CHEMICAL CLEANING AND FLUSHING OF PIPING SYSTEMS

[Salmet]

DEAR MEMBERS,

One of our vendors for chemical cleaning of carbon steel piping systems (conforming to ASME B31.1), is proposing citric acid solution for this purpose. I will be thankful if any one can refer me an MS excel calculation sheet/calculations in order to confirm the efficient pressure required for this purpose.

Also I would request your opinion that would I need further treatment for safe disposal of cleaning solutions despite neutralization of citric acid with Sodium carbonate solution followed by Flushing with rust inhibitor consisting of 0.5 percent sodium nitrite (NaNO2), 0.25 percent disodium phosphate (Na2HPO4), and 0.25 percent monosodium phosphate (NaH2PO4).

Thanks in advance.

 

[LittleInch]

Citric acid? New one on me. Cleaning of what and for what purpose?

Don't understand your question about pressure - can you explain further?

This all seems a bit unecesary to me, but maybe you need it for some sort of sterile use?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[KoachCSR]

I'm familiar with this type of chemical cleaning being utilized for field-erected boilers and HRSGs - intended to remove grease, rust, scale, etc. from the internal heat transfer surfaces. In my experience, temperature is a much more critical parameter than pressure to increase the effectiveness of the chemicals used. The only real pressure required is that which is needed to effectively circulate water throughout the boiler.

I would be very hesitant to perform a chemical clean on simply a piping system. If you have piping which has been "mothballed" that you are trying to re-use, I would recommend an alternative to chemically cleaning it as you've described. At a minimum, I would remove all valves and instruments, and jumper around all equipment in the system. Soft parts of any kind will be "eaten up" by the chemicals.

Disposal specifics will depend entirely on your locale - typically, after neutralization, this wastewater can be either discharged to an industrial process sewer (if at an existing industrial plant which is equipped to handle such) or be trucked off and disposed off properly.