Sonic spray of H.sub.2 SD.sub.4 in a swirling heated air stream
First Claim
1. Method of injecting an acid conditioning agent into a flue gas stream containing fly ash to be conditioned to enhance the efficiency with which the fly ash can be electrostatically precipitated comprising the steps of:
- passing a liquid acid conditioning agent under pressure through a first line into a nozzle holder incorporating a sonic atomizing nozzle at a temperature lower than its vaporizing temperature;
passing a gas from a first supply source under pressure through a second line into said nozzle, said nozzle incorporating means to produce sonic vibrations capable of breaking up said liquid acid into a mist plume having an average droplet size of about 10 microns;
passing a stream of hot gas from a second supply source having a temperature greater than the vaporization temperature of said liquid acid and of a value of at least about 500°
F., tangentially into one end of a cylindrical chamber in which said nozzle holder and nozzle are mounted in such a manner that said stream of hot gas will travel in a helical manner and will entrain and vaporize substantially all of the acid mist plume emanating from said nozzle; and
passing the stream of hot gas containing said vaporized acid into said flue gas stream after it has traversed the length of said cylindrical chamber.
2 Assignments
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Accused Products
Abstract
In order to reduce the electrical resistance of entrained fine particles of fly ash resulting from the burning of low sulfur coal and to enhance the efficiency of their collection by an electrical precipitator means, there is a conditioning of the particles carried in the flue gas stream by having a vapor of H2 SO4 condensed and adsorbed on the particles themselves. Sulfuric acid at ambient temperature is mixed with air in an acoustic nozzle to form a mist having an average particle size of about 10 microns which is injected uniformly into a cyclonically flowing stream of hot gas in a chamber located adjacent an upstream inlet duct portion of the precipitator unit. The hot gas in the chamber vaporizes the acid which is then injected into the precipitator inlet duct so that the acid can condense on the particles. The hot gas is preferably obtained from the combustion air preheater.
48 Citations
17 Claims
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1. Method of injecting an acid conditioning agent into a flue gas stream containing fly ash to be conditioned to enhance the efficiency with which the fly ash can be electrostatically precipitated comprising the steps of:
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passing a liquid acid conditioning agent under pressure through a first line into a nozzle holder incorporating a sonic atomizing nozzle at a temperature lower than its vaporizing temperature; passing a gas from a first supply source under pressure through a second line into said nozzle, said nozzle incorporating means to produce sonic vibrations capable of breaking up said liquid acid into a mist plume having an average droplet size of about 10 microns; passing a stream of hot gas from a second supply source having a temperature greater than the vaporization temperature of said liquid acid and of a value of at least about 500°
F., tangentially into one end of a cylindrical chamber in which said nozzle holder and nozzle are mounted in such a manner that said stream of hot gas will travel in a helical manner and will entrain and vaporize substantially all of the acid mist plume emanating from said nozzle; andpassing the stream of hot gas containing said vaporized acid into said flue gas stream after it has traversed the length of said cylindrical chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for injecting a vapor of liquid acid into a flue gas stream to condition fly ash in the stream and enhance the efficiency with which the fly ash can be electrostatically precipitated downstream of the apparatus comprising at least one cylindrical chamber positioned adjacent to and in communication with said flue gas stream;
- a source of liquid acid;
a source of compressed air;
at least one sonic nozzle for delivering an acid mist, said nozzle being mounted on a nozzle holder in said at least one chamber on the axis of said chamber near one end thereof;
a pump for delivering acid to said nozzle under pressure;
said nozzle being connected to said sources of acid and air by flow lines, said chamber having a tangential inlet opening near said one end in communication with a source of hot gas and an outlet opening near the other end thereof in communication with said flue gas stream, said openings being positioned to cause said hot gas to follow a helical path around and past the spray pattern of mist from said at least one nozzle to entrain the mist and vaporize it before it is injected into the flue gas stream. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
- a source of liquid acid;
Specification