Exergy recuperation of mid and low quality heat by chemical reactions

Takao Nakagaki, Takayuki Ozeki, Yuuta Watanabe

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Conventional thermal power generation, as typified by gas turbines, has steadily increased power generation efficiency by elevating temperature of heat, but there is a limit to the maximum availability of electric energy. Exergy rate is a unified index indicating the quality of energy in deferent forms. We have no way in thermal conversion to extract all of the availability, while almost hydrocarbon fuels have exergy rate around 95%. 25% of exergy is inevitably lost through the combustion process from chemical to heat at maximum temperature of 2000°C. Hydrogen's low exergy rate provides "exergy recuperation" in which degrading 12% from 95% to 83% can take low quality heat up to availability of 83% as a kind of chemical heat pump. Chemically Recuperated Gas Turbine (CRGT) is a specific example, and dimethyl ether (DME) is one of the most suitable fuels because steam reforming occurs around 300°C. Electrochemical partial oxidation (EPOx) is another way to convert mid-quality heat into electric energy as much as difference between change in Gibbs free energy and change in enthalpy. This paper reports concept and industrially-feasible applications of this unconventional and non-cascadic use of heat.

Original languageEnglish
Title of host publicationASME 2011 5th International Conference on Energy Sustainability, ES 2011
Pages2017-2023
Number of pages7
EditionPARTS A, B, AND C
DOIs
Publication statusPublished - 2011 Dec 1
EventASME 2011 5th International Conference on Energy Sustainability, ES 2011 - Washington, DC, United States
Duration: 2011 Aug 72011 Aug 10

Publication series

NameASME 2011 5th International Conference on Energy Sustainability, ES 2011
NumberPARTS A, B, AND C

Conference

ConferenceASME 2011 5th International Conference on Energy Sustainability, ES 2011
CountryUnited States
CityWashington, DC
Period11/8/711/8/10

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Renewable Energy, Sustainability and the Environment

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  • Cite this

    Nakagaki, T., Ozeki, T., & Watanabe, Y. (2011). Exergy recuperation of mid and low quality heat by chemical reactions. In ASME 2011 5th International Conference on Energy Sustainability, ES 2011 (PARTS A, B, AND C ed., pp. 2017-2023). (ASME 2011 5th International Conference on Energy Sustainability, ES 2011; No. PARTS A, B, AND C). https://doi.org/10.1115/ES2011-54702