Please use this identifier to cite or link to this item:
Files in This Item:
There are no files associated with this item.
Title: Thermodynamic Analysis of a Regenerative Brayton Cycle Using H-2, CH4 and H-2/CH4 Blends as Fuel
Authors: Lopez-Ruiz, Gontzal; Castresana, Joseba; Maria Blanco-Ilzarbe, Jesus
Abstract: Considering a simple regenerative Brayton cycle, the impact of using different fuel blends containing a variable volumetric percentage of hydrogen in methane was analysed. Due to the potential of hydrogen combustion in gas turbines to reduce the overall CO<mml:semantics>2</mml:semantics> emissions and the dependency on natural gas, further research is needed to understand the impact on the overall thermodynamic cycle. For that purpose, a qualitative thermodynamic analysis was carried out to assess the exergetic and energetic efficiencies of the cycle as well as the irreversibilities associated to a subsystem. A single step reaction was considered in the hypothesis of complete combustion of a generic H<mml:semantics>2</mml:semantics>/CH<mml:semantics>4</mml:semantics> mixture, where the volumetric H<mml:semantics>2</mml:semantics> percentage was represented by <mml:semantics>fH2</mml:semantics>, which was varied from 0 to 1, defining the amount of hydrogen in the fuel mixture. Energy and entropy balances were solved through the Engineering Equation Solver (EES) code. Results showed that global exergetic and energetic efficiencies increased by 5\% and 2\%, respectively, varying <mml:semantics>fH2</mml:semantics> from 0 to 1. Higher hydrogen percentages resulted in lower exergy destruction in the chamber despite the higher air-excess levels. It was also observed that higher values of <mml:semantics>fH2</mml:semantics> led to lower fuel mass flow rates in the chamber, showing that hydrogen can still be competitive even though its cost per unit mass is twice that of natural gas.
Keywords: hydrogen combustion; Brayton cycle; gas turbines; exergy analysis; renewable energies; POWER-TO-GAS; STORAGE-SYSTEMS; WIND POWER; TURBINE; IMPACT
Issue Date: 2022
Publisher: MDPI
Type: Article
DOI: 10.3390/en15041508
E-ISSN: 1996-1073
Funder: University of the Basque Country [GIU19/029, IT1314-19]
Appears in Publication types:Artículos científicos

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.