Nano-sized zeolite supported catalysts and methods for their production
According to one or more embodiments described, a zeolite supported catalyst may be synthesized by a process that includes combining a colloidal mixture with a metal oxide support material to form a support precursor material, processing the support precursor material to form a support material, and impregnating the support material with one or more metals to form the zeolite supported catalyst. The colloidal mixture may include nano-sized zeolite crystals, and the nano-sized zeolite crystals may have an average size of less than 100 nm.
1. A method for synthesizing a zeolite supported catalyst suitable for hydrocracking reactions, the method comprising:
combining a colloidal mixture with a metal oxide support material to form a support precursor material, where the colloidal mixture comprises nano-sized zeolite crystals having an average size of less than 100 nm, and the metal oxide support material comprises a small pore size metal oxide having a pore volume of from 0.4 mL/g to 0.6 mL/g and a large pore size metal oxide having a pore volume of from 0.8 mL/g to 1.2 mL/g;
processing the support precursor material to form a support material; and
impregnating the support material with one or more metals to form the zeolite supported catalyst.
2. The method of claim 1 , where the colloidal mixture is formed by autoclaving a mixture containing at least a quaternary ammonium salt, silica, alumina, and water.
3. The method of claim 2 , where the quaternary ammonium salt is tetramethylammonium hydroxide.
4. The method of claim 2 , where the mixture containing at least quaternary ammonium salt, silica, aluminum, and water has a molar ratio of:
1 mole of alumina;
from 15 moles to 35 moles of the quaternary ammonium salt;
from 20 moles to 80 moles of silica; and
from 250 moles to 1000 moles of water.
5. The method of claim 1 , where the small pore size metal oxide is combined with the colloidal mixture comprising nano-sized zeolites before the large pore size metal oxide is combined with the colloidal mixture comprising nano-sized zeolites.
6. The method of claim 1 , where the support precursor material further comprises nitric acid.
7. The method of claim 1 , where the metal oxide support material is alumina.
8. The method of claim 1 , where the metal oxide support material is porous alumina.
9. The method of claim 1 , where the step of processing the support precursor material comprises drying the support precursor material to form an extrudable material.
10. The method of claim 1 , where the step of processing the support precursor material comprises shaping the support precursor material.
11. The method of claim 10 , where the support precursor material is extruded.
12. The method of claim 1 , where the step of processing the support precursor material comprises hydrothermally treating the support precursor material.
13. The method of claim 12 , where hydrothermally treating the support precursor material comprises exposing the support precursor material to a pressure of from 2 bar to 4 bar and at a temperature of from 450° C. to 600° C. for 0.5 hours to 3 hours.
14. The method of claim 12 , where the hydrothermal treatment produces self-generated steam.
15. The method of claim 1 , where the step of impregnating the support material comprises contacting the support material with a solution comprising one or more metal catalyst precursors, where the metal catalyst precursors comprise one or more of Ni, W, Mo, Co.
16. The method of claim 1 , where the step of processing the support precursor material comprises shaping the support precursor material followed by hydrothermally treating the support precursor material.