Ni catalysts supported on activated carbon from petcoke and their activity for toluene hydrogenation

Petroleum coke (petcoke) is an abundant resource that can potentially be converted to catalyst support materials through activation to increase the surface area and reduce the sulphur content. In this work, potassium hydroxide (KOH) catalysed activation was employed with petcoke to produce activated carbons, which were characterised with nitrogen physisorption, X-ray diffraction, scanning electron microscopy and temperature-programmed reduction. With activation temperatures between 500 and 800 degrees C, the surface area increased from 4?m2/g to between 200 and 2400?m2/g while the sulphur content was reduced from 6.6?wt% to between 1 and 0.2?wt%. Nickel catalysts (nominally 5?wt%) were prepared on the activated carbon supports using wet impregnation. The activities of these catalysts were measured for toluene hydrogenation in a plug-flow reactor with a toluene liquid hourly space velocity of 2.4/h, a pressure of 1.38?MPa, and a H2/toluene mole ratio of 90. The catalytic activity varied between zero for nickel supported on petcoke to 98% conversion, with essentially 100% to methylcyclohexane for nickel supported on carbon activated at 750 degrees C. Thus, activated carbon from petcoke was a suitable support for Ni-based catalysts when used for toluene hydrogenation as a model reaction. (C) 2011 Canadian Society for Chemical Engineering