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Title: PFBC freeboard firing under part load conditions development of a CFD based design tool

Conference ·
OSTI ID:20006826

ABB is currently building a second generation Pressurized Fluidized Bed Combined-Cycle (PFBC) plant in Cottbus, Germany. It will generate heat and electricity for the city of Cottbus, burning locally mined brown coal. In this plant, which is based on ABB's P200 PFBC module, a freeboard firing system operated with light oil will for the first time ever be used to maintain a high inlet temperature to the GT35P machine also at part load. This promotes oxidation of CO and makes selective non-catalytic NO{sub x} reduction effective also in this load range. In the present work a modeling tool is being developed in support of the design of the freeboard firing system and to help evaluate the performance of this system during operation. Another purpose of this tool is to check the sensitivity of the temperature distribution in the freeboard against a maldistribution of the fuel. For these purposes a model based on the full set of mass, momentum and energy balances was established. A commercially available computational fluid dynamics (CFD) program package was used to implement and solve the model. For the solution a stepwise approach has been chosen: in a first step the penetration of the oil jet into the freeboard, its dispersion, gasification and combustion has been modeled for a single jet. For these calculations a locally very fine grid was used. In a second step the freeboard with multiple oil jets will be described. In this latter step it will be necessary to reduce the spatial resolution significantly due to the limitation of computational resources. In the present paper the approach will be described in detail and some first computational results concerning the combustion of an oil spray will be presented.

Research Organization:
Technical Univ. Hamburg-Harburg, Hamburg (DE)
OSTI ID:
20006826
Report Number(s):
CONF-990534-; TRN: IM200008%%433
Resource Relation:
Conference: 15th International Conference on Fluidized Bed Combustion, Savannah, GA (US), 05/16/1999--05/19/1999; Other Information: 1 CD-ROM. Operating system required: Windows 3.x; Windows 95/98/NT; Macintosh, Power Macintosh; UNIX. All systems need 2X CD-ROM drive.; PBD: 1999; Related Information: In: Proceedings of the 15th national conference on fluidized bed combustion, by Reuther, R.B. [ed.], [1800] pages.
Country of Publication:
United States
Language:
English