Division BAT 65: In order to reduce the load of HCl and phosgene sent to the final waste gas treatment and to increase resource efficiency, BAT is to recover HCl and phosgene from the process off-gas streams of TDI and/or MDI plants by using an appropriate combination of the techniques given below.
United Kingdom
| Technique | Description | Applicability | |
|---|---|---|---|
| a. | Absorption of HCl by wet scrubbing | See BAT 8d. | Generally applicable |
| b. | Absorption of phosgene by scrubbing | See Section 12.1. The excess phosgene is absorbed using an organic solvent and returned to the process | Generally applicable |
| c. | HCl/phosgene condensation | See Section 12.1 | Generally applicable |