Division BAT 29 In order to prevent or reduce SOX, HCl and HF emissions to air from the combustion of HFO and/or gas oil in boilers, BAT is to use one or a combination of the techniques given below.

United Kingdom

Technique		Description	Applicability
a.	Duct sorbent injection (DSI)	See description in Section 8.4	Generally applicable
b.	Spray dry absorber (SDA)
c.	Flue-gas condenser
d.	Wet flue-gas desulphurisation (wet FGD)		There may be technical and economic restrictions for applying the technique to combustion plants of < 300 MW_th. Not applicable to combustion plants operated < 500 h/yr. There may be technical and economic restrictions for retrofitting existing combustion plants operated between 500 h/yr and 1 500 h/yr
e.	Seawater FGD		There may be technical and economic restrictions for applying the technique to combustion plants of < 300 MW_th. Not applicable to combustion plants operated < 500 h/yr. There may be technical and economic restrictions for retrofitting existing combustion plants operated between 500 h/yr and 1 500 h/yr
f.	Fuel choice		Applicable within the constraints associated with the availability of different types of fuel, which may be impacted by the energy policy of the Member State

Table 15

BAT-associated emission levels (BAT-AELs) for SO₂ emissions to air from the combustion of HFO and/or gas oil in boilers

Combustion plant total rated thermal input(MW_th)	BAT-AELs for SO₂ (mg/Nm³)
These BAT-AELs do not apply to plants operated < 1 500 h/yr.
For plants operated < 500 h/yr, these levels are indicative.
For industrial boilers and district heating plants put into operation no later than 27 November 2003 and operated < 1 500 h/yr, the higher end of the BAT-AEL range is 400 mg/Nm³.
The higher end of the BAT-AEL range is 175 mg/Nm³ for plants put into operation no later than 7 January 2014.
For industrial boilers and district heating plants put into operation no later than 27 November 2003, which are operated < 1 500 h/yr and for which wet FGD is not applicable, the higher end of the BAT-AEL range is 200 mg/Nm³.
	Yearly average		Daily average or average over the sampling period
	New plant	Existing plant^f1	New plant	Existing plant^f2
< 300	50–175	50–175	150–200	150–200^f3
≥ 300	35–50	50–110	50–120	150–165^f4 ^f5

Annotations

f1: These BAT-AELs do not apply to plants operated < 1 500 h/yr.
f2: For plants operated < 500 h/yr, these levels are indicative.
f3: For industrial boilers and district heating plants put into operation no later than 27 November 2003 and operated < 1 500 h/yr, the higher end of the BAT-AEL range is 400 mg/Nm³.
f4: The higher end of the BAT-AEL range is 175 mg/Nm³ for plants put into operation no later than 7 January 2014.
f5: For industrial boilers and district heating plants put into operation no later than 27 November 2003, which are operated < 1 500 h/yr and for which wet FGD is not applicable, the higher end of the BAT-AEL range is 200 mg/Nm³.