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Recent content by mbt22

  1. mbt22

    LINE NUMBERING FOR STEAM TRAPS

    I agree that they need a number, it's just whether they sit under the same line designation as the main line the same way a branch to an instrument might. It's physically continuous, same temperature, pressure, overpressure protection and fluid, but different diameter and flow rate. I could...
  2. mbt22

    LINE NUMBERING FOR STEAM TRAPS

    Does it add value to have all these 'lines' numbered? They're presumably short lengths hanging off a major system. Matt
  3. mbt22

    Hi all while designing a tall pres

    Also check with the client, they may not want structural packing supports to constrain what they due in the future when the inevitable debottleneck or repack with the latest shiny packing comes along, Matt
  4. mbt22

    2 relief valves

    This will not work as you intend it to, the 3 psig valve will not protect your instrument. Regulator fails, pressure rises to 3 psig; 1st relief valve lifts, some flow diverted to vent but not all so accumulation continues; pressure in line rises to 25 psig; second RV lifts. The instrument...
  5. mbt22

    Effect of Supply/Return Temperature at Heat Production Efficiency

    Easiest way to prove this is to draw out the two systems and do the maths over the whole cycle to compare where the energy goes, then calculate your own coefficient of performance. Your heat load is given by M.Cp.dT, the electrical energy extracted by the change in enthalpy over the turbine...
  6. mbt22

    Hot Oil Drain Tank with N2 Blanketing System PSV Sizing

    In other words, as met11 has said a couple of times, a relief valve is not the right control for this gas filled vessel. Flame impinges on vessel, walls heat up, internal temperature and pressure increases (probably limited by heat transfer rather than in equilibrium), strength of wall drops as...
  7. mbt22

    NOx Emissions from Ammonia Flares

    Sorry for the delay in replying. You're right, I made the implicit assumption that any flare is a diffusion flame, not premixed, and designed to give destruction of the material fed to it. Matt
  8. mbt22

    NOx Emissions from Ammonia Flares

    Where do you see a contradiction between your two links? You're burning NH3 to a mixture of NOx and water,. Unless you're doing some form of selective catalytic oxidation, 1 mol of NH3 produces 1 mol of NOx plus whatever little bit of NOx you get from the combustion air. Matt
  9. mbt22

    Latent heat of vaporization

    Yes, the relieving pressure and the temperature the mixture boils at at that pressure. Talking through what happens inside the vessel to cause this relief case with a colleague may help, starting from a pool fire ignition underneath it at normal operating conditions. Matt
  10. mbt22

    Latent heat of vaporization

    Temperature, not pressure.
  11. mbt22

    Latent heat of vaporization

    I suspect someone's given you the wrong relieving conditions. If you're starting with liquid propylene oxide under a nitrogen blanket, boiling PO will hit relieving pressure at 155 deg C. Assuming your RV lifts at this point, it won't get any hotter until it has boiled dry, at which point you...
  12. mbt22

    FAQ

    US Chemical Safety Board. Personally, legal action seems to inhibit learning rather than encourage it. CSB or Marine/Air Accident Investigation Branches reports for example, looking for root causes and preventative actions for whole industries rather than legal accountability for a specific...
  13. mbt22

    Does the power industry not like to hire engineers with tech experience?

    Not power, but I wouldn't see a single internship in another field as being wedded to that field. Ten or twenty years experience and no good reason for moving field, maybe. Emphasise the transferrable technical skills, and be ready to explain why you weren't interested in going back to the...
  14. mbt22

    Tank Cleaning - Non Phenolic Sour water

    H2S<25% of LEL and O2 content are rather less important criteria than toxic exposure. Matt
  15. mbt22

    Removing oxygen from water using nitrogen sparging

    Pure nitrogen bubbles going in have zero partial pressure O2, and ideally going out are in equilibrium with the water, containing O2/H2O/N2. Oxygen is more volatile than water(!), you reduce the concentration of oxygen in the water. Matt
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