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Recent content by sshep

  1. sshep

    Drying Vessel to -40oF DewPoint

    Probably there was a pocket of free water which was holding you up. That will take a long time to evaporate with a steady purge, especially if it is not in the N2 flow path. Pressure purging is a more effective way remove free water because it creates internal flow at all points in the system...
  2. sshep

    Piping downstream Expander goes upward to 15m from Expander centerline

    This was an interesting 2 phase flow observation which I believe is assisted by the formation of very fine drops from the expander, and easily carried along with the gas flow. The coalescing to a liquid phase requires low velocity and a little time. The actual settling time is from Stokes Law...
  3. sshep

    Internal Projection on Level Nozzle of Steam Seperator Drum

    My Friends, A knock out drum on high pressure steam header has 3/4" internal projection on the level nozzles. These nozzles are for a bridle pipe that serves a dP level transmitter and a reflex level gage. The bottom (liquid) nozzle needs a repair and they asked permission to reinstall...
  4. sshep

    Can relief valve at positive displacement pump discharge routed to blowdown vessel instead of suctio

    Relief back to the suction vessel sounds perfect- simple and easy to evaluate. Relief to a new system will have additional complexity. Best wishes, sshep
  5. sshep

    Pressure Testing of Pipe - Leave the Control Valves and Instrumentation in place?

    Hey Matt, It sounds like the control valve should be replaced with a temporary spool. The instruments should be disconnected. One project i worked on crushed many pressure capsules by not isolating instruments during hydrotest- unless you are sure, it is better not to risk it. Best wishes, Sshep
  6. sshep

    Cooling Medium Expansion Drum Lower than Consumer

    If the drum is pressurized, it is not neccessary to be at the highest point. I have seen many tempered water systems with expansion drum at grade, and serving elevated exchangers. Best wishes, Sean
  7. sshep

    Internal of a distillation column

    Hello Hosein, 1- looks like a feed or drawoff nozzle with bolt in parts 2- downcomer bolting bar outside weirs 3- downcomer bolting bar inside weirs 4- (cant see it) arrow points to tray support ring 5- unsure, need to see drawings 6- looks like bolting bars for sloped downcomers 7- unsure...
  8. sshep

    Significant increasing a packed distillation column capacity just with new bed supports?

    Hey guerky, The bed support you describe sounds poorly thought out in temrs of capacity limitations. Maybe it wasn't an issue inthe original design and done cheap and simple. I know Lieberman's check. I am not sure void fraction can be used as open area in the calculation of effective open...
  9. sshep

    Redirecting flash steam in boiler feedtank

    Hey Davkoo, I just wanted to add another idea which I think is even easier and cheaper: consider recovering the heat from the liquid stream before flashing into the tank. A pumped liquid stream will be easy to reroute compared to trying to recover the flash steam. You need only find a cold...
  10. sshep

    Distillation process control

    Hello Fahad3608, If you have access to process simulation tools, you should check out the temperature and composition profiles for one of your distillation examples. Fix the reflux and distillate at plant values, and look at the profiles and splits for different tower heights. A short column...
  11. sshep

    Paralleling multiple safety relief devices for a pressure vessel

    Hello Plantprowler, It is permissible to have a single nozzle serving two relief valves, or even have them on the process piping. Check API RP 520 part II- Installation of pressure relieving devices; which includes typical layouts. The key design parameter is the allowable pressure drop in the...
  12. sshep

    Sparging hot gas

    Hello robot6, I also think you can use the same principles of direct steam injection into cold water. Search komax.com. I got a lead to a scepter tank heat from engtips many years ago, but they have many solutions, and possibly high temp alloy. I am sure there are others. Mixing a gas reactant...
  13. sshep

    Thermosyphon Reboiler Design

    Hello Txheat, FYI, Aspen-Tech is offering a free 4hr "virtual training" on this subject. The title is: EHX903 Reboilers - Designing and Troubleshooting Thermosiphon Reboilers. A USA course is set for 7-Jun. You can register on their website and download training materials. best wishes, sshep
  14. sshep

    Increasing the diameter of a steam line for a steam coil inside a batch still

    Hello tmengineer, I think your concern about the lower steam velocity impairing the heat transfer rate may be not be real. You are assuming that the heat transfer rate is limited due to film resistance on the steam side. Someone has estimated a heat transfer rate to calculate the area needed...
  15. sshep

    Thermosyphon Reboiler Design

    Txheat, The hydraulics are very important, but the vendor is getting paid to address this via the design and it is best not to try and do his mechanical design job. Concentrate on the process design, and then check his proposal to see if it is reasonable. In the case of a vertical thermosyphon...
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