Study On Synthesis Of Zeolite Beta At Low Costs

Zeolite Beta is a promising catalytic material. At the present time, the dominating synthetic method is hydrothermal synthesis, which restricts the application of industry to zeolite Beta because of complex synthetic process and high costs. The studying on the new synthetic method means signality.The experiment is based on synthesis of zeolite Beta at low costs, so hydrothermal synthesis and steam-assisted synthesis are compared. By the betterment on the process of dry gel conversion of steam-assisted synthesisand introducing a cheap template TEABr, a new synthetic method-solid-phase synthesis is obtained. XRD, SEM and FT-IR indicate that the structure of zeolite Beta by solid-phase synthesis is good. Compared with steam-assisted synthesis and hydrothermal synthesis, solid-phase synthesis is promising and economical, which simplifies the synthetic process and reduce the costs.In this paper, the effect of crystallization temperature, crystallization time, alkalinity, the amount of template on the crystallinity of products is studied. The results indicate that when SiO₂ is used as silicic source, NaAlO₂ as aluminium source, TEABr as template, the best condition of technics is ( SiO₂/Al₂O₃=30): OH^-/SiO₂=0.40, TEABr/SiO₂=0.15, 4% crystal introduced ( compared with the total mass of silicic source ), 130℃as crystallization temperature 4 days as crystallization time. On this condition, the structure of zeolite Beta is good and the intensity of MOR is lower.During the process of small scale in the laboratory, the method of pretreatment of raw material is confirmed, which provides experimental evidence for the industrialisation on solid-phase synthesis of zeolite Beta. Large scale repeats the result of small scale, and the crystallinity of products is higher and MOR is lower. The product of large scale as assistant catalyzer is introduced into main catalyzer for FCC reaction ( especially heavy Oil, usually petroleum residue ), which can obtain more propylene and improve the amount of translation of raw material and liquid. By analyzing the problem of large scale, it seems that the concentration of TEA⁺ is differdnt in the reactive system and Br^- existed in TEABr leads to the small amount of TEA⁺, which block the effective formation of products and reduce the amount of translation. The experiment attempts three disposal methods which are conglutinate churning up and mill to improve the output. The results indicate that mill is better. The output reaches 70% which is 10% higher than before.