Study On Chromaticity Source Analysis And Ozone Decolorization Of Caprolactam Wastewater

Caprolactam is the important intermediate and raw material for producing polyamide-6(PA-6). Industrial methods for producing caprolactam and its wastewater treatment methods, and ozone decolorization process were briefly introduced firstly in this paper. The wastewater produced during the new technics for producing caprolactam, cyclohexanone ammoximation, is a kind of wastewater with high chemical oxygen demand (COD), high nitrogen strength and chroma. To advance a small step in resolving the wastewater treatment difficulty, the compositions of wastewater were detected by gas chromatograph-mass spectrometer (GC-MS), and the reason of impurities format ion was analyzed. Studies have shown that the wastewater chroma is mainly due to the byproducts, such as cyclohexanone azine and nitrocyclohexane. To solve the chromaticity pollution problems, small scale experimental device of the ozone oxidation were adopted. Studies have shown when the wastewater flow is0.5m3/h, the stay time is15min and the ozone dose is30mg/L, the dislodging rate of COD reaches27%, and the chroma reduces from450times to40times. Finally, based on the small pilot study, the design package of caprolactam wastewater decolorization process is developed.