Liquid Phase Crystallization Of Sapo - 34 Molecular Sieve Prepared By The Pilot Study

SAPO-34molecular sieve is considered as a suitable catalyst for methanol to low-carbon olefins (MTO) system recently, with higher methanol conversions and superior selectivity of ethylene and propylene. Liquid-phase Crystallization Method is one of preparing SAPO-34methods that have obtained patents. With the above method, pilot amplification experiments and research have been conducted, and has laid the foundation of its industrialization.According to the experimental data of lab test, Liquid-phase Crystallization Method can be split into three steps:First is raw material industrialization, that is choosing industrial raw materials than reagent; Second, mixing process amplification, in which using pilot equipment in mixing process on the basis of industrial raw materials; the last is crystallization process amplification, which means conducting crystallization amplification process based on pilot amplification test of the mixing process.In the stage of raw materials industrialization, specific contents of the experiment as follows:Utilizing industrial materials to research the effects of raw materials in the process. So a beaker (D=90mm,V=0.25L) is used as mixing device and a stainless steel autoclave(De=60mm,V=0.2L) as crystallization facility; Second stage, take use of a glass guide channel mixing device with dimension300mm and volume25L, in order to research the effect factors such as agitating type, stirring power, mixing speed in amplificatory process; Crystallization stage, by using a stainless steel autoclave (De=500mm,V=50L) to research the influence of crystallization time, and temperature.By analyzing the results, the optimum operating condition is chosen to be:using industrial raw materials and double row leaf agitator with variable power constant speed of140r/min in mixing process, and crystallization temperature is180℃and the time is120h.This paper analyses the effect factors, and presents a performance evaluation on SAPO-34molecular sieve in the pilot amplification experiment that used liquid crystallization method. The result is that:the conversion of methanol has reached95%, and the total selectivity of ethylene and propylene has been up to77%.