Propane KOH Treaters

[ShadedSun]

I am working on a project right now where we would like to replace our existing Molecular Sieve Absorbtion Towers with a KOH Treatment system. I am not very familiar with the overall operation and chemical reactions associated with this process.

If you could please reply regaurding this matter, I would really appreciate it!

Thank you in advance!

Sean

 

[TD2K]

Why would you be looking into replacing an existing process with another process that you don't even understand?

I realize you've come here to ask that question but you should have done some base work to decide first this makes sense for your operations.

 

[ShadedSun]

This existing mol sieve operation at one of our gas plants currently required sweet fuel gas to regenerate the bed and our fuel gas supplier might me pulling out and we will no longer have access to this sweet fuel gas. This is the main reason why we are looking at a disposible liquid sweetening system to remove the trace amounts of COS, H2S, Light Mercaptans, H20, etc., to meet the C3 pipeling specs.

I have been looking at the (ZnO) + CaCl2 and also the (KOH + MeOH) + CaCl2 systems.

To my understanding, it looks like both treatments do very similar jobs. Do you have any experience with any of these processes? If so, what are the differences?? I have heard that the Zinc Oxide treatment is much more expensive then the KOH treatment! Is that true??

And, could you please guide me to and great sources reguarding this subject.

Thank you in advance!

Sean

 

[MortenA]

Would it be worth considering "bottled gas"?

Best Regards

Morten

 

[TD2K]

What sort of flow rates are you looking at, operating conditions and how much H2S and other sulfur components are to be removed? I don't have any experience in these processes but I know from previous posts, others do but they'll need some specifics to comment.

 

[krossview]

Hi fellows

It looks there may be a good opportunity to convert the existing sweet gas mole sieve over and use them for liquid service. A few years back I was involved in a study to remove H2S, COS, CS2 and Mercaptans from a LPG stream.
One of the options was to use a Mole Sieve to remove the H2S and Mercaptans. However, Mole Sieves are not good at removing COS and poisons the sieve. KOH removal was another option we looked at and was considered one of the better alternatives if I remember correctly. One word of caution. do your home work and find out what levels of H2S, COS, CS2 and Mercaptans you have. Plus check out what you need for instrumentation to measure and test these components.

I would recommend to talk to some mole sieve vendors to check out the options. You may be able to save yourself and the company a pile of money if you can re-use the existing mole sieves.

Good luck

Krossview

 

[ShadedSun]

Thanks for replying guys. I have been working on many other projects in the meantime and this one was kinda put on hold for a while but now I am working on it again.

Our flow rates of C3 ar ~ 1400 m3/d flowing through the existing mole sieve and its contaminant levels are as follows:

COS: ~10ppm
H2S: ~0ppm
RSH (Light Mercaptans): ~180ppm
H2O: ?? (enough to knock out)

So, we are basically worried about removing the light mercaptans and the COS.

I am looking at a process right now of re-sweetening the sour regen gas and re-using it. So, I am looking at a gas sweetening unit right now. The regen gas volume is ~28000 m3/d. Temp range: (-10 - 200 deg.c) Press:~200 psig

Any recomendations on the sweetening process?


Before, when I put this question out, I did make a mistake. We DO still have access to sweet fuel gas for regen gas after the company pulls out. It is the gas sweetening process that we will no longer have access to. (Sorry guys!)

Please reply soon!

Thanks!