CATALYTIC-HYDROGENATION OF AROMATIC-HYDROCARBONS IN A TRICKLE-BED REACTOR

The hydrogenation of the main components of an anthracene oil has been investigated in a cocurrent downflow trickle bed reactor at 623 K and 9.8 MPa. The catalyst employed was sulfided Ni-Mo/gamma-Al2O3. The pr oduct of the effectiveness factor and chemical rate constant was deter mined for the reactions involved in the hydrogenation of naphthalene, acenaphthene, phenanthrene, anthracene, fluoranthene and pyrene. React ion rates were expressed as a weighted average of the rate on the liqu id-covered surface and on the dry surface. The external surface of the catalyst was considered to consist of a dynamic and a low liquid rene wal area. The latter, identified as the area wetted by stagnant liquid , was assumed to be not reactive. The product of the effectiveness fac tor and the intrinsic rate constant were determined for dry and wetted catalyst surfaces by employing an estimation of the unit fraction of inactive surface. An estimation of the effectiveness factors was perfo rmed by employing the kinetic constants previously determined by Rosal et al. (Ind. Eng. Chem. Res., 31 (1992) 1007-12). The results showed that the effectiveness factor for the wetted surface followed a patter n in good agreement with theoretical predictions and was especially lo w for the hydrogenation of anthracene, a reaction whose rate was relat ively high. (C) 1988 SCI.