Synthesis And Pore Structure Of Mesozeolite Y

Zeolite Y is mainly used in oil refining industry as the main active component of fluid catalytic cracking (FCC) catalysts for its large surface area, well hydrothermal stability, strong acidity and low cost. However, its micropores at 0.74 nm still limits the diffusion of adsorbed molecules in most cases, particularly in the FCC and hydrocracking applications.The limited pore size of zeolite imposes large diffusion and spatial resistance, greatly reduces the accessibility of active sites. Based on this point, zeolites Y cannot fulfill catalytic cracking of heavy oil for special applications. Therefore, the introduction of mesopores into zeolite Y becomes a key part. In order to meet these needs, a lot of work has been done to introduce mesopores into zeolite Y, and increase the accessibility of the active sites in zeolite Y.This paper mainly through the use of TPOAC and CTAB template for mesoporous "Templating Method" and TPOAC silanization Si-MCM-41 as solid silicon source for "bond-blocking", and then successful synthesized mesozeolite Y.1. Mesoporous zeolite NaY-T have been successfully synthesized through hydrothermal method by using organosilane surfactant TPOAC as template, at the same time, the Si/Al of zeolite Y have been increased slightly.The experimental results show that:compared to 90 degree, the crystallization temperature 75 degree is more suitable for the growth of zeolite Y; at the same time, synthesis of zeolite Y under the conditions of Na2O/H2O=0.011, and TPOAC/SiO2=1.0%. Under these conditions, the prepared mesoporous Y-T zeolite contains mesopores 5-6nm, and a smaller spherical morphology by nanograins piled into cauliflower-like spheres particle, and its Sext also have a significant increase (SBET=847m/g, Sext=206m/g). By the Si/Al experiment increases in mesozeolite Y in the formula can be seen:the Si/Al of mesoporous zeolite Y-T have slightly increase with the increase of the formula in the silicon aluminum ratio (from 2.65 to 3.10). The hydrothermal stability of the sample is still need to be improved. The sample is still having good structural parameters when the sample is amplified to 450mL2. We use the low cost CTAB to replace TPOAC as the template for mesozeolite Y, and successfully prepared mesozeolite Y-C with a FAU structure. The experiment data shows that:the choice of the feeding sequence is CTAB-Al-Si-SDA, which can get better performance of mesoporous Y-C zeolite. The crystallization temperature compared to 75 degree, are more suitable for the growth of crystallization of zeolite Y at 50 degree. Compared the sample that was prepared under different content of CTAB shows that, when the CTAB content is low, the crystal growth well, but no effects in the introduction of mesoporous; when the content of CTAB is too high, zeolite Y not growing, so we choose the CTAB content of 5%. Y-C zeolite prepared under these conditions containing mesoporous 3-4nm, morphology of 500nm about cauliflower sphere particles, the Sext is significantly increased (SBET=86Om2/g, Sext=219m2/g).3. We use the TPOAC silanization Si-MCM-41 as solid silicon source TM, and then followed by "bond-blocking" method with TM, we successfully synthesis mesozeolites Y-B. By comparing the various organosilane coupling agent TPOAC (TM) and Y-5669 (YM) of the synthesized samples:In the samples with TM, its relative degree of crystallinity and pore structure parameters are superior to the samples with YM. Therefore, we choose TM as the solid silicon source to prepare Y-B zeolite. By comparing the crystallization time, we can see that:with the extension of crystallization time, the relative degree of crystallinity of the zeolite increases; but when the crystallization time was extended to 11 days, the Sext of samples is decreased sharply, so we choose the crystallization time for 8 days. Y-B zeolite prepared under these conditions containing mesoporous 2-3nm, and a smaller spherical morphology by nanograins piled into cauliflower-like spheres of about 500nm particle, and its Sext also have a significant increase (SBET=863m2/g, Sext=150m2/g).