METHOD OF COLLECTING SUB-MICRON PARTICLES FROM A HOT GAS EFFLUENT STREAM

• US 3,755,990 A
• Filed: 05/08/1972
• Issued: 09/04/1973
• Est. Priority Date: 05/08/1972
• Status: Expired due to Term

• Current Assignee: UOP Des Plaines IL A NY General Partnership
• Original Assignee: Leslie C. Hardison
• Inventors: Hardison, Leslie C.
• Primary Examiner(s): Nozick, Bernard
• Application Number:
  US05/251,512
• Time in Patent Office: 484 Days
• Field of Search: 55/71,73,80,83,84,90,93,94,222,223,233,238,240,250,259 261/17,16,115-117,128,133,DIG.54
• US Class Current: 95/223
• CPC Class Codes: B01D 47/00 Separating dispersed particles from gases, air or vapours by liquid as separating agent B01D45/10 takes precedence; fractionating columns or parts thereof B01D3/16
• CPC Class Codes: Y10S 261/54 Venturi scrubbers

Abstract

A hot gaseous effluent having a high percentage of sub-micron sized particles is mixed with a hot saturated gas stream and then subjected to rapid cooling so as to provide a fog and condensation of water droplets around solid particles in the gas stream. The resulting gas stream with enlarged particles is then passed to wet scrubber means so that particles can be removed and a cleaned gas stream discharged from the system.

Claims

2. The method of claim 1 further characterized in that said hot particle laden stream is introduced into the lower portion of a vertically oriented saturation zone to pass countercurrent to a descending liquid flow and said separate gaseous stream is introduced to the upper portion of the saturation zone to flow concurrently with water spray addition thereto, whereby a separately humidified gas stream may combine with the laden gas stream and a comingled gaseous stream discharged from the saturation zone to said mixing-condensing zone.

3. The method of claim 1 further characterized in that the mixed gas stream from the mixing-condensing zone with entrained particulates carrying condensed water thereon is introduced into a down flowing venturi scrubber zone and water is supplied to the throat of said venturi scrubber zone that is collected and transferred from the saturation zone effecting water addition to the laden gas stream.

4. A system for removing fine particulates from a particle laden hot effluent gas stream, which comprises in combination, a gas saturation chamber having inlet means for said hot gas stream, an additional inlet for a gas stream, cooler than said hot gas stream said chamber further having water inlet means thereto and internal water distributing means traversing the paths of the gas streams therein to effect a saturation thereof, a gas outlet from said chamber, a mixing-condensing chamber connected with said gas outlet, external air conduit and cooling means connected with the interior of said mixing-condensing chamber to inject cool air therein whereby to provide water droplet condensation on entrained particles in the mixed stream, means connecting said mixing-condensing chamber to a particle scrubber means, and said scrubber means having at least a particle discharge means and a cleaned gas outlet, whereby a resulting cooled and cleaned effluent gas stream is discharged from the system.

5. The system of claim 4 further characterized in that a cooled gas inlet means connects with said mixing-condensing section at the upper end thereof, whereby a chilled gaseous stream may be intermixed with the laden gas stream being discharged from the gas saturation chamber.

6. The system of claim 4 further characterized in that said mixing-condensing section is provided with indirect heat exchange means across the interior thereof, whereby the gas mixture flowing therethrough will be subjected to cooling and supersaturation conditions and such that resulting water droplets may form on entrained particles.

7. The system of claim 4 further characterized in that the particle scrubber means provides for a downflow into a venturi type scrubber and water is provided to the throat of said scrubber from conduit means connecting with the lower portion of said gas saturation chamber.

8. The system of claim 4 further characterized in that said gas saturation chamber is vertically disposed and has a lower hot gas stream inlet, an upper air inlet, an intermediate mixed gas stream outlet, and separate contact means are positioned between each of said inlets and said outlet whereby the hot gas stream and air inlet stream may each be separately subjected to humidification;

a water inlet and distributing means positioned in the upper portion of said chamber whereby water may be distributed downward throughout the length thereoF and into contact with each contact means, and water conduit means connected between said scrubber means and said water distributing means whereby at least a portion of the water to the latter is obtained from said scrubber means.