Operating Status of Uprating Gas Turbines and …

1 Mitsubishi Heavy Industries, Review Vol. 44 No. 4 (Dec. 2007)1 Operating Status of UpratingGas Turbines and Future Trendof Gas Turbine DevelopmentLarge frame gas Turbines for power generation have been developed with more emphasis on improving theirthermal efficiency based on the technology for raising to higher temperatures supported by such component technol-ogy as cooling and materials. Mitsubishi Heavy Industries, Ltd. (MHI) developed a 1,100 oC class D-type gas turbinein the 1980s and constructed the world's first successful large-scale combined cycle power plant. Since then, MHIhas developed the F-type and G-type gas Turbines with even higher turbine inlet temperature and has deliveredmany of them in Japan as well as overseas while accumulating successful commercial operations.

2 MHI has con-stantly improved these gas Turbines , adding to their successful operation. Now, MHI is participating in a nationalproject to promote the development of component technology for the next generation 1,700oC class gas turbine,whose thermal efficiency will be improved significantly by raising the turbine inlet Introduction1. Introduction1. Introduction1. Introduction1. IntroductionLarge frame gas Turbines fired by natural gas startedplaying an important role as the main facility in com-bined cycle power plants in the 1980s. Since then, theirthermal efficiency has been continuously improved byraising the turbine inlet temperatures. Recently, as glo-bal environmental issues grow ever more serious, theKyoto Protocol which came into force in February 2005requires the Japanese government to comply with its CO2reduction quota.

3 This in turn calls for power generationfacilities with even higher 1984, MHI developed the M701D gas turbine witha 1,100oC turbine inlet temperature and installed it inUnit No. 3, Higashi Niigata Thermal Power Station ofthe Tohoku Electric Power Co., which was the first large-scale combined cycle power plant in the world. Furtherto the successful operation of this gas turbine, MHI suc-ceeded in developing the F-type and G-type gas turbineswith even higher turbine inlet temperature as shown inFig. 1 Fig. 1 Fig. 1 Fig. 1 Fig. 1 while constantly accumulating successful opera-tions in various large-scale thermal power plants. Theresulting dramatic improvement in the combined cyclethermal efficiency shown in TTTTT able 1able 1able 1able 1able 1 has significantlycontributed to cutting down on energy consumption andpollution in the exhaust 10 20 40 80 160 3201 5001 4001 3001 2001 1001 000M501GM 501FM 251M 701DM 501BM 701BM701FM 701G2M151M 501 DFig.

4 1 History of MHI's large frame commercial gas turbinesMHI has improved the gas turbine performance by raising the turbine inlet temperatures while developing models from D-type, F-type to inlet temperature (oC)Scale designHigher temperatureLNG fired thermal power plantwith large capacityUnits and , Higashi Niigata Thermal Power Station of Tohoku Electric Power turbine output (MW)KEIZO TSUKAGOSHI*1 JUNICHIRO MASADA*1 AKIMASA MUYAMA*1 YOICHI IWASAKI*1 EISAKU ITO*2*1 Takasago Machinery Works*2 Takasago Research & Development Center, Technical Headquarters2 Mitsubishi Heavy Industries, Review Vol. 44 No. 4 (Dec. 2007)Since then, MHI has been continuously improving theF-type and G-type gas Turbines for better performancecharacteristics to meet the needs of a society concernedwith global environmental issues.

5 At the same time, toproduce gas Turbines of even higher thermal efficiency,MHI is participating in a national project to develop a1,700oC class gas turbine doing research and develop-ment of the necessary component paper introduces the features of the improvedtechnology applied to the advanced F-type and G-typegas Turbines and operation results as well as the par-ticipation scheme and plans of the research anddevelopment of the component technologies for the1,700oC class gas turbine, in the national Technological features and operation results of ad-2. Technological features and operation results of ad-2. Technological features and operation results of ad-2.

