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We are facing a problem due to the high content of phenol in LPG treatment spent caustic. Due to this high levels, we are having problems to discard this to the wastewater system.
I do not expect to have such levels of phenol (over than 5000 wppm) in a caustic solution used only to treat LPG. Is it normal to have high phenol content in these type of spent caustic? The sulphides level is lower than this.
The LPG is produced in a Delayed Cooking Unit and is previously treated in a amina section to remove H2S. The caustic treatment is a Merox type, but due to some operational problems, the caustic strengh used is 17%. The phenol level is high even in the spent caustic of the extraction section.
30/12/2016 A: Prakash Pimparkar, Environmental Consulting Services , prakash.pimparkar@yahoo.in
This is not unusual as details are not available as to how are toy treating this waste as phenol is highly biodegradable subject to acclimatisation and constant feed.Though pre-treatment of caustic in air oxidation is feasible is an expensive proposition, so try to treat in your common or combined wastewater treatment unit.
30/07/2016 A: Egbert van Hoorn, Hocon B V, Egbertvh@hotmail.com
Phenols are fairly unusual in LPG.
Phenols are normally removed by an upstream water wash like in the FCC unit.
You should check if the analytical method used is correct.
More details are required to evaluate the overall treating scheme.
It is quite possible that phenols are not present but that other components have been identified as such.
Do you experience problems with the amine system or the Merox unit?
20/07/2016 A: Satyalal Chakravorty, Sr Consultant, satya1354@yahoo.co.in
FCC & Delayed Coker LPG are the main sources of phenolic caustics in refinery. The stripped sour water generated out of stripping the sour water effluents of FCCU & Coking units contains Phenol. Stripped sour water when used in Crude Desalters can result in pickup of certain amount of phenols in crude oil stream.
One of the methods of reduction of phenol from Spent caustic before treatment in effluent plant is Wet Air oxidation(WAO). Low temperature WAO will not oxidize phenol . Mid temperature wet air oxidation (200-220 °C) will oxidize phenols .High temperature wet air oxidation (240-260 °C) will oxidize almost all phenols and reduce a majority of the COD producing a biodegradable effluent.
12/07/2016 A: NS Murthy, Suez, murthy.ns.ext@suez.com
It is rather unusual to get phenols in LPG stream. Check weathering of LPG. Also, ensure that caustic circulation is not common with Jet Merox which can then pick up phenols from Jet fraction.
12/07/2016 A: Vijay Beleri, Rateau energy systems, v_beleri@hotmail.com
Are you using an electrostatic coalescer in your lpg merox unit?