[itssunny]

HI EVERY ONE;
                   I HAVE A PROBLEM REGARDING ADDITION OF "MEROX WS" (CATALYST) TO THE SYSTEM (LPG MEROX). KINDLY GUIDE AND TELL ME ABOUT THE REGULAR SCHEDULE OF ITS ADDITION TO MAINTAIN THE SHAKE TEST WITH IH THE RANGE.

                   

[eugenedakin]

Hello itssunny,

I am not familiar with the WS portion of Merox, and I am assuming that your plant is using the process as show in the following link:

http://en.wikipedia.org/wiki/Merox

I need to know the parameters that you need to meet.

Some process questions are:
1) Is the flow of LPG consistent (no upsets)
2) Does the caustic become contaminated - if so, with what?
3) What are the flowrates of LPG versus NaOH?
4) Where are you experiencing problems?
5) What (specifically) types of problems are you encountering?

Answering some of these questions will help me - be able to help you.

Best wishes,

Eugene

[itssunny]

Hello Eugene,
                 Thanx, for reply, yes we are using the same kind of process given in the link. Merox WS, is just the catalyst name, which we are using in this process. which we added batch wise in the system.
                 LPG flow is not consistent, and fluctuating b/w 18-23 m3/hr.
                 Caustic flow remains constant @ 0.85m3/hr.
                 Our major problem is that, the "shake test" which is the field test used to check proper regeneration of rich caustic, ranges b/w 0-120 sec. is not under control.
To control this we use excess air and excess temperature. In alkaline environment, excess air and temperature causes leakage in equipments. other problem is the additional cost of caustic replacement, which we have to replace frequently due poor regeneration of caustic.
            I hope you can understand this problem and help me in this regard.
Best wishes

Itssunny

[eugenedakin]

Hello itssunny,

There are a few potential problems that come to mind, and I will need you to verify them for me.

When performing the shake test, there is a good chance that oxygen reacts with mercaptan, and provides test results that are lower than what is actually in the coalescer.

Poor caustic regeneration is typically caused by the formation of contaminant salts.

Possible suggestions that may help you out (you will need to check on these possible solutions):
1) re-run the tests in the absence of air - try and get reproducible titration values
2) check the quality of the testing equipment (is the NaOH test solution fresh, or old?)
3) have a laboratory run tests on potential contaminants in the system (variations of sodium salts)
4) minimize the water contamination in the LPG feed

These are a few suggestions, and there are plenty more.

I hope this helps you troubleshoot the issues.

Best wishes,

Eugene

[itssunny]

Hello Eugene,
                  your suggestions are quite right but we just check the circulating caustic spentness, which always lies in the range, in the laboratory. (range = 0-20%).Shake test (field test) is carried out in a simple bottle and there is a chance of entering air in it but entering oxygen is not an issue. (Recommended UOP method).
There is always a schedule for the addition of catalyst (Merox WS) but we do not a regular schedule of its addition and if you have any idea about that, share it so that we may solve these issues. If you have any other question about that you may ask.

Regards,

Sunny