In this paper, the weight hourly space velocity (WHSV) is defined as the ratio of the hourly feed molar flow rate of ethanol and water mixture to the catalyst molar. The ethylene selectivity (Sethylene), the diethyl-ether selectivity (Sdiethyl-ether), the propylene selectivity (Spropylene), the ethanol conversion (Cethanol) and the ethylene yield (Yethylene) are defined as the following: