US 4,208,192 A · Sonic spray of H.sub.2 SD.sub.4 in a swirling heated air stream

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 H.sub.2 SO.sub.4 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.

Claims17

Dependent claims

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.degree. 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 more elements

Dependencies are inferred from the claim text.

Sonic spray of H.sub.2 SD.sub.4 in a swirling heated air stream

Life of this patent

Sonic spray of H.sub.2 SD.sub.4 in a swirling heated air stream

Life of this patent

Abstract

Claims17