Regeneration of acid containing peroxy acids of sulfur
View Patent ↗A method for treating a spent oxidizing acid which contains at least one of H 2 O 2 and one or more peroxy acids of sulfur comprising contacting the spent oxidizing acid with a quantity of SO 2 in excess of an equilibrium quantity required to convert the H 2 O 2 and peroxy acids of sulfur to sulfuric acid.
1. A method for treating a spent oxidizing acid solution which comprises the steps of:
(a) injecting a spent sulfuric acid solution which contains at least one of H 2 O 2 , H 2 SO 5 , and/or other peroxy acid(s) of sulfur into a drying tower in a spent acid regeneration plant;
(b) circulating a sulfuric acid stream into the drying tower counter-currently with a process gas which enters the tower having an SO 2 concentration of about 5% by volume or greater;
(c) wherein SO 2 , which becomes dissolved in the circulating sulfuric acid stream, reaches a value in excess of a stoichiometric quantity required to convert the at least one of H 2 O 2 , H 2 SO 5 , and/or and any other peroxy acids of sulfuric acid that may be present in the spent oxidizing acid solution to sulfuric acid.
2. The method of claim 1 , wherein the spent oxidizing acid comprises spent Piranha solution.
3. The method of claim 1 , wherein the SO 2 reacts with greater than 98% of the at least one of H 2 O 2 , H 2 SO 5 , and any other peroxy acids of sulfuric acid that may be present in the spent oxidizing acid solution.
4. The method of claim 1 , wherein a product sulfuric acid stream is taken from the drying tower circulating sulfuric acid stream and comprises 90 wt % or more H 2 SO 4 .
5. The method of claim 4 , wherein the product sulfuric acid comprises 96 wt % or more H 2 SO 4 .
6. The method of claim 1 , further comprising the steps of:
catalytically converting excess SO 2 leaving the drying tower to SO 3 ; and
absorbing the catalytically converted SO 3 into a sulfuric acid stream.