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  1. mp662

    Strange top pressure issue in Distillation Column

    So we got the ultrasonic meter working on the cooling water and did a heat balance of the condenser. It is only doing about 1.2 MMBTU/hr cooling, while our heat input to the column is 1.6 MMBTU/hr. The design flow is 50000 lb/hr cooling water, and we are getting 35000. The pressure drop...
  2. mp662

    Strange top pressure issue in Distillation Column

    One interesting thing to note is that the reflux is about 85 degrees subcooled. The inlet vapor is 150 C and the outlet liquid is 45 C. Right before the column (about 3') the reflux line is about 130 C. The reflux line drops down about 10' vertically in a goose neck. The temperature at the...
  3. mp662

    Strange top pressure issue in Distillation Column

    sshep: The pressure instruments have their outputs to the DCS. We put about 5 separate pressure gauges on the column and they all confirm what the instruments read so I don't believe we have a measurement issue.
  4. mp662

    Strange top pressure issue in Distillation Column

    katmar: Why was the old condenser replaced? - due to baffle thinning. It was built 60 years ago and in rough shape. Have you checked that the old condenser was built to drawing? Is it possible that some tubes near the vapor inlet nozzle were removed if the same problem was experienced at the...
  5. mp662

    Strange top pressure issue in Distillation Column

    We installed a new like-for-like condenser on a small distillation column. After startup, we couldn’t pull down vacuum like we used to on the column (500 mmHg now vs 350 mmHg before). After 2 air leaks were found, the top pressure improved slightly, however the top pressure still remained...
  6. mp662

    Storage tank with concrete floor

    I have a firewater tank complying with NFPA code that requires an inspection every 3 years.  It also requires an internal inspection complying with API 653.  3 years ago, it was inspected and the floor was shot.  At that time, a concrete floor was poured in the tank and put back in service.  Our...
  7. mp662

    Fixed tubesheet HX shell side cleaning

    We've tried acetone, 20% NaOH, 98% sulfuric, and a few others. 98% sulfuric was the only one that worked, unfortunately we cannot use that due to corrosion, availability, safety, etc. We are going with a 20% sulfuric mixture with corrosion inhibitors. It did OK during a lab test as far as...
  8. mp662

    Fixed tubesheet HX shell side cleaning

    Thank you for all the replies. Unfortunately this stuff is almost like hard glue. It is a polymer fouling that basically laughs at typical acid washing solutions that we've lab tested. We are going to try a more aggressive acid solution to wash the exchanger. If that doesn't do it, we may...
  9. mp662

    Fixed tubesheet HX shell side cleaning

    I have a fixed tubesheet heat exchanger with massive fouling on the shell side (design was 10 psig drop, now closer to 50 psig). Thermal scans of the exchanger show a large blockage in 2 baffled sections of the exchanger. Tried chemical cleaning it with a non-aggressive solution, but it did...
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