US 4,999,167 AGranted

Low temperature No.sub.x /So.sub.x removal apparatus

OwnerArthur P. Skelley, James C. McMichaelinventors

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Abstract

Exhaust gases from a process fired boiler are diverted from a stack prior to emission to the atmosphere through a duct system to a plurality of series connected heat exchangers. The exhaust gases are progressively reduced from an elevated temperature, for example in the range between about 350.degree.-525.degree. F., in stages to an ambient temperature of about 50.degree. F. At each stage heat from the exhaust gases is transferred from the gases to another medium, such as water, which is fed back to the boiler to reduce the energy cost of operating the boiler. At ambient temperature the exhaust gases are subjected to an atomized spray of a reagent solution that absorbs the contaminants in the exhaust gases. Absorption of the contaminants into solution with the atomized reagent spray is promoted by contact of the spray and exhaust gases on the surface of a fibrous batting. With the exhaust gases at ambient temperature the percentage of contaminants in the flue gas that enters into solution with the reagent is substantially increased. Thus the reagent absorbs the contaminants, and the exhaust gases are emitted after further moisture separation substantially free of contaminants.

Claims9

Dependent claims

An apparatus for recovering heat from flue gas and removing the contaminants from the flue gas comprising,

a duct structure having an inlet for receiving exhaust gases at an elevated temperature and containing contaminants,
a plurality of heat exchangers connected in series to one another in said duct structure,
means for conveying the contaminated exhaust gases through the series connection of said heat exchangers to progressively remove heat from the exhaust gases and reduce the temperature of the exhaust gases,
a temperature controller having a coolant circulating therethrough for receiving the exhaust gases and being heated by the exhaust gases to transfer heat from the exhaust gases to the coolant and reduce the temperature of the exhaust gases from an elevated temperature to an ambient temperature,
means positioned in the duct structure for spraying the exhaust gases at ambient temperature with a finely divided stream of liquid reagent to combine the contaminants in solution with the reagent,
a chamber connected to said duct structure and including means for receiving the exhaust gases and contaminants in solution with the reagent,
an absorption enhancer contained in said chamber for receiving the contaminants in solution with the reagent and the exhaust gases to promote removal of the contaminants from the exhaust gases and entrance of the contaminants into solution with the liquid reagent, and
a stack connected to said chamber means for conveying from said duct structure the exhaust gases at ambient temperature and substantially free of the contaminants.

5 more elements

An apparatus for removing contaminants from the exhaust gases of a combustion process comprising,

a vessel having an inlet for receiving exhaust gases containing contaminants and an outlet for emitting the exhaust gases,
a source of reagent solution,
means for supplying the reagent solution to said vessel to maintain a preselected level of reagent solution in said vessel,
means for partitioning the interior of said vessel between said inlet and said outlet to form a serpentine path of interconnected channels for the flow of exhaust gases through said vessel from said inlet to said outlet above the surface of the reagent solution,
means for adjusting the level of reagent solution in said vessel to vary the cross sectional area of said channels and control the flow rate of the exhaust gases through said channels, and
means positioned in said vessel and connected to said source of reagent solution for subjecting the flow of exhaust gases through said vessel to a spray of reagent solution as the exhaust gases follow said serpentine path through said vessel to combine the contaminants in solution with the reagent so that the exhaust gases exit said vessel at said outlet substantially free of contaminants.

3 more elements

Dependencies are inferred from the claim text.