Division BAT 41 In order to prevent or reduce NOX emissions to air from the combustion of natural gas in boilers, BAT is to use one or a combination of the techniques given below.
United Kingdom
| Technique | Description | Applicability | |
|---|---|---|---|
| a. | Air and/or fuel staging | See descriptions in Section 8.3. Air staging is often associated with low-NOX burners | Generally applicable |
| b. | Flue-gas recirculation | See description in Section 8.3 | |
| c. | Low-NOX burners (LNB) | ||
| d. | Advanced control system | See description in Section 8.3. This technique is often used in combination with other techniques or may be used alone for combustion plants operated < 500 h/yr | The applicability to old combustion plants may be constrained by the need to retrofit the combustion system and/or control command system |
| e. | Reduction of the combustion air temperature | See description in Section 8.3 | Generally applicable within the constraints associated with the process needs |
| f. | Selective non–catalytic reduction (SNCR) | Not applicable to combustion plants operated < 500 h/yr with highly variable boiler loads. The applicability may be limited in the case of combustion plants operated between 500 h/yr and 1 500 h/yr with highly variable boiler loads | |
| g. | Selective catalytic reduction (SCR) | Not applicable to combustion plants operated < 500 h/yr. Not generally applicable to combustion plants of < 100 MWth. There may be technical and economic restrictions for retrofitting existing combustion plants operated between 500 h/yr and 1 500 h/yr | |