Aim and Objective:
The research focuses on recent progress in the production of light olefins.
Hence, the common catalyst of the reaction (SAPO-34) deactivates quickly because of coke
formation, we reorganized the mechanism combining SAPO-34 with a natural zeolite in order to
delay the deactivation time.
Materials and Methods:
The synthesis of nanocomposite catalyst was conducted
hydrothermally using experimental design. Firstly, Clinoptilolite was modified using nitric acid
in order to achieve nano scaled material. Then, the initial gel of the SAPO-34 was prepared using
DEA, aluminum isopropoxide, phosphoric acid and TEOS as the organic template, sources of
Aluminum, Phosphor, and Silicate, respectively. Finally, the modified zeolite was combined with
SAPO-34's gel.
Results:
20 different catalysts due to D-Optimal design were synthesized and the nanocomposite
with 50 weight percent of SAPO-34, 4 hours Crystallization and early Clinoptilolite precipitation
showed the highest relative crystallinity, partly high BET surface area and hierarchical structure.
Conclusion:
Different analysis illustrated the existence of both components. The most important
property alteration of nanocomposite was the increment of pore mean diameters and reduction in
pore volumes in comparison with free SAPO-34. Due to low price of Clinoptilolite, the new
catalyst develops the economy of the process. Using this composite, according to formation of
multi-sized pores located hierarchically on the surface of the catalyst and increased surface area,
significant amounts of Ethylene and Propylene, in comparison with free SAPO-34, were
produced, as well as deactivation time that was improved.
