Recovery of chlorine dioxide from gas streams
AssigneeInternational Paper Company
InventorsRobert L. Graff, Larry A. Couture, Al G. Lewis
Life of this patent
Estimating the term…
Abstract
A method for recovering chlorine dioxide from a gas. The method involves contacting gas containing chlorine dioxide with an alkaline metal base and peroxide to form an alkaline metal chlorite solution, and oxidizing the alkaline metal chlorite solution to generate chlorine dioxide.
Claims13
In a method for recovering chlorine dioxide entrained in vent gas from a cellulose pulp bleaching process employing chlorine dioxide as a bleaching agent, the improvement comprising:
- a) contacting a chlorine dioxide containing gas vented from a cellulose pulp bleaching process with an alkaline metal base and peroxide to form an alkaline metal chlorite solution;
- and
- b) oxidizing the alkaline metal chlorite solution with a mixture of chlorine dioxide and an acid in the presence of pulp to produce chlorine dioxide.
A method for recovering chlorine dioxide from bleach plant vent gas comprising:
- a) contacting bleach plant vent gas containing chlorine dioxide with an alkaline metal base and hydrogen peroxide in a bleach plant vent gas scrubber to form an alkaline metal chlorite solution;
- and
- b) contacting the alkaline metal chlorite solution with a mixture of chlorine dioxide and an acid in the presence of pulp to produce chlorine dioxide.
A method for scrubbing chlorine dioxide from bleach plant vent gas comprising:
- a) contacting chlorine dioxide in the bleach plant vent gas with alkaline metal base and peroxide in a vent gas scrubber to form an alkaline metal chlorite solution;
- b) removing the alkaline metal chlorite solution from the scrubber;
- and
- c) reacting the alkaline metal chlorite solution with a mixture of chlorine dioxide and an acid in the presence of the pulp.
Dependencies are inferred from the claim text.