TH39341A - Method for Producing Oxidized White Quart - Google Patents

Abstract

The method for producing oxidized white liquor from white liquor in which sodium sulfide is oxidized to sodium sulfate involves contact between oxygen-containing gas and the white liquor at a minimum temperature of 110°C, where the total pressure of oxygen and water vapor does not exceed 9.2 atmospheres during contact.

Claims (10)

1. The method to oxidize the sodium sulfide present within white liqueur to sodium sulfate, thus producing oxidized white liqueur, involves bringing the oxygenated gas and liqueur into contact in a plug flow reactor at a minimum temperature of approximately 110°C and a total pressure of at least approximately 9.2 absolute atmospheres. 2. The method under claim 1, where the temperature is at least approximately 120°C. 3. The method under claim 1, where the temperature is at least approximately 130°C. 4. The method under claim 1, where the total pressure is at least approximately 11.3 absolute atmospheres and the temperature is at least approximately 130°C. 5. The method under claim 1, where the total pressure is at least approximately 18 absolute atmospheres and the temperature is at least approximately 200°C. 6. The method under Claim 1, in which the plug-flow reactor consists of a column with a structured packing, allows contact between the white liquor and the oxygen contained within the white liquor and the oxygen stream, respectively. The oxygen in the gas and the white liquor come into contact by introducing streams of white liquor and oxygen-containing gas into the top and bottom of the column, respectively. This causes contact between the white liquor and the oxygen contained within the white liquor and the oxygen stream, respectively. Consequently, the white liquor is oxidized, and the stream of the product, consisting of the oxidized white liquor, is removed from the bottom of the column. 7. The method under claim 6, which involves drawing the superstructure current from the top of the column and introducing that superstructure current into the bottom of the column. 8. The method under claim 6, which involves heating the white liqueur to the reaction temperature to initiate the oxidation of sodium sulfide and then using the heat of the sodium-sulfide reaction with oxygen to sustain the oxidation of sodium sulfide. 9. The method under claim 6, which continues with the extraction of the upstream current into the new column, involves pumping the bottom current of the column, consisting of oxidized white liquor, from the bottom of the column through a eductor with a low-pressure inlet connected to the top of the column. The upstream current is then drawn through the eductor with the low-pressure inlet and carried along with it in the bottom current of the column to create a combined current and a high-pressure outlet connected to the bottom of the column. This combined current is then introduced into the bottom of the column through the eductor with the high-pressure outlet. 10. The method under claim 6 involves drawing the over-the-tower stream and introducing it into a new column by pumping the refrigerant through a gas outlet with a low-pressure inlet connected to the top of the column, drawing the over-the-tower stream through the gas outlet with a low-pressure inlet and carrying it with the refrigerant to create a combined stream, and releasing the combined stream through a gas outlet with a high-pressure outlet. The combined stream is then released to the phase separator, and the over-the-tower stream is separated from the refrigerant in the phase separator, and the over-the-tower stream from the phase separator is introduced into the bottom of the column. (Clause 10, 3 pages, 2 figures)