JT (Joule-Thomson) Assembly

The JT assembly provides hydrocarbon dew point control and increased recovery of natural gas liquids (NGL). The JT Plant consists of a gas-to-gas heat exchanger with hot gas bypass, liquid-to-gas heat exchanger, JT valve, cold separator, methanol injection system and control system, all mounted on a single skid.

Exterran’s Joule-Thomson Assembly makes it easy for you to recover valuable NGL and reduce the water and hydrocarbon dew point of your production stream to pipeline specifications. This self-contained, skid-mounted system can be quickly installed and started up, making it ideal for short-term, space-constrained operating environments.

Key Benefits


  • Recovers valuable natural gas liquids
  • Latest ASME design and construction standards ensure high performance


  • Compact design and fast deliver allow quick startup in minimal space
  • Reduces BTU content of fuel gas proportional to inlet BTU


  • Option to lease or own the unit
  • Added assurance of a warranty on our manufactured products that runs 12 months from startup or 18 months from delivery, whichever comes first
  • Prompt, professional service, support and spare parts from local technicians in or near every major oil & gas producing region in the U.S. and numerous areas around the world

How it Works

The assembly consists of a gas/gas exchanger with hot gas bypass, JT valve, cold separator, methanol injection system and control system.

Following gas/liquid separation and gas dehydration, high-pressure gas enters the assembly through the gas/gas exchanger and chiller for pre-cooling. Methanol is injected to prevent formation of hydrates, and the raw natural gas passes through a JT valve. The resulting pressure drop causes expansion of the gas and a significant temperature reduction due to the Joule-Thompson effect.

The cooled gas is routed to the cold separator to remove the condensed NGL. The outlet gas from the cold separator is routed through the gas/gas exchanger for inlet cooling. The NGL from the cold separator is routed through the inlet NGL/gas exchanger and then to a separate optional pressurized NGL storage tank.

Standard Features & Options

Standard Features

  • JT valve with pressure pilot controller
  • NGL/gas exchanger
  • ASME code gas/gas exchanger
  • ASME code -20 °F cold separator
  • Temperature controller
  • Instrument gas/air manifold
  • Sight glass assembly
  • Methanol pump and delivery system
  • Cold thermal insulation
  • Hot gas bypass system for startup
  • Heavy-duty steel skid with lifting lugs
  • Thermal relief valves


  • Upstream Dehydration
  • Hairpin exchangers
  • Control isolation valves
  • Ethylene glycol injection system
  • NGL bullet tank
  • 3-phase separator
  • Unit leasing