Division BAT 49 In order to prevent or reduce CO emissions to air from the combustion of iron and steel process gases, BAT is to use one or a combination of the techniques given below.
United Kingdom
| Technique | Description | Applicability | |
|---|---|---|---|
| a. | Combustion optimisation | See descriptions in Section 8.3 | Generally applicable |
| b. | Oxidation catalysts | Only applicable to CCGTs. The applicability may be limited by lack of space, the load requirements and the sulphur content of the fuel | |
Table 29
BAT-associated emission levels (BAT-AELs) for NOX emissions to air from the combustion of 100 % iron and steel process gases
| Plants combusting a mixture of gases with an equivalent LHV of > 20 MJ/Nm3 are expected to emit at the higher end of the BAT-AEL ranges. | |||
| The lower end of the BAT-AEL range can be achieved when using SCR. | |||
| For plants operated < 1 500 h/yr, these BAT AELs do not apply. | |||
| In the case of plants put into operation no later than 7 January 2014, the higher end of the BAT-AEL range is 160 mg/Nm3. Furthermore, the higher end of the BAT-AEL range may be exceeded when SCR cannot be used and when using a high share of COG (e.g. > 50 %) and/or when combusting COG with a relatively high level of H2. In this case, the higher end of the BAT-AEL range is 220 mg/Nm3. | |||
| For plants operated < 500 h/yr, these levels are indicative. | |||
| In the case of plants put into operation no later than 7 January 2014, the higher end of the BAT-AEL range is 70 mg/Nm3. | |||
| Type of combustion plant | O2 reference level (vol-%) | BAT-AELs (mg/Nm3)f1 | |
|---|---|---|---|
| Yearly average | Daily average or average over the sampling period | ||
| New boiler | 3 | 15–65 | 22–100 |
| Existing boiler | 3 | 20–100f2 f3 | 22–110 f4 f5 |
| New CCGT | 15 | 20–35 | 30–50 |
| Existing CCGT | 15 | 20–50 | 30–55 f6 |
As an indication, the yearly average CO emission levels will generally be:
-
< 5–100 mg/Nm3 for existing boilers operated ≥ 1 500 h/yr,
-
< 5–35 mg/Nm3 for new boilers,
-
< 5–20 mg/Nm3 for existing CCGTs operated ≥ 1 500 h/yr or new CCGTs.
Annotations
Footnotes
- f1
-
Plants combusting a mixture of gases with an equivalent LHV of > 20 MJ/Nm3 are expected to emit at the higher end of the BAT-AEL ranges.
- f2
-
The lower end of the BAT-AEL range can be achieved when using SCR.
- f3
-
For plants operated < 1 500 h/yr, these BAT AELs do not apply.
- f4
-
In the case of plants put into operation no later than 7 January 2014, the higher end of the BAT-AEL range is 160 mg/Nm3. Furthermore, the higher end of the BAT-AEL range may be exceeded when SCR cannot be used and when using a high share of COG (e.g. > 50 %) and/or when combusting COG with a relatively high level of H2. In this case, the higher end of the BAT-AEL range is 220 mg/Nm3.
- f5
-
For plants operated < 500 h/yr, these levels are indicative.
- f6
-
In the case of plants put into operation no later than 7 January 2014, the higher end of the BAT-AEL range is 70 mg/Nm3.