Entrained-Flow Gasification Processes

Xu, Z., Gong, Y., and Jiang, X. GSP entrained flow gasification process and its application prospects in China. Clean Coal Technology (China), 1998, 4, 9. 

Brown, B. W., Smoot, L. D., Smith, P. J., Hedman, P. O. (1998). Measurement and prediction of entrained-flow gasification processes. American Institute of Chemical Engineers Journal, 34, 435-446. 

Direct Quench. Direct quench systems inject water or cool recycle gas into the hot raw gas leaving the gasifier. Essentially all moving-bed gasifiers use a total water quench to remove tars and oils from the raw gas before heat recovery. However, fluidized-bed and entrained-flow gasification processes often use partial gas or water quenches as well. 

Dow Entrained-Flow Gasification Process." Technical Brief. Palo Alto,... 

Dow Entrained-Flow Gasification Process." Technical Brief. Palo Alto, California Electric Power Research Institute, January 1989. TB.GS.61.1.89. 

WEW Process (24,25). Vereingte Elektrizitatswerke Westfalen is a German electric utility that has developed a unique dry feed, entrained-flow gasification process. The VEW concept relies on partial gasification with preheated air to produce low-Btu-coal-derived gas and char. After waste heat recovery, steam generation, and sulfur removal, the coal gas is fired in a combustion turbine. The char is fired in a pulverized coal boiler with the hot flue gas from the combustion turbine serving as the preheated combustion oxidant. This design requires additional cleanup of the pulverized boiler flue gas to meet emission requirements. 

PRessurized ENtrained FLOw) gasification technology. Initially developed by Krupp Uhde. Krupp and Shell. They split in 1981 and both developed their own coal gasification process. 

Kovac R.J. and O Neil DJ, "The Georgia Tech Entrained Flow Pyrolysis Process," Pyrolysis and Gasification, Q.L, Ferrero, K, Maniatis, A. Buekens, and A.V. Bridgwater, eds., Elsevier Applied Science 1989, pp. 169-179,... 

Schingnitz, M. and Mehlhose, F. The GSP-process entrained-flow gasification of different types of coal. Clean Coal Technology Conference, Sardinia, Italy, 2005. 

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. 

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. 

Another actual pyrolysis-based biorefinery concept is the Bioliq process that was developed at the Karlsruhe Institute of Technology (KIT).Bioliq aims at the production of synthetic fuels such as Fischer-Tropsch diesel and chemicals from biomass. Synthesis based on synthesis gas requires pressures of up to 10 MPa. High-pressure entrained flow gasification provides high-quality tar-free syngas with low methane contents. 

All coal gasification processes operate at high temperatures. Therefore, all gasification processes must recover some heat. In fluidized-bed and entrained-flow gasification, heat recovery can represent more than 15% of the energy in the feed coal. 

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. 

Similar to current situations with demonstration scale coal gasification processes, the greatest amount of development activity is in entrained-flow coal gasification processes. This is likely due to the inherent operating and environmental advantages of entrained flow gasification. 

In addition to the coal properties, the reasonable and unified boundary conditions need to be defined in order to evaluate and compare processes. The first section of Table 5.11 presents process-related variables. The gasification pressure was set to 30 bar, a typical value for integrated gasification combined cycle (IGCC) power plants as well as some chemical syntheses (e.g., Fischer-Tropsch) [60,65]. In the case of slagging entrained-flow gasification, the gasification temperature was set at >100 K above the ash fluid temperature for the reasons discussed in Section 4.5.2. A typical value is between -1-100 and -1-150 K [61]. The thermal capacity of the modeled reactors was set to a thermal input of 500 MW on the basis of the LHV as a suitable size for a state-of-the-art reactor. 

Hla, S.S., Harris, D.J., and Roberts, D. (2006) CFD modelling for an entrained flow gasification reactor using measured intrinsic kinetic data. Proceedings of the Fifth International Conference in CFD in the Process Industries. 

Influence of coal blend component kinetics on entrained flow gasification performance. Ninth International Conference on CFD in the Minerals and Process Industries (CSIRO), http // www.cfd.com.au/cfd confl2/PDFs/... 

Svoboda, K., Pohofely, M., Hartman, M., and Martinec, J. (2009) Pretreatment and feeding of biomass for pressurized entrained flow gasification. Fuel Process. Technol, 90, 629-635. 

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