Engineering:Closed-cycle gas turbine

From HandWiki
Closed-cycle gas turbine schematic

C compressor and T turbine assembly
w high-temperature heat exchanger
ʍ low-temperature heat exchanger
~ mechanical load, e.g. electric generator

A closed-cycle gas turbine is a turbine that uses a gas (e.g. air, nitrogen, helium, argon,[1][2] etc.) for the working fluid as part of a closed thermodynamic system. Heat is supplied from an external source.[3] Such recirculating turbines follow the Brayton cycle.[4][5]

Background

The initial patent for a closed-cycle gas turbine (CCGT) was issued in 1935 and they were first used commercially in 1939.[3] Seven CCGT units were built in Switzerland and Germany by 1978.[2] Historically, CCGTs found most use as external combustion engines "with fuels such as bituminous coal, brown coal and blast furnace gas" but were superseded by open cycle gas turbines using cleaner-burning fuels (e.g. "gas or light oil"), especially in highly efficient combined cycle systems.[3] Air-based CCGT systems have demonstrated very high availability and reliability.[6] The most notable helium-based system thus far was Oberhausen 2, a 50 megawatt cogeneration plant that operated from 1975 to 1987 in Germany.[7] Compared to Europe where the technology was originally developed, CCGT is not well known in the US.[8]

Nuclear power

Gas-cooled reactors powering helium-based closed-cycle gas turbines were suggested in 1945.[8] The experimental ML-1 nuclear reactor in the early-1960s used a nitrogen-based CCGT operating at 0.9 MPa.[9] The cancelled pebble bed modular reactor was intended to be coupled with a helium CCGT.[10] Future nuclear (Generation IV reactors) may employ CCGT for power generation,[3] e.g. Flibe Energy intends to produce a liquid fluoride thorium reactor coupled with a CCGT.[11]

Development

Closed-cycle gas turbines hold promise for use with future high temperature solar power[3] and fusion power[2] generation.

They have also been proposed as a technology for use in long-term space exploration.[12]

Supercritical carbon dioxide closed-cycle gas turbines are under development; "The main advantage of the supercritical CO2 cycle is comparable efficiency with the helium Brayton cycle at significantly lower temperature" (550 °C vs. 850 °C), but with the disadvantage of higher pressure (20 MPa vs. 8 MPa).[13] Sandia National Laboratories has a goal of developing a 10 MWe supercritical CO2 demonstration CCGT by 2019.[14]

See also

References

  1. ↑ Nitrogen or Air Versus Helium for Nuclear Closed Cycle Gas Turbines | Atomic Insights
  2. ↑ 2.0 2.1 2.2 "AN ASSESSMENT OF THE BRAYTON CYCLE FOR HIGH PERFORMANCE POWER PLANTS". http://aries.ucsd.edu/LIB/REPORT/CONF/ANS00/schleicher.pdf. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 Frutschi, Hans Ulrich (2005). Closed-Cycle Gas Turbines. ASME Press. ISBN 0-7918-0226-4. http://asmedl.aip.org/ebooks/asme/asme_press/802264. Retrieved 7 December 2011.  Note: front matter (including preface and introduction; PDF link) is open access.
  4. ↑ Thermodynamics and Propulsion: Brayton Cycle
  5. ↑ A REVIEW OF HELIUM GAS TURBINE TECHNOLOGY FOR HIGH-TEMPERATURE GAS-COOLED REACTORS
  6. ↑ Keller, C. (1978). "Forty years of experience on closed-cycle gas turbines". Annals of Nuclear Energy 5 (8–10): 405–422. doi:10.1016/0306-4549(78)90021-X. 
  7. ↑ "Nuclear Power: Small modular reactors". Power Engineering. 7 June 2012. http://www.power-eng.com/news/2012/06/07/nuclear-power-small-modular-reactors.html. [yes|permanent dead link|dead link}}]
  8. ↑ 8.0 8.1 McDonald, C. F. (2012). "Helium turbomachinery operating experience from gas turbine power plants and test facilities". Applied Thermal Engineering 44: 108–181. doi:10.1016/j.applthermaleng.2012.02.041. 
  9. ↑ "ML-1 Mobile Power System: Reactor in a Box | Atomic Insights". http://atomicinsights.com/1995/11/ml1-mobile-power-system-reactor-box.html. 
  10. ↑ IAEA Technical Committee Meeting on "Gas Turbine Power Conversion Systems for Modular HTGRs"[yes|permanent dead link|dead link}}], held from 14–16 November 2000 in Palo Alto, California. International Atomic Energy Agency, Vienna (Austria). Technical Working Group on Gas-Cooled Reactors. IAEA-TECDOC--1238, pp:102-113[yes|permanent dead link|dead link}}]
  11. ↑ Introduction to Flibe Energy: YouTube Video (~20 min) and PDF of slides used
  12. ↑ Introduction to Gas Turbines for Non-Engineers (see page 5)
  13. ↑ V. Dostal, M.J. Driscoll, P. Hejzlar, "Archived copy". http://web.mit.edu/jessiek/MacData/afs.course.lockers/22/22.33/www/dostal.pdf.  MIT-ANP-Series, MIT-ANP-TR-100 (2004)
  14. ↑ Sandia National Laboratories: Supercritical CO2-Brayton Cycle

External links



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