Application Of Small Angle X-ray Scatter In Y Zeolite Synthesis Process

As zeolite is widely used in petroleum engineering process,the requirement of microporous structure and morphology of zeolite is continuously increasing.It can not only promote the development of zeolite with new topological structure but also accelerate the synthetic technique of the classical zeolite and its innovation.To better control the microstructure of zeolite and develop high-efficiency synthetic technique,knowing the synthetic process and formation mechanism is very crucial.It is necessary to use all kinds of testing methods and analysis technology to study the synthesis and mechanism of zeolite.Although the conventional techniques play an important role in zeolite research,the further development of new analysis methods in zeolite synthetic process can promote the understanding of synthesis and mechanism in a new viewpoint.In this work,based on the concentrated synthesis system,using a cheap silicon source as raw material,a high-efficient technique was developed for NaY zeolite synthesis.And the role of structure direct agent(SDA)and the effect of zeolite synthetic chemistry were also studied.Incombination with the study on its synthetic process,small angle X-ray scatter(SAXS)was introduced to characterize the synthetic process of SDA,crytallization process of zeolite and the synthesized zeolite.Firstly,to improve the synthetic efficiency of NaY zeolite,the new and cheap silicon source is used in concentrated system.And a series of factors were investigated,including the type of SDA,gel SiO2/Al2O3 ratio,reaction gel alkalinity,time of crystalling and so on.With repeat experiment,the synthesis recipe and technical parameters were optimized.The synthesized NaY zeolite have a relative crystallinity higher than 95 %,SiO2/Al2O3 ratio about 5.30,the particle size within 300 ~ 500 nm.This process exhibits high silica's ultilization ratio about 69 %,which increases by 15 percentage points compared to that of normal industrial zeolite Y.Secondly,for better use of the SAXS in this system,the important experiment parameters of SAXS technique were investigated specifically to improve its analysis method.The experiments were carried out at the 1W2 A SAXS station in Beijing Synchrotron Radiation Facility(BSRF).Some experimental conditions and data pre-processing methods were determined,including the choice of beam center when the beamstop at different position,the effect of scatter curve when change the range of integration area and a method to calculate the shaft diameter and shaft ratio of rotating ellipsoid.And a method that calculate the sample thickness using testing parameters was proposed.The research results show that different sample thickness only influence the ratio of minimum sized particles and changing the exposure time could make up the effect taken by different sample thickness.Finally,SAXS was used to characterize the growth process of SDA and the NaY zeolite.It is found that when SDA aging at different temperature,the growth rate had a maxima value.As the temperatue rising,the growth rate of the aluminosilicon species first increase and then the growth rate of species particles remain unchanged.And using SAXS to characterize the Na Y zeolite with mesoporous,Porod curves and its partical size were analysized.