C2 - Optimization of existing systems: Improvement of plants in operation and design of additional units
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The document discusses the optimization of gas extraction systems and changes in gas composition during operation, specifically citing the Krafla plant's experiences. Renovations made in gas extraction systems have led to increased capacities and efficiency, particularly in the Krafla and Reykjanes plants. Key changes include adjustments in design premises due to varying gas content and improved ejector systems resulting in enhanced production output.
![Krafla – Changes in gas content
• Plant orginal design is for:
• 1% NCG in HP steam
• 0,15% NCG in LP steam
• (0,78% of total steam)
• During construction the Krafla
volcano erupted and gas content
increased.
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
1975 1980 1985 1990 1995 2000 2005 2010 2015NCGcontent[%]
NCG content in steam in Krafla GPP % of total steam](https://image.slidesharecdn.com/davido-180529115434/85/C2-Optimization-of-existing-systems-Improvement-of-plants-in-operation-and-design-of-additional-units-7-320.jpg)
![Changes in design premise
• Orginal 2250 kg/h
• 0,78% of total steam
• 1983 -> 3.738 kg/h
• 1,3% of total steam
• 1984 -> 4.390 kg/h
• 1,52% of total steam
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
1975 1980 1985 1990 1995 2000 2005 2010 2015NCGcontent[%]
NCG content in steam in Krafla GPP % of total steam](https://image.slidesharecdn.com/davido-180529115434/85/C2-Optimization-of-existing-systems-Improvement-of-plants-in-operation-and-design-of-additional-units-10-320.jpg)
C2 - Optimization of existing systems: Improvement of plants in operation and design of additional units
- 1. Verkís Consulting Engineers | +354 422 8000 | verkis.com | verkis@verkis.com Davíð Örn Benediktsson Mechanical Engineer Verkís consulting Engineers - Iceland Date: Thursday, April 26th Optimization of existing systems Improvements or plants in operation and design of additional units
- 2. What changes during operation? • Reservoir enthalpy • Can increase and decrease • Well head pressure • Usually decreases with time • Well productivity • Non Condensible Gas (NCG) content • NCG composition
- 4. Gas extraction system – Changes in gas composition • Gas is deliberately overestimated when design premises are set. • Wells drilled during construction can have different gas content than design premises. • Gas content and composition can change during operation.
- 5. Source: Jónas Ketilsson et al OS-2011-02
- 6. Source: Jónas Ketilsson et al OS-2011-02
- 7. Krafla – Changes in gas content • Plant orginal design is for: • 1% NCG in HP steam • 0,15% NCG in LP steam • (0,78% of total steam) • During construction the Krafla volcano erupted and gas content increased. 0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 1975 1980 1985 1990 1995 2000 2005 2010 2015NCGcontent[%] NCG content in steam in Krafla GPP % of total steam
- 8. Gas extraction renovation 1983 • Orginal design, two stage ejecor system: • Capacity 2.250 kg/h (100%) • 2 x 100% ejecors on each stage • 1 x 100% intercondenser • No aftercondenser • System supplied with Turbine. • New ejectors bought on first stage • Capacity 3.738 kg/h
- 9. Gas extraction renovation in 1984 by Verkís (VST) • Nameplate capacity increased to 4.390 kg/h of NCG • Two stage ejecor system • 78%+22% first stage • 70%+30% second stage • The orginal intercondenser used as aftercondenser. • New larger intercondenser
- 10. Changes in design premise • Orginal 2250 kg/h • 0,78% of total steam • 1983 -> 3.738 kg/h • 1,3% of total steam • 1984 -> 4.390 kg/h • 1,52% of total steam 0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6 1,8 1975 1980 1985 1990 1995 2000 2005 2010 2015NCGcontent[%] NCG content in steam in Krafla GPP % of total steam
- 11. Krafla NCG system - LRVP • Second turbine put in operation in 1999 • Orginal gas extraction system erected • New LRVP installed in 1999 • 22.200 m3/h • 14°C suction temperature • 0.10 bar-a suction pressure • Operators were not happy with the performance and used the ejector system
- 12. Krafla unit 2 NCG system renovation by Verkís • Same setup as installed for unit 1 in 1984. • 4390 kg/h NCG suction • 120 mbara suction bressure • 27°C suction temperature • Operated at 93 mbar without problems. • 3,6 kg/s steam savings • 2 MW increased production
- 13. Reykjanes gas extraction system • 1 x 100% two stage ejector system for each unit. • One identical common spare system for both units. • Condenser specified for 2% NGC in steam • Gas extraction system specified for 1,5% NCG in steam • Operation 0,8 % NCG in steam
- 14. Reykjanes gas extraction system renovation • Reduced ejector capacity to fit actual operating conditions • Lower gas content • Lower suction pressure • Motive steam reduction results in 1,18 MW increased production • New ejectors designed to fit existing flanges • Short replacement time • Short payback