Modulation Of Particle Size Of Mesoporous Aluminosilicates With High Hydrothermal Stability

By means of precursor assembling, the hydrothermal stability of mesoporous aluminosilicates is improved highly, which is in favour of its application in heavy oil catalytic cracking. However the large particle size of mesoporous aluminosilicates synthesized by this means brings about some problems in preparation of Catalysts. Thus it is important to reduce the particle size of products in this system.The particle size of the product can be effectively reduced by addition of surfactant Tween 20. Characterization results of TMas indicate that average particle size is 8.500 μm, total surface area is 875 m2·g-1, total pore volume is 0.97 cm3·9g-1 and average pore diameter is 3.42nm. After hydrothermal treatment for 10 h, the reserved ratio of total surface area and total pore volume are 32% and 32%, respectively.In Polyvinyl alcohol (PVA) synthesis system, dispersion of P123 micelles is improved, where PVA used as dispersant. On the other hand, PVA molecules combine with product by hydrogen bonding, which could form a protective film on the surface, thus the aggregation between the product reduce. The results indicates that:the average particle size is 6.643 μm, total surface area is 850.7 m2·g-1, total pore volume is 0.94 cm3·g-1 and average pore diameter is 3.4 nm. After hydrothermal treatment for 10 h, the reserved ratio of total surface area and total pore volume are 32% and 34%, respectively.Based on the result of lab test, pilot scale synthesis of mesoporous zeolite using PVA has been achieved. The results indicates that:the average particle size is 8.673 μm, total surface area is 856.1 m2·g-1, total pore volume is 0.67 cm3·g-1 and average pore diameter is 3.44 nm. After hydrothermal treatment for 10 h, the reserved ratio of total surface area and total pore volume are 30% and 34%, respectively.