Conversion of sulfur in blank liquor to eliminate odorous emissions and facilitate the collection of sulfate soaps
AssigneeGulf States Paper Corporation
InventorsRobert R. Fuller, Donald Blanton Morris
Life of this patent
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Abstract
Oxidation and fixing of sulfur and sulfur compounds in weak black liquor is accomplished by methods which insure minimal odorous sulfur emissions and which facilitate the collection of sulfate soaps. By critical adjustment of certain parameters substantially complete oxidation of sulfur and sulfur compounds is achieved, with maximum utilization of oxygen, while enhancing the collection of sulfate soaps and minimizing the production of foam. Various methods are disclosed for the oxygenation of weak black liquor, including the utilization of reaction columns, conical reactors, and venturis.
Claims29
A method of oxidizing substantially all of the sulfur in weak black liquor from a kraft pulp process which comprises oxidizing sulfur in the weak liquor at a point in the process between the blow tank and the pulp washer by the injection into the liquor of sufficient oxygen-rich gas to oxidize substantially all of the sulfur present in the weak black liquor and until the sulfide concentration in the weak black liquor is substantially zero.
In a kraft pulp process, the steps of oxidizing substantially all the sulfur in fiber-containing weak black liquor with oxygen-rich gas between the blow tank and the washer without removal of the fiber from the liquor and until the sulfide concentration in the weak black liquor is substantially zero, and thereafter separating soap from the black liquor.
A method of oxidizing sulfur in black liquor from a kraft pulp process, which comprises pumping the black liquor through an inlet of a vertical reaction chamber and downwardly through the reaction chamber while injecting an oxygen-rich gas into said black liquor and causing small gas bubbles to be dispersed in the liquor and to flow upwardly through said reaction chamber, and discharging oxygenated black liquor from said reaction chamber near the lower end thereof, the flow velocity of the black liquor through said inlet being at least about 8 feet per second, and the flow velocity of the oxygenated black liquor to be discharged from said reaction chamber being less than about 1 foot per second, the amount of oxygen-rich gas injected being sufficient to oxidize substantially all of the sulfur present in the black liquor and the oxidizing being carried out until the sulfide concentration is substantially zero.
Dependencies are inferred from the claim text.