| Summary: | 碩士 === 逢甲大學 === 化學工程學所 === 93 === Along with environmental consciousness rising, any developments and applications which may be able to pollute the ecology will be restricted. In accordance to this green trend, searching for new energies and their development have become an important issue. Among all of the new types of energy, the evolution of hydrogen energy receives the most attention.
The goal of this study is to focus on hydrogen production by autothermal steam reforming of ethanol in a palladium-silver alloy membrane reactor. Hydrogen which only permeates through a palladium-silver alloy membrane can be collected on the permeation side with high purity. The palladium-silver alloy membrane tube used for this experiment was made by eletroless plating technique, with an overall thickness of about 30μm. An industrial catalyst MDC-3 was employed for autothermal steam reforming of ethanol reaction. The operating temperatures ranged from
320℃ to 450℃ and the pressures between 3atm to 9atm. The reactant of water/ethanol molar ratio is 1:1, the O2/ethanol molar ratio ranging between 0 to 0.7, and varying feed rate between 0.39 to 0.63 mL/min ( WHSV= 5 ~ 8 h-1). The experimental results show that the amount oxygen feed to the reactor will determine the thermal equilibrium of total reaction. It is a steam reforming reaction at nO2/nC2H5OH = 0, which is an endothermic reaction, so there is an optimal ethanol conversion of 82.07% at the lowest pressure and highest temperature (P= 3 atm, T= 450℃). When nO2/nC2H5OH = 0.7, the total reaction is dominated by the partial oxidation of ethanol, which is exothermic. At nO2/nC2H5OH = 0.2, the total reaction tends to be an endothermic reaction, but it behaves like a steam reforming reaction at high temperatures while at the low temperature (T= 320℃) the ethanol conversion is still promoted to 62% due to the presence of oxygen. At nO2/nC2H5OH = 0.2, WHSV= 8 h-1, 9 atm, and 450℃, the maximum fluxes of hydrogen of 122.89 mole/m2*h is obtained due to high feed rate and high ethanol conversion.
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