Abstract: A first AC power source comprising a power plant (18), and a second power source, typically grid (10), are normally connected via a high speed isolation switching means (19) to provide sufficient AC power to a critical load (14). The power plant (18) comprises a power generating means, e.g. a fuel cell, (60) and a power conditioning system (PCS) (62) having an inverter (64). Power assurance means (65; 10?, 66, 64, 70; 74, 75) is/are operatively connected to at least one of the first and second power sources to enhance an even and continuous supply of power to the critical load (14). The power assurance means (65; 10?, 66, 64, 70; 74, 75) is/are operatively connected to the PCS inverter (64), and may be one, or a combination of, a surge suppression means (65), a double-conversion power connection means (10?, 66, 64, 70) having a rectifier (66); and/or stored energy means (74), such as a capacitor (75).

Abstract: A site management system (11) is provided for a power system (8) at site in a utility distribution grid (10). The power system (8) includes multiple fuel cell power plants (18) and one or more loads (14), for selective connection/disconnection with the grid (10) The site management system (11) controls the power plants (18) in an integrated manner, alternatively in a grid connected mode and a grid independent mode. The multiple power plants (18) at the site may be viewed and operated as a unified distributed resource on the grid (10). The site management system (11) provides signals representative of the present power capability (Kw Capacity—88) of each of the power plants (18), and a signal (Total Kw Capacity—95) representative of the total present power capability at the site. These power representations are used to appropriately assign power dispatch loadings to the respective fuel cells (18) in the grid connected mode and in the grid independent mode, and may also be used for load shedding.

Abstract: A first AC power source comprising a fuel cell power plant (18), and a second power source, typically grid (10), are normally connected via a high speed isolation switching means (19) to provide sufficient AC power to a critical load (14). The fuel cell power plant (18) comprises a fuel cell (60) and a power conditioning system (PCS) (62) having an inverter (64). Power assurance means (65; 10″, 66, 64, 70; 74, 75) is/are operatively connected to at least one of the first and second power sources to enhance an even and continuous supply of power to the critical load (14). The power assurance means (65; 10″, 66, 64, 70; 74, 75) is/are operatively connected to the inverter (64) of the PCS (62), and may be one, or a combination of, a surge suppression means (65), a double-conversion power connection means (10″, 66, 64, 70) having a rectifier (66); and/or stored energy means (74), such as a capacitor (75).

Abstract: A site management system (11) is provided for a power system (8) at site in a utility distribution grid (10). The power system (8) includes multiple fuel cell power plants (18) and one or more loads (14), for selective connection/disconnection with the grid (10). The site management system (11) operates to control the power plants (18) in an integrated manner, alternatively in a grid connected mode and in a grid independent mode. The utility is able to view and treat the multiple power plants (18) at the site as a single, unified distributed resource on the grid (10). The site management system (11) provides signals representative of the present power capability (Kw Capacity—88) of each of the power plants (18), and a signal (Total Kw Capacity—95) representative of the total present power capability at the site. These power representations are used to appropriately assign power dispatch loadings to the respective fuel cells (18) in the grid connected mode and in the grid independent mode.

Abstract: A power system (8) is provided for economically supplying uninterrupted electrical power to one or more critical loads (14). One or more fuel cell power plants (18) provide one substantially continuous source of power, and a utility grid (10) provides another source of power. The fuel cell power plants (18) are adapted to be, and are, normally substantially continuously connected and providing power to, the critical load(s) (14). A rapidly-acting static switch (19) selectively connects and disconnects the grid power supply (10) to the critical load(s) (14) and with the fuel cell power plant(s) (18). A switch controller (49, 45) controls the state of the static switch (19) to connect the grid power source (10) with the critical load(s) (14) and the fuel cell power plant(s) (18) during normal operation of the grid (10), and to rapidly (less than 4 ms) disconnect the grid power source (10) from the load(s) (14) and fuel cell power plant(s) (18) when operation of the grid (10) deviates from normal beyond a limit.

