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Abstract
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This paper deals with a double effect heat transformer-aided carbon dioxide capture unit with transcritical
carbon dioxide power generation for a coal-fired steam power plant. In the proposed system a double absorption
heat transformer is used to upgrade low energy level steam into high-level and drive carbon dioxide capture unit.
Also, a transcritical carbon dioxide power generation that is utilized captured carbon dioxide to generate power
and compensate a portion of the required electrical energy of the carbon dioxide capture unit. This system avoids
extracting high-grade temperature steam extracted from high-pressure stage of steam turbine and hence overall
thermal efficiency of power plant increases compared to the reference systems. Comprehensive thermodynamic
and economic evaluations are conducted to reveal the feasibility of the presented system. The results show that
the evaporator temperature has the highest effect on net power output. An increase of 10 K in the evaporator
temperature from 80 °C to 90 °C, leads to a reduction of 4.9% in generated power. However, a 50% increase in
carbon dioxide capture rate from 40% to 90%, leads to a rise of 23.4% in the exergy destruction rate. Moreover,
the payback period is approximately 4 years and 6 months.
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