at a low concentration, you simply don't need more chemical. If the chemical strength is limited you can increase time of wash, but in most cases the down-time is more costly than the chemical.

 

[Shanzon]

Ok...so I understand, probably no limitatios to temperature....I'm gonna go check my supplier...thanks a lot..

I have other topic, my water source use to have pH around 8.5...do I need to consider this topic to when I think about the impact of this carbonates in water.