Technological Innovation Research Of Y Zeolite Preparation Process

Since the beginning of the 1970s,Y zeolite cracking has been widely used in FCC due to the good performance.In industry,NaY zeolite was first synthesized and then modified.In NaY synthesis,silicon utilization has been low. Mother liquor is discharged with a large number of silicon,which is wasteful and pollute the environment.NaY modification typically include switching, filtering, washing and calcining unit operation.Due to the use of ammonium salts as exchange medium,a large number of high ammonia wastewater is generated in the washing produce filtration, polluting the environment.Roasting is the most critical process in the preparation of Y-zeolite modified process.There are many factors that affect product quality. We need optimize the various operating conditions to meet the performance of different zeolite catalyst.Firstly, this paper studies the environmental problems caused by NaY liquor efflux and its impact on the yield of molecular sieve, through the study we found acidic aluminum sulfate and NaY mother liquorcan generate alumina gel,which can be re-used in the synthesis of NaY, significantly improving the yield of the molecular sieve, and reducing effluent suspended solids content.Secondly, the paper discusses the factors affecting the joint use of the pre-exchange process on the quality ofNaYzeolite during the first exchange filter washing operation. The research shows that pre-switching technology can achieve recycling of high ammonia ammonium water, turning it into a low-water-ammonia emissions, reducing high ammonia water treatment costs.Finally, for the zeolite lattice contraction difficulties, low degree of crystallinity and other issues by two exchange and one roasting process, roasting process operating conditions are optimized and the internal structure of the drum roaster is improved. The results showed that the temperature and residence time on the roasting significant effect, the improved quality has been greatly improved molecular sieve.Through molecular sieve preparation technology improvements, not only the zeolite yield increased, but also the energy and material consumption reduced, and the manufacturing costs reduced, and the intrinsic quality of zeolite has increased, which provides a guarantee for the production of high quality catalyst.