History

The Kiviter process is based on the earlier vertical retort technology (Pintsch's generator). This technology underwent a long process of development. The early concept of central inlet of the heat carrier was later replaced by a concept of heat carrier gas cross flow in the retort.

The Kiviter technology has been used in Estonia since 1921, when first experimental Kiviter retorts were built. The first commercial scale oil plant based on the Kiviter technology was built in 1924.

From 1955 to 2003, Kiviter technology was used for oil shale processing also in Slantsy

Slantsy

Slantsy is a town and the administrative center of Slantsevsky District of Leningrad Oblast, Russia, situated on the Plyussa River, west of St. Petersburg. Population: ....

, Russia.

Technology

The Kiviter process is classified as an internal combustion technology. The Kiviter retort is a vertical cylindrical vessel that heats coarse oil shale with recycled gases, steam, and air. To supply heat, gases (including produced 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 carbonaceous

Carbonaceous

Carbonaceous is the defining attribute of a substance rich in carbon. Particularly, carbonaceous hydrocarbons are very unsaturated, high-molecular-weight hydrocarbons, having an elevated carbon:hydrogen ratio....

 spent residue (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...

) are burnt within the retort. Raw oil shale is fed into the top of the retort, and is heated by the rising gases, which pass laterally through the descending oil shale causing decomposition of the rock. Pyrolysis is completed in the lower section of the retort, where the spent shale contacted with more hot gas, steam and air is heated to about 900 °C (1,652 °F) to gasify and burn the residual carbon (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...

). Shale oil

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...

 vapors and evolving gases are delivered to a condensing system, where condensed shale oil is collected, while non-condensable gases are fed back to the retort. Recycled gas enters the bottom of the retort and cools the spent shale, which then leaves the retort through a water-sealed discharge system.

The Kiviter process uses large amounts of water, which is polluted during processing, and the solid waste residue contains water-soluble toxic substances that leach into the surrounding area.

Commercial use

The Kiviter process is used by the Estonian Viru Keemia Grupp

Viru Keemia Grupp

Viru Keemia Grupp is an Estonian holding group of oil shale industry, power generation, and public utility companies.-Operations:VKG's two main areas of operations are shale oil extraction, and electricity and heat production and distribution....

's subsidiary VKG Oil. The company operates several Kiviter retorts, the largest of them having a processing capacity of 40 tonnes per hour of oil shale feedstock.

See also

• Oil shale in Estonia
  Oil shale in Estonia
  Oil shale in Estonia is an important resource for the national economy. Estonia's oil shale deposits account for just 17% of total deposits in the European Union but the country generates 90% of its power from this source...
  
  
• Alberta Taciuk Process
  Alberta Taciuk Process
  The 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...
  
  
• Petrosix
  Petrosix
  Petrosix 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 process
  Galoter process
  The 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 process
  TOSCO II process
  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...
  
  
• Fushun 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:...
  
  
• Paraho process
  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:...