Union process
Encyclopedia
The Union process is an above ground shale oil extraction technology for production of shale oil
, a type of synthetic crude
oil. The process uses a vertical retort where heating causes decomposition of oil shale
into shale oil, oil shale gas
and spent residue. The particularity of this process is that oil shale in the retort moved countercurrent from the bottom upward to the top by a mechanism known as a rock pump. The process technology was invented by the American oil company Unocal Corporation
in late 1940s and was developed through several decades. The largest oil shale retort ever built was the Union B type retort.
area of Colorado
, southern Piceance Basin
. The development of the Union process began in the late 1940s, when the Union A retort was designed. This technology was tested between 1954 and 1958 at the company-owned tract in the Parachute Creek. During these tests, up to 1,200 tonne per day of oil shale was processed, resulting of 800 oilbbl/d shale oil, which was refined at a Colorado refinery. More than 13000 barrels (2,066,834.8 l) of gasoline and fuels were produced. This production was finally shut down in 1961 due to cost.
In 1974, the Union B process, evolved from the Union A process, was developed. In 1976, Union announced its plans to build a Union B demonstration plant. Construction started in 1981 at Long Ridge in San Miguel County, Colorado
, and the plant was started its operations in 1986. It was closed in 1991 after production of 5 Moilbbl shale oil.
The Union retort is a vertical shaft retort. The main difference to other vertical shaft retorts such as Kiviter, Petrosix, Paraho and Fushun is that crushed oil shale is fed through the bottom of the retort rather than the top. Lumps of oil shale in size of 3.2 to 50.8 mm (0.125984251968504 to 2 in) are moved upwards through the retort by a solids pump (known as a "rock pump"). Hot gases, generated by internal combustion or circulated through the top of the retort, decompose the oil shale while descending. The pyrolysis occurs at the temperature of 510 °C (950 °F) to 540 °C (1,004 °F). Condensed shale oil and gases are removed from the retort at the bottom. Part of the gases is recirculated for pyrolysis and fueling combustion, while other part could be used as product gas. The spent shale is removed from the top of the retort. After cooling with a water, it is conveyed to the waste disposal.
and ammonia
. Oil vapors are cooled by the raw oil, thus minimizing polymer formation among the hydrocarbon fractions.
Shale oil
Shale oil, known also as kerogen oil or oil-shale oil, is an unconventional oil produced from oil shale by pyrolysis, hydrogenation, or thermal dissolution. These processes convert the organic matter within the rock into synthetic oil and gas...
, a type of synthetic crude
Synthetic crude
Synthetic crude is the output from a bitumen/extra heavy oil upgrader facility used in connection with oil sand production. It may also refer to shale oil, an output from an oil shale pyrolysis. The properties of the synthetic crude depend on the processes used in the upgrading. Typically, it is...
oil. The process uses a vertical retort where heating causes decomposition of oil shale
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...
into shale oil, 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 spent residue. The particularity of this process is that oil shale in the retort moved countercurrent from the bottom upward to the top by a mechanism known as a rock pump. The process technology was invented by the American oil company Unocal Corporation
Unocal Corporation
Union Oil Company of California, dba Unocal is a defunct company that was a major petroleum explorer and marketer in the late 19th century, through the 20th century, and into the early 21st century. It was headquartered in El Segundo, California, United States.On August 10, 2005, Unocal merged...
in late 1940s and was developed through several decades. The largest oil shale retort ever built was the Union B type retort.
History
Union Oil Company of California (Unocal) started its oil shale activities in 1920s. In 1921, it acquired an oil shale tract in the Parachute CreekParachute, 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 ....
area of Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, southern Piceance Basin
Piceance Basin
The Piceance Basin is a geologic structural basin in northwestern Colorado, in the United States. It includes geologic formations from Cambrian to Holocene in age, but the thickest section is made up of rocks from the Cretaceous Period...
. The development of the Union process began in the late 1940s, when the Union A retort was designed. This technology was tested between 1954 and 1958 at the company-owned tract in the Parachute Creek. During these tests, up to 1,200 tonne per day of oil shale was processed, resulting of 800 oilbbl/d shale oil, which was refined at a Colorado refinery. More than 13000 barrels (2,066,834.8 l) of gasoline and fuels were produced. This production was finally shut down in 1961 due to cost.
In 1974, the Union B process, evolved from the Union A process, was developed. In 1976, Union announced its plans to build a Union B demonstration plant. Construction started in 1981 at Long Ridge in San Miguel County, Colorado
San Miguel County, Colorado
San Miguel County is one of the 64 counties of the state of Colorado of the United States. The county is named for the San Miguel River. The county population was 6,594 at U.S. Census 2000...
, and the plant was started its operations in 1986. It was closed in 1991 after production of 5 Moilbbl shale oil.
Process
The Union process can be operated in two different combustion modes, which are direct and indirect. The Union A (direct) process is similar to the gas combustion retort technology, classified as an internal combustion method, while the Union B (indirect) process is classified as an externally generated hot gas method.The Union retort is a vertical shaft retort. The main difference to other vertical shaft retorts such as Kiviter, Petrosix, Paraho and Fushun is that crushed oil shale is fed through the bottom of the retort rather than the top. Lumps of oil shale in size of 3.2 to 50.8 mm (0.125984251968504 to 2 in) are moved upwards through the retort by a solids pump (known as a "rock pump"). Hot gases, generated by internal combustion or circulated through the top of the retort, decompose the oil shale while descending. The pyrolysis occurs at the temperature of 510 °C (950 °F) to 540 °C (1,004 °F). Condensed shale oil and gases are removed from the retort at the bottom. Part of the gases is recirculated for pyrolysis and fueling combustion, while other part could be used as product gas. The spent shale is removed from the top of the retort. After cooling with a water, it is conveyed to the waste disposal.
Advantages
The Union retort design has several advantages. The reducing atmosphere in the retort allows the removal of sulfur and nitrogen compounds through the formation of hydrogen sulfideHydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
and ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
. Oil vapors are cooled by the raw oil, thus minimizing polymer formation among the hydrocarbon fractions.
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...
- 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:...
- Kiviter processKiviter process-History:The Kiviter process is based on the earlier vertical retort technology . This technology underwent a long process of development...
- 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:...
- 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:...
- PetrosixPetrosixPetrosix 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...
- TOSCO II processTOSCO II processThe 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...
- Superior multimineral processSuperior multimineral processThe Superior multimineral process is an above ground shale oil extraction technology designed for production of shale oil, a type of synthetic crude oil. The process heats oil shale in a sealed horizontal segmented vessel causing its decomposition into shale oil, oil shale gas and spent residue...