PROCESS AND PLANT FOR RECOVERING ACRYLIC ACID

摘要

The present invention relates to the process for recovering acrylic acid, comprising the steps
a) division of a heated mother acid stream in direction of an absorption column (201) and a dissociation column (205),b) feeding of a heated mother acid substream as runback to the dissociation column (205),c) feeding-in of at least one stripping gas stream to the dissociation column (205),d) feeding-in of a secondary component stream comprising oligomeric acrylic acid from the condensation column (201) to the dissociation column (205),e) dissociation of part of oligomeric acrylic acid in the dissociation column (205) to give monomeric acrylic acid,f) removal of secondary components comprised in the secondary component stream in the dissociation column (205),g) discharge of monomeric acrylic acid as gas mixture with introduced circulating stripping gas stream from the dissociation column (205) andh) feeding-in of the gas mixture to the condensation column (201).

主权项

1. A process for recovering acrylic acid, which comprises the steps of
a) division of a heated mother acid stream from a crystallization apparatus in the direction of an absorption column (201) and in the direction of a dissociation column (205), b) feeding of the first heated mother acid substream as runback to the uppermost tray of the dissociation column (205), c) feeding-in of at least one stripping gas stream below the lowermost tray of the dissociation column (205), d) feeding-in of a secondary component stream comprising oligomeric acrylic acid from the condensation column (201) to a middle tray of the dissociation column (205), e) dissociation of at least part of the oligomeric acrylic acid from the secondary component stream in the dissociation column (205) to give monomeric acrylic acid, f) removal of the secondary components comprised in the secondary component stream by countercurrent rectification in the superposed dissociation column (205), g) discharge of the monomeric acrylic acid without condensation as gas mixture with the introduced circulating stripping gas stream at the top of the dissociation column (205) and h) feeding-in of the gas mixture below the lowermost tray of the condensation column (201).