Siemens Westinghouse

Siemens Westinghouse Power Corporation Pittsburgh, Pennsylvania... 

FIGURE 6.12 Siemens Westinghouse SOFC cross-sectional micrograph, showing a dense YSZ electrolyte deposited by EVD [48]. Reprinted from [48] with permission from Elsevier. 

Siemens Westinghouse Power Corporation (SWPC) has three TSOFC systems employing tubular cell technology operating on user sites. All were produced in their Pittsburgh, Pennsylvania facility. The capacities of the systems are 220 kilowatts, 100 kilowatts, and 25 kilowatts. 

The Siemens Westinghouse TSOFC commercialization plan is focused on an initial offering of a hybrid fuel cell/gas turbine plant. The fuel cell module replaces the combustion chamber of the gas turbine engine. Figure 1-8 shows the benefit behind this combined plant approach. Additional details are provided in Section 8. As a result of the hybrid approach, the 1 MW early commercial unit is expected to attain -60% efficiency LHV when operating on natural gas. 

Siemens Westinghouse is planning a number of tests on power plants that are prototypes of future products. All systems employ the tubular SOFC concept and most are combined with gas turbines in a hybrid configuration. Capacities of these systems are 250 kilowatts atmospheric, 300 kilowatt class hybrid, and 1 megawatt class hybrid. They are to operate at various sites in the U.S., Canada, and Europe. Some of them are discussed below. 

The 25 kW TSOFC power unit (see Siemens Westinghouse, above) was fitted with a prereformer similar to the FCE and operated with JP-8 (766 hours) and DF-2 (1555 hours) while the unit was installed at FCE s Highgrove Station. 

Sealless Tubular Configuration The most developed solid oxide fuel cell is the Siemens Westinghouse tubular cell. This approach results in eliminating seal problems between adjacent cells. A schematic representation of the cross section of the present Siemens Westinghouse... 

Siemens Westinghouse, in conjunction with Ontario Hydro Technologies, tested AES cells at pressures up to 15 atmospheres on both hydrogen and natural gas (22). Figure 8-8 illustrates the performance at various pressures ... 

This natural gas fuel cell power system is based on a pressurized TSOFC combined with a combustion turbine developed by Siemens Westinghouse (52). Most TSOFC power plant concepts developed to date have been based on atmospheric operation. However, as shown in... 

The referenced Siemens Westinghouse pnblication presented the cycle concept and overall performance valnes. Neither specific stream information nor assnmptions were presented. The stream data and assumptions presented here were developed by Parsons. The stream data were developed using an ASPEN simulation which yielded performance numbers in general agreement with the publication. 

Section 8, the cell voltage increases with cell pressure. Thus, operating with an elevated pressure will yield increased power and efficiency for a given cycle. In addition, the use of a pressurized SOFC will also allow integration with a combustion turbine. The combustion turbine selected for integration by Siemens Westinghouse is the unique 1.4 MW Heron reheat combustion turbine, a proposed product of Heron (53). 

The cycle discussed here is based on a Siemens Westinghouse publication for a 4.5 MWe plant. Recent information from Siemens Westinghouse, plans for commercialization of a scaled down 1 MWe version of this dual pressure TSOFC/Heron cycle. A 1 MW cycle was not available in the literature. 

Siemens Westinghouse provided TSOFC performance values for the HP and LP conditions, which Parsons incorporated into the systems analysis. 

Figure 9-23 Diagram of a proposed Siemens-Westinghouse hybrid system (Taken from DOE Project Fact Sheet - Fuel Cell/ATS Hybrid Systems)...

Siemens-Westinghouse Power Corporation, of Pittsburgh, PA, with a subcontract to Allison Engine Company, evaluated a pressurized solid oxide fuel cell coupled with conventional gas turbine technology without a steam plant. The system was operated at a pressure of 7 atm. The fuel cell generated 16 MW of power and the gas turbine generated 4 MW of power. The process showed 67 % efficiency as developed. An efficiency of 70 % is deemed achievable with improvement in component design. The COE is predicted to be comparable to present day alternatives. NOx levels were less than 1 ppm. 

Siemens-Westinghouse Power Corporation, Pittsburgh, PA, and Solar Turbines developed a conceptual design of an economically and technically feasible 20-MW, 70-% efficient natural gas-fueled power system that employs solid oxide fuel cells operating at elevated pressure in conjunction with an Advanced Turbine System gas turbine. The fuel cell, operated at 9 atm pressure, generated 11 MW of power. Two Solar Mercury 50 gas turbines were used to generate 9 MW of power. The results of the study indicated a system efficiency near 60 %. A low COE relative to conventional power generation is predicted. 

Siemens-Westinghouse Power Corporation of Pittsburgh, PA developed and fabricated the first advanced power plant to combine a solid oxide fuel cell and a gas turbine. The microturbine generator was manufactured by Northern Research and Engineering Corporation of Woburn, Mass. The factory acceptance test was completed in April 2000. Southern California Edison will operate the new hybrid plant at The National Fuel Cell Research Center at the University of California-Irvine. A year of testing in a commercial setting will be performed at this site. The system cycle is expected to generate electric power at 55 % efficiency. 

A 320-kilowatt hybrid system is also in the planning stages. An initial commercial offering of a one MW fuel cell-microturbine power plant in late 2002 will be the end results of this Department of Energy/Siemens Westinghouse partnership program (70). 

This section of the handbook contains field site information. Most of the worldwide summaries were extracted from an lEA paper. Information on the U.S. Department of Defense (DoD) Fuel Cell Demonstration was taken from the following web site www.dodfuelcell.com. Finally, Fuel Cell Energy, IFC, and Siemens Westinghouse provided information on their field sites. The IFC PAFC summary includes a number of projects reported by DoD. In the DoD demonstration program, a total of 30 PAFC units were installed at DoD sites across the United States. These were model B and C PC-25 units. 

Canada Ontario Hydro has tested a single Siemens-Westinghouse cell for 1725 hours. Over 1425 of the hours were at elevated pressure of 5 atm. 

Europe The ELSAM/EDB project for a 100 kWe Siemens-Westinghouse SOFC field unit has operated from January 1998. The unit will operate until January 2000 with a total of 17,500 test hours according to the plan. 

United States Siemens-Westinghouse projects on SOFC include a 250 kWe tubular prototype at the Irvine University campus (California), that will be operated by Southern California Edison Company. It is pressurized to 3.5 bar and thus is expected to give 200 kWe a coupled microturbine gives an additional 50 kWe. The have operated a tubular SOFC at pressures up to 15 atm. 

Siemens Westinghouse provided DOE with information on their fuel cell field units. This information is provided in Table 11-6. 

Table 11-6 Siemens Westinghouse SOFC Field Units...

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