METHYLENE DICHLORIDE RECUPERATION METHOD AND INSTALLATION FOR IMPLEMENTATION THEREOF Russian patent published in 2003 - IPC

FIELD: chemical engineering. SUBSTANCE: invention is characterized by using, for methylene dichloride recuperation, high-boiling organics, for instance specific oils, as absorbents capturing methylene dichloride vapors taken off from the process circuit with gas carrier flow. Process is realized in "ideal displacement" mode with countercurrent of contacting phases under conditions assuring extremely full removal of methylene dichloride from gas carrier. Optimal conditions for removal of methylene dichloride from saturated absorbent upon double-step heating are found: in the course of film flow over the surface heated to 105-110 C and in the course of jet-drop flow over heat- conducting packing heated to 115-120 C. Offtake of methylene dichloride vapor from the zone wherein it is released during thermal regeneration of adsorbent is achieved through thermal diffusion provided by methylene dichloride pressure gradient between its release and condensation zones. Appropriate installation comprises venting assembly and compressor for taking off methylene dichloride vapor from process circuit; vapor absorption unit constructed in the form of two in-series connected packed absorption columns; apparatus for releasing methylene dichloride vapor from saturated absorbent; cooled condenser connected to liquid methylene dichloride collector over cooler; and heat recuperator. Methylene dichloride release apparatus is constructed in the form of completely heat-insulated shell-and-tube heat exchanger provided with (i) distribution manifold for passing saturated absorbent into tubular space and (ii) connecting pipes for withdrawing heating steam condensate. Apparatus has drop catcher in its top section in the form of packed cylindrical device. EFFECT: improved quality of product, reduced power consumption and fire risk of process. 6 cl, 16 dwg, 7 tbl, 9 ex