The Research On Ion Exchange Process In The Pure Removal Of Ammonium Sulphate From Caprolactam

This dissertation explored the application of ion-exchange resin in the purification of caprolactam aqueous solution from the industrial set of caprolactam production in Baling Branch, Yingshan Petrochemical Co.,SlNOPEC. Influencing factors, such as, the temperature, the residence time, and the propentes of ion exchange resin, was investigated systematically, viamonitoring the changes in the conductance and extinction index of caprolactam aqueous solution after ion-exchanging treatment. The experiments were performed over both a laboratory-based micro ion-exchange device. consisting of two columns in series connection and a simulated minitype ion-exchanger, consisting of three columns in series connection and linking directly to the industrial set of caprolactam production. The results shown that the optimized operation conditions for the purification of caprolactam aqueous solution via ion-exchange process,that are temperature in 43~48℃and residence time about 33 ~40 min, with the conductance and extinction index of inlet caprolactam aqueous solution being respectively smaller than 25μs/cm and 1.5.The operation stability and regeneration of ion-exchange resin in practical runs were tested over the industrial three-columns-in-series-connection ion-exchanger associated with 70 kt/a set of caprolactam production. It was found that the stability and regeneration of ion-exchange resin could be affected seriously by the characteristics of resin, such as, the ion-exchange capacity, the ion-exchange selectivity, the physical and chemical stability, the chemical and textural structure, and the particle size. The integrative control of these factors enables the reduction and even the elimination of issues associated usually with resin in industrial operation, for examples, the frequent regeneration, the long regeneration time, the low coefficient of utilization, and the contamination from metal ions.Taking into all the above factors, the operation parameters of ion-exchange process were optimized and utilized in the purification of caprolactam aqueous solution from the in-running 70 kt/a industrial set and in-testing 140 kt/a ones of caprolactam production.Besides the technology of ion-exchange resin, some novel arts were also tested for the purification of caprolactam aqueous solution from the in-testing 140 kt/a industrial set of caprolactam production, such as, the improved ion-exchangeprocess in continuous operation mode, the membrane separation technology, the electrodeionization (EDI) purification technology. Comparing with the conventional technology of ion-exchange resin, the combination of the above technologies has been found to present at least two advantages:Ⅰ) the high efficiency of the removal of organic impurities in caprolactam aqueous solution andⅡ) the effective decrease of the production of waste water from the regeneration of ion-exchange resin. It is expected that the research work in this dissertation would be providing a strong technological support to establish a novel art with independent intellectual asset in the form of copyright and/or patent in Baling Branch,Yingshan Petrochemical Co., SINOPEC.