Abstract: A power system (8) is provided for economically supplying uninterrupted electrical power to one or more critical loads (14). One or more fuel cell power plants (18) provide one substantially continuous source of power, and a utility grid (10) provides another source of power. The fuel cell power plants (18) are adapted to be, and are, normally substantially continuously connected and providing power to, the critical load(s) (14). A rapidly-acting static switch (19) selectively connects and disconnects the grid power supply (10) to the critical load(s) (14) and with the fuel cell power plant(s) (18). A switch controller (49, 45) controls the state of the static switch (19) to connect the grid power source (10) with the critical load(s) (14) and the fuel cell power plant(s) (18) during normal operation of the grid (10), and to rapidly (less than 4 ms) disconnect the grid power source (10) from the load(s) (14) and fuel cell power plant(s) (18) when operation of the grid (10) deviates from normal beyond a limit.

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: 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: The gas stream which emanates from landfills is treated to produce a purified gas which is essentially a hydrocarbon such as methane which can be used as the fuel source in a fuel cell power plant, or can be used in other power plants which use natural gas as a fuel. The landfill gas passes through a system which removes essentially all of the hydrogen sulfide; water; organic sulfur and halogen compounds; and solid contaminants from the gas stream. The resultant purified gas stream can be cleanly flared; used to power an energy plant; or put to other useful purposes.

Abstract: A gaseous mixture of hydrogen and carbon dioxide is used as the fuel cell fuel or anode gas, and air is used as the oxidant or cathode gas in a nonalkaline fuel cell power plant. In feeding the fuel gas through the anode side of the fuel cell, hydrogen is removed during the electrochemical reaction and the fuel gas which is exhausted from the anode side has a much higher proportion of carbon dioxide to hydrogen than the entering fuel gas. The fuel gas exhaust is fed through a carbon dioxide absorber to remove carbon dioxide from the fuel exhaust. The carbon dioxide is recovered from the absorber for useful purposes and the hydrogen gas leaving the absorber is dewatered and burned in a reformer. Carbon dioxide emissions from the power plant are thus greatly reduced benefiting the environment.

Abstract: To avoid using high quality heat to boil water condensed from a moist gas stream and to increase the overall thermal efficiency in a system requiring a supply of steam obtained by boiling water condensed from a moist gas stream, the condensing of the desired amount of water is done in a combined condenser/boiler wherein the condensed out water is separated from the gas stream, reduced in temperature, and throttled to a pressure wherein it is converted to steam back in the condenser/boiler using only the heat of condensation and sensible heat from the moist gas stream during the condensing step.

Abstract: A power system (8) is provided for economically supplying uninterrupted electrical power to one or more critical loads (14). One or more fuel cell power plants (18) provide one substantially continuous source of power, and a utility grid (10) provides another source of power. The fuel cell power plants (18) are adapted to be, and are, normally substantially continuously connected and providing power to, the critical load(s) (14). A rapidly-acting static switch (19) selectively connects and disconnects and reconnects the grid power supply (10) to the critical load(s) (14) and with the fuel cell power plant(s) (18) for abnormal and normal grid operation, respectively. A switch controller (49, 45) controls the state of the static switch (19) to connect the grid power source (10) with the critical load(s) (14) and the rapidly (less than 4 ms) make the disconnections and the reconnections.

Abstract: A site management system (11) is provided for a power system (8) at site in a utility distribution grid (10). The power system (8) includes multiple fuel cell power plants, e.g., fuel cells, (18) and one or more loads (14), for selective connection/disconnection with the grid (10). The site management system (11) controls the power plants (18) in an integrated manner, alternatively in a grid connected mode and a grid independent mode. The multiple power plants (18) at the site may be viewed and operated as a unified distributed resource on the grid (10). The site management system (11) provides signals representative of the present power capability (Kw Capacity—88) of each of the power plants (18), and a signal (Total Kw Capacity—95) representative of the total present power capability at the site.