Division BAT 36 In order to reduce NOx emissions from a recovery boiler, BAT is to use an optimised firing system including one or a combination of the techniques given below.
United Kingdom
| Technique | Description | Applicability | |
|---|---|---|---|
| a | Optimising the recovery boiler by controlling the firing conditions | See Section 1.7.1.2 | Generally applicable |
| b | Staged injection of spent liquor | Applicable to new large recovery boilers and major recovery boilers refurbishments | |
| c | Selective non-catalytic reduction (SNCR) | Retrofitting of existing recovery boilers may be limited due to scaling problems and associated increased cleaning and maintenance requirements. For ammonium-based mills, no application was reported; but due to specific conditions in the waste gas, SNCR is expected to be without effect. Not applicable to sodium-based mills due to explosion risk |