The TOSCO II process is an above ground retorting technology for
shale oil extraction
Shale oil extraction is an industrial process for unconventional oil production. This process converts kerogen in oil shale into shale oil by pyrolysis, hydrogenation, or thermal dissolution. The resultant shale oil is used as fuel oil or up ...
, which uses fine particles of
oil shale
Oil shale is an organic-rich fine-grained sedimentary rock containing kerogen (a solid mixture of organic chemical compounds) from which liquid hydrocarbons can be produced. In addition to kerogen, general composition of oil shales constitut ...
that are heated in a
rotating kiln. The particularity of this process is that it use hot ceramic balls for the heat transfer between the retort and a heater. The process was tested in a 40 tonnes per hour test facility near
Parachute, Colorado.
History
TOSCO II process is a refinement of the Swedish Aspeco process.
[
] The
Tosco Corporation purchased its patent rights in 1952.
[ In 1956, the Denver Research Institute performed research and development of this technology, including testing of a 24 ]ton
Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses.
Mainly it describes units of weight. Confusion can arise because ''ton'' can mean
* the long ton, which is 2,240 pounds
...
per day pilot plant, which operated until 1966. Later the technology development was continued under Tosco's own directions.[
] In 1964 Tosco, Standard Oil of Ohio, and Cleveland Cliffs Iron Company formed Colony Development, a joint venture company to develop the Colony Shale Oil Project
Colony Shale Oil Project was an oil shale development project at the Piceance Basin near Parachute Creek, Colorado. The project consisted of an oil shale mine and pilot-scale shale oil plant, which used the TOSCO II retorting technology, develo ...
and to commercialize the TOSCO II technology. The project was ended in April 1972.[
]
Technology
The TOSCO II process is classified as a hot recycled solids technology.[
] It employs a horizontal rotating kiln-type retort. In this process, oil shale is crushed smaller than and enters the system through pneumatic lift pipes in which oil shale is elevated by hot gas streams and preheated to about .[
] After entering into retort, oil shale is mixed with hot ceramic balls with temperature from to . This increase the oil shale temperature to between and , in which pyrolysis occurs. In the pyrolysis process, kerogen
Kerogen is solid, insoluble organic matter in sedimentary rocks. Comprising an estimated 1016 tons of carbon, it is the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. It ...
decomposes to oil shale gas Oil shale gas (also: retort gas or retorting gas) is a synthetic non-condensable gas mixture (syngas) produced by oil shale thermal processing (pyrolysis). Although often referred to as shale gas, it differs from the natural gas produced from shale ...
and oil vapors, while the remainder of the oil shale forms spent shale. Vapors are transferred to a condensor ( fractionator) for separation into various fractions
A fraction (from la, fractus, "broken") represents a part of a whole or, more generally, any number of equal parts. When spoken in everyday English, a fraction describes how many parts of a certain size there are, for example, one-half, eight ...
.[ At the kiln passage, the spent shale and the ceramic balls are separated in a perforated rotating separation drum (]trommel
A trommel screen, also known as a rotary screen, is a mechanical screening machine used to separate materials, mainly in the mineral and solid-waste processing industries.Stessel et al. 1996, pp. 558-568. It consists of a perforated cylindrical d ...
).[ The crushed spent shale falls through holes in the trommel, while ceramic balls are transferred to the ball heater.][
] Combustible shale gas is burned in the ball heater to reheat the ceramic balls.[
The overall thermal efficiency of TOSCO II process is low because the energy of spent shale is not recovered and much of the produced shale gas is consumed by the process itself. The efficiency could be increased by burning char (carbonaceous residue in the spent shale) instead of shale gas as a fuel of the ball heater. The process' other disadvantages are mechanical complexity and large number of moving parts. Also the lifetime of ceramic balls is limited. Disposal of spent shale includes environmental problems because it is very finely crushed and contains carbon residue.][
]
See also
* Alberta Taciuk Process
* Kiviter process
* Petrosix process
* Galoter process
* Fushun process
The Fushun process is an above-ground retorting technology for shale oil extraction. It is named after the main production site of Fushun, Liaoning province in northeastern China.
History
The Fushun process was developed and utilized for the extra ...
* Paraho process
* Lurgi-Ruhrgas process
References
{{Reflist
Oil shale technology