The evaluation of oxy-fuel combustion deployment at the Mirfa Plant in UAE

  • Vinicius Bueno

Student thesis: Master's Thesis

Abstract

Oxy-fuel combustion is currently one of the promising options for carbon dioxide capture and has been undergoing rapid development in research, pilot and demonstration scales in the last decades. The oxy-fuel combustion consists of using oxygen instead of air as the oxidant gas, which results in producing a CO2-enriched flue gas that facilitates further purification in addition to reducing nitrogen oxides formation. Nonetheless, there are still some technical barriers that hinder deploying the technology in a commercial scale. The main challenge within this technology is the generation of oxygen, which is expensive to produce from air separation units, whether by adsorption or cryogenic means. In Mirfa Plant situated in Abu Dhabi, there exists an opportunity of utilizing waste oxygen produced from air separation unit, which provides gaseous nitrogen (GAN) for injection into on-shore gas reservoirs. This large quantity of high purity oxygen could be utilized for oxy-fuel power plant with CCS, which results in reducing the cost of operation and energy consumption of air separation units in addition to providing a stream of CO2 that will be used for EOR activities. This work assessed the techno-economic aspects to evaluate the feasibility of deploying different oxy-fuel combustion schemes, considering natural gas and coal as fuel and coupled to a CPU. The ASU successfully improved the oxygen quality from the Mirfa Plant waste stream from 71% to 99.9%. For the natural gas-fired configuration, 319.1 MW of electricity was produced corresponding to a gross cycle efficiency of 49% and a net efficiency of 36.4% after accounting for the energy penalty of the whole facility. The coal-fired system, in its turn, generated 237.5 MW of electricity, with gross and net efficiencies of 43.6% and 30% respectively. Ultimately, over 95% of CO2 was purified from the flue gas in both settings, with purity up to 97%. From the economic point of view, the CAPEX and OPEX estimated for both systems allowed the calculation of the LCOE, which showed that the coal option represented the most economic viable setting. This work also discussed the technical, political and socioeconomic barriers to deploy oxy-comb ustion technologies.
Date of AwardMay 2017
Original languageAmerican English

Keywords

  • Fuel Combustion
  • On-shore gas reservoirs
  • Natural gas
  • Oxy-combustion technologies
  • Mirfa Plant.

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