Second-generation PFBC systems R and D. Monthly report, July 1--July 31, 2000

No work was performed on Phase 2; the two remaining Multi Annular Swirl Burner test campaigns are on hold pending selection of a new test facility (replacement for the shut down UTSI burner test facility) and identification of associated testing costs. Phase 3 of the Second-Generation PFB Combustion Plant conceptual design prepared in 1987 is being updated to reflect the benefit of pilot plant test data and the latest advances in gas turbine technology. The updated plant is being designed to operate with 95% sulfur capture and a single Siemens Westinghouse (SW) 501G gas turbine. Using carbonizer and gas turbine data generated by Foster Wheeler (FW) and SW respectively, Parsons Infrastructure and Technology prepared preliminary plant heat and material balances based on carbonizer operating temperatures of 1,700 and 1,800 F, the former yielded the higher plant efficiency and has been selected for the design update. The 501G gas turbine ha san air compressor discharge temperature of 811 F and an exhaust temperature of 1,140 F. Both of these streams represent high sources of heat and must be cooled, the air to 600 F to be compatible with a 650 F PCFB pressure vessel design temperature and the exhaust for a 275 F stack gas temperature. Because of their relatively high temperature, they can be used for feed water heating, steam generation and/or steam superheating and reheating. As a result, the plant could have one boiler (the PCFB boiler), or as many as three boilers if their cooling is used to generate steam. Three different plant arrangements using one, two and then three boilers were considered with the three-boiler arrangement minimizing the feedwater flow/steam turbine size and maximizing the plant efficiency. After reviewing the three arrangements it was felt the operating complexity associated with a three-boiler plant did not justify the 1/2 point increase in plant efficiency it provided and a two-boiler plant was selected