Control of combustion-generated nitrogen oxides by selective non-catalytic reduction [An article from: Journal of Environmental Management]

This digital document is a journal article from Journal of Environmental Management, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Controlling nitrogen oxides (NO"x) emissions is becoming a daunting technical challenge as increasingly strict emission limits are being imposed. The stringent regulations have prompted the innovation and characterization of NO"x control technologies suitable for various applications. This paper presents a review on NO"x removal techniques with particular reference to selective non-catalytic reduction (SNCR) technology. This includes initially how SNCR emerged as a technology along with a comparison with other relevant technologies. A review of various features related to selective non-catalytic gas phase injection of ammonia and ammonium salts (as reducing agent) is presented. The use of urea solution as a reducing agent and its performance in laboratory and pilot scale tests as well as large-scale applications is also discussed. Use of cyanuric acid as a potential reducing agent is also presented. The underlying reaction mechanisms have been reviewed for ammonia, urea and cyanuric acid for the explanation of various observations. Computational fluid dynamics (CFD) modeling as applied to SNCR is also presented. Subsequently the use of SNCR coupled with other in-combustion and post-combustion NO"x control techniques is elaborated. Additionally, a two-stage NO"x removal strategy to control un-reacted ammonia slip and to improve overall efficiency is discussed. At the end a summary is given which highlights various areas needing further research.