Combined fuel cell and fuel combustion power generation systems
A power generation system is provided which converts chemical energy in one or more fuels into electrical and/or mechanical power. The system includes both fuel cells to directly convert electrical energy in a fuel into electrical power and at lest one combustor and expander to generate mechanical power, optionally than converted to electrical power in a generator. Fuel cell products disclosed from the fuel cell are entered into the combustor to be heated along with products of combustion created in the combustor and expanded in the expander along with the products of combustion.
1. A combined fuel cell and fuel combustion power generation system, comprising in combination:
a source of a first fuel, the first fuel containing hydrogen;
a source of oxygen;
a fuel cell downstream from said source of fuel and said source of oxygen, said fuel cell having a discharge for at least fuel cell products produced within said fuel cell including water, said fuel cell having an output for electrical power, and said fuel cell adapted to convert at least a portion of the first fuel and the oxygen into the fuel cell products while releasing electrical power from said output;
a combustor downstream from said fuel cell discharge, said combustor adapted to combust a second fuel with oxygen in the presence of the fuel cell products from said discharge, the second fuel including hydrogen, said combustor adapted to produce elevated temperature and elevated pressure combustion products including water, said combustor including an exhaust for a mixture of the combustion products and the fuel cell products, the mixture including water;
an expander downstream from said combustor exhaust, said expander having a power outlet, said expander adapted to produce power by expanding the mixture of the combustion products and the fuel cell products, and release the power through said power outlet; and
wherein said source of oxygen includes an air separation unit having an air inlet and an oxygen enriched air outlet, said air separation unit adapted to separate at least a portion of nitrogen out of the air entering said air separation unit from said air inlet, such that fluids at said oxygen enriched air outlet have a greater amount of oxygen therein than is present in the air at said air inlet.
2. The system of claim 1 wherein said oxygen enriched air outlet contains a majority oxygen.
3. The system of claim 2 wherein said oxygen enriched air outlet contains substantially pure oxygen.
4. The system of claim 1 wherein said air separation unit is adapted to liquefy at least a portion of the air entering said air separation unit from said air inlet to separate at least a portion of nitrogen from the air.
5. A combined fuel cell and fuel combustion power generation system, comprising in combination:
a source of a first fuel, the first fuel containing hydrogen;
a source of oxygen;
a fuel cell downstream from said source of fuel and said source of oxygen, said fuel cell having a discharge for at least fuel cell products produced within said fuel cell including water, said fuel cell having an output for electrical power, and said fuel cell adapted to convert at least a portion of the first fuel and the oxygen into the fuel cell products while releasing electrical power from said output;
a combustor downstream from said fuel cell discharge, said combustor adapted to combust a second fuel with oxygen in the presence of the fuel cell products from said discharge, the second fuel including hydrogen, said combustor adapted to produce elevated temperature and elevated pressure combustion products including water, said combustor including an exhaust for a mixture of the combustion products and the fuel cell products, the mixture including water;
an expander downstream from said combustor exhaust, said expander having a power outlet, said expander adapted to produce power by expanding the mixture of the combustion products and the fuel cell products, and release the power through said power outlet;
wherein at least one of said fuels includes carbon therein and a portion of the mixture of the fuel cell products and the combustion products includes carbon dioxide at said combustor exhaust;
wherein a separator is located downstream from said combustor, said separator separating at least a portion of the water from a portion of the carbon dioxide within the mixture of the fuel cell products and the combustion products;
wherein said separator is located downstream from said expander; and
wherein a compressor is located downstream from a CO2 outlet of said separator, said compressor sufficiently compressing the CO2 for injection of the CO2 into a terrestrial formation spaced from the atmosphere.
6. The system of claim 5 wherein said terrestrial formation is an at least partially depleted oil well.