Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion does not always result in fire, because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of the reaction. While activation energy must be supplied to initiate combustion, the heat from a flame may provide enough energy to make the reaction self-sustaining.
Coke is a grey, hard, and porous coal-based fuel with a high carbon content and few impurities, made by heating coal or oil in the absence of air—a destructive distillation process. It is an important industrial product, used mainly in iron ore smelting, but also as a fuel in stoves and forges when air pollution is a concern.
Wood gas is a fuel gas that can be used for furnaces, stoves, and vehicles. During the production process, biomass or related carbon-containing materials are gasified within the oxygen-limited environment of a wood gas generator to produce a combustible mixture. In some gasifiers this process is preceded by pyrolysis, where the biomass or coal is first converted to char, releasing methane and tar rich in polycyclic aromatic hydrocarbons.
Producer gas is fuel gas that is manufactured by blowing a coke or coal with air and steam simultaneously. It mainly consists of carbon monoxide (CO), hydrogen (H2), as well as substantial amounts of nitrogen (N2). The caloric value of the producer gas is low (mainly because of its high nitrogen content), and the technology is obsolete. Improvements over producer gas, also obsolete, include water gas where the solid fuel is treated intermittently with air and steam and, far more efficiently synthesis gas where the solid fuel is replaced with methane.
The pyrolysis process is the thermal decomposition of materials at elevated temperatures, often in an inert atmosphere. Temperature can be understood as thermal vibration. At high temperatures, excessive vibration causes long chain molecules to break into smaller molecules. The word is coined from the Greek-derived elements pyro "fire", "heat", "fever" and lysis "separating".
Gasification is a process that converts biomass- or fossil fuel-based carbonaceous materials into gases, including as the largest fractions: nitrogen (N2), carbon monoxide (CO), hydrogen (H2), and carbon dioxide (CO2). This is achieved by reacting the feedstock material at high temperatures (typically >700 °C), without combustion, via controlling the amount of oxygen and/or steam present in the reaction. The resulting gas mixture is called syngas (from synthesis gas) or producer gas and is itself a fuel due to the flammability of the H2 and CO of which the gas is largely composed. Power can be derived from the subsequent combustion of the resultant gas, and is considered to be a source of renewable energy if the gasified compounds were obtained from biomass feedstock.
Charring is a chemical process of incomplete combustion of certain solids when subjected to high heat. Heat distillation removes water vapour and volatile organic compounds (syngas) from the matrix. The residual black carbon material is char, as distinguished from the lighter colored ash. By the action of heat, charring removes hydrogen and oxygen from the solid, so that the remaining char is composed primarily of carbon. Polymers like thermoset, or most solid organic compounds like wood or biological tissue, exhibit charring behaviour.
In atmospheric chemistry, NOx is shorthand for nitric oxide and nitrogen dioxide, the nitrogen oxides that are most relevant for air pollution. These gases contribute to the formation of smog and acid rain, as well as affecting tropospheric ozone.
The Karrick process is a low-temperature carbonization (LTC) 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 450 °C (800 °F) to 700 °C (1,300 °F) in the absence of air to distill out synthetic fuels–unconventional oil and syngas. It could be used for a coal liquefaction as also for a semi-coke production. The process was the work of oil shale technologist Lewis Cass Karrick at the United States Bureau of Mines in the 1920s.
Shale oil extraction is an industrial process for unconventional oil production. This process converts kerogen in oil shale into shale oil by pyrolysis, hydrogenation, or thermal dissolution. The resultant shale oil is used as fuel oil or upgraded to meet refinery feedstock specifications by adding hydrogen and removing sulfur and nitrogen impurities.
Environmental impact of the oil shale industry includes the consideration of issues such as land use, waste management, and water and air pollution caused by the extraction and processing of oil shale. Surface mining of oil shale deposits causes the usual environmental impacts of open-pit mining. In addition, the combustion and thermal processing generate waste material, which must be disposed of, and harmful atmospheric emissions, including carbon dioxide, a major greenhouse gas. Experimental in-situ conversion processes and carbon capture and storage technologies may reduce some of these concerns in future, but may raise others, such as the pollution of groundwater.
Combustion Resources, Inc. was a consulting company based in Provo, Utah, United States. It provided consulting services in the fields of fuel and combustion, such as testing of flow and mixing systems, reactor design, gas and particle sampling, gasification modeling, and shale oil extraction design and testing. The company was incorporated in 1995 as a spin-off from the Center for Advanced Combustion Engineering Research, joint collaboration between Brigham Young University and the University of Utah.
The Galoter process is a shale oil extraction technology for the 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. Decomposition is caused by mixing raw oil shale with hot oil shale ash generated by the combustion of carbonaceous residue (semi-coke) in the spent residue. The process was developed in the 1950s, and it is used commercially for shale oil production in Estonia. There are projects for further development of this technology and expansion of its usage, e.g., in Jordan and the USA.
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. The technology is named after its inventor William Taciuk and the Alberta Oil Sands Technology and Research Authority.
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.
The Lurgi–Ruhrgas process is an above-ground coal liquefaction and shale oil extraction technology. It is classified as a hot recycled solids technology.
The Nevada–Texas–Utah retort 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.
The 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 (retort) causing its decomposition into shale oil, oil shale gas and spent residue. The particularities of this process is a recovery of saline minerals from the oil shale, and a doughnut-shape of the retort. The process is suitable for processing of mineral-rich oil shales, such as in the Piceance Basin. It has a relatively high reliability and high oil yield. The technology was developed by the American oil company Superior Oil.
KENTORT II is an above-ground shale oil extraction process developed by the Center for Applied Energy Research of the University of Kentucky. It is a hot recycled solids fluidized bed retorting process developed since 1982 for processing the eastern United States Devonian oil shales. The concept of this process was initiated in 1986 in the test unit.
Spent shale or spent oil shale is a solid residue from the shale oil extraction process of producing synthetic shale oil from oil shale. It consists of inorganic compounds (minerals) and remaining organic matter known as char—a carbonaceous residue formed from kerogen. Depending on the extraction process and the amount of remaining organic matter, spent shale may be classified as oil shale coke, semi-coke or coke-ash residue, known also as oil shale ash. According to the European Union waste list all these types of spent shale are classified as hazardous waste.
