Apparatus for a process for redissociating michael adducts which are present in a liquid f and have been formed in the preparation of acrylic acid or esters thereof

Abstract

A redissociating apparatus to carry out a process for redissociating Michael adducts which are present in a liquid F with a proportion by weight of ≧10% by weight and have been formed in the preparation of acrylic acid or esters thereof is provided. The apparatus comprises a pump P, a separating column K with separating internals and a circulation heat exchanger UW, wherein, for the purpose of supplying the cleavage energy, the pump P sucks in bottoms liquid from the bottom space of the separating column K and, via the circulation heat exchanger UW, continually recycles it into the bottom space above the level of the bottoms liquid, and wherein the pump P is a radial circulation pump with an open impeller.

1 . An operating unit to conduct the process for redissociating Michael adducts, comprising:
 a separation column K having ajoined in vertical order, a bottom space, a separating space and a top space;   a radial centrifugal pump P having a semiopen radial impeller; and   an indirect heat exchanger UW having a primary space and a secondary space;   wherein   the liquid Feed Point I is located in the separating space of the column above a lowest separating internal,   the separating space of the column K comprises separating internals,   the centrifugal pump P is intermediate in a flow line between the bottom space of the column K and an inlet of the secondary space of indirect heat exchanger,   an outlet line of the secondary space of the indirect heat exchanger is connected to the column K at a Feed Point II which is in the bottom space of the column K,   Feed Point II is located below the lowermost separating internal of the separating column K and above the level S of the bottoms liquid, and is not directed toward the bottoms liquid,   the primary space and the secondary space of the indirect heat exchanger are separated by a material dividing wall D.   
     
     
         2 . The operating unit according to  claim 1 , wherein the separating internals in the separating space of column K comprise dual-flow trays. 
     
     
         3 . The operating unit according to  claim 1 , wherein the indirect heat exchanger UW is a forced circulation flash heat exchanger with the proviso that a throttle apparatus is present between the feed point II and the exit of the mass flow {dot over (M)} from the at least one secondary space of the forced circulation flash heat exchanger, and a working pressure upstream of the throttle apparatus is greater than the gas pressure GD in the bottom space in flow direction. 
     
     
         4 . The operating unit according to  claim 1 , further comprising a stripping gas inlet located in the bottom space of the separating column K above the level S of the bottoms liquid and below the lowermost separating internal of the separating column K. 
     
     
         5 . The operating unit according to  claim 1 , wherein the indirect heat exchanger UW is a tube bundle heat exchanger. 
     
     
         6 . The operating unit according to  claim 1 , wherein the semiopen radial impeller is a simple plate on which vanes are mounted, such that a cross section increases from the inside outward due to an increasing circumference.