Division BAT 66: In order to reduce emissions to air of organic compounds (including chlorinated hydrocarbons), HCl and chlorine, BAT is to treat combined waste gas streams using a thermal oxidiser followed by caustic scrubbing.
United Kingdom
Description:
The individual waste gas streams from DNT, TDA, TDI, MDA and MDI plants are combined to one or several waste gas streams for treatment. (See Section 12.1 for the descriptions of thermal oxidiser and scrubbing.) Instead of a thermal oxidiser, an incinerator may be used for the combined treatment of liquid waste and the waste gas. Caustic scrubbing is wet scrubbing with caustic added to improve the HCl and chlorine removal efficiency.
Table 9.1
BAT-AELs for emissions of TVOC, tetrachloromethane, Cl2, HCl and PCDD/F to air from the TDI/MDI process
| The BAT-AEL only applies to combined waste gas streams with flow rates of > 1 000 Nm3/h. | |
| The BAT-AEL is expressed as a daily average or an average over the sampling period. | |
| The BAT-AEL is expressed as an average of values obtained during 1 year. TDI and/or MDI produced refers to the product without residues, in the sense used to define the capacity of the plant. | |
| In the case of NOX values above 100 mg/Nm3 in the sample, the BAT-AEL may be higher and up to 3 mg/Nm3 due to analytical interferences. | |
| Parameter | BAT-AEL(mg/Nm3, no correction for oxygen content) |
|---|---|
| TVOC | 1–5f1 f2 |
| Tetrachloromethane | ≤ 0,5 g/t MDI producedf3 ≤ 0,7 g/t TDI produced |
| Cl2 | < 1 f4 |
| HCl | 2–10 |
| PCDD/F | 0,025–0,08 ng I-TEQ/Nm3 |
The associated monitoring is in BAT 2.
Annotations
Footnotes
- f1
-
The BAT-AEL only applies to combined waste gas streams with flow rates of > 1 000 Nm3/h.
- f2
-
The BAT-AEL is expressed as a daily average or an average over the sampling period.
- f3
-
The BAT-AEL is expressed as an average of values obtained during 1 year. TDI and/or MDI produced refers to the product without residues, in the sense used to define the capacity of the plant.
- f4
-
In the case of NOX values above 100 mg/Nm3 in the sample, the BAT-AEL may be higher and up to 3 mg/Nm3 due to analytical interferences.