Oxygenated Compounds as Reducing Agent for NOx Removal in a Selective Non-Catalytic Reduction (SNCR) System

Nitric oxides (NO_x), a mixture of nitric oxide (NO) and nitrogen dioxide (NO₂), are some of the most toxic pollutants formed during combustion processes.  Increasing concerns over air quality and new regulations have forced, and will continue to force, thousands of power plants and other such large combustion furnaces to install NOx emissions control systems. Selective noncatalytic reduction (SNCR) technology is one of the technologies that has been used for NOx removal, in which a reducing agent, usually ammonia (or urea), is added to the combustion gas stream at 700-900°C. However, the current SNCR efficiency is much lower than that of Selective Catalytic Reduction (SCR) technology, due to easy oxidation of NH₃ in the high temperature region. This paper presents the use of oxygenated compounds as reducing agents, which improves the NOx removal efficiency over 20% for the SNCR process [1].

 Reference

 [1] Maoqi Feng, Rijing Zhan, Ketone/water mixtures for nox removal, US 8,535,627 B1.