merox caustic carryover
merox caustic carryover
(OP)
Hello everybody
My question is the following:
We have a merox process for treating naphtha. It has a coalex demister on top of the extractor column to remove caustic from the hydrocarbon stream. Upstream of the column is a naphtha splitter reflux drum and pump. Downstream is storage and export facilities. Currently there's no caustic carryover equipment to deal with a blip in the hydrocarbon flowrate. It seems like a good idea to put in some equipment to deal with this transient condition. Looking at previous projects it seems that a caustic holdup drum (but no sand settler)is typically installed. There's a range of holdups of 3 minutes and 20 minutes.
Has anyone any experience of the requirement for such equipment and if so which of the 2 (3mins or 20mins) looks more reasonable, and what is the basis for this holdup?
many thanks
My question is the following:
We have a merox process for treating naphtha. It has a coalex demister on top of the extractor column to remove caustic from the hydrocarbon stream. Upstream of the column is a naphtha splitter reflux drum and pump. Downstream is storage and export facilities. Currently there's no caustic carryover equipment to deal with a blip in the hydrocarbon flowrate. It seems like a good idea to put in some equipment to deal with this transient condition. Looking at previous projects it seems that a caustic holdup drum (but no sand settler)is typically installed. There's a range of holdups of 3 minutes and 20 minutes.
Has anyone any experience of the requirement for such equipment and if so which of the 2 (3mins or 20mins) looks more reasonable, and what is the basis for this holdup?
many thanks





RE: merox caustic carryover
RE: merox caustic carryover
Many thanks for post - I take your point about retention time.
However the size of particles, by which I mean the size of the water particles in the separator/holdup drum outlet, is unknown. Any ideas of what to take for this?
A further complication/question - In the licensor (UOP) proposal they suggest (on our insistence because they didn't propose additional equipment items) holdup drum plus sand settler. I assume that crude separation occurs in the holdup drum and remaining water droplets are coalesced in the downstream sand settler. I also assume (have asked the licensor this question) that the first drum takes slugs of caustic but has no continuous level control- this assumes that slugs occur but that the operators intervene and regain control of the process (ie. stop the disturbance that caused the blip in the first place).