The gasification industry has identified improved performance of entrained flow gasifiers as arequirement for Integrated Gasification Combined Cycle (IGCC) power plants to becommercially viable. Recent review papers by [Steigel et al, 2001] and [Holt, 2001a] identifiedseveral items that could lead to improved Reliability, Availability and Maintainability of solidfuel gasifiers. Some specific problem spots included fuel injector life, refractory wear, carbonconversion and slag management. Better understanding of how these are impacted by operationalchanges such as fuel type, slurry content and oxidizer flow would be highly beneficial. Bothreview papers highlighted the need to make greater use of Computational Fluid Dynamics (CFD)modeling of gasifiers. In the last ten years, CFD modeling has been a key tool in improving theperformance of the current fleet of pulverized coal fired electric utility boilers. Likewise, CFDmodeling can provide insights into the flow field within the gasifier that will lead to improvedperformance. An excellent review of recent CFD modeling studies conducted for a wide range ofgasifier systems is available in [IEA, 2000].As part of our DOE Vision 21 project, Reaction Engineering International (REI) is developing aCFD modeling capability for entrained flow gasifiers. Our efforts are focused on twoconfigurations: (1) a single stage, down fired system and (2) a two stage system with multiplefeed inlets that could be opposed or tangentially fired. These systems are representative of thedominant, commercially available gasifier systems [NRC,1995], [Holt, 2001b]. The single stagegasifier contains a single fuel injector, located along the gasifier centerline, through which fuel,an oxygen stream and possibly steam are injected. The two stage gasifier consists of two sectionsconnected by a diffuser. Each section can have two or four feed injectors. The first stage is aslagging combustor used to separate the ash from the slag and to provide hot gases to the secondstage. Char escaping from the gasifier can be separated from the solids downstream and recycledto the first stage. Additional coal and oxidant can be injected into the second stage where theadditional fuel is devolatilized and partially gasified. For both classes of gasifiers hot mineralmatter is deposited on the wall as slag. The slagging behavior is a critical to protecting therefractory-lined walls of the gasifier from the harsh environment within the gasifier. Inadequateslagging can lead to excessive refractory wear. However, too much slag can also adverselyimpact gasifier performance. At present, commercial sized gasifiers used for power generationdo not achieve complete carbon conversion of solid fuel with only a single pass through thegasifier. An example of a commercial sized single stage, downfired gasifier is the Texaco
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