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run length of 347ss tubes

Home Forums Coking Technical Heaters & Furnaces run length of 347ss tubes

This topic contains 4 replies, has 2 voices, and was last updated by  Anonymous 16 years, 4 months ago.

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  • #4294


    What is the typical the heater run-length after change to 347ss?

  • #7703


    When you say run lengths, are you talking about tube life or are you talking about run lengths before you have to decoke? If you are talking about tube life, I don’t think 347 has be in long enough to determine tube life yet. If you are talking about run lengths between decokes, it will depend of how hard you run your heater. If you start to run higher tube skin temps, you will coke just about as fast but the higher skin temp won’t tend to damage the tube material as fast as 9 chrome would. I hope that this makes soom since.

  • #7702


    One thing I need to say. If you do change you tube material to 347, you will need to use soda ash in you pig decoking water.

  • #7698


    Hi Dear All
    If we are planning to replace the 9Cr tube to 347ss or Aloized tube.
    Which is best?
    And let you to select,which material is you want?

  • #7531


    You should considered all maintenance implication to change from 9 Cr to SS 347 such a pigging as another guess told you. Also the quality of your fuel gas is a key point. Evaluate the risk of sensitization even thoug SS347 is estable material in the front of degradation, you should considered that.
    Alonized: Remember any holiday in the internal coating will cause a inmediate failure, alonized final product offered an excellent protection to high temperature, but if you need reparation after installation you should considered that the coating will be destroyed in the welding are, and also the Al can cause a welding deffects.
    I hope it helps,
    Sincerely,. MCdeC

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