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In mild hydro cracker, we have amine absorber column to reduce/remove H2S from Recycle gas. Due to amine foaming, amine is carry over to recycle gas compressor.
Any one can share their experience to reduce foaming of amine or how to do Oil skimming in amine columns and what are the parameters to be monitored while doing this activity.
How can we know Oil skimming is completed and there is no foaming in the column?
 
Answers
21/04/2015 A: Zoltan Fodor, MOL Group / Production Technology, zfodor@mol.hu
Also, there are additives which can eliminate foaming, if you can't prevent it any other way.
06/04/2015 A: Sarath Konda, DuPont India, sharathsatya@gmail.com
Amine foaming could be due to following reasons:
1. HC in getting into amine scrubber
2. Some dirt or corrosion product in the Amine scrubber (lesser possibility)
If there are separation issues or feed compositions changes in your CHPS, there is a possibility of saturated vapor carryover to amine scrubber and condensed HC could cause foaming.
Upset in ARU could also cause HC carryover in Lean Amine and this could also lead to foaming. Lower Lean amine temperature also leads condensation of lighter material in amine scrubber resulting in foaming.
Depending upon the problem solutions will vary but, It is better to create a schedule for regular skimming of recycle gas scrubber. Once in a shift is ideal to avoid foaming and amine carryover to recycle gas compressor
26/05/2014 A: Narendra Naidu, Bapco, nbpnnaidu@gmail.com
Common Amine carryover problems are due to
1. Solids in the Lean Amine, check if other units in the refinery that use the same Amine whether they have the similar foaming problems (Dirty or improper Filtration of the lean Amine, change the filter elements).
2. Due to HC in the Lean Amine, check your Activated Charcoal Filter, it must be saturated , replace the Charcoal.
3. The Lean Amine temperature must be low compared to the recycle Gas temperature (should be 5c higher/hotter then your inlet recycle gas temperature to the Absorber).
4. Worst is you have physical carryover of HC from the Cold Separator, check if reducing the compressor flow or the level in the Cold Separator helps.
29/04/2014 A: Lindsay McRae, Pall Corporation, Lindsay_McRae@pall.com
Amine absorber foaming on HDT, HDS and MHC recycle H2 gas line is a pretty common issue and can lead to severe H2 recycle gas compressor reliability issues. The good news is that is can usually be solved with various types of improved filtration and separation equipment and usually the payback is very quick.
There is a few possible solutions you can consider. You can address the root cause of the problem and tackle the amine foaming in the first instance. If you prevent the amine foaming incidents, the amine carryover should cease and your H2 recycle gas quality should be on spec also. PALL provides consulting services & pilot test equipment to help determine the root cause of the amine foaming and then provides equipment that provides lasting solutions that will promote stable amine plant performance and improved recycle gas compressor reliability.
The solution to your issues could be improving the inlet separation on the sour gas line to remove the HC's before the amine absorber, a new LG coalescer on the sweet gas line installed before the compressor, upgrading or replacing the amine loop mechanical filter or perhaps more than one of these.
The other approach is to address the symptom of the foaming and install a high efficiency Liquid Gas coalescer before the recycle gas compressor to catch any amine carryover that does occur. Such 'amine compatible' LG coalescers can be used to debottleneck amine plants and prevent amine carryover into recycle gas compressors where either the recycle gas flow rate has increased ( e.g. plant debottlenecking) or where foaming and amine carryover is occurring such as you describe here. Such an approach will not address the foaming incidents or severity, but will protect the MHC H2 recycle gas compressor and improve its reliability.
Oil skimming in the base of the amine absorber or from the flash tank is not very effective as the interfacial tension (IFT) is very low and the residence time is not nearly sufficient to get a decent separation. It's far better to keep the hydrocarbon liquid out of the absorber in the in the first place by improving or replacing the inlet device with a high efficiency Liquid Gas coalescer. PALL Technical Staff can measure the amount and type of HC liquids present in the inlet gas so that a lasting solution can be designed and installed. The amount and type of liquid HC's present is a key parameter in LG coalescer sizing. What type of inlet device do you have installed currently? Is it a KO pot, mesh pad, or cyclonic device or filter-separator of some type?
Amine absorber delta P correlates pretty well with foaming incident occurrences and this is often used as a measurement tool for amine foaming incidents.