Method for increasing the production capacity of sulfuric acid plants and processes
AssigneeVulcan Materials Company
InventorPeter H. Peng
Life of this patent
Estimating the term…
Abstract
A process for removing SO.sub.2 from a gas mixture including SO.sub.3 and SO.sub.2 having a volume ratio of SO.sub.3 to SO.sub.2 greater than 1. The process includes intimately contacting the gas mixture in a contacting zone, removing a stream of purified gas containing less SO.sub.2 than the gas mixture from an upper portion of the contacting zone, and removing a stream of sulfuric acid from a lower portion of the contacting zone. Also provided are processes for manufacturing sulfuric acid utilizing the process for removing SO.sub.2 which allow increasing the production of concentrated sulfuric acid solutions by producing more sulfur trioxide without an increase of sulfur dioxide emissions.
Claims25
A process for removing SO.sub.2 from a gas mixture comprising SO.sub.3 in an amount greater than zero and less than or equal to 15% by volume, SO.sub.2 in an amount greater than zero and less than or equal to 5,000 ppm by volume and a volume ratio of SO.sub.3 to SO.sub.2 greater than 1 which process comprises introducing said gas mixture into a contacting zone at a temperature between about 50.degree. and about 150.degree. C. comprising aqueous sulfuric acid containing more than 90% by weight H.sub.2 SO.sub.4 and 1 to 25 parts of a peroxide compound per million parts of said aqueous sulfuric acid;
- converting SO.sub.2 to H.sub.2 SO.sub.4 in said contacting zone;
- converting SO.sub.3 to H.sub.2 SO.sub.4 in said contacting zone;
- removing a stream of purified gas from an upper portion of the contacting zone;
- and removing a stream of sulfuric acid from a lower portion of the contacting zone.
In a process for the commercial manufacture of sulfuric acid in a sulfuric acid manufacturing plant in which a sulfur dioxide containing gas and an oxygen-containing gas are reacted in a catalytic oxidation zone into a mixture comprising sulfur trioxide and sulfur dioxide having a volume ratio of SO.sub.3 to SO.sub.2 greater than 1, which process comprises introducing said mixture of sulfur trioxide and sulfur dioxide into an SO.sub.3 absorber containing an aqueous sulfuric acid medium possessing an H.sub.2 SO.sub.4 concentration greater than 90%;
- the improvement which comprises introducing 1 to 25 parts of a peroxide compound per million parts of said aqueous sulfuric acid medium into said SO.sub.3 absorber;
- absorbing sulfur trioxide in said medium to produce H.sub.2 SO.sub.4 ;
- dissolving and oxidizing the sulfur dioxide in said medium to produce additional sulfuric acid, reducing the SO.sub.2 concentration in said mixture such that the sulfur dioxide content in the remaining gas phase is maintained at a concentration of less than 4 lb SO.sub.2 per short ton of H.sub.2 SO.sub.4 produced;
- and removing a stream of sulfuric acid and a stream of emission gas from said absorber.
In a process for the manufacture of sulfuric acid in a sulfuric acid manufacturing plant, which process comprises:
- introducing a sulfur-containing feed material into a reaction zone maintained at conditions suitable for producing gaseous sulfur dioxide;
- introducing at least a portion of the gaseous sulfur dioxide in the presence of an oxygen-containing gas into a catalytic conversion zone maintained at conditions suitable for converting the gaseous sulfur dioxide into a gas mixture containing sulfur trioxide and sulfur dioxide;
- introducing the mixture of sulfur dioxide and sulfur trioxide into a lower portion of an SO.sub.3 absorber containing a downwardly moving sulfuric acid absorption medium maintained at a temperature above 50.degree. C. and up to about 150.degree. C.;
- the improvement which comprises
- introducing 1 to 25 parts of a peroxide compound per million parts of said sulfuric acid absorption medium into said SO.sub.3 absorber;
- removing a stream of purified emission gas from an upper portion of the absorber, and removing a stream of sulfuric acid product from a lower portion of the absorber while keeping SO.sub.2 emissions from the process no more than 4 lbs SO.sub.2 per short ton of H.sub.2 SO.sub.4 produced.
Dependencies are inferred from the claim text.