Xie Zaiku

Influence of alkalinity on particle size distribution and crystalline structure in synthesis of zeolite beta

Abstract Influence of alkalinity (OH-/SiO2) on particle size distribution and crystalline structure in synthesis of zeolite beta at a short crystallization period (60 h) has been studied. The results indicate that the highest crystallinity of synthetic zeolite beta at alkalinity of 0.24, 0.35 occurs when Al2O3·H2O and NaAlO2 are respectively used as aluminium sources. At an alkalinity higher than 0.39, zeolite beta can not be obtained when Al2O3·H2O is used as aluminium source. The difference of particle sizes between zeolite beta synthesized from gels of different alkalinity is 0.7–0.8 μm. The widest particle size distribution of zeolite beta synthesized occurs when the alkalinity is 0.23–0.24. Along with the increase of the alkalinity, zeolite beta synthesized changes as follows: vibration peak of 1071 cm−1 by IR moves to a higher position, the framework Si/Al ratio determined by 29Si MAS NMR first increases gradually and then decreases, but the change of OhAl/TdAl ratio determined by 27Al MAS NMR is contrary to that of the framework of the Si/Al ratio. In addition, the Si(O−) site existing in the TEA-β is confirmed by NMR, and the mechanism of alkalinity influencing crystallization is discussed.

Petrochemical technology innovation and prospects facing resources and environment challenges

At present, Chinas petrochemical industry is facing significant challenges of resources and environment. Innovation of petrochemical technologies is very important for promoting the sustainable development of Chinas petrochemical industry and ensuring national energy security. This article gives some examples of innovation practices on reaction engineering, process coupling and strengthening, new catalytic material developments and integrated innovation in recent years, and summarizes some experience and understanding on innovation concept and innovation ways, etc. Finally, on the basis of analyzing the future trend and demand of petrochemical industry, outlook and suggestions are given on enhancing technological development and innovation for Chinas petrochemical industry.