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Recent content by georgeverghese

  1. georgeverghese

    Flame Arrestors on Natural Gas and Oxygen Vent Lines

    But in this case, the oxidant is already within the pipe, so I dont see what the FA will do to arrest the combustion. Besides, combustion can occur anywhere in the pipe where static could generate a spark.
  2. georgeverghese

    Flame Arrestors on Natural Gas and Oxygen Vent Lines

    Why do you need a FA for O2 vent lines ? Its not flammable.
  3. georgeverghese

    Heat Exchanger one stream out of service

    It is a process design error to set unequal design T for shellside and tubeside in this case. But now that steam is to be permanently disconnected, it probably doesnt matter. A PSV on shellside set at 24barg is still required to cater for tube rupture failure.
  4. georgeverghese

    Potential for hydraulic transients with liquid restriction orifice isenthalpic expansion

    That RO is probably sized to prevent overloading this line with excess flow that could potentially rattle and shake this line off its supports, given line pressure is 700-800psig. So its not meant for operational throttling. Add a choke or needle valve either upstream or downstream of the...
  5. georgeverghese

    Common Venting CAT II: Flue Sizing

    A common vent header for fired equipment is a BAD idea - always insist on individual vents.
  6. georgeverghese

    Requirement of Manual Ball valve between ESDV and MOV in Pig trap area

    They want DBB upstream of the critical ESDV so that the ESDV can be safely removed without having to depressure the entire upstream pipeline. Otherwise, the Plant Owner may be forced to consider risky alternatives, of which there are many. But I dont see an intermediate bleed. The DN500 MOV is a...
  7. georgeverghese

    Design Pressure due to Deflagration

    You may wish to query the rational for these unusually large dia lines. Why is the max operating pressure only 1barg? Can you not allow for a higher operating pressure that will reduce line dia ? Or is there some limitation due to low design pressure of equipment connected to this flare system...
  8. georgeverghese

    Premature Deterioration of Ozone Diffuser Gaskets – Request for Support

    From what I see on Google ( search fake viton gasket), you may be using a generic FKM gasket, and not genuine Viton "While the term "Viton" is often used interchangeably with FKM (fluoroelastomer), it's actually a trademark of Chemours Company. Therefore, there's no official "fake Viton"...
  9. georgeverghese

    Lpg Production

    If your focus is on LPG production from natural gas, then do you need to produce a methane only stream from demethanizer as shown in diagram ? Instead, you can operate a de ethanizer without de methanizer, which will give you a sales gas stream with C1 and C2, while NGL will contain C3 and...
  10. georgeverghese

    static mixer

    Ask them about flow turndown range - that should also be weighed in for selection criteria. At low flow, mixing will be more difficult.
  11. georgeverghese

    Entrainment rate of wind over the top of a stack

    Google tells me atmospheric air cools down by an average of 0.65degC per 100metres rise in altitude, so this is the driving force for the natural convection effect. There is an error in your warehouse height. This should help https://en.wikipedia.org/wiki/Stack_effect
  12. georgeverghese

    Check valve on fuel return line - NFPA 20

    See if this helps : https://www.linkedin.com/pulse/diesel-fuel-return-line-bleed-back-mike-trumbature My guess is this check valve requirement on "fuel supply pressure recycle return line to fuel tank" is valid only when BOTH of the following are applicable a)the return line enters the fuel...
  13. georgeverghese

    A333 Gr 6 Minimum Temperature

    Typically, this piping stress ratio route to allowing some exceedence on lower design temp is not used, since the actual stresses whilst in operation may well exceed what you compute in the design office. Since this is a marginal exceedence, see if the process engineer can calculate a higher...
  14. georgeverghese

    Determining flow through a half full gravity return oil line

    Self venting gravity flow lines are typically sized to keep the Froude number N_Fr < 0.31 (in SI units). See equation 6-138 in Perry Chem Engg Handbook (7th edn) for N_Fr expression which accounts for liquids with density other than water - there is no viscosity term here though, so maybe keep...
  15. georgeverghese

    Determining flow through a half full gravity return oil line

    Avoid high or low point piping pockets in the return lines to the main oil tank - all return lines should be free venting so entrained air or process gas doesnt get trapped at these pockets. Hydraulic flow equations wont help if these lines are pocketed.

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