What is refiners experience with reference to reformer packinox exchanger effective cleaning ? How can this exchanger be best cleaned?
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05/06/2015
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Jesus Perez, Alfa Laval Packinox, jesus.perez@alfalaval.com
The Packinox heat exchanger is a very simple equipment. There are few of them at a given site (maximum 3 of them in a medium sized refinery) and their maintenance requirements are quite low. Most refineries or petrochemical manufacturers have a heat exchanger dedicated maintenance crew constantly inspecting or supervising the cleaning of the hundreds of shell and tube exchangers in a site everyday. This crew might get involved with a Packinox inspection once every 5 years so the skills and knowledge required for its inspection might not be freshly available in their minds therefore, we recommend you always contact Alfa Laval Packinox Services directly for advice on cleaning. Over the years we have collected many hours of hands on experience on fouled units and have developed many procedures for cleaning depending on the foulants such as controlled combustion for decoking of channels.
The most important routine maintenance is the monitoring of the Packinox operation. The main parameters are hot end approach and pressure drops. Alfa Laval Packinox Services encourages all customers to provide this data routinely in order to predict cleaning requirements. Other routine maintenance include cleaning of the liquid feed filters and the spray bar conical strainers by means of on line back flushing.
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06/01/2015
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Mike Watson, Tube Tech International Ltd, mike.watson@tubetech.com
As world leaders in cleaning Reformer and Platformer Texas Towers herewith some comments.
One needs first to understand the likely fouling characteristics before establishing clean-ability and subsequent method. Is it oil, catalyst, PCA's plus ROT HIT data etc
Simple rule of thumb: If the spaces between any plate design eg packinox, are blocked / bridged with compacted deposit causing high dp , drop off in production and / or loss in heat transfer coefficient then you may be too late to clean. Traditional thinking goes for chemical cleaning BUT in most cases it makes things worse. Chemicals require a clear passageway and need to achieve a certain m per second flow rate to be effective.
Most process assets are sold on the basis that they wont foul. However changing run lengths, down and upstream conditions make carryover and fouling extremely common but unexpected by clients so expect it to foul and plan ahead for it.
Fouling can be seen between 3 and 33 years of running. Fouling occurs early on but until the first 25% excess design capacity is reached and fired heaters occasionally compensated for its reduced performance, few take heed of the ROT HIT data and MWatt mounting regret costs.
Law of averages says your asset will foul at some time so whatever you have saved on an inaccessible unit today you will lose in replacement and downtime costs due to the inability to clean or inspect.
Regardless of process design Tube Tech can advise on the simplest modifications to make your exchanger accessible, therefore cleanable and ultimately inspect-able in the event of future fouling without worry.
Future Suggestion:
Shell and Tube designs is actually the easiest to clean on BOTH the Tube AND Shell side no matter how severe the blockages to as new condition
Tube and Shell side fouling often consists of poly-cyclic aromatics / PNA’s and must be handled with care due to their carcinogenic nature hence remote/robotic technology has been developed to overcome the safety limitations of manual, close proximity water jetting. Deposit consistency/characteristics tend to vary from solid hydrocarbon coke formations mixed with tenacious gum like residue.
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05/01/2015
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Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Packinox exchangers are very difficult to clean, The only thing you can do is try some sort of water wash or chemical cleaning. It depends on what is causing the fouling. I have seen them fouled with ammonium chloride, polymer from processing high end point naphtha and catalyst fines. The small channels and low DP make it easy for the chemical cleaning fluids to bypass the fouled areas rather than removing the deposits. Good luck!
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