6 Technological features and operation results of ad-2. Technological features and operation results of ad-vanced F-type and G-type gas turbinesvanced F-type and G-type gas turbinesvanced F-type and G-type gas turbinesvanced F-type and G-type gas turbinesvanced F-type and G-type gas turbinesTo date, MHI's F-type and G-type gas Turbines haveaccumulated about 3,800,000 hours and 500,000 success-ful Operating hours, respectively. In the meantime, theyhave continuously been incorporated with the latest tech-nology to achieve higher performance. The technologicalfeatures and operation results of the improved itemsapplied recently are as Technological features of advanced G series Technological features of advanced G series Technological features of advanced G series Technological features of advanced G series Technological features of advanced G series gasturbineturbineturbineturbineturbineFi gure 2 Figure 2 Figure 2 Figure 2 Figure 2 shows the advanced technological featuresthat have recently been applied to the G-type gas tur-bines.

7 After testing these technological features on anM501G gas turbine at MHI's long-term demonstrationfacility and verifying their performance and reliability1,they were installed in the commercial, large frame gasturbines for power plants as shown in Fig. andinstallation at site199719981999200020012002200320042005 20062007 Fig. 2 Improved items and verification schedule The improved items for type-G gas Turbines are tested and verified at MHI's long-term demonstration facility M501G before installing them in commercial gas Advanced combustor2. Advanced 1st-stage blades and vanes1.

8 Steam cooled blade ring3. Advanced exhaust diffuser1. Steam cooled blade ring2. Advanced 1st-stage blades and vanes3. Advanced exhaust diffuser4. Advanced combustorLong-term demonstration facility at MHI TakasagoMachinery Works Advanced M501G (North America)M701G1 (Unit , Higashi Niigata Thermal Power Station)M701G2 (Unit , Kawasaki Thermal Power Station)Manufacturing advancedcomponentsInstallation in demonstration facilityVerification on long-term demonstration facility machineAfter verification in long-term demonstration facility, each advanced component is manufactured for GT for commercial power operationTestoperationManufacture andinstallation at siteStartingtestoperationCommercialopera tionManufacturing advancedcomponentsInstallation on demonstration facilityVerification on long-term demonstration facility 1 Transition of MHI gas turbine performanceFor 60 Hz utilitiesThe first operation year of prototype machine (year)Gas turbine power output (MW)

9 Gas turbine efficiency (% LHV)Combined cycle efficiency (% LHV)Pressure ratioFor 50 Hz utilitiesThe first operation year of prototype machine (year)Gas turbine power output (MW)Gas turbine efficienc (% LHV)Combined cycle efficiency (% LHV)Pressure ratio02040608080120-30 0 30 60 90 120 150 180 Fig. 3 System and structure of the stem cooled blade ringBy letting steam pass through, the clearance expands by warming during startingup while the clearance reduces more than that of the previous model by coolingunder loaded operation to improve the turbine performance.: Rotational speed: Load: Radial clearanceRotational speed, load (%) FromHRSGFrom combustor coolingoutlet Into combustor cooling inlet1st-stage blade ring2nd-stage blade ring1st-stage vane2nd-stage vane2nd-stage bladeClearance -30 0 30 60 90 120 150 18002040608080120 Rotational speed, load (%) Conventional blade ring Clearance Time (minutes)Time (minutes)Stem cooled blade ring1st-stage bladeMitsubishi Heavy Industries, Review Vol.

10 44 No. 4 (Dec. 2007)3(1) The stem cooled blade ringThe G-type gas turbine employs a steam coolingtechnique for the combustor. This positive utiliza-tion of steam has enabled the clearance control of theturbine blade chip. Figure 3 Figure 3 Figure 3 Figure 3 Figure 3 shows the structure andsystem of M701G2 as an example. During start-up,steam running through the turbine blade ring cool-ing passages heats up the turbine blade ring to expandthe tip clearances. When in loaded operation, steamcools down the blade ring to optimize the tip clear-ances. This system optimizes the clearances betterduring operation to improve the turbine performancethan the previous one.