Petrosix

Petrosix refers both to an above-ground oil-shale retorting technology developed by Petrobras and to the industrial operation that applies it at São Mateus do Sul in Paraná, Brazil. The installation processes oil shale from the Irati Formation, a Permian geological formation within the Paraná Basin, and converts the kerogen contained in the shale into shale oil, gas, liquefied shale gas and sulfur. Petrobras began investigating the extraction of oil from Brazilian oil shale in 1953. The company progressively developed the process through laboratory, pilot, demonstration and semi-commercial facilities. An Irati Profile Plant with a 5.5-metre internal-diameter retort entered service in 1972 and began limited commercial operation in 1980. A small pilot retort using the modern Petrosix configuration began operation in 1982, followed by a 2-metre demonstration unit in 1984. An 11-metre vertical shaft retort entered service in December 1991, and commercial production began in 1992. The Petrosix facility is notable for the scale of its surface retort. Its 11-metre-diameter vertical shaft reactor has been described as the world's largest operational surface oil-shale pyrolysis retort. The operation uses two retorts and processes approximately 8,500 tonnes of oil shale per day, according to the referenced encyclopedia material. The principal large retort has a stated capacity of about 6,200 tonnes of shale per day and a nominal output of approximately 3,870 barrels of shale oil daily, alongside shale gas, liquefied shale gas and sulfur. In the process, mined shale is crushed and screened into lump particles generally between 12 and 75 millimetres. The prepared material enters the top of a vertical cylindrical retort and moves downward while externally generated hot gas is introduced into the vessel. At roughly 500 degrees Celsius, the kerogen decomposes and produces oil vapour and gas. The vapour is removed from the upper section, while spent shale is cooled in the lower section using recirculated gas before being discharged. Oil droplets are recovered through a wet electrostatic precipitator, and the resulting gas stream is divided for heat recirculation, spent-shale cooling and further treatment. Gas treatment separates useful fuel gas and liquefied petroleum gas, while sulfur is recovered from the process stream. The technology is tailored to the physical and geological characteristics of the Irati oil shale rather than being a general-purpose refinery process. Its principal technical limitations include the inability of the retort to process particles smaller than approximately 12 millimetres and the fact that heat contained in char in the shale is not used through combustion in the described configuration. Petrosix is therefore best understood as an industrial technology and facility identity within Petrobras's oil-shale activities, rather than as a consumer-facing product brand.

Petrosix emerged from Petrobras's long-running effort to develop a commercially practical method for extracting hydrocarbons from Brazilian oil shale. The program began in 1953 and focused on the Irati Formation, a Permian oil-shale resource in the Paraná Basin. Rather than relying on an underground conversion method, Petrobras developed an above-ground retorting system in which mined and prepared shale is heated in a surface reactor until its kerogen decomposes into oil vapour and gas. A 5.5-metre internal-diameter semi-works retort, known as the Irati Profile Plant, came on line in 1972. The plant had a stated capacity of 2,400 tonnes per day and entered limited commercial operation in 1980. Petrobras subsequently tested the configuration that became the Petrosix process. A pilot retort with an internal diameter of 0.2 metres began operation in 1982, and a 2-metre demonstration retort followed in 1984. These stages allowed the company to move from experimental work toward a larger commercial unit. The first retort using the current Petrosix technology, with an 11-metre diameter, was brought into service in December 1991. Commercial production began in 1992 at the São Mateus do Sul operation. The large vertical shaft retort was designed by Cameron Engineers and incorporated separate upper pyrolysis and lower spent-shale cooling sections. The facility subsequently operated two retorts and processed approximately 8,500 tonnes of oil shale daily, making it one of the most significant commercial surface oil-shale operations described in the reference material. Petrosix uses lump shale as feedstock. After mining, the material is transported to crushing and screening equipment, where it is prepared into particles typically ranging from 12 to 75 millimetres. The material enters through the top of the retort and descends through the pyrolysis zone. Externally generated hot gas is injected around the middle of the vessel, heating the shale to approximately 500 degrees Celsius. The kerogen breaks down into oil vapour and gas, while the solid residue continues downward. A gas-recirculation arrangement supplies process heat and recovers energy from the lower section. Some retort gas is reheated in a furnace and returned to the pyrolysis zone. Another portion is introduced at the bottom to cool the spent shale; as that gas warms, it moves upward and contributes additional heat. The remaining gas stream is cooled and treated to remove light oil and water before further separation. Oil mist is collected in a wet electrostatic precipitator, and downstream treatment produces fuel gas, liquefied petroleum gas and recovered sulfur. The principal industrial output is shale oil, supplemented by oil-shale gas, liquefied gas and sulfur. The stated nominal output for the 11-metre retort is approximately 3,870 barrels of shale oil per day, or about 550 tonnes, together with 132 tonnes of oil-shale gas, 50 tonnes of liquefied oil-shale gas and 82 tonnes of sulfur. These figures describe the referenced retort configuration rather than a current financial or production report. The technology's design is adapted to the Irati resource and has operational constraints. Fine particles below approximately 12 millimetres cannot be processed in the retort and may represent a substantial share of crushed feed. The described configuration also does not use the potential combustion heat of char contained in the shale. Nevertheless, Petrosix represents a notable example of a surface oil-shale technology developed from pilot-scale research into commercial operation and remains associated with Petrobras's São Mateus do Sul oil-shale complex.

