Abstract: A fluidized bed combustion system in which a separator receives a mixture of flue gases and entrained particulate separated material from a fluidized bed in a furnace. A pressure seal valve connects an outlet of the separator to the furnace or a fluidized bed heat exchanger disposed adjacent the furnace for recycling the separated particulate separated material back to the furnace. The pressure seal valve includes a downflow leg, and upflow leg and a horizontal leg connecting the downflow leg to the upflow leg. A horizontal overflow leg is connected to the upflow leg and at least two return legs connect the overflow leg to the furnace. The separated material from the separator passes through the legs of the pressure seal valve and sometimes through a heat exchanger (if included) before reentering the furnace.

Abstract: An apparatus and method of operating a steam generator tube bank are disclosed in which a water drum of a typical steam drum/water drum combination is replaced with a plurality of smaller readers to permit the use of rapping, or mechanical rappers, to clean the tubes extending between the steam drum and the headers. The steam generator tube bank of the present invention comprises a steam drum or collecting header, a plurality of headers extending below the steam drum, and a plurality of tubes extending between the steam drum and the headers and placing the steam drum and headers in fluid flow communication. The headers are sized to permit debris or deposits which accumulate on the tubes to be removed by rapping the headers, thereby inducing vibration of the headers and the tubes. The tubes are arranged in rows, and the headers are arranged to form rows of axially-aligned pairs of headers.

Abstract: An apparatus and method of operating a fluidized bed reactor for combusting refuse derived fuel is disclosed. The reactor includes a fluidized furnace section 30 and stripper/cooler section 80. A downwardly sloping grid 28 extends across the furnace section 30 and stripper/cooler section 80 to a drain 78 in the stripper/cooler section 80, and directional nozzles 38 disposed in the grid fluidize the beds in the furnace section 30 and stripper/cooler section 80 and forcibly convey relatively large particulate material across the grid 28, through the furnace section 30 and stripper/cooler section 80, and to the drain 78 for disposal. A refractory layer 36 is provided along the grid 28 surface to reduce the height of the nozzles 38 within the furnace section 30, thereby helping to prevent relatively large particulate material from becoming entangled with or stuck to the nozzles 38.

Abstract: An apparatus and method of operating a fluidized bed reactor for combusting refuse derived fuel is disclosed. The reactor includes a fluidized furnace section 30 and stripper/cooler section 80. A downwardly sloping grid 28 extends across the furnace section 30 and stripper/cooler section 80 to a drain 78 in the stripper/cooler section 80, and directional nozzles 38 disposed in the grid fluidize the beds in the furnace section 30 and stripper/cooler section 80 and forcibly convey relatively large particulate material across the grid 28, through the furnace section 30 and stripper/cooler section 80, and to the drain 78 for disposal. A refractory layer 36 is provided along the grid 28 surface to reduce the height of the nozzles 38 within the furnace section 30, thereby helping to prevent relatively large particulate material from becoming entangled with or stuck to the nozzles 38.

Abstract: A fluidized bed combustion system and method in which a recycle heat exchange section is located within an enclosure housing the furnace section of the combustion system. The flue gases and entrained solids from a fluidized bed in the furnace section are separated and the flue gases are passed to a heat recovery section and the separated particulate material to the recycle heat exchange section. The recycle heat exchange section includes a bypass chamber for permitting the separated solids to pass directly from the separator to the furnace section. A heat exchange is provided in the recycle heat exchange section to transfer heat from the separated material in the recycle heat exchange section to a fluid flow circuit for heating the fluid flow circuit and reducing the temperature of the separated material. The separated material of the recycle heat exchange section is then passed back to the furnace section.