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Sunday, July 16, 2017

Crude Distillation Fouling in Vacuum Systems


  1. Norm I experienced a similar phenomena at the Sat Gas Plant Depropanizer tower in a refinery in Garyville Louisiana back in the 1980s. The rubber/polymer strips formed on the Depropanizer column bubble caps from the feed tray to the bottom tray, and the only chemical found to readily dissolve the polymer was sulfuric acid. During operation the polymer was found trapped under the tray bubble caps, holding them open, which caused lost tower separation efficiency in the lower section. So it was either acid wash the tower with sulfuric acid, or clean the trays manually. The company decided sulfuric acid wash was too risky, and elected a mechanical manual tray clean. The company was injecting inexpensive oil field light naphthas into the raw crude at the time but the actual source of this material was never identified. I presumed the material entered the depropanizer feed along with other C4 crude tower overhead liquid materiqls. Mark Edwards

  2. Good morning! We are currently struggling with corrosion brought on by this foulant in our Vacuum OH Liquid Ring Compressor skid. We already operate at maximum pass pressures in the Vacuum Furnace and the boot is so small it the level is not representative of the tower's size. Change out the condensate wash with diesel? I assume this is acting as a thinner to keep the "goo" from rubberizing?

    1. Problem with corrosion in overhead is usually due to HCL evolved in the flash zone of the vacuum tower.

      However, fouling deposits will be iron sulfide not ferrous chloride.

      Diesel will not solve the problem; it is only there because it has lower vapor pressure than water.

      Call me to discuss at (504) 430-0757‬

      Norm Lieberman