• 1992

  Commercial production starts

  [1]Petrosixen.wikipedia.org

  Commercial production begins at the São Mateus do Sul oil-shale operation.

• 1991

  11-metre retort enters service

  [1]Petrosixen.wikipedia.org

  The first large 11-metre retort using the current Petrosix technology is brought into service in December.

• 1984

  Demonstration retort is commissioned

  [1]Petrosixen.wikipedia.org

  A 2-metre demonstration retort follows the pilot unit, supporting the transition toward commercial-scale processing.

• 1982

  Pilot Petrosix retort starts

  [1]Petrosixen.wikipedia.org

  A 0.2-metre internal-diameter pilot retort using the emerging Petrosix configuration begins operation.

• 1980

  Limited commercial operation begins

  [1]Petrosixen.wikipedia.org

  The Irati Profile Plant begins limited commercial operation as Petrobras continues scaling its oil-shale technology.

• 1972

  Irati Profile Plant enters service

  [1]Petrosixen.wikipedia.org

  A 5.5-metre internal-diameter semi-works retort with a stated capacity of 2,400 tonnes per day begins operation.

• 1953

  Petrobras begins oil-shale development

  [1]Petrosixen.wikipedia.org

  Petrobras starts developing a method to extract oil from the Irati Formation's oil shale, establishing the research program that later becomes associated with Petrosix.

A Petrobras-developed, large-scale surface retorting technology specialized for extracting hydrocarbons from Irati Formation oil shale.

• Oil-shale pyrolysis technology

  Petrosix process

  An above-ground retorting process that heats prepared lump oil shale with externally generated hot gas. The heat decomposes kerogen into oil vapour and gas, which are subsequently separated and treated. The process is configured for the Irati Formation's shale and uses gas recirculation for pyrolysis and spent-shale cooling.

• Industrial oil-shale reactor · 1991

  Petrosix 11-metre retort

  A vertical shaft surface retort with an 11-metre diameter, designed by Cameron Engineers and placed into service in 1991. Its upper section performs pyrolysis and its lower section cools spent shale. The unit is described as the world's largest operational surface oil-shale pyrolysis retort.

• Hydrocarbon product · 1992

  Shale oil

  The principal liquid hydrocarbon product recovered when kerogen in Irati oil shale is thermally decomposed in the Petrosix retort. The referenced configuration has a nominal output of approximately 3,870 barrels per day from the large retort.

• Gas products · 1992

  Oil-shale gas and liquefied oil-shale gas

  Gaseous products recovered from retort vapours and processed gas streams. Part of the gas is recirculated for process heat, while treated streams can yield fuel gas and liquefied petroleum gas.

• By-product · 1992

  Sulfur

  A sulfur product recovered during treatment of the gas stream generated by oil-shale retorting. The reference material gives a nominal output of approximately 82 tonnes per day for the stated large-retort configuration.

1. 1Petrosixen.wikipedia.org