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Continuous Fluid-Bed Reactor (low-pressure, 4 lb/hr)

The system allows for the study of pyrolysis and gasification reactions, processing, and product generation applicable to internal combustion engines, gas turbines, and fuel cells. Products have included solids, liquids, and gases, including coal char, ash, basaltic rock, diesel fuel, water, and various proprietary compounds. The unit has also been used in combustion tests and in the processing of lunar soil simulant.

The CFBR can be used in conjunction with a sulfur reactor and a bench-scale hot-gas filter vessel. Various process gases or liquids can be used for reactants. Procedures exist to handle hazardous materials such as H2S, HCN, and HCl.

Operating Conditions

  • Output capacity: 1 to 4 lb/hr.
  • Nominal temperature: 1550°F (840°C) (metal reactor). The uniform temperature profile in the reactor minimizes tar generation (< 1ppm).
  • Pressure: 165 psi (155 psig).
  • Syngas production: 8, 1.5–2 scfm (air vs. O2-blown).
  • Warm-gas cleanup capability: full stream.
  • Capable of 24/7 operation.

Feedstocks

  • Coal
  • Biomass
  • Nontraditional fuels (i.e., plastics, automotive shredder residue) up to 60% moisture

Gases

  • Bottled gas, house nitrogen, house air, and any liquid desired (such as water) may be used.
  • Previously used gases include CO, CO2, NO, NO2, H2, N2, air, O2, HCl, and C4H10. Water and ethanol were used as reactants.

Superheater

The superheater is 20 ft of 3/8-in. tubing coiled into an 18-in. ceramic fiber heater.

Cyclone

The cyclone is constructed of 316H stainless steel Schedule 80 pipe. The first (bottom) section is made of 3-in. pipe and is 33 in. long. The top reactor section is made of 4-in. pipe and is about 18 in. long. The two sections are connected with a 316H weld reducer. The cyclone is heated with a ceramic fiber heater capable of operating at a temperature of 1650°F (900°C) and 200 psig.

Reactor

The reactor has two ceramic fiber heaters to maintain vessel temperature and eliminate hot spots. Gases leaving the cyclone can pass through a reactor vessel designed for testing of sulfur and chlorine sorbents. Two cartridges are available for use, one 4 in. long and one 8 in. long; the lines leading to it are externally heated. The cartridges have been utilized to contain a fixed bed of zinc-based sorbent to reduce the H2S concentrations or to contain calcium-based sorbent for the removal of chlorine gases from the fuel gases. A hydrogen separation membrane is also installed on this unit.

Condensation Trains

The gas stream then enters one of two condensation trains. The two condensation trains are identical, each consisting of a water-cooled indirect heat exchanger, followed by two glycol-cooled indirect heat exchangers. One train is for mass balance sampling and the other for heatup, unsteady-state conditions, and cooldown. The first condenser pot is indirectly cooled by water and typically cools the gas stream from 570°F (300°C) to 200°F (95°C). The next two condensers, also indirect, are glycol-cooled. The exit gas temperature is typically 50°F (10°C). A glass wool filter is used to capture aerosols passed through the condenser system. A wet scrubber has also been used to neutralize any chlorine still present in the gas stream before the gas is depressurized, sampled, and metered.

Data Collection

A Genesis© software package is used for process control and data acquisition. Sixty-two data points are stored on disk every 30 seconds and are updated on the screen every 2 seconds. The data are stored in a spreadsheet that can be downloaded or replayed graphically using the Genesis software. Pressure drop across the bed is measured by two transmitters, and thermocouples throughout the unit measure temperature. Online continuous emission monitors for H2, CO, CH4, CO2, and H2S together with an online Foxboro 931C gas chromatograph are utilized for measuring gas compositions. If desired, the gas composition of the product gas stream can be adjusted slightly by adding bottled gas to the gas stream entering the reactor.

Useful Links

Sulfur Reactor

Bench-Scale Hot-Gas Filter Vessel

Hydrogen Separation Membrane