| Mesoporous aluminatesilicates(MAs)has high specific surface area,regular and adjustable pore structure,large pore volume,diverse frame structure and other excellent characteristics.It has extremely broad development prospects in the field of heavy oil catalytic cracking,but its hydrothermal stability is relatively Poor,limiting its industrial application.Our group reported that "MASTER-1" was obtained by introducing microporous molecular aluminatesilicates’s primary and secondary structural units into the pore wall of the MAs through the precursor assembly technology."MASTER-1" as the active component of "LPC-65" oil refining catalyst,was used in millions of tons of Industrial catalytic device.However,there are defects in the synthesis process:low utilization rate of the template agent P123,large water consumption.To solve above problems the following studies were conducted in the paper:(1)The surfactant Polyvinylpyrrolidone(PVP)was added as an assist template to the P123 solution system.Due to its molecular structural characteristics,PVP molecules can be attached to the surface of the P123 micelles.It enters the interior of micelle P123 and forms active mixed micelles.The mixed micelles have stronger hydrophilicity and are not easy to agglomerate.The inorganic salt ions in the solution are assembled on the micelles more efficiently,thus improving the utilization rate of the template agent P123,reducing the water consumption was reduced,and promoting the industrialized production process,under the premise of MAs performance.The utilization rate of the synthesis process template agent P123 was 0.86 g P123/g zeolite,the water consumption was 18 g H2O/g zeolite,the Sbet(total specific surface area)of the product was 965.2 m2.g-1,and the Vtotal(total pore volume)was 0.99 cm3.g-1 After hydrothermal treatment,the Sbet of the product was 367.9 m2.g-1,the retention rate was 38.1%,and the Vtotal was 0.57 cm3.g-1,the retention rate was 57.6%.The effects of PVP specifications and PVP addition on synthetic products were also investigated.(2)Introduce PVA as an assist template agent into the high concentration P123 system as a composite template agent system to synthesize MAs.PVA molecules cover the surface of P123 micelles to form active mixed micelles.PVA acts as a soft film on the surface of P123 micelles The effect makes the assembly efficiency of mixed micelles and inorganic salt ions higher,and PVA can interact with water to generate hydrogen bonds to reduce the surface tension of water,which was more conducive to the uniform distribution of mixed micelles in the solution system and inhibits micelle agglomeration.In this way,a regular and ordered MAs was obtained with low synthesis cost.The utilization rate of the template P123 was 0.82 g P123/g zeolite,the water consumption was 17 g H2O/g zeolite.The Sbet(total specific surface area)of the product was 755.4 m2.-1,the Vtotal(total pore volume)was 0.99 cm3.g-1.After hydrothermal treatment the Sbet was 251.2 m2.g-1,the retention rate was 32.3%,and the Vtotal was 0.49 cm3.g-1,the retention rate was 49.5%.The influence of the amount of PVA added on the synthetic products was investigated,and the pilot scale-up synthesis was of the P123/PVA system was carried out.(3)Introduce Ba2+into the circulation process to improve the conventional mother liquor circulation process.Add an appropriate amount of Ba2+before each circulation of mother liquor to allow it to fully react with SO42-to generate BaSO4 precipitate.After removing the precipitate by filtration,The effect of SO42-on P123 molecules and micelles is removed so that inorganic salt ions can be assembled smoothly on the micelle surface.Five cycles were successfully carried out by this process,which solved the defects of conventional mother liquor circulating product.Further improved the utilization rate of industrial P123 and reduced the water Consumption.The utilization rate of the template P123 is 0.71 g P123/g zeolite,the water consumption is 16 g H20/g zeolite,the Sbet is 891.2 m2.g-1,and the Vtotal is 0.91 cm3.g-1.After hydrothermal treatment,the Sbet is 298.6 m2.g-1,the retention rate is 33.5%,and the Vtotal is 0.55 cm3.g-1,the retention rate is 60.4%. |
