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  1. Sawsan311

    Allocation of Water in waste heat steam generators

    Thanks George for your great inputs, considering only LP of High pressure saturated steam (without superheating) then allocating the waste heat stream on tube side makes more sense to me to optimize the design thickness of the shell side in view of the high design temperature requirement...
  2. Sawsan311

    Allocation of Water in waste heat steam generators

    Dear All, I have been reviewing several design schemes where waste heat steam generators have the water fed/generated steam fed on the shell side as a design measure for condensate removal and minimized pressure drop/water hammer issues in case of allocated on tube side while in other designs...
  3. Sawsan311

    Nitrogen Purity for Secondary seal gas of Hydrocarbon Centrifugal compressors

    Thanks There is no article being referred to, this is from the operational experience and compressor vendors recommendations. @georgeverghese, yes primary seal gas is filtered and superheated slipstream process gas, yet, still there has been issues such as compressor fouling in presence of high...
  4. Sawsan311

    Nitrogen Purity for Secondary seal gas of Hydrocarbon Centrifugal compressors

    Dears, Across many designs and existing installations of associated HC gas centrifugal compressors, nitrogen used as secondary labiranth seal is typically of 95%-98% purity and easily supplied by membrane technology. Recently, there has been some views on the need to change the required...
  5. Sawsan311

    Stefan-Boltzmann Fire for Depressurization

    Hi, can you confirm that your blowdown rate estimation is for the fire scenario and not the warm adiabatic case since the thread you are referring to is discussing a totally different objective like MDMT check which we perform using ischoric adiabatic modelling and falls with different...
  6. Sawsan311

    Sizing Non-critical Plant Air Receiver Buffer Vessels

    LittleInch, thanks. There is evidently no doubt in the need to have a sufficiently larger receiver vessel that accommodates any downtime or cut-off int he supply to the critical IA users besides the prioritization shifting from the less-critical to the more electrical loads using pressure...
  7. Sawsan311

    Sizing Non-critical Plant Air Receiver Buffer Vessels

    Agreed George, the main intent of our discussion is whether we need to provide exclusive buffer vessel downstream the air compressor which would pass full demand and handle 1-2 minutes load/unload time gap. Attached snap from presentation sent by Pierre shows plant air receiver upstream the...
  8. Sawsan311

    Sizing Non-critical Plant Air Receiver Buffer Vessels

    Thanks all for your great inputs! From what is discussed above and as georgeverghese advised, the automatic start-up of the standby compressor upon the loss of the air supply pressure (at a set point higher than the PAL acting on the PCVs closing the less priority users, accommodating the...
  9. Sawsan311

    Sizing Non-critical Plant Air Receiver Buffer Vessels

    Each compressor is as high as 50% of the total load which is considerable, maintaining minimum pressure supply to critical consumers is evidently captured by the sizing of the IA dry air receiver . In case the operational intent is to maintain steady constant minimum disturbance to the IA...
  10. Sawsan311

    Sizing Non-critical Plant Air Receiver Buffer Vessels

    Dear All, In some application we deploy dedicated plant air supply from air compressor packages for use as utility cleaning stations such as purging equipment. This non-critical supply can be fed directly after the air compressor and upstream the dryer package. In this case, is there any...
  11. Sawsan311

    Auto-Variable Pitch for Air coolers Control

    Dear All, I need your feedback on the experience in implementing Auto-Variable Pitch for greenfield applications of forced or induced draft coolers. I believe it can offer a degree of air flow control but do have some reliability issues. Appreciate sharing your experience or any lessons...
  12. Sawsan311

    Air side fouling resistance of Air coolers

    Sorry there was a typo error, the unit of the fouling resistance is 1/U = m2.K/W
  13. Sawsan311

    Air side fouling resistance of Air coolers

    Agreed, the resistance is assigned to the tube side exposed to the air and to accommodate degree of fouling and dirt accumulation on the tube side of the air cooler. The mentioned number is confirmed with the units in m2. K / W2 and value of 0.00035 which is comparable to other process...
  14. Sawsan311

    Air side fouling resistance of Air coolers

    Dear All, The air side fouling resistance was specified as 0.00035 W.m2/K in one of the engineering specifications. In my view, this is even almost equivalent to crude oil applications I would like to ask the basis of such specification, is this targeted to maximize the pressure drop across...
  15. Sawsan311

    Compliance of ASME SEC VII for Pressure Vessels

    Thank you very much for your feedback
  16. Sawsan311

    Compliance of ASME SEC VII for Pressure Vessels

    Dear All, if the design involves a pressure vessel which shall be designed (UV stamped) in accordance with ASME SEC VII code, and if fire is the only overpressure scenario, would it be acceptable to waive the requirement of PSV since UG-140 of the same code is stating overpressure protection...
  17. Sawsan311

    PSV lifted below Set Pressure

    First ensure your PSV inlet pipe is upstream any demisting device otherwise it would have been responding to an artificially lower set pressure. Spring loaded type should not have been selected due to: 1. blowdown is maximum 7%-10% as per ASME SEC VII code and hence operating pressure shall not...
  18. Sawsan311

    CO2 Compressors- IGV control Versus VSD control

    Thanks Mr.George, I agree with you. I think you meant power increase upon efficiency reduction at low flow rates Regards
  19. Sawsan311

    Common Anti-surge recycle Across multi-stage CO2 compressor

    Thanks Mr.George, actually with CO2 the cryogenic behavior and hydrate formation becomes extremely problematic with a common anti-surge recycle, this is why designs tend to deploy individual recycle lines. Additionally, the interactions between the stage AS loops can be tackled by loop...
  20. Sawsan311

    CO2 Compressors- IGV control Versus VSD control

    Thans alot Mr. georgeverghese, Yes, antis-ruge control is always required integrated either with the perfomance controller through the common IGV or VSD. I also think that for parallel trains operation and the need to maintain network pressure, VSD would be better than IGV at each machine to act...

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