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US 8,815,202 B2Granted
Process for producing sulfuric acid with low levels of nitrogen oxides
AssigneeE. I. Du Pont de Nemours and Company
InventorsHasan Dindi, Donald James Loftus
Life of this patent
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Abstract
A process for producing sulfuric acid with reduced levels of nitrogen oxides (NOx) within a typical sulfuric acid production line. A hydrazine source material can be mixed with a sulfuric acid effluent at a temperature of at least about 90° C. for a period of at least 1 minute to reduce the level of NOx is the sulfuric acid effluent.
Claims19
A process for producing sulfuric acid with reduced levels of niter or nitrogen oxides (NOx) comprising:
- a) providing an absorption tower wherein sulfur trioxide is absorbed in a sulfuric acid feed having a first sulfuric acid solution to produce a sulfuric acid effluent having i) a second sulfuric acid solution which has a higher concentration than the first sulfuric acid solution, ii) a NOx concentration greater than about 5 ppm by weight (as NO3) and iii) an effluent temperature greater than or equal to about 90° C.;
- and
- b) admixing a hydrazine source selected from the group consisting of hydrazine sulfate, dihydrazine sulfate and hydrazine hydrate with the sulfuric acid effluent to form a hydrazine-treated sulfuric acid effluent, the treated sulfuric acid effluent being maintained at a temperature of greater than or equal to 90° C. for a maintenance period of at least 1 minute.
Dependencies are inferred from the claim text.