CO2 Emissions Challenge in Japan and Siemens AG Proposals for Sustainable Use of Modern Turbine Technology for CO2 Reduction

Transcription

1 siemens.com/power-generation-services CO2 Emissions Challenge in Japan and Siemens AG Proposals for Sustainable Use of Modern Turbine Technology for CO2 Reduction CEPCI October 26-30, 2014 Jeju island, Korea Authors: Wolfgang Bergemann Siemens AG Power Generation Services Power and Gas

2 Table of Contents 1. Introduction Method Modernization of the HP/IP Turbine BB Reliability issues Blade design Modernization solutions Modernization of the LP Turbine Type BB Reliability issues Blade design Modernization solution Conclusion References Disclaimer Page 2 of 14

3 1. Introduction After the massive tsunami tragedy in Fukushima in March 2011, Japan shut down all nuclear power. Hence the entire existing fleet of more than 110 GW fossil fuel power plants, in addition to the hydropower plants and some wind and solar plants, were faced with covering the entire electricity demand. Due to this, the CO 2 emissions intensity in Japan has increased. One of the measures for environmental conservation, including countermeasures against global warming, is modernizing fossil power plant turbines by increasing efficiency or reducing fuel consumption at same output. If requested, Siemens Energy can contribute toward overcoming this challenge with their modern, state-of-the-art technology for blades, seals and casing design, especially for the fleet built by MHI under a Westinghouse license. Based on our experiences with turbine modernizations on Westinghouse units in the US, Mexico, Thailand and the United Kingdom of Saudi Arabia, we can offer wide a variety of products for these MHI units combined with low outage durations and extended maintenance intervals. Siemens already has experience with modernizing MHI-manufactured units in Japan after very successfully modernizing both NPP Sendai 1 & 2 turbines in 2006 and Method One of the best methods for reducing CO 2 emissions is modernizing the turbine. The success of this approach can be guaranteed when the modernization results in a reduction of fuel consumption while keeping same output, but achieved with a lower steam flow rate or output improvement with same steam flow rate. A 1% efficiency improvement of a 500 MW coalfired power plant saves up to 35,000 t of carbon dioxide (CO 2 ) per year. Turbine modernization also remedies all known reliability issues. This can be achieved mainly by replacing main components such as rotors and inner casings and reusing existing outer casings. Using all of the knowledge from Westinghouse Building Block (BB) design and the latest Siemens blade design, the target can be met. This paper uses the turbine modernization of the HP/IP Turbine BB 44 and LP Turbine BB 73 as examples of our wide range of capabilities and experience which describe a typical ~ 500MW unit. Page 3 of 14

4 3. Modernization of the HP/IP Turbine BB Reliability issues Based on technical knowledge and design criteria from decades ago we are now experiencing some technical issues with units operating on a long-term basis as shown in Fig. 1. Fig Blade design The blade design is based on Siemens AG blade design with its famous 3DS/ DV Blades, shown in Fig. 2, which were developed in the late nineties. This blade design has been used for several turbine modernizations and was adopted for new apparatus designs. All newly manufactured or erected steam turbine plants in last 15 years use this highly efficient design. Page 4 of 14

5 Fig Modernization solutions Based on our and customer requests, Siemens has developed two different solutions. One for base load operated units or so-called full arc admissions and one for load-following and two-shift operation or a so-called partial arc solution shown in Fig. 3, 4, 5. Fig. 5 also shows some expected thermodynamic numbers. Page 5 of 14

6 Fig. 3 Fig. 4 Page 6 of 14

7 Fig. 5 The proposed solution shows feasibilities, especially for efficiency improvements which can be converted into lower fuel consumption while keeping same output. Siemens also developed new strategy to shorten the outage duration as a maintenance cost-saving measure. The main driver has been the reuse of existing outer casing and pipes and extractions. Shown here in Fig. 6: Page 7 of 14

8 Fig Modernization of the LP Turbine Type BB Reliability issues Based on technical knowledge and design criteria from decades ago we are now experiencing some technical issues with units operating on a long-term basis as shown in Fig. 7. Especially the Stress Corrosion Cracking (SCC) history is important due to the fact that Siemens has strived to find out the root cause of the occurrence of SCC and has developed sufficient measures to avoid SCC. Today, Siemens has gone more than 2 decades without any SCC on rotors manufactured by Siemens. Page 8 of 14

