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  1. tmengineer

    Inspection of thermal oil heater internal / external

    Hello, I've got a job coming up where I'm performing an inspection of a thermal oil heater as part of routine maintenance checking The heater is horizontal 1500kW gas fed, 2.5 years old, with thermal fluid being pumped around the internal pipe coil The gas line to the burner will be...
  2. tmengineer

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

    Hello, Thanks for your replies! Stonecold, we do make (dimple) jackets for some process vessels but unfortunately the still body has already been made so I'd much prefer to find a solution without putting a jacket on the side. Closed loop heater systems with a re-circulation line and heat...
  3. tmengineer

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

    Hello, I'm designing a steam coil to be used in a batch process still - we are manufacturing the still and the steam coil and the P&ID is being done by others. The steam inlet line is DN65 and in order to get a sufficient heating area* inside the still a double layered coil is going to be...
  4. tmengineer

    Experience with mulitpass condensers

    Georgevergese, The internal diameter of the tubes is 17mm. C106 copper is basically pure (99.85%) and the tubesheet will be made of brass (Cu + Zn) alloy. The use of copper is due to a process constraint; the condenser + subcooler is being used in a whisky distillery where the contact between...
  5. tmengineer

    Experience with mulitpass condensers

    Hi EdStainless, The cooling tubes are made out of copper (C106 half hard 10 gauge). The water quality for the region is defined as "soft" on the UK water agency website and has Calcium mgCa/l = 2.90, Calcium mgMg/l = 1.1, hardness as mg/l CaCO3 = 11.76, Clark degrees 0.82, French degrees...
  6. tmengineer

    Experience with mulitpass condensers

    Hello, I'm just about finished the thermal design of a multipass condenser and subcooler system and would like to know if anyone has some real world experience with these units to compare with the theory I've been using: I'm proposing to use a vertical shell and tube condenser then vertical...
  7. tmengineer

    Tank Implosion due to insufficient vent diameter

    Duwe6, At 80 degrees C and 1 atm the saturated vapour pressure of water is 481 mbar (calculated with the Buck equation - similar to Antoine but simpler), and the water vapour pressure is 478 mbar. The temperature which the saturated vapour pressure is 478 mbar is 79.82 degrees C (again...
  8. tmengineer

    Tank Implosion due to insufficient vent diameter

    Hello! Sorry for the late reply - I haven't forgotten about this I've just been busy doing some other work for the last few days. I'll get back to you properly next week once I've had a chance to look at this again. Thank you so much for your contributions so far!
  9. tmengineer

    Tank Implosion due to insufficient vent diameter

    bimr, Yes when using the ideal gas law for a constant volume (closed system) and dT from 20 degrees C to 80 degrees C the overpressure is 207.4 mbar (155.6 mm Hg). And also, when modelling the tank as a closed system with a pure water at 80 degrees C pool at the bottom the vapour pressure is...
  10. tmengineer

    Tank Implosion due to insufficient vent diameter

    Will the incoming hot water not heat up the air inside the tank causing it to expand and cause an overpressure?
  11. tmengineer

    Tank Implosion due to insufficient vent diameter

    I'm sorry to change tack but the production manager told me that the tank failed due to the overpressure caused by the hot rinsing rather a vacuum from draining. The vent was probably still blocked as discussed above but now I'm looking at it from a different approach. I want to know what the...
  12. tmengineer

    Tank Implosion due to insufficient vent diameter

    Zdas, Sorry I didn't see your second comment until I was re-reading the thread this morning. That's good - if the pipe calculations suggest that an unrestricted pipe would provide an adequate flow rate then that's a useful result. I'll focus on the possibility of an obstruction in the pipe...
  13. tmengineer

    Tank Implosion due to insufficient vent diameter

    It's pumped away. Why do you ask?
  14. tmengineer

    Tank Implosion due to insufficient vent diameter

    Compositepro, I think I mislead you slightly - the tank cools naturally without cold water addition, it is in a similar tank that cold water is added, and yes this causes a greater pressure drop than the outflow of 900 l/min. I have made a spreadsheet for the rapid cooling scenario which I...
  15. tmengineer

    Tank Implosion due to insufficient vent diameter

    Hi 1gibson, I'm pretty sure that the vent is the problem. There is 8 fermenters, 4 with 4" -> 5" vents, and 4 with 6" vents (they were installed in 2 phases) and the 4 with 6" vents do not show as much sign of damage as the 4" -> 5" lines do. The fermenters have "switchers" in the gas space...
  16. tmengineer

    Tank Implosion due to insufficient vent diameter

    Thanks for the replies! Zdas04, I've used two forms of the Spitzlgass equation and got flow rates of 19.66 m^3/ min and 43.74 m^3/min. Both seem quite high and I did them in a quickly so I'll double check the units to see if I've made an error there, but at the minute because the gas flow rate...
  17. tmengineer

    Tank Implosion due to insufficient vent diameter

    Hello, A vessel has imploded due to having an insufficient vent diameter and I have been tasked with calculating the new appropriate diameter. The original vent was 4", 20m long, with 3 elbows, had a fan which wasn't used in the pipe and increased in diameter to 5" after 5m. The tank...
  18. tmengineer

    Checking for weld defects using low pressure pneumatic testing

    Hello, For a 100 m^3 tank would a test pressure of 0.6 barg be sufficient to detect if there was a defect/ leak in any of the welds? A small overpressure is required for safety concerns as the tank would have to be located in close proximity (>10m) to the workshop as that is where the...
  19. tmengineer

    Finglow Yeild Stress Figure

    I have found the yield stress values that Finglow is using - it is displayed on the reports generated. Corus, I thought the yield stress would be an important factor for tanks failing but I might be wrong. Why doesn't the yield stress come into it? I've been reading into buckling more as a...
  20. tmengineer

    Finglow Yeild Stress Figure

    Hello, I'm using Finglow 3D December 2013 to calculate the minimum shell thickness of a tank which is required to withstand a vacuum pressure of 100 mbar made from SS 304. I'd like to know the figure that Finglow uses for the yield stress for BS 1501-304-S11 but cannot find it on the...
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