Deactivation in Continuous Deoxygenation of C18-Fatty Feedstock over Pd/Sibunit

• Published in: Topics in catalysis 2013-06, Vol.56 (9-10), p.714-724
• Main Authors: Madsen, Anders Theilgaard, Rozmysłowicz, Bartosz, Mäki-Arvela, Päivi, Simakova, Irina L., Eränen, Kari, Murzin, Dmitry Yu, Fehrmann, Rasmus
• Format: Article
• Language: English
• Subjects: Catalysis; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Industrial Chemistry/Chemical Engineering; Original Paper; Pharmacy; Physical Chemistry
• ISSN: 1022-5528; 1572-9028
• DOI: 10.1007/s11244-013-0030-5

Catalytic continuous deoxygenation of stearic acid, ethyl stearate and tristearin without any solvents was investigated using Pd/Sibunit as a catalyst in a trickle bed reactor at 300 °C. The main emphasis was to investigate the effect of gas atmosphere and catalyst deactivation. In addition to liquid-phase analysis made offline by GC, also online gas-phase analysis with IR were performed. The main liquid-phase product coming from all reactants was n -heptadecane. In addition to deoxygenation, which was observed for all substrates, also C 18 and C 16 alkanes were formed from tristearin. The relative ratios between stearic acid, ethyl stearate and tristearin conversions to alkanes after 3 days time-on-stream were 2.8/2.3/1.0, respectively using 5 % H 2 /Ar as a gas atmosphere, whereas rapid catalyst deactivation occurred with all substrates under H 2 -lacking atmosphere. The spent catalyst’s specific surface area profile along the downward reactor was maximum in the middle of the catalyst beds with the highest pore shrinking in the beginning and at the end of the reactor catalyst segments in the case of stearic acid and tristearin deoxygenation whereas that decreased consecutively as ethyl stearate passed through the reactor.