Studies on Aromatic Hydrogenation Catalysts and Kinetics

• Main Authors: Ben-Chang Kang, 康文成
• Other Authors: Ting-Chia Huang
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/95581844386595119599

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 .