Q & A > Question Details
In our CCR we are facing with the feed side plugging of the Packinox CFE heat exchanger. Could you tell me the reasons of this phenomenon? Have anybody experienced the same? What about the solutions? Till when is it worth cleaning?
30/06/2016 A: Dani Wibowo, -, broer_tgp04@yahoo.com
Try to blow the spray bar by sudden opening valve downstream of filter. It works.
26/05/2016 A: Patrick Bullen, UOP, patrick.bullen@uop.com
As stated by others, fouling is either a physical or a chemical related problem. Physical meaning upstream particles found the exchanger, (e.g. spray bars for plate exchangers, surface area of tubes or plates) that come from either the unit or in coming from upstream in the naphtha feed. The other is chemical. Typically, fouling reactions occur due to oxygen contaminated feed. However, other contaminants can also generate heavy hydrocarbons that will foul the exchanger.
If you are a member of the AFPM, there is a very good presentation from the 2015 Fall Q&A, Process & Principals on fouling in exchangers in both NHT and Platforming unit. Use link below
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18/05/2016 A: Jesus Perez, Alfa Laval Packinox, jesus.perez@alfalaval.com
Even though CCR fluids should in theory be clean, some abnormal operating conditions and/or corrosion of upstream lines and equipment may lead to fouling in the Packinox exchanger. In this case, the first action is to identify the foulant. Then, according to the nature of the foulant, an adequate chemical cleaning agent can be used during turnaround. In case of severe fouling by organic products (gums or coke), a decoking by controlled combustion can be efficiently performed. Do not hesitate to contact Alfa Laval Packinox for assistance.
18/05/2016 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
I would guess that something coming in with naphtha feed from storage is the most likely culprit. It could solids of some kind such as corrosion products that have built up in the bottom of the feed tank over time, which are now being entrained into the feed. If there were any water entrained in the feed it would leave behind any dissolved solids when the water evaoprates. If this were going on you would likely be seeing high levels of moisture and chlorides in the recycle hydrgen though.
The common material that could lead to plugging in Packinox is Poly Nuclear Aromatics (PNA). PNA's are fused aromatics with a characteristic red/orange color. That's why it is also known as red oil. It generally is found in cold spots in the process and can lead to plugging and pressure drop problems. This phenomenon can also be found around the recycle compressor.
Operation under severe conditions of high temperature, high EP feed and low H2/HC promotes formation of this material.
Depending on the blockage severity, it can be used chemical or mechanical cleaning, but always it is important that waste must be treated as hazardous
Former reference could be useful in this web site. link: http://www.eptq.com/qandaquestion.aspx?q=e6cc2aa9-1b72-40c2-99c8-4db8283f0dc0
18/05/2016 A: Peter Marsh, XBP Refining Consultants Ltd, peter.marsh@xbprefining.co.uk
Plugging of Packinox spraybars (feed injectors) can occur if the spraybar holes are too small, if the parallel feed filters are located a long way from the Packinox exchanger or if the feed filter elements have failed. The spraybar holes should be 3 mm diameter and protected with a conical strainer with 3 mm diameter holes inserted at the mounting flange of the spraybar insertion nozzle. If the feed filters are located a long way from the Packinox exchanger, the interconnecting pipework should be fabricated from stainless steel. The filter elements should be basket strainer type rated for a maximum pressure drop of (say) 5 bar. The basket should comprising a perforated basket with 5 mm diameter holes internally lined with a 60 mesh screen fabricated from 300 series stainless steel. It is usually economic to make provision for on-line backflushing of the spraybar to flare using the hydrogen pressure in the Packinox exchanger shell.
18/05/2016 A: Yogesh Bhintade, Raffinerie Heide, bhintadeyogesh@gmail.com
Check for presence of olefins, oxygen content, iron in the feed.
Avoid anybsource of oxygen, if feed is from storage tank make sure ut is nitrogen blanketed. Normally there is also a feed filter in front of packinox. Check delta P of the same. Maybe check free water,chloride, normally chloride content in recycle gas ..
You can try vacuum cleaning or back blwing or manual cleaning