Azep gas turbine combined cycle power plants thermo-economic analysis

• Conventional power plants based on fossil fuel without CO2 capture produce flue gas streams with concentrations Of CO2 between 3% and 15%, contributing to the threat of increasing global warming. Existing capture technologies such as post-combustion flue gas treatment using chemical absorption or pre-combustion carbon removal suffer from significant efficiency penalties as well as major increase in investment costs. Alternatively, combustion in O-2/CO2 atmospheres also requires expensive and energy-consuming oxygen supplies. A less energy intensive concept for oxygen production is a Mixed Conducting Membrane (MCM) reactor which produces pure oxygen from compressed air. The MCM reactor is best integrated into a conventional gas turbine combined cycle, called Advanced Zero Emissions Plant (AZEP), to provide an efficient and cost-effective power plant altogether. In this paper the economic performance of four different combined cycle alternatives in two different gas turbine sizes are evaluated; a 50 MWe size based on the Siemens SGT800 gas turbine and a 400 MWe size based on the Siemens SGT5-4000F gas turbine. ne evaluated combined cycles are one conventional combined cycle, one combined cycle with post-combustion CO2 capture and two optimised AZEP cases from a previous thermodynamic study. One AZEP alternative provides 100% CO2 capture and is thus a true zero emissions alternative, whereas the second alternative uses a sequential combustion system which enables 85% of the CO2 to be captured, making a comparison with traditional post-combustion treatment easier. The results show that the AZEP concept presents a more competitive system in terms of efficiency and economy compared to traditional capture systems.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Nyckelord

thermo-economy

combined cycles

CO2 capture

zero emissions

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