Nevada–Texas–Utah Retort
Encyclopedia
The Nevada–Texas–Utah Retort process (also known as NTU, Dundas–Howes or Rexco process) was an above ground shale oil extraction technology to produce shale oil
, a type of synthetic crude
oil. It heated oil shale in a sealed vessel (retort
) causing its decomposition into shale oil, oil shale gas
and spent residue. The process was developed in the 1920s and used for shale oil production in the United States and in Australia. The process was simple to operate; however, it was ceased from the operation because of a small capacity and labor extensiveness.
retorts and it is considered as a predecessor of the Gas Combustion Retort
and the Paraho
processes. It was invented and patented by Roy C. Dundas and Raymond T. Howes in 1923. The process was improved by David Davis and Georg Wigthman Wallace, a consulting engineer of the NTU Company. In 1925, the NTU Company built a test plant at Sherman Cut near Casmalia, California
.
In 1925–1929, the process was also tested by the United States Bureau of Mines
in the Oil Shale Experiment Station at Anvil Point in Rifle, Colorado
. Retorting was carried out from 17 January to 28 June 1927. The plant was dismantled when work was terminated in June 1929. One of the leading technologist involved in this stage was Lewis Cass Karrick
, an inventor of the Karrick process
. In 1946–1951, two pilot plants with nominal capacities of 40 tons of raw oil shale
were located at the same location. More than 12,000 barrels of shale oil was produced during this period. During the World War II
, three NTU retorts were operated at Marangaroo, New South Wales
, Australia
. Almost 500,000 barrels of shale oil was produced by these retorts by retorting local torbanite
.
to generate heat for an oil shale pyrolysis
(chemical decomposition
). The retort was designed as a steel cylinder, lined with fire brick
s. At the top it was equipped with an air supply pipe and at the bottom it was equipped with an exhaust pipe. The batch of crushed oil shale was loaded from the top; after that the retort was sealed. To start the pyrolysis process the fuel gas was ignited at the top of retort, and air injection into the retort started. The supply of fuel gas stopped after the upper quarter of the oil shale batch started to burn. At the same time the air injection continued bringing temperature in the burning part to about 1500 °F (815.6 °C).
The heated gas caused a pyrolysis on the lower part of oil shale and produced shale oil and oil shale gas are escaped from the retort through exhaust pipe at the bottom of retort. The pyrolysis occurred at the temperature about 800 °F (426.7 °C). By time-being, the combustion zones moved downward, and the char
(semi-coke) produced as a solid residue of pyrolysis, ignited to burn as additional fuel for combustion. This caused the pyrolysis zone to move downward to the lower parts of retort. After combustion zone reached to the bottom of retort, air injection was stopped to stop combustion. After burning of char, the shale oil production ceased and only spent oil shale ash remained in the retort. The bottom of retort could opened for removal of the oil shale ash after retorting process. Operating the NTU retort with nominal capacity of 40 ton of raw oil shale, the full process cycle took about 40 hours. The shale oil yield varied from 80% to 85% of Fischer Assay
.
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. It heated oil shale in a sealed vessel (retort
Retort
In a chemistry laboratory, a retort is a glassware device used for distillation or dry distillation of substances. It consists of a spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heated...
) causing its decomposition 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 process was developed in the 1920s and used for shale oil production in the United States and in Australia. The process was simple to operate; however, it was ceased from the operation because of a small capacity and labor extensiveness.
History
The NTU Retort was a successor of the 19th century coal gasificationCoal gasification
Coal gasification is the process of producing coal gas, a type of syngas–a mixture of carbon monoxide , hydrogen , carbon dioxide and water vapour –from coal...
retorts and it is considered as a predecessor of the Gas Combustion Retort
Gas Combustion Retort Process
The gas combustion retort process was an above-ground retorting technology for shale oil extraction...
and the Paraho
Paraho process
The 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:...
processes. It was invented and patented by Roy C. Dundas and Raymond T. Howes in 1923. The process was improved by David Davis and Georg Wigthman Wallace, a consulting engineer of the NTU Company. In 1925, the NTU Company built a test plant at Sherman Cut near Casmalia, California
Casmalia, California
Casmalia is a census-designated place in Santa Barbara County, California located just outside the borders of Vandenberg Air Force Base about southwest of Santa Maria. The ZIP Code is 93429, and the community is inside area code 805. The population was 138 at the 2010 census.-History:Casmalia is...
.
In 1925–1929, the process was also tested by the United States Bureau of Mines
United States Bureau of Mines
For most of the 20th century, the U.S. Bureau of Mines was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources.- Summary :...
in the Oil Shale Experiment Station at Anvil Point in Rifle, Colorado
Rifle, Colorado
The City of Rifle is a Home Rule Municipality in Garfield County, Colorado, United States. The population was 6,769 at the 2000 census. Rifle is a regional center of the cattle ranching industry located along Interstate 70 and the Colorado River just east of the Roan Cliffs, which dominate the...
