Research on gas phase ultra-stabilization method of small grain Y zeolite molecular sieve
Abstract: In order to solve the problem of poor thermal stability and hydrothermal stability of small-grained Y molecular sieves, ultra-stable Y molecular sieves were prepared using NaY molecular sieves of different particle sizes as raw materials, SiCL, and gas phase ultra-stabilization methods. Different particle sizes and Effects of different silicon-to-aluminum ratios on the physical and chemical properties, microreaction activity and hydrothermal stability of Y molecular sieves. The results show that the hydrothermal stability of small-grained Y molecular sieves can be greatly improved by using SiCL and gas-phase ultra-stabilization methods to dealuminate and silicone the molecular sieves: small-grained Y molecular sieves with a particle size of about 700 mm and unit cell constants greater than 2.440 nm are ultra-stable. After Y molecular sieve is hydrothermally aged at 800C, 4 h, and 100% water vapor, its acidity and relative crystal retention are equivalent to those of gas-phase ultra-stable Y molecular sieves with conventional particle sizes. Since the small-grain ultra-stable YA molecular sieve has more active external surface centers, it is more conducive to the reaction of macromolecules that cannot diffuse into the molecular sieve pores. The reaction results of 1.3.5-triisopropylbenzene show that its conversion rate is higher than It is 15~23 percentage points higher than the conventional particle size ultra-stable Y molecular sieve.
