Free Water Knockout Vessels
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Vapor Recovery Towers - Fabrication Services


TransTech delivers custom engineered and fabricated vapor recovery towers (VRTs) for effectively capturing and reducing storage tank VOC emissions to help facilities meet EPA NSPS OOOO (Quad O) regulations. VRTs can also eliminate potential in-system oxygen from oil or condensate storage tank batteries.

We bring in-depth knowledge of VRT operating principals and decades of oil and gas processing expertise to every project, ensuring safe, reliable operation of your vessel. Our VRT solutions help you retain resources—and add revenue to your operations by leveraging incremental profits through midstream natural gas and natural gas liquids (NGL) markets.


A Vapor recovery tower is a tall, vertically oriented pressure vessel installed between a production separator (or heater treater) and oil or condensate storage tanks. VRTs are designed to capture flash gas prior to crude oil or condensate entering liquid storage tanks. VRTs offer a final opportunity to capture valuable hydrocarbon vapors within the process train.

Liquids enter the VRT via a vessel inlet and reside within the vessel for a prescribed period of time to allow for separation to occur. Operating at near atmospheric pressure VRTs simulate the same breathing (standing), working and flash losses (VOC emissions) that crude oil or condensate storage tanks would normally generate.

Liquid level within the VRT is kept below the oil outlet nozzle to create a space for vapor above the oil. A vapor recovery unit or other pressure control device is used to maintain a nominal pressure of 1 to 5 psig within the VRT to reduce the chance of air entering the recovered gas. Meanwhile, exiting oil is pushed up to the oil outlet via a down corner pipe to prevent any vapors from being pushed up and over to the liquid storage tanks.

Vapors captured by the VRT can be directed to a vapor recovery unit for processing and placed into a natural gas sales pipeline or under certain circumstances, can be flared.


  • Reduce flash emissions
  • Capture more product for sales
  • Boost site revenue
  • Prevent vapor release from tank thief hatches
  • Reduce and eliminate VOC emissions
  • Reduce backpressure on storage tanks
  • Minimize and eliminate oxygen in gas pipelines
  • Reduce regulatory risk
  • Protect VRUs (Vapor Recovery Units) from vapor pressure surges
  • Manage heavy and lighter grade crudes



  • Fittings & flanges
  • Inlet
  • Outlet
  • Liquid level indicator
  • Temperature & pressure gauges
  • Lift lugs
  • Vent
  • Overflow
  • Drain
  • Exterior ladder
  • Cleanout & base plate
  • Platform
  • Manways
  • Stainless steel construction
  • American Welding Society – AWS
  • ASME Section VIII, Div. I Standards
  • American Society for Testing & Materials - ASTM


  • Platforms
  • Cages
  • Interconnected piping
  • Catwalks
  • Stairs
  • Cold weather protection/insulation
  • Advanced corrosion protection
  • More


Call us to speak with one of our ASME pressure vessel fabrication experts about your  vapor recovery tower fabrication needs at: 1-888-206-4563

—or click to contact us below:

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FREE ASME Pressure Vessel Material Analysis - MAWP - Max Allowable Working Pressure Guidance

FREE Preliminary Vessel Material Analysis

Without the right data to optimize your vessel design, it's easy to miscalculate design pressure by overcompensating for MAWP.  This can lead to incorrectly sized vessels and other  issues including unnecessary costs, underperforming assets—and disappointing ROI,

Let our AMSE vessel design experts assist you with a FREE preliminary material analysis!  We'll help you determine the right material grade & thickness for your pressure rating for optimal vessel performance, often leading to:

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