Patent ID: 7291194
Filing Date: 2007-11-06
Classification: B01D,B01F,F23J,Y10S,Y10T

Abstract:
1. A thermal mixer for reducing overall temperature of flue gas supplied to a fabric filter containing fabric having a maximum temperature tolerance, the flue gas supplied from at least two spray dry absorbers which are each operable to cool flue gas passing therein, the mixer comprising: a housing having a first inlet passage for flue gas from a first spray dry absorber, a second inlet passage for flue gas from a second spray dry absorber, an outlet passage for supplying flue gases from the first and second spray dry absorbers to a fabric filter, and a mixing passage between the inlet passages and the outlet passage, the mixing passage having an axis; a plurality of damper vanes extending at least partly across the mixing passage and having a mixing position for mixing together the flue gases from the first and second inlet passages to supply mixed gas to the outlet passage at relatively high pressure drop in the mixing passage, the vanes having a non-mixing position for passage of the flue gases from the first and second inlet passages without mixing to supply unmixed gas to the outlet passage at relatively low pressure drop, the vanes in the non-mixing position being parallel to, and spaced from each other, with each vane lying in a plane that is parallel to the axis of the mixing passage in the non-mixing position; each vane extending from a bottom to a top of the mixing passage and the vanes being spaced from each other horizontally across the mixing passage; and actuator means connected to the vanes for moving the vanes to the mixing position when one of the spray dry absorbers is not operating to cool the flue gas passing therein so that the temperature of the mixed flue gas is intermediate the temperature of flue gas that has been cooled and the flue gas that has not been cooled, the actuator means moving the vanes to the non-mixing position when the first and second mixing inlet passages both receive cooled flue gas.