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SUITE 204
CARNEGIE, PA 15106

PHONE: 412-429-2713
FAX: 412-429-4068


Opposed Fired Supercritical Boilers

Gibson Units 1-3

Steag Energy Services (formerly ESA) has employed CFD modeling to address NOx control at five 600+ MW Foster Wheeler designed supercritical opposed fired units belonging to two utilities. Beginning in 1991, Steag Energy Services (formerly ESA) employed CFD modeling to assist the Cinergy Gibson station in their low NOx retrofit program for compliance with Phase I of the CAAA 1990. Gibson Unit 1 was simulated by Steag Energy Services (formerly ESA) to compare vendor offerings of low NOx burners and overfire air to determine the best balance of NOx reduction and operational impact. Once a vendor was selected, the modeling was used to refine the offered design to improve performance, in a coordinated effort between Steag Energy Services (formerly ESA), Gibson, and the vendor.

CFD model of Gibson Unit 3. Coal particle traces and overfire air penetration surfaces are shown.

During 1992, the CFD model of Gibson 1 was rebuilt to represent Gibson Unit 3. Units 3 and 4 were retrofit with a different overfire air design, and consequently functioned differently than Units 1 and 2. This second overfire air design was duplicated in the model and validated to test data taken by Steag Energy Services (formerly ESA).

Beginning in 1995, Steag Energy Services (formerly ESA)  employed CFD modeling for the Gibson Unit 3 to address waterwall wastage. All the Gibson furnaces faced an alarming increase in waterwall tube wastage, substantially increasing the maintenance costs for those units. CFD modeling was employed to explore corrosion as the possible cause, and to assess mechanisms responsible for the corrosion. CFD modeling predicted reducing conditions along the side walls, which explained test results indicating high H2S concentrations at the same location. Based on laboratory research, the conclusion was drawn that the reducing conditions allowed for a H2S based attack on waterwall tubes. Once this cause was identified, the modeling was used to design a windbox modification to feed waterwall slots to solve the problem. This solution resulted in a joint Steag Energy Services (formerly ESA) and Cinergy patent, US Patent Number 5,809,913.

In 1996, Steag Energy Services (formerly ESA) modeled Unit 2, in a combined project with Foster Wheeler. For the project, the CFD model of Unit 1 was adapted to Unit 2 and extended to include the upper furnace reheat/superheat tubes. This project coupled the CFD model of Gibson to Foster Wheeler's proprietary boiler performance code, to address the impact of a boiler nose on furnace exit temperature profile and thermal performance. In the course of the project, the CFD model of Gibson gained extensive validation to the expected heat transfer distribution between furnace waterwalls, platen superheat surface, and exit enthalpy.

Hudson Unit 2

CFD model of Amine Enhanced Fuel Lean Gas Reburn Process on Hudson Unit 2

In 1999, Steag Energy Services (formerly ESA) modeled PSEG Hudson Unit 2, another Foster Wheeler design supercritical unit. Steag Energy Services (formerly ESA)  employed CFD modeling to select gas injector locations for a Fuel Lean Gas Reburn (FLGRTM) system. The design of the FLGR system had to integrate with an existing urea SNCR system (NOxOUTTM) to become a large scale installation of the Amine Enhanced Fuel Lean Gas Reburn (AEFLGRTM) technology.

In 2001, Steag Energy Services (formerly ESA) modeled Gibson Unit 4, to assess redesign of the existing OFA system. Multiple OFA port locations and combinations were simulated to optimize the injection of OFA for NOx control, LOI, and side wall reducing atmosphere.