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Recent content by PetroBob

  1. PetroBob

    Effectiveness of Process Simulators at modelling sour water strippers

    Thanks George! Useful to know; maybe if we get enough water projects going forward then my company can justify getting electrolyte version of Pro II. (Its not going to help me for this calculation however.)
  2. PetroBob

    Effectiveness of Process Simulators at modelling sour water strippers

    I've been asked to model a sour water stripper that will use natural gas to strip H2S from sour water, using VMG Sim/Symmetry process modelling software. (My company moved away from using HYSYS due to the high cost and insufficient oil industry work in recent years; we only have VMG Sim now.)...
  3. PetroBob

    Stamping non-essential engineering documents

    Thanks for the input folks. In this instance I was referring to instrument datasheets (eg temperature gauges, pressure transmitters, level gauges & suchlike), and also mechanical equipment datasheets (eg pumps, vessels, tanks, etc). The datasheets provide technical information regarding the...
  4. PetroBob

    Stamping non-essential engineering documents

    Thanks for the advice folks, however it doesn't quite answer my question. What I want to know is, has anyone seen datasheets that are stamped? And more generally, which less-critical engineering documents should or should not be stamped? The question about who prepared the work versus who...
  5. PetroBob

    Stamping non-essential engineering documents

    I'm being asked to provide a professional engineering stamp on non-essential engineering documents such as instrument datasheets, equipment datasheets, etc. I say non-essential, because these datasheets are required deliverables for some projects, but not others. Is this normal or should I push...
  6. PetroBob

    Separation of boiler from human occupied areas, MCC, etc

    Hi, can someone please direct me to the code or standard used in North America to determine where a boiler can be located in relation to a motor control center, and human occupied areas (eg a control room or office, etc). Ie is there a minimum required distance from fired equipment? In this...
  7. PetroBob

    PSV relieving to atmosphere - fire case

    I am being asked to stamp an existing design that includes PSV venting to atmosphere. Relief case is pool fire under the vessel, and hence causing boiling of flammable liquids in the vessel. Liquid Mr = 54, ie heavier than air (although maybe not if hot). I'm accustomed to having PSV outlet to...
  8. PetroBob

    Design pressure of PSV discharge piping

    Thanks folks for the useful replies. I have accepted the higher design pressure, provided the valves can operate with the stipulated max backpressure of 500 kPag.
  9. PetroBob

    Design pressure of PSV discharge piping

    Our client is insisting that PSV discharge piping must have the same design pressure as the PSV set pressure of 1200 kPag (175 psig). Normally PSV discharge piping would have lower design pressure since it's open pipe to flare, ie pressure is limited to backpressure from hydraulic losses in the...
  10. PetroBob

    Colour used for hand marked updates to engineering drawings

    Many thanks for the reply bimr. Do they use this for other disciplines than Process? Eg for Civil drawings?
  11. PetroBob

    Colour used for hand marked updates to engineering drawings

    What colours are typically used for checking and updating process drawings? What about other engineering disciplines, eg civil drawings? Typically companies I've worked with use red for additions, green for deletions and blue or black for comments (that are not CADDED). This is for hand...
  12. PetroBob

    Bottled nitrogen cooling due to JT effect

    Thanks Gaswell, MortenA and sshep for all the interest. Your check from first principles against simulators like HYSYS is very interesting. Unfortunately, in this instance, there are times when the gas may be supplied via a high pressure gas cylinder mounted on a vehicle, therefore the client...
  13. PetroBob

    Bottled nitrogen cooling due to JT effect

    Waqasmanzoor, itdepends and LittleInch, many thanks for the useful replies. Xeng & gaswell, I agree HYSYS alone is not sufficient for this thermodynamic calculation; however it was a useful tool to provide a quick preliminary JT check before calculating heat transferred from the metal. The...
  14. PetroBob

    Bottled nitrogen cooling due to JT effect

    Thanks David. It's fairly small flow rate - purging natural gas out of 100 m3 of equipment + piping, in say 2 to 3 hours. It sounds as though residual heat will mitigate the problem provided bottles are room temp. Should we be concerned if gas bottles are located outdoors in winter, where...
  15. PetroBob

    Bottled nitrogen cooling due to JT effect

    We are letting nitrogen down from high pressure cylinders at 4250 psig / 29,300 kPag, to just above atmospheric. The nitrogen will be used to purge piping and equipment. I understand that the nitrogen will get very cold due to JT cooling. HYSYS gives very alarming temperatures; eg if bottles...

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