Q & A

Welcome to the ePTQ's Q&A: the technology Q&A for the refining, gas, biofuels and petrochemical processing industries.
You can browse existing questions and answers by topic or date or carry out a freetext search.
Using it is simple: try it out for yourself now.
And if you want to ask a question on any aspect of hydrocarbon process technology or plant, or answer a question that has been posed, just register and login. It will take you only seconds to do so.

We are excited to be Strategic Partner of the World Refining Association’s ERTC: Ask the Experts. This new event from the organisers of ERTC, the biggest and most important event for the European downstream industry, is the only event in Europe offering process and maintenance engineers a platform to ask their burning questions about the everyday challenges facing their plant and hear the practical solutions from industry experts.

This face to face interactive event, features experts from leading European refineries and technology providers; engineers will have the chance to hear unparalleled knowledge through interactive discussions such as fishbowl panels, Q&A Panels and Poster Sessions. Learn more here: asktheexperts.wraconferences.com  


Browse the Q & A
Search by Text Search By Date


Enter Search Criteria
 

Search by Date 

 
Search by Topics  

Recent Questions
Date  Replies
08/11/2019 Q: We are operating cooling tower with circulation rate of about 10,000 m3/hr. Recently a case of oil ingress occurred through one of the coolers in a process unit. This oil ingress resulted in increasing the cooling water supply temperature from 29 degC to about 36 degC. Although oil content in the cooling tower has been reduced to below 10 ppm by appropriate chemical dosing the problem of high CWS temperature still persists. Cooling tower fans and CW distribution through fills have been checked and found to be working fine. Can anyone suggest some measures for reducing this CW supply temperature back to normal?  
08/11/2019 Q: We are operating cooling tower with circulation rate of about 10,000 m3/hr. Recently a case of oil ingress occurred through one of the coolers in a process unit. This oil ingress resulted in increasing the cooling water supply temperature from 29 degC to about 36 degC. Although oil content in the cooling tower has been reduced to below 10 ppm by appropriate chemical dosing the problem of high CWS temperature still persists. Cooling tower fans and CW distribution through fills have been checked and found to be working fine. Any measures for reducing this CW supply temperature back to normal?  
03/11/2019 Q: What are the adverse conditions which may lead to formation of clinker and syntering during FCCU catalyst regeneration?  
19/10/2019 Q: This is with reference to High pressure exchanger overhauling job being carried out at DHT unit during ongoing Turnaround Shutdown. During Shell side combined hydro testing of Effluent-Feed Hot Exchangers bank (90E03A,B,C,D) to attend suspected leaks, cracks found in one of the exchanger (90E03D) tube sheet near Pass partition plate weld joint. Please refer attached photographs for location of cracks observed and also attached exchanger drawings. Thickness of Tube sheet is 372 mm and metallurgy is SS 321. Presently, grinding of T/s Crack location was done up to 15 mm and still crack exists.

Prior to finding cracks, profuse leaks from some tubes (67 nos in 90E03C, 6 no in 90E03D where T/S cracks found) were observed during hydro testing @ 127 Kg/cm2 (HT Pressures: Shell-127 Kg/cm2. Tube-227 Kg/cm2). These leaky tubes were plugged with SS 321 plugs using TIG filler wise ER347 and subsequently hydro test was done during which one crack in T/S observed.

In this regard, we require urgent guidance to understand repair methodology/testing etc.

(Photos & video i want to share but unable to do)
(1)
08/10/2019 Q: Can someone explain what does the pressure ratio and the critical pressure ratio mean in the following link? Also, does anyone have an Excel related to steam silencer design?
https://www.geothermal-energy.org/pdf/IGAstandard/WGC/2005/1345.pdf
 
Recently Answered Questions
Date  Replies
19/10/2019 Q: This is with reference to High pressure exchanger overhauling job being carried out at DHT unit during ongoing Turnaround Shutdown. During Shell side combined hydro testing of Effluent-Feed Hot Exchangers bank (90E03A,B,C,D) to attend suspected leaks, cracks found in one of the exchanger (90E03D) tube sheet near Pass partition plate weld joint. Please refer attached photographs for location of cracks observed and also attached exchanger drawings. Thickness of Tube sheet is 372 mm and metallurgy is SS 321. Presently, grinding of T/s Crack location was done up to 15 mm and still crack exists.

Prior to finding cracks, profuse leaks from some tubes (67 nos in 90E03C, 6 no in 90E03D where T/S cracks found) were observed during hydro testing @ 127 Kg/cm2 (HT Pressures: Shell-127 Kg/cm2. Tube-227 Kg/cm2). These leaky tubes were plugged with SS 321 plugs using TIG filler wise ER347 and subsequently hydro test was done during which one crack in T/S observed.

In this regard, we require urgent guidance to understand repair methodology/testing etc.

(Photos & video i want to share but unable to do)
(1)
19/12/2010 Q: Our project has an amine FCCU and amine sweetening and SRU, but sulfur recovery will be in service 1 year after FCCu start up. There is a problem with feedstock of SRU that must be sent to acid flare (with 32 m length). What can we do with this stream with 80%wt h2s witout sending it to flare? (4)
01/10/2019 Q: Hello,

In our refinery we have an alkylation unit with HF and in recent dates we have had many problems with the acid vaporizer of the HF regeneration column (acid leaks from the tubes). The tube bundle is monel 400 and the heating medium is tempered medium pressure steam. Do any of you have similar experiences and could you help us find the failure mechanism?

Thank you.
(2)
07/10/2019 Q: What are the alternatives to hydrojetting to clean heat exchangers in a refinery?

Are there any chemical cleaning solutions available to clean after bypassing the exchanger?

Thank you
(3)
23/06/2019 Q: We are facing problem of shorter run length of our Delayed Coker Unit(DCU). The furnace coil inlet pressure increases to design limit within a very short interval i.e. 30-35 days after the SAD, however the tube skin temp remains well below the design limit.
The feed to the DCU unit is VR from VDU, having asphaltene about 5% & CCR about 17%. The COT, BFW flow and other operating parameters are maintained as per the design operating guidelines.
Can anyone help to identify reasons for the drop in the run length of our DCU?
(7)
Post