Paraho II Technology

The Paraho II retort is the centrepiece of the technology demonstration plant. This technology demonstration plant has recently produced quantities of high quality transport fuel such as ultra low sulphur diesel and jet fuel.
The demonstration plant features:
  • A crushing plant where the oil shale is crushed to an average size of 10mm in diameter
  • A screening and sizing plant which includes a briquetter to produce material from finer pieces of oil shale (resembles a BBQ bead)
  • A shale dryer
  • The Paraho IIretort
  • Measure tanks
  • Process water treatment tower
  • Gas treatment works
  • An oil upgrading facility (mini refinery)
  • Storage tanks
  • Product roll-out facility
In the vertical retort, oil shale passes gradually down through a series of temperature zones under the force of gravity, taking approximately six hours to travel from the top of the structure to the bottom.
The key zone in the retort is where the oil shale is heated to about 500ºC to extract the kerogen, or organic material, contained in the shale. The kerogen rises up the structure as a vapour of oil droplets which is sent to the oil recovery section.
The retort is a completely sealed vessel and the temperature of the shale when it exits the bottom of the structure is about 190ºC.
QER utilises waste heat and gas recycling to reduce energy usage in the retorting process. Any excess process water and gas are removed from the retort and sent to treatment facilities, where ammonia and sulphur are removed.
The remaining process water is used to moisten, and cool to about 70ºC, the processed shale before it is returned to the mine area for eventual rehabilitation.
Sustainable facts about Paraho II™
There are more than 60 oil shale processing technologies, but many of them are at little more than experimental stage. Primary amongst the proven technologies is the vertical shaft retort Paraho technology, developed in Colorado, USA, during the 1970s/early 1980s.
QER, in association with the technology owners, recommissioned the Paraho pilot plant facility in Colorado in 2005 and conducted 5 years of testing on 10,000 tonnes of representative samples of Queensland oil shales utilising the Paraho process. QER set key criteria to determine the suitability of the technology for further development. Broadly these criteria included:
  • Environmental (emissions) performance
  • Retort performance (throughput rate and yield)
  • Process stability
  • Process controllability
  • Process predictability
  • Waste product management.
The Paraho process proved to be robust, reliable, responsive and controllable.