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:
Aug. 19, 1997
Filed:
Mar. 16, 1995
Stanislaw Michalak, Ratingen, DE;
Joseph R Comparato, Naperville, IL (US);
John E Hofmann, Naperville, IL (US);
Nalco Fuel Tech, Naperville, IL (US);
Abstract
The removal of SO.sub.x and particulates, and preferably also NO.sub.x, from the combustion gases of a large boiler, is simplified while efficiency is improved. In a primary treatment zone, a slurry comprising an alkaline SO.sub.x -reducing composition and preferably a nitrogen-containing composition effective to reduce NO.sub.x, is introduced into combustion gases at a temperature of from about 900.degree. to about 1300.degree. C. The gases are cooled by initial contact with steam-generating means, and then by contact with an gas-to-gas heat exchanger. Cooled gases are then subjected to a secondary treatment in which they are first humidified and further cooled by introduction of a water spray or aerosol to reduce the temperature to 100.degree. C. or below. Contact between the SO.sub.x -reducing composition and the humidified gases is maintained for a reaction period of at least 2 seconds. Particulate solids are then separated from the gases with a fabric filter. The cleaned gases are reheated by the gas-to-gas heat exchanger prior to discharge to the atmosphere. Reductions of SO.sub.x of greater than 80% are achieved, preferably 90 to 95%.