API RP 536 2nd Edition, December 1, 2006
Post-Combustion NOx Control for Fired Equipment in General Refinery Services
Includes all amendments and changes through Reaffirmation Notice , September 2013
Additional Comments: C53602 * CONTAINS FOLDOUTS
Published By:American Petroleum Institute (API)
This recommended practice covers the mechanical description, operation, maintenance, and test procedures of post-combustion NOx control equipment for fired equipment in general refinery service. It does not cover reduced NOx formation through combustion design techniques, such as flue gas recirculation (FGR) and staged combustion.
This document covers two of the methods of post combustion NOx reduction:
a. Selective Non-Catalytic Reduction (SNCR).
b. Selective Catalytic Reduction (SCR).
SNCR is a process where the addition of ammonia or urea into the flue gas stream causes the oxides of nitrogen to convert to nitrogen and water vapor. The basis for the selection and limitations of the SNCR systems are described in 4.1.
SCR is a process where the addition of ammonia into the flue gas stream in the presence of a suitable catalyst causes the oxides of nitrogen to convert to nitrogen and water vapor. The basis for the selection of the various catalyst types are described in 4.2.