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Recent content by ggordonstewart

  1. ggordonstewart

    Guidance Regarding Liquid Holdup

    The liquid hold-up you calculate is at steady state conditions. If the throughput changes, or the inlet pressure or temperature changes, then the calculated hold-up also changes. If the hold-up volume decreases between two operating conditions, the difference in volume will arrive as a slug. G...
  2. ggordonstewart

    Slug catchers sizing

    Gas Conditioning and Processing, Vol.1: The Basic Principles by John M. Campbell, published by: John M. Campbell and Company has a good section on 2-phase flow in both horizontal and vertical pipes. If you have access to a good process simulator such as Hysys, you can calculate the liquid...
  3. ggordonstewart

    H2S Levels in Natural Gas

    You have a very serius safety issue that you seem to want to ignore. Just because this is SE Asia, it does not mean that you should be prepared to endanger the life and health of the crew. Extreme safety precautions should be exercised in any H2S environment. Every year people die or are...
  4. ggordonstewart

    DEHYDRATOR

    At the same purity, all glycols (MEG, DEG and TEG) have similar equilibrium dewpoints. However, you have to remember that the circulation rate required is based on the mols of Glycol vs. the mols of water and adjust accordingly. Also, the Glycol Reconcentrator operating temperature will change...
  5. ggordonstewart

    How acid is formed in dry 14% SO2 gas line ?

    Since you are using air as your oxygen source to combust with sulphur, you need to realize that air contains 5 ppm of hydrogen and 2 ppm methane (From analysis of Handbook of Physics and Chemistry). This is probably enough hydrogen to form the water and hence the acid that is causing the...
  6. ggordonstewart

    ANSI Flange Ratings

    Thank you. That was exactly what I was looking for. G. Gordon Stewart, P.Eng. Gas & Oil Process Engineering Consultant http://www.ggordonstewart.com/ ggstewar@telusplanet.net
  7. ggordonstewart

    ANSI Flange Ratings

    This site gives flange dimensions, but not pressure ratings at various temperatures. G. Gordon Stewart, P.Eng. Gas & Oil Process Engineering Consultant http://www.ggordonstewart.com/ ggstewar@telusplanet.net
  8. ggordonstewart

    ANSI Flange Ratings

    Does anyone know where I can find ANSI 16.5 Pressure/Temperature Ratings for Flanges Class 150, 300, 600 & 900 on the internet? G. Gordon Stewart, P.Eng. Gas & Oil Process Engineering Consultant http://www.ggordonstewart.com/ ggstewar@telusplanet.net
  9. ggordonstewart

    JT Effect in Gas Pipelines

    Heat transfer in pipelines can be very complicated due to the variance in the soil that occurs along the length of the pipeline. If you are trying to determine the distance between line heaters so that the temperature of the gas never falls below the hydrate temperature, then you have be be...
  10. ggordonstewart

    Downhole heating systems

    Many companies employ stem injection to heat the heavier crude in tar sand oil production (Alberta and California). G. Gordon Stewart, P.Eng. Gas & Oil Process Engineering Consultant http://www.ggordonstewart.com/ ggstewar@telusplanet.net
  11. ggordonstewart

    Gas drying - glycol consumption

    As stated, the losses occur at 3 points. The main point of loss is the Reboiler Still Column Overheads. At Atmosheric pressure and an Overhead Temperature of 240 F, the theoretical TEG losses will be 1% of the water removed from the Gas Stream (by weight). This can be reduced by sizing the...
  12. ggordonstewart

    natural gas water and H.C dewpointing

    In order to determine the water and hydrocarbon dewpoint, I would need to know the complete gas analysis, inlet temperature, inlet pressure, flow configuration, tower size, bed depth, cycle length, regeneration flow rate, heat duty (regeneration), cooler duty, etc. This is not an analysis that...
  13. ggordonstewart

    How to determine the HC dew point temp in such sale gas contract.

    Because of the retrograde nature of natural gas, the dewpoint temperature at a given pressure is not the same for other pressures. For most natural gases, the peak (maximum) temperature occurs between 400 and 800 psia, normally around 600 psia. If the pressure after the expander is around 600...
  14. ggordonstewart

    When do you have to apply "lethal service"?

    Theoretically, if a leak of the substance contained within the pressure vessel is lethal to anyone exposed to the leak, the vessel should be designated "Lethal Service". However, the ASME Code makes it the responsibility of the Owner/Operator of the vessel to designate the service...
  15. ggordonstewart

    Multi phase flow in pipelines

    There are some commercially available software programs that help you to estimate pressure drops, liquid hold-up and surge/slug volumes such as Hysys and PipeFlo. This is not an exact science, so err on the side of caution when designing a piping system and eliminate any potential cause of...

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