Entrained flow gasification

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Under an entrained-flow gasification is meant a specific process for the gasification of coal, natural gas, petroleum, or biomass. The system itself is called an entrained flow carburetor .

principle

Heinrich Koppers, pioneer of entrained flow gasification

In principle, it is a high-temperature direct-current reactor (up to 2000 ° C) which, in addition to gaseous and liquid, can only process starting materials ( starting materials , grain size <90 µm) ( coal , natural gas , petroleum fractions , biomass in the form of a suspension ). One advantage of the process is that the very high temperatures largely suppress the formation of tar and destroy other organic pollutants. Another is that, in contrast to fixed bed and fluidized bed gasifiers , they can also be operated with gases and liquids. The heavy metals contained in the starting materials are integrated into the vitrified slag in an eluate-proof manner . By recycling the coke residue in the raw gas, the starting material can be completely gasified with a high degree of thermal efficiency . Nickel on Al 2 O 3 , CaO or MgO supports is usually used as the catalyst for the reaction .

Entrained flow gasifiers are mostly tubular reactors that are heated from the outside. Entrained-flow gasifiers are only operated autothermally with solid fuels . The fuel is ground to ~ 0.1 mm fine dust, thoroughly mixed with the gasifying agent consisting of water vapor and oxygen or air and converted in a dust flame at ~ 1300 ° C. The dust reacts at the high flame temperature, which can be regulated by the amount of oxygen, in a short time of about one second. The resulting synthesis gas contains a lot of dust because the ash components are finely distributed, melt and partially sublime at the high temperature. Part of the molten ash forms a slag jacket and thus protects the inner wall of the reactor from corrosion.

Because of the very high synthesis gas temperature, some of the energy can be recovered with chemical quenching by blowing in coke powder . As a result of the endothermic gasification reaction C + H 2 O → CO + H 2 , the synthesis gas cools down to 900 - 1000 ° C without the formation of significant amounts of tar. The unconverted coke powder surplus has to be separated and recycled .

historical development

  • 1940s: Development of pressureless entrained flow gasification by Friedrich Totzek, employee of Heinrich Koppers ( Koppers-Totzek reactor )
  • from 1950 slag bath process by blowing coal dust and gasifying agent into molten slag
    • pressureless: Rummel Otto process
    • under pressure: Saarberg-Otto process.
  • 1952 First commercial entrained flow carburetor to Koppers-Totzek in Finland
  • 1978 Entrained flow gasification under pressure in the Texaco process according to the Ruhrchemie / Ruhrkohle variant. Commissioning of a 40 bar demo system at Ruhrchemie
  • 1980 Entrained flow gasification under pressure: Shell-Koppers process. Test facility in Hamburg-Harburg with 150 t per day.
  • 1986 Print version of the Koppers-Totzek process : PRENFLO (pressurized entrained flow). Commissioning of a 30 bar demo system in Fürstenhausen, Saar
  • 1987 Start-up of the Ruhr synthesis gas plant using the Texaco process for 250,000 t / a of hard coal

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