Abstract:
A fuel gas selective oxidizer assemblage (2) for use in a fuel cell power plant is formed from a series of repeating components, each of which includes a plurality of separate selective oxidizer gas passages (20) and a plurality of adjacent coolant passages (22). The selective oxidizer gas and coolant passages are preferably formed by corrugated metal sheets (16, 18) which are interposed between planar metal sheets (10, 12, 14). One of the planar metal sheets (14) forms a common wall between the selective oxidizer gas passages and the coolant passages so as to provide enhanced heat transfer between the reformate gas in the selective oxidizer gas passages and the coolant. Each of the components includes a first outer planar metal sheet (10), a medial planar sheet (14), and a second outer planar metal sheet (12). Each of the planar metal sheets is separated from the next by the corrugated metal gas (16) and coolant passage sheets (18).
Abstract:
The concentration of carbon monoxide in a gaseous medium is reduced by selective catalytic oxidation in the presence of gaseous oxygen by passing the gaseous medium through a quantity of a catalyst capable of oxidizing carbon monoxide in an exothermic reaction at temperatures within a given temperature range. The temperatures encountered in the catalyst are controlled in such a manner that the exothermic reaction takes place first above a threshold temperature below which the catalyst would be rapidly inactivated at the relatively high carbon monoxide concentrations present in the gaseous medium as it enters an inlet portion of the catalyst quantity, and subsequently in an outlet portion of the catalyst quantity at less than the threshold temperature to further reduce the carbon monoxide concentration to a desired minimum level below that achievable at temperatures above the threshold temperature.
Abstract:
The effluent gas stream from anaerobic waste water treatment digesters is treated to remove trace amounts of hydrogen sulfide and other contaminants. The chemical equation involved relies on the reaction of hydrogen sulfide with oxygen to form water plus elemental sulfur. The removal system includes a variable control line for adding air to the effluent gas stream; a filter for removing solids, entrained liquids and bacteria from the oxygen-enriched gas stream; a blower for directing the filtered gas stream into a potassium promoted activated carbon bed wherein the above chemical reaction takes place; and sensors for measuring the content of oxygen and hydrogen sulfide at the entrance and exit of the activated carbon bed. When the hydrogen sulfide content of the exiting gas stream exceeds a predetermined level, the amount of air added to the gas stream is increased until the predetermined level of hydrogen sulfide is achieved in the exiting gas stream.
Abstract:
Sulfur and sulfur compounds are removed from a gas stream, such as a hydrocarbon fuel gas stream so as to render the gas stream suitable for use in a fuel cell power plant. Natural gas and recycled hydrogen enters the hydrodesulfurizer assembly at a temperature of about 120 DEG F. The gas stream is heated to a temperature of about 625 DEG F whereupon it enters a desulfurizing bed (44) formed from a mixture of platinum catalyst deposited on alumina pellets (46) and a pelletized zinc oxide hydrogen sulfide absorbent (48). The gas is cooled to an exit temperature of about 525 DEG F as it passes through the desulfurizer bed. The desulfurizer bed is combined with a shift converter (6) which reduces carbon monoxide in the desulfurized gas stream after the latter has passed through a steam reformer bed.
Abstract:
The gas stream which is produced in and emanates from landfills, anaerobic digesters and other waste gas streams is treated to produce a purified gas which is essentially a hydrocarbon such as methane and which can be used as the fuel source in a fuel cell power plant. The gas stream passes through a simplified purification system which removes essentially all of the sulfur compounds, hydrogen sulfide, and halogen compounds from the gas stream. The resultant gas stream can be used to power a fuel cell power plant which produces electricity, or as a hydrocarbon fuel gas for other applications.