| 摘要 |
A process is described for continuous elimination of formaldehyde from an exhaust gas or exhaust air stream using an aqueous scrubbing solution in a packed scrubbing tower, fresh scrubbing solution being added to at least a withdrawn part of the used scrubbing solution, two part-stream quantities of scrubbing solution containing consumed starting materials and reaction products being led away from the bottom of the packed scrubbing tower, of which one part-stream quantity is returned to the packed scrubbing process, this part-stream quantity, directly after leaving the packed scrubbing tower, being continuously replenished with an aqueous alkali metal hydroxide solution and aqueous hydrogen peroxide solution in such a manner that the scrubbing solution quantity in the bottom of the packed scrubbing tower remains constant and the replenished scrubbing solution contains 1.1 to 1.7 times the stoichiometrically required amount of alkali metal hydroxide and 1.0 times the stoichiometrically required amount of hydrogen peroxide, the other part-stream quantity, in contrast, being discharged untreated. <IMAGE>
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