TOSCO II process
Encyclopedia
The TOSCO II process is an above ground retorting technology for shale oil extraction, which uses fine particles of oil shale
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
.
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
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
and to commercialize the TOSCO II technology. The project was ended in April 1972.
-type retort. In this process, oil shale is crushed smaller than 0.5 inches (13 mm) and enters the system through pneumatic lift pipes in which oil shale is elevated by hot gas streams and preheated to about 500 °F (260 °C). After entering into retort, oil shale is mixed with hot ceramic balls with temperature from 1200 °F (648.9 °C) to 1600 °F (871.1 °C). This increase the oil shale temperature to between 900 °F (482.2 °C) and 1100 °F (593.3 °C), in which pyrolysis occurs. In the pyrolysis process, kerogen
decomposes to oil shale gas
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
. At the kiln passage, the spent shale and the ceramic balls are separated in a perforated rotating separation drum (trommel
). 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.
Oil shale
Oil shale, an organic-rich fine-grained sedimentary rock, contains significant amounts of kerogen from which liquid hydrocarbons called shale oil can be produced...
that are heated in a rotating kiln
Rotary kiln
A Rotary kiln is a pyroprocessing device used to raise materials to a high temperature in a continuous process. Materials produced using rotary kilns include:* Cement* Lime* Refractories* Metakaolin* Titanium dioxide* Alumina* Vermiculite...
. 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
Parachute, Colorado
The Town of Parachute is a Statutory Town in Garfield County, Colorado, United States. The population was 1,006 at the 2000 census.-Geography:Parachute is located at ....
.
History
TOSCO II process is a refinement of the Swedish Aspeco process. The Tosco CorporationTosco Corporation
Tosco was an independent US based petroleum refining and marketing corporation. It was founded in 1955 in Santa Monica, California by A&P heir Huntington Hartford, and originally focused on extracting oil from oil shale and developing alternative energy sources.-Oil shale operations:In 1964...
purchased its patent rights in 1952. In 1956, the Denver Research Institute
University of Denver
The University of Denver is currently ranked 82nd among all public and private "National Universities" by U.S. News & World Report in the 2012 rankings....
performed research and development of this technology, including testing of a 24 ton
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
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
Standard Oil of Ohio
Standard Oil of Ohio or Sohio was an American oil company that was acquired by British Petroleum, now called BP.It was one of the successor companies to Standard Oil after the antitrust breakup in 1911. Standard Oil of Ohio was the original Standard Oil company founded by John D. Rockefeller. It...
, and Cleveland Cliffs Iron Company formed Colony Development, a joint venture company to develop the Colony Shale Oil Project
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, developed by Tosco Corporation...
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 kilnRotary kiln
A Rotary kiln is a pyroprocessing device used to raise materials to a high temperature in a continuous process. Materials produced using rotary kilns include:* Cement* Lime* Refractories* Metakaolin* Titanium dioxide* Alumina* Vermiculite...
-type retort. In this process, oil shale is crushed smaller than 0.5 inches (13 mm) and enters the system through pneumatic lift pipes in which oil shale is elevated by hot gas streams and preheated to about 500 °F (260 °C). After entering into retort, oil shale is mixed with hot ceramic balls with temperature from 1200 °F (648.9 °C) to 1600 °F (871.1 °C). This increase the oil shale temperature to between 900 °F (482.2 °C) and 1100 °F (593.3 °C), in which pyrolysis occurs. In the pyrolysis process, kerogen
Kerogen
Kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the huge molecular weight of its component compounds. The soluble portion is known as bitumen. When heated to the right...
decomposes to oil shale gas
Oil shale gas
Oil shale gas is a synthetic gas mixture produced by oil shale pyrolysis. Although often referred to as shale gas, it differs from the natural gas produced from shale, which is also known as shale gas.-Process:...
and oil vapors, while the remainder of the oil shale forms spent shale. Vapors are transferred to a condensor
Condenser (heat transfer)
In systems involving heat transfer, a condenser is a device or unit used to condense a substance from its gaseous to its liquid state, typically by cooling it. In so doing, the latent heat is given up by the substance, and will transfer to the condenser coolant...
(fractionator
Fractional distillation
Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. It is a special type of distillation...
) for separation into various fractions
Fraction (chemistry)
A fraction in chemistry is a quantity collected from a sample or batch of a substance in a fractionating separation process. In such a process, a mixture is separated into fractions, which have compositions that vary according to a gradient. A fraction can be defined as a group of chemicals that...
. At the kiln passage, the spent shale and the ceramic balls are separated in a perforated rotating separation drum (trommel
Trommel
A trommel is a screened cylinder used to separate materials by size - for example, separating the biodegradable fraction of mixed municipal waste or separating different sizes of crushed stone....
). 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 ProcessAlberta Taciuk ProcessThe Alberta Taciuk process is an above-ground dry thermal retorting technology for extracting oil from oil sands, oil shale and other organics-bearing materials, including oil contaminated soils, sludges and wastes...
- Kiviter processKiviter process-History:The Kiviter process is based on the earlier vertical retort technology . This technology underwent a long process of development...
- Petrosix processPetrosixPetrosix is currently the world’s largest surface oil shale pyrolysis retort with an diameter vertical shaft kiln, operational since 1992. It is located in São Mateus do Sul, Brazil, and it is owned and operated by the Brazil energy company Petrobras. Petrosix means also the Petrosix process, an...
- Galoter processGaloter processThe Galoter process is a shale oil extraction technology for a production of shale oil, a type of synthetic crude oil. In this process, the oil shale is decomposed into shale oil, oil shale gas, and spent residue...
- Fushun processFushun processThe 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:...
- Paraho processParaho processThe Paraho process is an above ground retorting technology for shale oil extraction. The name "Paraho" is delivered from the words "para homem", which means in Portuguese "for mankind".-History:...
- Lurgi-Ruhrgas processLurgi-Ruhrgas processThe Lurgi–Ruhrgas process is an above-ground coal liquefaction and shale oil extraction technology. It is classified as a hot recycled solids technology.-History:...