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Underground coal gasification (UCG) is an industrial gasification process, which is carried out in non-mined coal seams. It involves injection of a gaseous oxidizing agent , usually oxygen or air, and bringing the resulting product gas to the surface through production wells drilled from the surface.
The process is used heavily in the chemical industry, for example, to produce ethylene, many forms of carbon, and other chemicals from petroleum, coal, and even wood, or to produce coke from coal. It is used also in the conversion of natural gas (primarily methane ) into hydrogen gas and solid carbon char, recently introduced on an industrial ...
Cyanobacteria such as these carry out photosynthesis.Their emergence foreshadowed the evolution of many photosynthetic plants and oxygenated Earth's atmosphere.. Biological carbon fixation, or сarbon assimilation, is the process by which living organisms convert inorganic carbon (particularly carbon dioxide, CO 2) to organic compounds.
Gasification is the process of subjecting a feedstock to chemical reactions that produce gas. [10] [11] The first process used was the carbonization and partial pyrolysis of coal. The off gases liberated in the high-temperature carbonization of coal in coke ovens were collected, scrubbed and used as fuel.
Catalytic fast pyrolysis is a fast process in which the cellulose is broken down to a liquid biofuel. In this approach the cellulose is heated to 500 degrees Celsius in less than one second in a chamber to break apart the molecules. The catalyst forms chemical reactions that remove oxygen bonds and form carbon rings
In a large-scale technical implementation of hydrothermal carbonization of sewage sludge, it has been shown that about 20% of the fuel energy content contained in 90% end-dried HTC coal is required to heat the process. Furthermore, approximately 5% of the generated energy content is necessary for the electrical operation of the plant.
And also, after the gasification process, CO 2 takes up to 13% - 15.3% by mass in the syngas stream for biomass sources, while it is only 1.7% - 4.4% for coal. [29] This limit the conversion of CO to CO 2 in the water gas shift, and the production rate for H 2 will decrease accordingly.
The coal is baked in an airless kiln, a "coke furnace" or "coking oven", at temperatures as high as 2,000 °C (3,600 °F) but usually around 1,000–1,100 °C (1,800–2,000 °F). [2] This process vaporises or decomposes organic substances in the coal, driving off water and other volatile and liquid products such as coal gas and coal tar. Coke ...