| Summary: | 博士 === 國立成功大學 === 化學工程研究所 === 83 === High aromatics content in diesel fuel lowers fuel quality and
contributes significantly to the formation of undesired
emissions in exhaust gases . Because of the health hazards
associated with these emissions , the environmental regulations
governing the composition and limitations of aromatics in
diesel fuels are being tightened in the developed nations . In
this work , biaromatic compound naphthalene dissolved in n-
hexadecane was used as a model compound to simulate aromatics
in diesel fuels . Platinum is the most active noble metal
supported on γ-Al2O3 for aromatic hydrogentation at high
pressure . The optimal content of Pt was about 0.6-1.0 wt% .
The Pt/AAPx(alumina-aluminum phosphate) and Pt/ABx(aluminum
borate) catalysts have better aromatic hydrogen-ation activity
and thioresistance , but a lower cis-decalin selectivity than
Pt/γ-Al2O3 due to the more acidity of AAPx and ABx supports
than γ-Al2O3 . Large pore size of Pt/AAPcatalyst can be
obtained with good hydrogenation activity and thioresistance .
Adding phosphorus or boron to γ-Al2O3 support can improve the
aromatic hydrogenation activity and thioresistance of Pt/γ-Al2
O3 catalyst . But the activity and thioresistance of Pt-Px/Al2
O3 is not so good as Pt/Bx-Al2O3 catalyst . Experimental
results also in- dicate that more sulfur can be adsorbed on
catalyst at lower temperature , higher sulfur concentration and
low hydrogen pressure. The hydrogenation activity and
selectivity were investigated by using a reaction network
including isomerization of decalin and a power-law kinetic
model . The rates of tetralin hydrogen- ation and cis-decalin
isomerization could be described by pseudo- first-order
kinetics in excess hydrogen . The apparent activation energy
for hydrogenation of tetralin to cis-decalin and trans- decalin
are 9.88 and 7.25 kcal/mole, respectively .
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