Search results
Results from the WOW.Com Content Network
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.
Coal liquefaction is a process of converting coal into liquid hydrocarbons: liquid fuels and petrochemicals. This process is often known as "coal to X" or "carbon to X", where X can be many different hydrocarbon-based products. However, the most common process chain is "coal to liquid fuels" (CTL). [1]
The Fischer–Tropsch process is an important reaction in both coal liquefaction and gas to liquids technology for producing liquid hydrocarbons. [ 1 ] In the usual implementation, carbon monoxide and hydrogen, the feedstocks for FT, are produced from coal , natural gas , or biomass in a process known as gasification .
It is the largest coal liquefaction plant and the largest single emitter of greenhouse gas in the world. Secunda CTL consists of two production units. The Sasol II unit was constructed in 1980 and the Sasol III unit in 1984. [1] It has total production capacity of 160,000 barrels per day (25,000 m 3 /d). [2]
The underground coal gasification process. Underground coal gasification converts coal to gas while still in the coal seam (in-situ). Gas is produced and extracted through wells drilled into the unmined coal seam. Injection wells are used to supply the oxidants (air, oxygen) and steam to ignite and fuel the underground combustion process ...
The chemical composition of syngas varies based on the raw materials and the processes. Syngas produced by coal gasification generally is a mixture of 30 to 60% carbon monoxide, 25 to 30% hydrogen, 5 to 15% carbon dioxide, and 0 to 5% methane. It also contains lesser amount of other gases. [10]
Coal liquefaction emits more carbon dioxide than liquid fuel production from crude oil. Mixing in biomass and using carbon capture and storage (CCS) would emit slightly less than the oil process but at a high cost. [101] State owned China Energy Investment runs a coal liquefaction plant and plans to build 2 more. [102]
In the gasification of fine, undensified biomass such as rice hulls, it is necessary to blow air into the reactor by means of a fan. This creates very high gasification temperature, as high as 1000 C. Above the gasification zone, a bed of fine and hot char is formed, and as the gas is blow forced through this bed, most complex hydrocarbons are ...