Patent ID: 8703075
Filing Date: 2014-04-22
Classification: C07C

Abstract:
1. A carbonylation system for producing acetic acid comprising: (a) a reactor vessel adapted for carbonylating methanol or its reactive derivatives with carbon monoxide in the presence of a Group VIII metal catalyst and methyl iodide promoter in a liquid reaction mixture including acetic acid, water, methyl acetate and methyl iodide, the reactor being operated at a reaction pressure of from 300 psig to 500 psig; (b) a pre-flasher/post reactor vessel coupled to the reactor adapted to receive liquid reaction mixture forwarded thereto from the reactor, the pre-flasher/post reactor vessel also being coupled to a carbon monoxide source which is separate from liquid reaction mixture forwarded from the reactor to the pre-flasher/post reactor vessel and provides additional carbon monoxide thereto, wherein the pre-flasher/post reactor vessel is at a pressure of from 200 psig to 450 psig, with the proviso that the pressure in the pre-flasher/post reactor is at least 5 psi lower than the pressure in the reactor vessel and wherein the composition and conditions in the pre-flasher/post vessel are such that light ends are provided to a pre-flasher/post reactor vessel vent and a pre-flash mixture which is enriched in acetic acid and diminished in methyl iodide and methyl acetate as compared with the reaction mixture is formed; (c) a scrubber coupled to the vent of the pre-flasher/post reactor vessel adapted to recover light ends therefrom; (d) a flash vessel coupled to the pre-flasher/post reactor vessel adapted to receive liquid pre-flash mixture mixture forwarded thereto from the pre-flasher/post reactor vessel, the flasher vessel being at a pressure substantially lower than the pre-flasher/post reactor vessel pressure, the flash vessel being further adapted to flash a crude product stream from the pre-flash mixture and provide a recycle reaction mixture to the reactor; and (e) a purification section coupled to the flash vessel adapted to purify the crude product stream.