. Retorting was carried out from 17 January to 28 June 1927. The plant was dismantled when work was terminated in June 1929. One of the leading technologist involved in this stage was Lewis Cass Karrick
Lewis Karrick
Lewis Cass Karrick was an American petroleum refinery engineer, oil shale and coal technologist, and inventor. He patented several coal and oil shale related inventions, and he also refined and perfected a low-temperature carbonization and pyrolysis process for processing coal and other...
, an inventor of the Karrick process
Karrick process
The Karrick process is a low-temperature carbonization and pyrolysis process of carbonaceous materials. Although primarily meant for coal carbonization, it also could be used for processing of oil shale, lignite or any carbonaceous materials. These are heated at to in the absence of air to...
. In 1946–1951, two pilot plants with nominal capacities of 40 tons of raw 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...
were located at the same location. More than 12,000 barrels of shale oil was produced during this period. During the World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, three NTU retorts were operated at Marangaroo, New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
, Australia
Geology of Australia
Australia is a continent situated on the Indo-Australian Plate.The geology of Australia includes virtually all known rock types and from all geological time periods spanning over 3.8 billion years of the Earth's history.-Components:...
. Almost 500,000 barrels of shale oil was produced by these retorts by retorting local torbanite
Torbanite
Torbanite, also known as boghead coal, is a variety of fine-grained black oil shale. It usually occurs as lenticular masses, often associated with deposits of Permian coals. Torbanite is classified as lacustrine type oil shale....
.
Retort
The NTU retort was a vertical downdraft retort, which used internal combustionCombustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
to generate heat for an oil shale pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...
(chemical decomposition
Chemical decomposition
Chemical decomposition, analysis or breakdown is the separation of a chemical compound into elements or simpler compounds. It is sometimes defined as the exact opposite of a chemical synthesis. Chemical decomposition is often an undesired chemical reaction...
). The retort was designed as a steel cylinder, lined with fire brick
Fire brick
A fire brick, firebrick, or refractory brick is a block of refractory ceramic material used in lining furnaces, kilns, fireboxes, and fireplaces. A refractory brick is built primarily to withstand high temperature, but will also usually have a low thermal conductivity for greater energy efficiency...
s. At the top it was equipped with an air supply pipe and at the bottom it was equipped with an exhaust pipe. The batch of crushed oil shale was loaded from the top; after that the retort was sealed. To start the pyrolysis process the fuel gas was ignited at the top of retort, and air injection into the retort started. The supply of fuel gas stopped after the upper quarter of the oil shale batch started to burn. At the same time the air injection continued bringing temperature in the burning part to about 1500 °F (815.6 °C).
The heated gas caused a pyrolysis on the lower part of oil shale and produced shale oil and oil shale gas are escaped from the retort through exhaust pipe at the bottom of retort. The pyrolysis occurred at the temperature about 800 °F (426.7 °C). By time-being, the combustion zones moved downward, and the char
Char
Char is the solid material that remains after light gases and tar coal tar have been driven out or released from a carbonaceous material during the initial stage of combustion, which is known as carbonization, charring, devolatilization or pyrolysis.Further stages of efficient combustion are...
(semi-coke) produced as a solid residue of pyrolysis, ignited to burn as additional fuel for combustion. This caused the pyrolysis zone to move downward to the lower parts of retort. After combustion zone reached to the bottom of retort, air injection was stopped to stop combustion. After burning of char, the shale oil production ceased and only spent oil shale ash remained in the retort. The bottom of retort could opened for removal of the oil shale ash after retorting process. Operating the NTU retort with nominal capacity of 40 ton of raw oil shale, the full process cycle took about 40 hours. The shale oil yield varied from 80% to 85% of Fischer Assay
Fischer Assay
The Fischer assay is a standardized laboratory test for determining the oil yield from oil shale to be expected from a conventional shale oil extraction. A 100 gram oil shale sample crushed to...
.
Advantages and disadvantages
The advantage of the NTU Retort Process was simple design, simple operation, and limited need for external fuel. It was suitable for processing of wide variety of oil shales. The disadvantage of this process was a batch mode of operation not allowing continuous retorting, and therefore having small capacity being labor extensive at the same time. The process also had a relatively low oil yield and it required cooling water.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...
- 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...
- Kiviter processKiviter process-History:The Kiviter process is based on the earlier vertical retort technology . This technology underwent a long process of development...
- 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...
- 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...
- 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:...
- 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...