Air pollution reduction

• US 4,557,912 A
• Filed: 11/14/1984
• Issued: 12/10/1985
• Est. Priority Date: 11/14/1984
• Status: Expired due to Fees

• Current Assignee: Milton J. Maguire
• Original Assignee: Milton J. Maguire
• Inventors: Maguire, Milton J.
• Primary Examiner(s): Heller, Gregory A.
• Application Number:
  US06/673,193
• Time in Patent Office: 391 Days
• Field of Search: 423/242 R, 423/242 A, 423/523, 55/73
• US Class Current: 423/243.03
• CPC Class Codes: B01D 53/50 Sulfur oxides B01D53/60 takes precedence
• CPC Class Codes: B01D 53/507 by treating the gases with other liquids
• CPC Class Codes: C01B 17/82 of sulfuric acid using a nitrogen oxide process

Abstract

The method of reducing air pollution comprises treating air-polluting waste industrial flue gases containing sulfur dioxide in a manner effective to substantially reduce the content of sulfur dioxide therein and remove it in the form of a sulfuric acid by-product prior to discharge of the treated flue gases into the atmosphere. The treatment involves the use of towers and nitrogen oxides for effecting the oxidation of sulfur dioxide to the trioxide. Preferably, the waste industrial flue gas is separated into a low molecular weight fraction and a higher molecular weight portion, as by centrifugal action to concentrate the heavier sulfur dioxide molecules, before treating only the higher weight portion.

Claims

1. The method of reducing air pollution by treating air-polluting waste industrial flue gases containing sulfur dioxide in a manner effective to substantially reduce the content of sulfur dioxide therein and remove it in the form of a sulfuric acid by-product prior to discharge of the treated flue gases into the atmosphere, comprising

conduiting the waste industrial flue gases through means for removing solid particulate matter therefrom, separating said waste industrial flue gases into a low molecular weight fraction and a higher molecular weight portion, said separating step including conduiting the flue gases through a duct which turns sharply in direction to thereby effect a centrifugal throwing of the highest molecular weight molecules of the flue gas toward the outer side of the duct where they are swept out a separate duct for conduiting the same as said higher molecular weight portion to reactor tower means

conduiting at least said higher molecular weight portion of said flue gases to said reactor tower means, said higher molecular weight portion being that portion having a greater concentration of sulfur dioxide than in said waste industrial flue gas,

moving said portion upwardly through said reactor tower means while intimately intermingling said portion with a sufficient quantity of air oxygen and a sufficient quantity of a variety of nitrogen oxides for effecting oxidation of the sulfur dioxide content of said portion, and while simultaneously intimately intermingling with said portion a downward flow of a sufficient quantity of H₂ O for sulfuric acid to be formed as the product of substantially all sulfur dioxide that is oxidized in said reactor tower means, at least approximately 50% by weight of the sulfur dioxide passing through said reactor tower means being oxidized and formed into sulfuric acid within said reactor tower means,

passing to chamber means the gaseous mixture of air oxygen and nitrogen oxides and the flue gases remaining after movement of said portion through said reactor tower means,

moving said remaining gaseous mixture upwardly through said chamber means while simultaneously spraying H₂ O downwardly through said remaining gaseous mixture, to thereby effect further conversion of oxidized sulfur dioxide into sulfuric acid,

passing to absorption tower means the residual gaseous mixture from said chamber means,

substantially removing the nitrogen oxides from said residual gaseous mixture as it passes through said absorption tower means,

passing the final gaseous mixture resulting from the treatment in the absorption tower means into an exhaust stack,

discharging said final gaseous mixture into the atmosphere,

and simultaneously as the foregoing steps are conducted continuously,

withdrawing sulfuric acid from said reactor tower means, and

recycling the removed nitrogen oxides from the absorption tower means back into said reactor tower means.

2. The method of claim 1 wherein the movement of said portion through the reactor tower means comprises a movement thereof through one reactor tower followed by the movement thereof through a second reactor tower.

3. The method of claim 1 comprising introducing into said reactor tower means additional air oxygen beyond any present in said portion of said waste industrial flue gases.

4. The method of claim 1 additionally comprising the step of accelerating the discharge from the exhaust stack.

5. The method of claim 1 additionally comprising the step of accelerating the discharge from the exhaust stack by Venturi means through which is passed gaseous material other than that from said absorption tower means.

6. The method of claim 1 additionally comprising the step of accelerating the discharge from the exhaust stack by Venturi means through which is passed gaseous material comprising a lower molecular weight fraction of said waste industrial flue gases.

7. The method of claim 1 wherein said separating step additionally includes acceleration of the movement of said waste industrial flue gases through said duct having a sharp turn of direction.