Title: Thermodynamic analysis of a modified oxy-fuel cycle, high steam content Graz cycle with a dual-pressure heat recovery steam generator

Authors: Hossein Nami; Faramarz Ranjbar; Mortaza Yari; Sahand Saeidi

Addresses: Faculty of Mechanical Engineering, University of Tabriz, 29th Bahman Blvd., Tabriz, 51666, Iran ' Faculty of Mechanical Engineering, University of Tabriz, 29th Bahman Blvd., Tabriz, 51666, Iran ' Faculty of Mechanical Engineering, University of Tabriz, 29th Bahman Blvd., Tabriz, 51666, Iran ' Faculty of Mechanical Engineering, University of Tabriz, 29th Bahman Blvd., Tabriz, 51666, Iran

Abstract: Energy and exergy analyses are reported for a modified oxy-fuel cycle, which includes the Graz cycle with an atmospheric condensation and a dual-pressure heat recovery steam generator (HRSG). Oxy-fuel cycles are proposed to capture all the produced CO₂. Due to limited fossil fuel resources, it is necessary to optimise the use of energy in the power plant cycles as much as possible. The presented configuration improves the energy and exergy efficiency of the cycle with usage of dual-pressure HRSG instead of single pressure. In this study, thermodynamic analysis for the performance of modified Graz cycle has been done which shows the effect of different parameters on the performance of cycle. Results show that the thermal and exergy efficiencies increase up to 54.5% and 47.8%, respectively, by adding of dual-pressure heat recovery steam generator unit.

Keywords: dual pressure HRSG; thermodynamic analysis; oxy-fuel cycle; heat recovery steam generator; exergy analysis; energy analysis; pinch point; GRAZ cycle; CO2; carbon dioxide; carbon capture; energy efficiency; exergy efficiency.

DOI: 10.1504/IJEX.2016.079310

International Journal of Exergy, 2016 Vol.21 No.3, pp.331 - 346

Received: 11 Nov 2015
Accepted: 09 May 2016
Published online: 26 Sep 2016 *

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