This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to is achieved before gas turbine combustion. Therefore can be removed from fuel (rather than from exhausts, thus utilizing less demanding equipment) and made available for long-term storage, to avoid dispersion toward the atmosphere and the consequent contribution to the greenhouse effect. The strategy here proposed to achieve this goal is natural gas partial oxidation. The second part of the paper will address steam/methane reforming. Partial oxidation is an exothermic oxygen-poor combustion devoted to CO and production. The reaction products are introduced in a multiple stage shift reactor converting CO to Carbon dioxide is removed by means of physical or chemical absorption processes and made available for storage, after compression and liquefaction. The resulting fuel mainly consists of hydrogen and nitrogen, thus gas turbine exhausts are virtually devoid of The paper discusses the selection of some important parameters necessary to obtain a sufficient level of conversion in the various reactors (temperature and pressure levels, methane-to-air or methane-to-steam ratios) and their impact on the plant integration and on the thermodynamic efficiency. Overall performance (efficiency, power output, and carbon removal rate) is predicted by means of a computational tool developed by the authors. The results show that a net efficiency of 48.5 percent, with a 90 percent removal, can be obtained by combined cycles based on large heavy duty machines of the present technological status, either by using chemical or physical absorption.
Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles—Part I: Partial Oxidation
Contributed by the International Gas Turbine Institute (IGTI) of THE AMERICAN SOCIETY OF MECHANICAL ENGINEERS for publication in the ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Paper presented at the International Gas Turbine and Aeroengine Congress and Exhibition, Munich, Germany, May 8–11, 2000; Paper 00-GT-163. Manuscript received by IGTI November 1999; final revision received by ASME Headquarters February 2000. Associate Editor: D. R. Ballal.
Lozza , G., and Chiesa, P. (February 1, 2000). "Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles—Part I: Partial Oxidation ." ASME. J. Eng. Gas Turbines Power. January 2002; 124(1): 82–88. https://doi.org/10.1115/1.1395581
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