Abstract:
A combined cycle fuel cell includes a fuel cell such as a solid-oxide fuel cell (SOFC) comprising an anode that generates a tail gas. A hydrocarbon fuel reforming system that mixes a hydrocarbon fuel with the fuel cell tail gas downstream of the fuel cell partly or fully converts the hydrocarbon fuel into hydrogen (¾) and carbon monoxide (CO). A fuel path diverts a first portion of the reformed fuel to the inlet of the fuel cell anode. A cooler such as an Organic Rankine cycle (ORC) is optionally configured to remove heat from a residual portion of the reformed fuel and to deliver the cooled residual portion of the reformed fuel to a bottoming cycle that may be an external or internal combustion engine such as a reciprocating gas engine or gas turbine that is driven in response to the cooled residual portion of the reformed fuel.
Abstract:
A system and method are provided for boosting overall performance of a fuel cell while simultaneously separating a nearly pure stream of CO 2 for sequestration or for use in generating electrical power to further increase overall efficiency of the process. The system and method employ a heat exchanger system configured to generate a stream of fuel that is returned to the inlet of the fuel cell anode with a higher molar concentration of carbon monoxide (CO) and hydrogen (H 2 ) fuel than was initially present in the fuel cell anode outlet.
Abstract:
A combined cycle fuel cell includes a fuel cell such as a solid-oxide fuel cell (SOFC) comprising an anode that generates a tail gas. A hydrocarbon fuel reforming system that mixes a hydrocarbon fuel with the fuel cell tail gas downstream of the fuel cell partly or fully converts the hydrocarbon fuel into hydrogen (¾) and carbon monoxide (CO). A fuel path diverts a first portion of the reformed fuel to the inlet of the fuel cell anode. A cooler such as an Organic Rankine cycle (ORC) is optionally configured to remove heat from a residual portion of the reformed fuel and to deliver the cooled residual portion of the reformed fuel to a bottoming cycle that may be an external or internal combustion engine such as a reciprocating gas engine or gas turbine that is driven in response to the cooled residual portion of the reformed fuel.
Abstract:
A hybrid fuel cell plant includes a fuel cell and a fuel reformer that mixes a hydrocarbon fuel and steam together upstream of the fuel cell. The reformer partly or fully converts the hydrocarbon fuel and steam into a reformed fuel stream that includes hydrogen (H 2 ), carbon monoxide (CO) and carbon dioxide (C0 2 ). The fuel cell receives the reformed fuel stream at or above atmospheric pressure and also an air stream at or above atmospheric pressure that includes oxygen (0 2 ) and nitrogen (N 2 ) to generate a fuel cell hot exhaust stream that includes lean air, unoxidized CO and residual H 2 . The lean air stream has an 0 2 molar fraction less than that of the fuel cell inlet air. The hot exhaust stream is generated above atmospheric pressure when the reformed fuel and air stream are received by the fuel cell above atmospheric pressure. An internal or external combustion engine directly or indirectly generates power in response to the pressurized fuel cell hot exhaust stream to increase the efficiency of the fuel cell power plant. A Rankine cycle generates power in response to waste heat extracted from at least one of the fuel cell hot exhaust stream and hot exhaust gas generated by the combustion engine to further increase the efficiency of the hybrid fuel cell plant from 50% to above 70% efficiency.