Division II Secondary or end-of-pipe techniques, such as:

United Kingdom

Technique	Description	Applicability
(i) Selective catalytic reduction (SCR)	See Section 1.20.2	To avoid potential fouling downstream, additional filtering might be required upstream of the SCR. For existing units, the applicability may be limited by space availability
(ii) Selective non-catalytic reduction (SNCR)	See Section 1.20.2	For partial combustion FCCs with CO boilers, a sufficient residence time at the appropriate temperature is required. For full combustion FCCs without auxiliary boilers, additional fuel injection (e.g. hydrogen) may be required to match a lower temperature window
(iii) Low temperature oxidation	See Section 1.20.2	Need for additional scrubbing capacity. Ozone generation and the associated risk management need to be properly addressed. The applicability may be limited by the need for additional waste water treatment and related cross-media effects (e.g. nitrate emissions) and by an insufficient supply of liquid oxygen (for ozone generation). The applicability of the technique may be limited by space availability

Technique

Description

Applicability

(i)

Selective catalytic reduction (SCR)

See Section 1.20.2

To avoid potential fouling downstream, additional filtering might be required upstream of the SCR.

For existing units, the applicability may be limited by space availability

(ii)

Selective non-catalytic reduction (SNCR)

See Section 1.20.2

For partial combustion FCCs with CO boilers, a sufficient residence time at the appropriate temperature is required.

For full combustion FCCs without auxiliary boilers, additional fuel injection (e.g. hydrogen) may be required to match a lower temperature window

(iii)

Low temperature oxidation

See Section 1.20.2

Need for additional scrubbing capacity.

Ozone generation and the associated risk management need to be properly addressed. The applicability may be limited by the need for additional waste water treatment and related cross-media effects (e.g. nitrate emissions) and by an insufficient supply of liquid oxygen (for ozone generation).

The applicability of the technique may be limited by space availability

Notes on Division

Footnotes

f1: When antimony (Sb) injection is used for metal passivation, NO_X levels up to 700 mg/Nm³ may occur. The lower end of the range can be achieved by using the SCR technique.