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:
Nov. 05, 1991
Filed:
Dec. 04, 1989
Krupp Koppers GmbH, Essen, DE;
Abstract
The method of reducing a nitrogen oxides content of a flue gas generated on firing of a rich gas or combination coke oven having a plurality of heating walls forming dual heating flues, in which a single stage or multistage combustion takes place, and also having a plurality of regenerators for recovery of flue gas heat and preheating of an underfiring medium, includes the steps of mixing one portion of the flue gas drawn from one flue of the dual heating flues with the underfiring medium, gas and/or air, prior to or on admission to the other flue of the dual heating flues, or a regenerator connected with it, and circulating another portion of the flue gas additionally inside the dual heating flues. The method advantageously also may include recirculating externally at a predetermined flow rate the one portion of the flue gas considering the recirculating of the other portion of the flue gas inside the dual heating flues and controlling the recirculating so that a flame temperature in the heating flues is kept constant based on a heat balance in the heating flues, and feeding, during rich gas firing of the combination coke oven, the one portion of the flue gas recirculated externally only to those of the regenerators, which receive the underfiring media during lean gas operation, and, during rich gas operation, only to every second one of the regenerators.