9 Fig Blade design For our LP blade design, we use our 3DS blades for the drum stages. For the last stages L-0, L-1 and L-2, Siemens uses a standardized stage package specifically designed and, generally free-standing, finely-tuned L-0 blades and shrouded L-1, L-2 blades without damping wires or snubbers. For efficiency reasons, with some specific solutions, we offer also shrouded L-0 solution. An overview of the key technologies is shown in Fig. 8. Page 9 of 14

10 Fig Modernization solution The newly developed modernization solution has been implemented more than 45 times in the last couple of years. The most recent version of this 8.7m² rotor with 37.6 inch blade in the last stage blade (LSB) is very successful, reliable and very efficient. As shown in Fig. 9, all colored components were replaced by reusing existing outer casings. If the last stage blade has a larger area or heavier weight, all interferences would be taken into account and solved with a Design Analysis Report (DAR) which will be forwarded to customers. Thermodynamic evaluation shows potential of up to 3 5 MW per LP or, again, the same output with a lower steam flow rate. Page 10 of 14

11 Fig Conclusion Modernizing aging steam turbines with state-of-the-art technologies can improve turbine efficiency in general by five to six percent. Depending on the age of the design and operating time this can sometimes be even higher. Combined with the chance of fixing reliability issues, this method results in a high probability of reducing CO 2 emissions as well as increasing the service life and improving competitiveness. Due to the extension of inspection intervals up to 100,000 operating hours, maintenance costs can also be reduced. Page 11 of 14

12 6. References Jansen, M.; Ulm, W. (1995): Modern Blade Design for Improving Steam Turbine Efficiency, 1 st European Conference on Turbomachinery, Fluid Dynamic and Thermodynamic Aspects, University Nürnberg-Erlangen Simon, V.; Stephan, I.; Bell, R.M.; Capelle, U.; Deckers, M.; Schnaus, J.; Simkine, M. (1997): Axial Steam Turbines with Variable Reaction Blading, Advances in Turbine Materials, Design and Manufacturing, Proceedings of the 4 th International Charles Parsons Conference, London Harig, T.; Oeynhausen, H.; Turbine upgrades - Economic and technical potentials for conventional and nuclear plants; Reprint from BWK, March 2005 Siemens User Meetings and Siemens presentation materials Page 12 of 14

13 7. Disclaimer These documents contain forward-looking statements and information that is, statements related to future, not past, events. These statements may be identified either orally or in writing by words as expects, anticipates, intends, plans, believes, seeks, estimates, will or words of similar meaning. Such statements are based on our current expectations and certain assumptions, and are, therefore, subject to certain risks and uncertainties. A variety of factors, many of which are beyond Siemens control, affect its operations, performance, business strategy and results and could cause the actual results, performance or achievements of Siemens worldwide to be materially different from any future results, performance or achievements that may be expressed or implied by such forward-looking statements. For us, particular uncertainties arise, among others, from changes in general economic and business conditions, changes in currency exchange rates and interest rates, introduction of competing products or technologies by other companies, lack of acceptance of new products or services by customers targeted by Siemens worldwide, changes in business strategy and various other factors. More detailed information about certain of these factors is contained in Siemens filings with the SEC, which are available on the Siemens website, and on the SEC s website, Should one or more of these risks or uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described in the relevant forwardlooking statement as anticipated, believed, estimated, expected, intended, planned or projected. Siemens does not intend or assume any obligation to update or revise these forward-looking statements in light of developments which differ from those anticipated. Trademarks mentioned in these documents are the property of Siemens AG, its affiliates or their respective owners. Page 13 of 14

14 Published by and copyright 2015: Siemens AG Freyeslebenstrasse Erlangen, Germany Siemens Energy, Inc Alafaya Trail Orlando, FL , USA For more information, please contact our Customer Support Center. Phone: / Fax: / (Charges depending on provider) support.energy@siemens.com All rights reserved. Trademarks mentioned in this document are the property of Siemens AG, its affiliates, or their respective owners. Subject to change without prior notice. The information in this document contains general descriptions of the technical options available, which may not apply in all cases. The required technical options should therefore be specified in the contract. Page 14 of 14