In the late 1940s, these retorts were tested in the Oil Shale Experiment Station at Anvil Points in Rifle, Colorado.
[2] Before leasing a track at Anvil Points, a test of using the Paraho Direct process for limestone calcination in cement kilns was carried out.
[3] The semiworks unit achieved a maximum throughput capacity of 290 tons (263 tonnes) of raw oil shale per day.
[1] In 1976–1978, under the contracts with the United States Navy, Paraho technology was used for production of 100,000 barrels of crude shale oil.
[2] On 13 June 1980, the Department of Energy awarded $4.4 million contract (participants providing additional $3.7 million) for an 18-month study to construct an 18,000 TPD modular demonstration shale oil plant producing 10,000 BPD on a lease 40 miles southeast of Vernal, Utah.
In 1991, New PARAHO reported successful tests of SOMAT shale oil asphalt additive.
[9] On 14 August 2008, Queensland Energy Resources announced that it will use the Paraho Indirect technology for its Stuart Oil Shale Project.
In the Paraho Direct process, the crushed and screened raw oil shale is fed into the top of the retort through a rotating distributor.
The combustion takes place where air is injected at two levels in the middle of the retort below the pyrolysis section raising the temperature of the shale and the gas to 700 °C (1,292 °F) to 800 °C (1,472 °F).
[1] As a result, the fuel gas from the Paraho Indirect is not diluted with combustion gases and the char remains on the disposed spent shale.