| 摘要 |
PROBLEM TO BE SOLVED: To efficiently recover acetic acid a method wherein an acetic acid-contg. waste water is decomposed by heating by using a noble metal catalyst in the presence or absence of an oxygen-contg. gas under a pressure where the waste water is kept in a liq. phase and then, remaining acetic acid is recovered. SOLUTION: After a waste water delivered from a manufacturing plant for dimethyl terephthalate through a line 1 is transferred to a heat exchanger 3 by means of a waste water feeding pump 2 and is preheated therein, it is fed in a reactor 4 and an oxygen-contg. gas from a line 5 is pressure-elevated and it is joined with the waste water and the mixture is fed to the reactor 4. Then, after the waste water processed in this reactor 4 is cooled by means of the heat exchanger 3, it is introduced into an extracting tower 11 through a gas-liq. separator 8 and it is brought into countercurrent contact with an extracting agent introduced from a solvent feeding pump 12 to extract acetic acid with the layer of the extracting agent. Then, after the layer of the extracting agent taken out from the top of the extracting tower 11 is preheated by means of a heat exchanger 10, it is transferred to a dehydrating tower 17, wherein it is distilled to separate into an acetic acid component and a water-contg. component and the acetic acid component is recovered in an acetic acid tower 23. |
