The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 30, 1980
Filed:
Feb. 15, 1979
Volker Fattinger, Arlesheim, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
A process is described for separating SO.sub.2 from a current of gas containing the same, at least intermittently, in a concentration which is impermissibly high for discharge into the ambient atmosphere, with attendant production of sulfuric acid by the nitrogen oxide process, in which latter process the SO.sub.2 -containing gas initially flows through a dentriation zone, or first through a pretreatment zone forming a first sector of an SO.sub.2 -processinbg zone and then through the denitration zone, thereafter through the main sector of the SO.sub.2 -processing zone, and subsequently through a nitrogen oxide absorption zone, in the course of which flow it is brought into contact in at least one of the two sectors of the SO.sub.2 -processing zone with dilute acid having a H.sub.2 SO.sub.4 -concentration of less than 70% by weight (55.degree. Be) which acid is circulated through the sector concerned of this latter zone, while in the absorption zone the nitrogen oxides released in the denitration zone are absorbed by sulfuric acid, and nitrose-containing acid having a H.sub.2 SO.sub.4 -concentration of 70 to 80% by weight (55.degree. to 63.5.degree. Be) is drawn off from the absorption zone and fed into the denitration zone, which process further comprises