| 摘要 |
A method of operating a heavy ends column in an acetic acid production unit, said production unit comprising at least a reaction section, a light ends recovery section comprising a light ends distillation column, and a heavy ends column, wherein a stream comprising acetic acid and propionic acid obtained from the light ends recovery section is fed to the heavy ends column through a feed inlet positioned at an intermediate point in the heavy ends column, a product stream comprising essentially acetic acid is withdrawn from the heavy ends column through a sidedraw product outlet position above the feed inlet, and a product stream comprising the propionic acid is withdrawn from the heavy ends column through a heavy product outlet positioned below the feed inlet, wherein the heavy ends column is operated under conditions such that the pressure in the heavy ends column above the feed inlet is lower than the pressure of the stream comprising acetic acid and propionic acid that is fed to the heavy ends column, and wherein the head pressure of the heavy ends column is below 1.0 bara, the number of theoretical separation stages between the feed inlet and the sidedraw product outlet is at least 5, preferably at least 7, more preferably at least 10, and the pressure drop in the part of the heavy ends column between the feed inlet and the sidedraw product outlet is at most 10 mbar per theoretical separation stage. |
