Carbon Nano Fiber Growth on Reticulated Vitreous Carbon Foam
Special Symposium - EPIC-1: European Process Intensification Conference - 1
EPIC-1: Poster Session (EPIC - Poster) - P1
Keywords: solid foam, carbon nano fibers, structured catalyst support, multiphase reactor, hairy foam
Patrick W.A.M. Wenmakers, John van der Schaaf, Ben F.M. Kuster, Jaap C. Schouten*
Laboratory of Chemical Reactor Engineering, Eindhoven University of Technology,
P.O. Box 513, 5600 MB Eindhoven, the Netherlands.
Email: j.c.schouten@tue.nl, Internet: www.chem.tue.nl/scr
Modern catalytic multiphase reactors most often use so-called structured catalyst supports, instead of the familiar randomly packed beds. A new type of structured support is the so-called solid foam. Solid foam is an open-celled structured material with a high voidage (92% to 97%) and a high surface area (760 m2/m3 to 7600 m2/m3). Due to the high voidage, the pressure drop is low, while the high surface area of the solid foam enables high gas-liquid-solid mass transfer rates. Other advantages of solid foams are the large hydrodynamic operating window (including counter-current operation), low back mixing behavior, and a high liquid hold-up. However, due to the relatively low non-porous solids holdup usually there is insufficient surface area available for deposition of a sufficient large amount of catalyst. This paper reports the increase of the foam surface layer by growing Carbon Nano Fibers (CNFs) on the solid foam surface. The resulting so-called Hairy Foam has a surface area up to 55•106 m2/m3support.
In this paper, the growth of CNFs on reticulated vitreous carbon (RVC) foam is described. In order to grow the CNFs the RVC foam is coated with a catalytic metal (nickel). The nickel is deposited by homogeneous deposition precipitation where after the Ni/RVC sample is exposed to a carbonaceous gas, methane or ethylene, at 500°C or 600°C. Methane as a carbon source does not grow CNF growth for 500°C or 600°C. Ethylene as carbon source yields a CNF layer of approx. 80 m after 10 hours. The CNFs grown at 500°C have a fiber diameter of 75 nm to 500 nm. The CNFs grown at 600°C have a fiber diameter of 15 nm to 75 nm. The porosity of the CNF layer obtained at 600°C is visually denser than the layer obtained at 500°C.
The Hairy Foam is made catalytically active by deposition of Pt-particles on the surface of the CNF. The activity of the Pt/Hairy Foam catalyst is demonstrated using oxidation and hydrogenation reactions in a laboratory-scale reactor set-up at a large range of experimental conditions. A comparison is made with the activity of traditional slurry catalyst.
Presented Wednesday 19, 13:30 to 14:40, in session EPIC-1 Poster Session (EPIC - Poster) - P1.
