Controlling pollutants from boilers
First Claim
1. A method of controlling the emissions in the flue gas of the boiler in a municipal solid waste burning system having first and second economizers for both heating feed water for the boiler and cooling the flue gas from said boiler, a reactor through which said cooled flue gas flows, said reactor having means to introduce a basic reactant at a selected quantity flow rate in slurry form to reduce the acid content of the cooled flue gas, and a separator to separate particulates form said flue gas prior to discharging the flue gas, comprising the steps of:
- determining the acid content of the flue gas in advance of said reactor,changing the quantity flow rate of reactant in response to a change in the determined acid content to provide a quantity of reactant sufficient to reduce the acid content of the discharged flue gas below a given concentration; and
concurrently with changing the quantity flow rate of said reactant, changing the operations of said first and second economizers to effect an inverse change in the cooling of the flue as whereby the temperature of the flue gas entering the reactor is changed directly with the change in quantity flow rate of reactant introduced into said reactor.
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Accused Products
Abstract
A method and apparatus for controlling pollution and flue gases from a boiler using municipal solid waste as a fuel. The flue gases pass through internal and external economizers before entering a reactor in which the gases are treated with lime or other reactant in slurry form to neutralize the acid components of the flue gases. The heat of the flue gases dries the products of the reaction and the excess reactants so that they may be separated from the flue gas in subsequent separator, which is a baghouse filter. The feed of the reactant to the reactor is modified in accordance with the concentration of acid constituents in the flue gas, and concurrently the operation of the economizers is modified to raise the temperature of the flue gas exiting the economizers when the feed of reactant is increased and vice versa. The temperature of the flue gas is increased by causing the feed water to bypass the external economizer in direct relation to the quantity of reactant fed to the reactor.
27 Citations
15 Claims
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1. A method of controlling the emissions in the flue gas of the boiler in a municipal solid waste burning system having first and second economizers for both heating feed water for the boiler and cooling the flue gas from said boiler, a reactor through which said cooled flue gas flows, said reactor having means to introduce a basic reactant at a selected quantity flow rate in slurry form to reduce the acid content of the cooled flue gas, and a separator to separate particulates form said flue gas prior to discharging the flue gas, comprising the steps of:
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determining the acid content of the flue gas in advance of said reactor, changing the quantity flow rate of reactant in response to a change in the determined acid content to provide a quantity of reactant sufficient to reduce the acid content of the discharged flue gas below a given concentration; and concurrently with changing the quantity flow rate of said reactant, changing the operations of said first and second economizers to effect an inverse change in the cooling of the flue as whereby the temperature of the flue gas entering the reactor is changed directly with the change in quantity flow rate of reactant introduced into said reactor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of controlling the emissions in the flue gas of a municipal solid waste boiler having economizers for both heating feed water for the boiler and cooling the flue gas from said boiler, a reactor through which said cooled flue gas flows and from which the flue gas is discharged, said reactor having means to introduce a basic reactant and a liquid carrier at a selected quantity flow rate in slurry form to reduce the acid content of the cooled flue gas, said cooled flue gas evaporating said liquid carrier to further reduce the temperature of the flue gas discharged form said reactor and produce aired reactant particulates in said flue gas, and a separator to separate particulates from said flue gas prior to discharging the gas to atmosphere, comprising the steps of:
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determining the acid content of the flue gas; determining the temperature of the discharged flue gas; changing the quantity flow rate of reactant directly in response to a change in the determined acid content to provide a quantity of reactant sufficient to maintain the acid content of the discharged flue gas below a given concentration; changing the quantity flow rat of the slurry to maintain the determined temperature approximately constant; and concurrently with changing the quantity flow rates of reactant and slurry, changing the operations of said economizers to effect an inverse change in the cooling of the flue gas whereby the temperature of the flue gas entering the reactor is changed directly with the change in the quantity flow rate of the slurry introduced into said reactor to enable evaporation of said liquid carrier within said reactor. - View Dependent Claims (12, 13, 14, 15)
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Specification