초록 ▼

A sulfur trioxide conditioning system includes a catalytic converter that converts a portion of the sulfur dioxide in a flow of flue gas to sulfur trioxide. The catalytic converter includes a catalyst support, which is disposed across at least a portion of the cross section of a main duct from a bur

A sulfur trioxide conditioning system includes a catalytic converter that converts a portion of the sulfur dioxide in a flow of flue gas to sulfur trioxide. The catalytic converter includes a catalyst support, which is disposed across at least a portion of the cross section of a main duct from a burner to a heat recovery apparatus, and a catalyst on the catalyst support. The amount of the catalyzed surface exposed to the flow of flue gas is selectively varied to control the conversion of sulfur dioxide to sulfur trioxide.

대표청구항 ▼

1. A sulfur trioxide conditioning system for use in a fossil fuel-burning facility having a main duct for transporting sulfur dioxide-containing flue gas from a boiler, through a heat recovery apparatus, and to particulate removal equipment for subsequent discharge through a stack, the sulfur trioxi

1. A sulfur trioxide conditioning system for use in a fossil fuel-burning facility having a main duct for transporting sulfur dioxide-containing flue gas from a boiler, through a heat recovery apparatus, and to particulate removal equipment for subsequent discharge through a stack, the sulfur trioxide conditioning system comprising: catalytic converter means for converting a portion of the sulfur dioxide in the flue gas to sulfur trioxide, the catalytic converter means including a catalyst support adapted to be disposed across at least a portion of the cross section of a main duct, and a catalyst for the oxidation of sulfur dioxide to sulfur trioxide supported on the catalyst support; and adjustment means for selectively adjusting the amount of a surface area of the catalyst on the catalyst support which is exposed to a flow of flue gas in the main duct. 2. The sulfur trioxide conditioning system of claim 1, wherein the adjustment means includes a shield that movably fits over the catalyst support; and a mechanism that selectively causes the shield to move relative to the catalyst support to expose a selectable amount of the surface of the catalyst support to the flow of flue gas. 3. The sulfur trioxide conditioning system of claim 1, wherein the catalyst support is elongated, and the elongated direction lies parallel to the flow of flue gas. 4. The sulfur trioxide conditioning system of claim 1, wherein the catalyst support is substantially planar. 5. The sulfur trioxide conditioning system of claim 4, wherein the catalyst support further includes a channel therein parallel to the flow of flue gas. 6. The sulfur trioxide conditioning system of claim 4, wherein the catalyst support comprises a plurality of plates. 7. The sulfur trioxide conditioning system of claim 1, wherein the catalyst support is tubular. 8. The sulfur trioxide conditioning system of claim 7, wherein the adjustment means includes a tubular shield that movably fits inside the catalyst support; and a mechanism that selectively causes the shield to move relative to the tubular catalyst support to expose a selectable amount of the surface of the catalyst support to the flow of flue gas. 9. The sulfur trioxide conditioning system of claim 1, wherein the catalyst support comprises a plurality of tubes. 10. The sulfur trioxide conditioning system of claim 1, wherein the catalytic converter means comprises a plurality of spaced hollow tubes extending in the direction of the flow of flue gas, the catalyst being supported on the interior walls of the plurality of tubes, and a supporting assembly to which an upstream end of each of the tubes is attached, the supporting assembly being adapted to extend transversely to the flow of flue gas. 11. The sulfur trioxide conditioning system of claim 1, wherein the catalyst is selected from the group consisting of a vanadium oxide, an alkali metal pyrosulfates, and an alkali metal oxides. 12. The sulfur trioxide conditioning system of claim 1, further including control means for controlling the adjustment means. 13. The sulfur trioxide conditioning system of claim 12, wherein the control means includes measuring means for measuring an operating parameter of a fossil fuel-burning facility indicative of the total amount of sulfur trioxide required in the flow of flue gas; and selection means for selecting the position of the adjustment means, responsive to the measuring means. 14. The sulfur trioxide conditioning system of claim 13, wherein the selection means is operable to modulate the amount of surface area of the catalyst which is exposed to a flow of flue gas in the main duct, as the total amount of sulfur dioxide in the flow of flue gas changes. 15. A method for converting sulfur dioxide to sulfur trioxide in a flow of a flue gas in a fossil fuel power plant, comprising the steps of providing a catalytic converter having a catalyst support and a catalyst supported thereon, the catalyst being operable to catalyze the oxidation of sulfur dioxide to sulfur trioxide; and selectively adjusting the amount of surface area of the catalyst which is exposed to a flow of flue gas. 16. The method of claim 15, including the additional step of measuring an operating parameter of a fossil fuel-burning facility indicative of the total amount of sulfur trioxide required in the flow of flue gas, and wherein the step of selectively adjusting is operable responsive to the operating parameter measured in the step of measuring. 17. The method of claim 15, wherein the step of selectively adjusting includes the step of moving a shield relative to the surface supporting the catalyst to expose a selected amount of the surface to the flow of flue gas. 18. A fossil fuel-burning plant, comprising: a source of a flow of flue gas, the source including a burner of a fossil fuel; a heat recovery apparatus that preheats air to be supplied to the burner; apparatus for removing particulate matter from the flow of flue gas; a main duct extending from source of a flow of flue gas to the heat recovery apparatus and thence to the apparatus for removing particulate matter; catalytic converter means for converting a portion of the sulfur dioxide in the flue gas to sulfur trioxide, the catalytic converter means including a catalyst support having a catalyst supported thereon and being adapted to be disposed across at least a portion of the cross section of the main duct; and adjustment means for selectively adjusting the amount of surface area of the catalyst which is exposed to the flow of flue gas in the main duct. 19. The plant of claim 18, further including control means for controlling the adjustment means. 20. The plant of claim 19, wherein the control means includes measuring means for measuring an operating parameter of the plant indicative of the apparatus for removing particulate matter; and selection means for selecting the adjustment of the adjustment means, responsive to the measuring means. 21. The plant of claim 20, wherein the selection means is operable to modulate the amount of surface area of the catalyst which is exposed to a flow of flue gas in the main duct.