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  1. sahsanb

    Cracks during welding of St.St 347 piping after eight years in-service

    I don't believe temperatures in Ammonia Converter outlet line are high enough to initiate sensitization. This looks more like a high heat input related issue at the time of original welding. In-service cracking issue is quite prevalent in stabilized austenitic steels. At our site we have also...
  2. sahsanb

    SS 321H Material Welding Joints PWHT Necessity

    Rubje, First leakage was observed after 06 years of operation in 2016.
  3. sahsanb

    SS 321H Material Welding Joints PWHT Necessity

    Thank you very much gentleman for your feedback. We will take this into account while finalizing our execution strategy. Appreciate if you can recommend some literature to study the subject in more detail.
  4. sahsanb

    SS 321H Material Welding Joints PWHT Necessity

    Dear EdStainless, Thank you very much for your feedback. While we agree with intended benefits of PWHT, we are struggling with the fact that owing to field constraints implementing PWHT as per intent will remain a challenge and there is a possibility that we may end up with multiple other...
  5. sahsanb

    SS 321H Material Welding Joints PWHT Necessity

    Dear Experts, I am reaching out to you to seek your expert advice regarding our 14” OD & 12.7 mm thk. Process Air Line (SS 321 H metallurgy) operating at 550 oC (1022oF) which we intend to replace due to multiple Stress Relaxation related cracking related leakages in the past. Root cause of...
  6. sahsanb

    Secondary Reformer Refractory Damage

    Dear 0707, Yes we did have a forced shutdown a month before this observation. Plant was shutdown in a controlled manner and within pre-defined IOWs for OPS team. Our hot face refractory is rich in Alumina (~ 94%) while our insulating side refractory is quite close to Resco RS9 grade. High...
  7. sahsanb

    Secondary Reformer Refractory Damage

    Attaching the drawing and picture for review. https://files.engineering.com/getfile.aspx?folder=689ffb56-f9ba-4396-b444-89ce97dba0ea&file=Secondary_Reformer.pdf
  8. sahsanb

    Secondary Reformer Refractory Damage

    Dear Experts, Hope you are well. . I am writing this post to seek your expert opinion and guidance regarding a refractory issue faced recently at our site. Details are appended below. We have a catalyst loaded vessel (secondary reformer) at our ammonia plant. This equipment is refractory lined...
  9. sahsanb

    New Anhydrous Ammonia Storage Vessel Fabrication & Material Susceptibility to Ammonia SCC

    Thank you very much gentlemen for your detailed feedbacks. As ammonia fertilizer manufacturing plant operators we have faced Ammonia SCC related issues sporadically. RCA for most of the issues observed at our site have pointed to non-compliances to required fabrication requirements at the time...
  10. sahsanb

    New Anhydrous Ammonia Storage Vessel Fabrication & Material Susceptibility to Ammonia SCC

    Dear Experts, We are getting a new Ammonia Storage Vessel fabricated. Given below are major equipment design details Material (nozzles/ shell & heads): SA-333 GR.6 / SA-516 GR.60 Design Pressure: 30 kg/cm2 Design Temperature: -20/70 OC Material thickness: 32 mm As per equipment manufacturing...
  11. sahsanb

    Alternative material for Unalloyed Titanium in Heat Exchanger Tubes

    Have you considered bimetallic tubes such as Omegabond which have Titanium as substrate and Zirconium as top layer?
  12. sahsanb

    Double Wall Ammonia Storage Tank Inspection

    Dear Experts, Hope you are well. We have a double walled Ammonia Storage Tank at our site with below mentioned key specifications: Material: A-516 Gr 60 Height: 16 meters Inner Tank ID: 26 meters Operating Temperature: -33oC Capacity: 7,350 m3 Design Code: API 620 Commissioning Year: 2010 No...
  13. sahsanb

    Double Wall Ammonia Storage Tank Internal Inspection Necessity

    Dear Experts, Hope you are well. We have a double walled Ammonia Storage Tank at our site with below mentioned key specifications: Material: A-516 Gr 60 Height: 16 meters Inner Tank ID: 26 meters Operating Temperature: -33oC Capacity: 7,350 m3 Design Code: API 620 Commissioning Year: 2010 No...
  14. sahsanb

    CO2 Removal Unit Recurrent Leakages

    Just an update on subject issue, over the course of this week we have been conducting in-service PAUT of butt weld joints in said piping. Weld joints have been carefully selected in immediate vicinity of both leakages and areas of relatively higher flowrate than running pipe length. So far out...
  15. sahsanb

    CO2 Removal Unit Recurrent Leakages

    Dear Morten, Attached is a close up of elbow cut at its weld joint area. Point of leakage in the elbow is 9 o clock position. Most of the weld joint on elbow was removed during welding joint removal however as you can see the HAZ area at both top and bottoms side is eroded. Depth and...
  16. sahsanb

    CO2 Removal Unit Recurrent Leakages

    Dear Experts, Got our process engineer to model the flow rate at different zones of the piping and as per flow simulation velocities are not higher than licenser recommended flowrate at different pipe sizes. I have attached the flow rate simulation model and licenser recommended max fluid...
  17. sahsanb

    CO2 Removal Unit Recurrent Leakages

    Dear Andersen, Thank you for your feedback. We are struggling with why the HAZ is being attacked and that too of only upstream weld joint. Additionally with passivation layer intact, shouldn't corrosion become insignificant? Or is there any reason to believe that passivation layer can not form...
  18. sahsanb

    CO2 Removal Unit Recurrent Leakages

    Dear Experts, Over the last 1 month we have observed 02 leakages from our CO2 removal unit piping. Request your expert advice on what are the likely cause(s) for these leakages and what can be done to prevent any further leakages. Given below are brief details of the process and respective...
  19. sahsanb

    Globe Valve PTFE Gland Packing Failure

    Dear All, We are using plug globe valves as isolating valves on our ammonia circulation pumps. Temperature of service varies between zero degree C to ambient temperature of 25 degree C. We have recently been observing leakages from these valves glands. The valves were installed about 30 years...
  20. sahsanb

    Shell & Tube Heat Exchanger Hydraulic Tube Puller

    Hi, Our company is trying to setup a heat exchanger retubing facility at our site. Over the next few years we intend to re-tube heat exchangers with tubes in the size range of 1/2" to 1". I am developing a technical SOW for bidding purposes for a Electrically operated Hydraulic Tube Puller...
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