Controlling the particle size and particle size distribution in a process for continuous synthesis of molecular sieves

摘要

Applicants have developed a continuous process for synthesizing various molecular sieves. The process enables one to control both the particle size and particle size distribution. Any of the molecular sieves represented by the empirical formula on an anhydrous basis: rR2O:(SixAlyPz)O2, where R is at least one templating agent, "r" "x" "y" and "z" are the mole fractions of R, Si, Al and P respectively, can be prepared using this process. The process involves continuously adding reactive sources of the desired components along with a structure directing agent into a continuous crystallization reactor. Either interstage backmixing is introduced or the number of stages is adjusted in order to control particle size. Finally, one way to control particle size distribution is to split the product stream into at least two streams and flowing each stream to a wet miller operated at different severity and then reblending to obtain at least a bimodal distribution.