OpenLegislation

Division BAT 23 In order to prevent or reduce mercury emissions to air from the combustion of coal and/or lignite, BAT is to use one or a combination of the techniques given below.

United Kingdom

Technique		Description	Applicability
Co-benefit from techniques primarily used to reduce emissions of other pollutants
a.	Electrostatic precipitator (ESP)	See description in Section 8.5. Higher mercury removal efficiency is achieved at flue-gas temperatures below 130 °C. The technique is mainly used for dust control	Generally applicable
b.	Bag filter	See description in Section 8.5. The technique is mainly used for dust control
c.	Dry or semi-dry FGD system	See descriptions in Section 8.5. The techniques are mainly used for SO_X, HCl and/or HF control
d.	Wet flue-gas desulphurisation (wet FGD)		See applicability in BAT 21
e.	Selective catalytic reduction (SCR)	See description in Section 8.3. Only used in combination with other techniques to enhance or reduce the mercury oxidation before capture in a subsequent FGD or dedusting system. The technique is mainly used for NO_X control	See applicability in BAT 20
Specific techniques to reduce mercury emissions
f.	Carbon sorbent (e.g. activated carbon or halogenated activated carbon) injection in the flue-gas	See description in Section 8.5. Generally used in combination with an ESP/bag filter. The use of this technique may require additional treatment steps to further segregate the mercury-containing carbon fraction prior to further reuse of the fly ash	Generally applicable
g.	Use of halogenated additives in the fuel or injected in the furnace	See description in Section 8.5	Generally applicable in the case of a low halogen content in the fuel
h.	Fuel pretreatment	Fuel washing, blending and mixing in order to limit/reduce the mercury content or improve mercury capture by pollution control equipment	Applicability is subject to a previous survey for characterising the fuel and for estimating the potential effectiveness of the technique
i.	Fuel choice	See description in Section 8.5	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 7

BAT-associated emission levels (BAT-AELs) for mercury emissions to air from the combustion of coal and lignite

Combustion plant total rated thermal input(MW_th)	BAT-AELs (μg/Nm³)
The lower end of the BAT-AEL range can be achieved with specific mercury abatement techniques.
	Yearly average or average of samples obtained during one year
	New plant		Existing plant^f1
	coal	lignite	coal	lignite
< 300	< 1–3	< 1–5	< 1–9	< 1–10
≥ 300	< 1–2	< 1–4	< 1–4	< 1–7

Annotations

Footnotes

f1: The lower end of the BAT-AEL range can be achieved with specific mercury abatement techniques.