Prenflo process

Brief descriptions of commercial gasification processes can be found in the literature 4-8 gasification with steam (Exxon process), gasification with oxygen or air (Koppers-Totzek and Prenflo processes), and gasification with steam/oxygen or air mixtures (Shell, Winkler and Texaco processes). 

The Prenflo Process (Pressurized Entrained Flow Gasification), an advanced 25-30 bar version of the atmospheric Koppers-Totzek process, is currendy on its way to becoming operative. A demonstration plant designed for a coal throughput of 2.0 t/h has been operating since 1986. Apart from the fact that the raw gas provided by this process is obtained at an elevated pressure, its improved coal conversion rate promises a markedly better cold gas efficiency. Initially, the new process variant was launched in cooperation between Koppers and SHELL, but it is now pursued by the former alone while SHELL went its own way. 

This way led SHELL to the development of SHELL Coal Gasification Process (SCGP) which is today considerably further advanced than the Prenflo process. 

The GKT process operates at atmospheric pressure. With the development of pressurized entrained gasifiers (Texaco, Destec and Shell) no more atmospheric pressure gasifiers are likely to be built. Krupp-Koppers, the owners of the GKT gasifier, are developing their own pressurized entrained gasifier, the PRENFLO process. 

From 1974 until 1981, Krupp Koppers and Shell Oil were joint developers of what was then the Shell-Koppers coal gasification process. This development included a large (165-t/d) pilot plant at the Shell Oil Harburg refinery near Hamburg, Germany. When the partnership ended in June 1981, Shell continued its development of the Shell process (see Demonstration Technologies), and the Krupp Koppers effort evolved into the PRENFLO process. 

BTL [Biomass To Liquids] A general name for processes that convert biomass to liquid fuels. Examples are BTG, Carbo-V, Coskata, MKS, and RTP. A version of the PRENFLO process, originally developed for gasifying coal, can be used as the first stage. 

COMBISULF A process for removing sulfur compounds from the gases from combined-cycle power plants with integrated coal gasification. Carbonyl sulfide is removed by catalytic hydrolysis hydrogen sulfide is removed by selective absorbtion in aqueous MEDA and the sulfur is recovered from both processes by a modified Claus unit. Developed by Krupp Koppers and first operated in Spain in 1996. See PRENFLO. 

Koppers-Totzek A coal gasification process using an entrained bed. The coal is finely ground and injected in a jet of steam and oxygen into a circular vessel maintained at 1,500°C. Reaction is complete within one second. The ash is removed as a molten slag. The process was invented by F. Totzek at Heinrich Koppers, Essen, and further developed by Koppers Company in Louisiana, MO, under contract with the U.S. Bureau of Mines. The first commercial operation was at Oulu, Finland, in 1952 by 1979, 53 units had been built. Most of the plants are operated to produce a hydrogen-rich gas for use in ammonia synthesis. Developed by Lurgi. See also PRENFLO. 

The Koppers-Totzek process was first commercialized in 1952 and, by 1984, was used in 19 plants in 17 different countries [27]. The process uses powdered coal at atmospheric pressures in a parallel flow of 02 and H20 at temperatures of 1400-2000°C. The high process temperatures eliminate the formation of hydrocarbons and produce a gas containing 85—90% syngas (CO and H2). A process schematic is shown in Figure 2.26 [37]. Recent process developments include the Pressurized Entrained Flow Gasification (PRENFLO) with operating pressures being increased to 40 bars. 

In June 1981, the partnership between Shell and Krupp Koppers was terminated. Since that time, this gasification technology has been developed solely by Shell as the Shell Coal Gasification Process. Krupp Koppers has continued its own development of a similar pressurized, dry feed, entrained-flow gasification technology called PRENFLO. 

The Shell and PRENFLO coal gasification processes are quite similar they both use pressurized, dry feed, entrained-flow technologies with water wall-cooled gasifier vessels. 

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