An elevated target amount of electrolyte is used to initially fill a molten carbonate fuel cell that is operated under carbon capture conditions. The increased target electrolyte fill level can be achieved in part by adding additional electrolyte to the cathode collector prior to start of operation. The increased target electrolyte fill level can provide improved fuel cell performance and lifetime when operating a molten carbonate fuel cell at high current density with a low-CO.sub.2 content cathode input stream and/or when operating a molten carbonate fuel cell at high CO.sub.2 utilization.

Disclosed here is a supported catalyst comprising a thermally stable core, wherein the thermally stable core comprises a metal oxide support and nickel disposed in the metal oxide support, wherein the metal oxide support comprises at least one base metal oxide and at least one transition metal oxide or rare earth metal oxide mixed with or dispersed in the base metal oxide. Optionally the supported catalyst can further comprise an electrolyte removing layer coating the thermally stable core and/or an electrolyte repelling layer coating the electrolyte removing layer, wherein the electrolyte removing layer comprises at least one metal oxide, and wherein the electrolyte repelling layer comprises at least one of graphite, metal carbide and metal nitride. Also disclosed is a molten carbonate fuel cell comprising the supported catalyst as a direct internal reforming catalyst.

A method for replenishing an electrolyte of a molten carbonate fuel cell stack includes: preparing an electrolyte colloidal solution containing 10% to 20% of the electrolyte and having a viscosity of 200 to 800 Pa.Math.s; replenishing the electrolyte of the cell stack using the electrolyte colloidal solution prepared in step 1 to allow the electrolyte to adhere to an electrode and an internal channel of the cell stack; discharging excess electrolyte colloidal solution in the cell stack; and drying and discharging water or an organic solvent in the cell stack under an inert gas condition to complete replenishment of the electrolyte of the cell stack, and performing a discharge performance test.

Systems and methods are provided for improving the operation of molten carbonate fuel cells that include cathode current collector structures that have reduced contact area with the cathode in order to create increased cathode open surface area. Molten carbonate fuel cells that have cathode collectors with reduced contact area with the cathode can have an increased tendency to suffer structural difficulties during operation, such as formation of gaps between electrolyte and one or both electrodes. Use of a sintered anode in such a fuel cell can reduce or minimize the impact of such structural difficulties. The sintered anode can provide higher pore volume and/or a more stable pore structure and/or increased structural stability in a fuel cell that includes a cathode collector that has a reduced contact area with the cathode. This can maintain a more stable interface between the cathode and electrolyte and/or between the anode and the electrolyte.

There is described a direct carbon fuel cell system. The system includes fuel cells, each fuel cell having a porous fuel cell anode and a fuel cell cathode. The system further includes a molten carbonate electrolyte and a fuel supply apparatus for flowing a fuel slurry having carbon particles and a carbon carrier fluid to the fuel cell anodes in parallel. The carbon carrier fluid has a same composition as the molten carbonate electrolyte. An oxidant supply apparatus flows an oxygen-containing stream to the fuel cell cathodes in parallel. An electrolyte circulation apparatus circulates the molten carbonate electrolyte in contact with each of the fuel cells. During operation of the direct carbon fuel cell system to generate electric power, carbon is oxidized at the fuel cell anodes to produce carbon dioxide, and at the fuel cell cathodes oxygen and carbon dioxide react to produce carbonate ions.

A caulk composition includes: at least one powder component and at least one binder component. The powder component is a ball-milled powder component comprising ceria, zirconia, alumina, or a combination thereof. The powder component is a heat-treated powder component that has been heated to a temperature of at least 1500° C. The powder component is present in a concentration range of 65 wt % to 75 wt % of the caulk composition. The powder component has a particle size distribution of 95% less than 25 μm and 90% greater than 1 μm. The binder component is present in a concentration range of 25 wt % to 35 wt % of the caulk composition.

Molten carbonate fuel cells (MCFCs) are operated at elevated pressure to provide increased operating voltage and/or enhanced CO.sub.2 utilization with a cathode input stream having a low CO.sub.2 content. It has been discovered that increasing the operating pressure of a molten carbonate fuel cell when using a low CO.sub.2-content cathode input stream can provide unexpectedly large increases in operating voltage while also reducing or minimizing the amount of alternative ion transport and/or enhancing CO.sub.2 utilization.

A plant includes a fuel supply line for supplying high-pressure fuel gas; and at least one expander disposed in the fuel supply line and configured to extract power from the high-pressure fuel gas by expanding the high-pressure fuel gas.

Molten carbonate fuel cell configurations are provided that allow for introduction of an anode input gas flow on a side of the fuel cell that is adjacent to the entry side for the cathode input gas flow while allowing the anode and cathode to operate under co-current flow and/or counter-current flow conditions. It has been discovered that improved flow properties can be achieved within the anode or cathode during co-current flow or counter-current flow operation by diverting the input flow for the anode or cathode into an extended edge seal region (in an extended edge seal chamber) adjacent to the active area of the anode or cathode, and then using a baffle to provide sufficient pressure drop for even flow distribution of the anode input flow across the anode or cathode input flow across the cathode. A second baffle can be used to create a pressure drop as the anode output flow or cathode output flow exits from the active area into a second extended edge seal region (in a second extended edge seal chamber) prior to leaving the fuel cell.

An elevated target amount of electrolyte is used to initially fill a molten carbonate fuel cell that is operated under carbon capture conditions. The increased target electrolyte fill level can be achieved in part by adding additional electrolyte to the cathode collector prior to start of operation. The increased target electrolyte fill level can provide improved fuel cell performance and lifetime when operating a molten carbonate fuel cell at high current density with a low-CO.sub.2 content cathode input stream and/or when operating a molten carbonate fuel cell at high CO.sub.2 utilization.