Mother Liquor Recycling Synthesis Research Of Mesoporous Zeolites With High Performance

Amorphous pore wall of mesoporous zeolite is changed by the introduction of structural units of zeolite into pore wall of mesoporous zeolite via precursor assembly technique, which improves hydrothermal stability of it. In our group, conventional synthesis of mesoporous zeolite is synthesized in pilot scale via precursor assembly technique. However, high cost of synthesis (large amount of templating) and high water consumption greatly limit the industrial application in Residue Fluid Catalytic Cracking (RFCC). Therefor, reduction of the amount of template and water consumption is very important.After separation of assembly mother liquor and assembly product, there are numerous unreacted template and aluminosilicate species in assembly mother liquor. The template maintains the structure of micelles and equips the ability of assembly to generate mesopores. The MLR process reduces the amount of templating and water consumption leading to a significant reduction of the cost of synthesis. Comparing with the conventional method, the cost of synthesis of the MLR process reduces 24.3%. In order to achieve the pilot scale synthesis of mesoporous zeolite by MLR, mesoporous zeolite is synthesized by MLR in 10 L crystallization vessel in this paper. The results prove the good repeatability of pilot scale synthesis of products by MLR in 10 L crystallization vessel, which lay a foundation for industrial production of mesoporous zeolite by MLR.In this paper, the assembly mother liquor is recycled for five times and assembly product of each time is crystallized together. The final product is denoted as MLR-5. The consumption of templating agent (P123) is 0.99 g per g zeolite, which saves 30.8% compared with the conventional synthesis system (CS) (1.43 g template per g zeolite) and water consumption is 15.16 g H2O per g zeolite, which saves 63.9% compared with conventional synthesis system (42.01 g H2O per g zeolite). The BET surface area and total volume of MLR-5 are 806.3 m2·g-1 and 0.91 cm3·g-1, respectively. After hydrothermally treated in 100% water vapar at 800? for 10 hours, the reserved ratio values of BET surface area and total volume are 29.0% and 38.5%, indicating the high hydrothermal stability of MLR-5.Based on the result of lab test, in order to achieve the pilot scale synthesis of mesoporous zeolite by MLR, mesoporous zeolite is synthesized by MLR in 10 L crystallization vessel in this paper. The product is denoted as D-MLR. The BET surface area and total volume of D-MLR are 865.3 m2·g-1 and 0.96 cm3·g-1, respectively. After hydrothermally treated in 100% water vapar at 800? for 10 hours, the reserved ratio values of BET surface area and total volume are 25.0% and 52.1%, indicating the high hydrothermal stability of D-MLR. The repetitive inspection is carried out under optimal conditions for three times. The results prove the good repeatability of pilot scale synthesis of the product by MLR in 10 L crystallization vessel, which lay a foundation for industrial production of mesoporous zeolite by MLR.