Integrated power generation and carbon capture using fuel cells
AssigneeExxonMobil Research and Engineering Company
InventorsPaul J. Berlowitz, Timothy Andrew Barckholtz, Frank Hershkowitz, Alessandro Faldi
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Abstract
Systems and methods are provided for capturing CO2 from a combustion source using molten carbonate fuel cells (MCFCs). The fuel cells can be operated to have a reduced anode fuel utilization. Optionally, at least a portion of the anode exhaust can be recycled for use as a fuel for the combustion source. Optionally, a second portion of the anode exhaust can be recycled for use as part of an anode input stream. This can allow for a reduction in the amount of fuel cell area required for separating CO2 from the combustion source exhaust and/or modifications in how the fuel cells are operated.
Claims20
A method for capturing carbon dioxide from a combustion source, the method comprising:
- introducing one or more fuel streams and an O2-containing stream into a reaction zone;
- performing a combustion reaction in the combustion zone to generate a combustion exhaust, the combustion exhaust comprising at least about 20 vppm of NOx;
- processing at least a first portion of the combustion exhaust with a fuel cell array of one or more molten carbonate fuel cells to form a cathode exhaust stream from at least one cathode outlet of the fuel cell array, the one or more fuel cells each having an anode and a cathode, the molten carbonate fuel cells being operatively connected to the combustion exhaust through one or more cathode inlets in the fuel cell array;
- reacting carbonate from the one or more fuel cell cathodes with hydrogen within the one or more fuel cell anodes to produce electricity, an anode exhaust stream from at least one anode outlet of the fuel cell array comprising CO2 and H2;
- and
- separating CO2 from the anode exhaust stream in one or more separation stages to form a CO2-depleted anode exhaust stream.
A method for capturing carbon dioxide from a combustion source, said method comprising:
- capturing an output stream from a combustion source, said captured output stream comprising oxygen and carbon dioxide;
- processing the captured output stream with a fuel cell array of one or more molten carbonate fuel cells, the one or more fuel cells each having an anode and a cathode, the molten carbonate fuel cells being operatively connected to the carbon dioxide stream through one or more cathode inlets of molten carbonate fuel cells in the fuel cell array;
- reacting fuel with carbonate from the one or more fuel cell cathodes within the one or more fuel cell anodes to produce electricity, an anode exhaust stream from at least one anode outlet of the fuel cell array comprising carbon dioxide and hydrogen, at least a portion of the fuel reacted with carbonate comprising hydrogen recycled from the anode exhaust stream;
- separating H2 from the anode exhaust prior to separating CO2 from the anode exhaust;
- separating carbon dioxide from the anode exhaust stream in one or more separation stages after the separation of H2;
- and
- recycling at least a portion of the anode exhaust stream to the anode after separation of the carbon dioxide from the anode exhaust stream.
Dependencies are inferred from the claim text.