| abstract |
In the optimisation of disposal of a vapour sub-stream, contg. entrained valuable and/or inert materials, which is discharged as a steam-product stream from drying units operated with superheated steam and which is then (partially) condensed by heat exchange with a cooling medium, the novelty is that previously recovered condensate is used as the cooling medium in the condensation stage and is then subjected, together with the condensation heat extracted from the vapour sub-stream, to one or more thermal post-purificn. (distillation) stages; the loaded condensate is supplied as an aq. liq. phase to the thermal purificn. (distillation) operation and is partially re-evaporated by the transferred condensation heat; and a liq. stream, with increased concn. of entrained valuable and/or inert materials, is withdrawn from the distillation bottom phase. Also claimed is use of the process for waste gas- and polluted waste water-free removery of dried valuable materials which are useful as or in wetting, washing and/or cleaning agents and which are recovered from their water-contg. prepns. by drying with superheated steam. |