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Transport Reactor Development Unit (1-MW gasifier)

The TRDU is an advanced gasification power system that produces a combination of electricity, syngas, and hydrogen. The design provides a large utility-scale, low-capital-cost gasification system that can use state-of-the-art pollution control systems. A large hot-gas filter vessel follows the TRDU system for further gas cleanup testing.

Operating Conditions

  • Nominal feed rate: 200–500 lb/hr
  • Syngas production: 400 or 250 scfm (air vs. O2-blown)
  • Pressure: 120 psi
  • Nominal temperature: 2000°F (1090°C) (refractory-lined)
  • Warm-gas cleanup capability: slipstream, 5%

Data Collection

The unit is fully instrumented with an array of internal thermocouples, pressure and differential pressure transmitters, and gas flowmeters. All measured process variables are controlled and recorded by a computer-based process control and data acquisition system.


Solids enter the system in a nonpressurized hopper with a capacity of 2500 lb. The coal is gravity-fed into the pressurized coal lock hopper, which has a capacity of 1700 lb. A set of valves isolates the pressurized lock hopper from a small pressurized surge hopper, which maintains an uninterrupted flow of coal while the pressurized coal hopper is being filled. The feed auger drops the solids into a high-velocity gas stream of ambient temperature or preheated nitrogen or air (572°F/300°C). The solids can also be augered into the carbonizer rather than by pneumatic transport.

The TRDU proper consists of a riser section with an expanded mixing section at the bottom, a disengager on top of a solids standpipe, and a cyclone with its associated dipleg. The solids standpipe is connected to the riser mixing section by a J-leg transfer line. All of the components in the system are refractory-lined and designed to operate at 120 psig and at an internal temperature of 2000°F (1090°C).

The bulk of entrained solids leaving the riser is separated from the gas stream in the disengager and recirculated back to the riser via the standpipe and J-leg. Gas exiting the disengager is further screened of solids as it enters the cyclone. Gas exiting the cyclone passes through the hot-gas cleanup loop and proceeds to the gas quench train. Solids removed by the cyclone are reintroduced to the standpipe and, in turn, to the riser. A solids stream is withdrawn from the standpipe via a cooling auger system to provide a means of removing accumulated ash and spent sorbents.

Gas then passes through the sieve tower to remove tars and oils. Next is a series of two direct-contact water scrubbers (venturi scrubbers/cyclones) that are used when the gas stream contains minimal amounts of vaporized organic liquids. The gas stream is cooled to between 200° and 225°F (93° and 107°C) in the first water scrubber and to below 125°F (52°C) in the second scrubber. The gas from the second venturi is flared, and the liquid products are stored in 55-gal barrels. The flare operates at a temperature of 1800°F (982°C) and a residence time of 0.5 seconds.


  • The TRDU was initially built to facilitate testing at the Power Systems Development Facility in Wilsonville, Alabama.
  • Clients have included the U.S. Department of Energy, M.W. Kellogg (now Kellogg Brown & Root), Southern Company Services, Electric Power Research Institute, and the North Dakota Industrial Commission.

Useful Links

Large Hot-Gas Filter Vessel