Coal#Gasification

Coal gasification is the conversion of carbon ( C) into combustible gaseous compounds, especially water gas ( syngas ), producer gas and town gas.

History

Already Antoine Laurent de Lavoisier employed in connection with the investigation of water with coal gasification for the production of water gas to fill balloons. At the beginning of the 19th century, the English coal-gas industry method developed for coal gasification. The first generator was built in 1840. Then in 1854 a procedure was introduced to separate the hydrogen obtained in the water gas shift reaction from carbon monoxide by converted the carbon monoxide with excess water vapor to carbon dioxide. Meaningful coal gasification was then increased at the beginning of the 20th century, when the need for synthesis gases. In the 1920s, the Winkler method and in the 1930s, the Lurgi process was developed that was useful for the city gas industry. In the early 1950s the first Koppers Totzek reactor was put into operation, which allowed the gasification of coal dust with air. Considerations on the use of high-temperature reactors as a supplier of process heat for coal gasification were not realized.

Use

Town gas found its use especially in street lighting and interior lighting for large buildings in the 19th century. Many cities built gas plants for production of town gas from coal. The thereby formed by the Kohleentgasung coke was further used in the steel industry, and also as fuel. Only towards the beginning of the 20th century town gas was used for heating and cooking. From the 1960s it was gradually replaced by natural gas. In addition to the earlier production of town gas was or is the coal gasification meaningful for use in power plants, the chemical industry (synthesis gas) and for the metallurgical industry.

Water Gas

About the endothermic reaction:

Produced from coal, which has previously been heated by the combustion of air and water vapor, so-called water gas, a mixture of carbon monoxide and hydrogen. Is an equilibrium reaction.

This reaction was discovered in 1780 by Felice Fontana.

The resulting gas may be referred to as synthesis gas or syngas, since it is suitable for the synthesis of various chemical substances such as methanol.

Producer gas ( carbon monoxide )

Producer gas is produced by incomplete burning of coke with air:

Coal hydrogenation

In the hydrogenation of coal occur hydrocarbons of different chain lengths:

Depending on the chain length of the reaction products of gaseous ( methane, ethane, propane, butane) or liquid (higher alkanes which are used for example in gasoline and diesel fuel ). For liquid products is referred to as coal liquefaction.

Conversions

In this case, gases are generated in Sekundärrekationen from the products of coal gasification.

Conversion to hydrogen:

Conversion to methane:

Gasification process

For the gasification of coal gasification, different methods have been developed, incorporating the different requirements of the feedstocks ( coal, lignite), according to the granularity of the starting materials and on the desired end products account. In general, fixed-bed, fluidized bed and entrained flow gasifier can be distinguished. These are:

  • General Electric entrained-flow gasification (formerly Texaco )
  • The " Winkler gasifier ," and the " high-temperature Winkler method" ( HTW ), to the use of brown coal, peat, wood, and sewage sludge. The Winkler generator was developed in 1921 by the chemist Fritz Winkler at BASF. It is a fluidized bed gasifier.
  • The Koppers - Totzek process or Krupp Koppers Totzek (~ 1952) ( entrained flow gasifier )
  • The PRENFLO method of ThyssenKrupp Uhde GmbH ( entrained-flow gasification)
  • The Shell entrained flow gasification
  • The E -Gas entrained flow gasifier by ConocoPhillips
  • Sasol - Lurgi fixed bed pressure gasification ( development since ~ 1925)
  • " BGL ", British Gas Lurgi pressure gasifier ( Schlackebadvergaser ), eg Schwarze Pumpe industrial park
  • The GSP method ( after Georg Bilkenroth and Erich Rammler ), developed at the German Institute in Freiberg fuel and gas Schwarze Pumpe ( entrained flow gasifier, Braunkohlenhochtemperaturkoks )
  • Allothermic steam process ( from 1980)
Chemical equilibrium Freiberg University of Mining and Technology Open hearth furnace Boudouard reaction Water-gas shift reaction Integrated Authority File
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