Ethylene production from petroleum or natural gas is an energy intensive process. Bio-ethanol catalytic dehydration to ethylene is an attractive alternative for oil based ethylene. Catalytic dehydration conversion of bio-ethanol to ethylene using HZSM-5 modified by 3 wt% rare earth metal (lanthanum) was carried out in a laboratory bioreactor. The physicochemical properties of the catalyst were characterized. The stability test showed that ethanol conversion and selectivity over this catalyst could be maintained above 98% for more than 950 h. The regenerated catalyst also displayed high reactivity and stability of up to 830 h can be obtained. The effects of temperature, liquid hourly space velocity, particle size of catalyst, and bio-ethanol partial pressure on products formation rate were investigated. The external and internal diffusion resistances were eliminated and the kinetic control range was identified. An apparent kinetics model was used to describe the dehydration reaction of ethanol over 3 wt% La-HZSM-5 catalyst, and the kinetic parameters were determined.
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The authors gratefully acknowledge the funding from the National High-technology Research and Development Program of China (2006AA020101, 2007AA02Z213) and the National Program of Key Basic Research in China (2007CB707801).