An Investigation into Eicosane Hydrocracking Using a Simple Micro-Bomb Reactor

Abstract

A simple micro-bomb reactor (Fig. 1) has been constructed to facilitate rapid accumulation of experimental data for heavy oils reaction. With this apparatus, hydrocracking of eicosane has been examined at 450°C and under an initial hydrogen pressure of 7.9 MPa by varying the reaction period (t) from 9 to 180 min. The conversion of eicosane has been significant in that it reached more than 90% at t=180 min, producing paraffinic (C1-C19) and olefinic (C2-C19) hydrocarbons (Figs. 2 and 3). Although the results appeared complicated, a close inspection of the experimental data revealed an interesting aspect of bonds reptures in the initial stage of the eicosane reaction. Namely, the radical pairs formation has been considered to be the initiation of the reaction. The evidence is as follows: (1) Yield ratios for every j~20—j pairs converge to 1.0 at t=0 (Fig. 4). (2) Degree of production of hydrocarbons with a carbon number of j and that of hydrocarbons with a carbon number of 20 — j can be extrapolated to the same value at t=0 (Figs. 5 and 7). (3) Degree of production of a paraffinic hydrocarbon with a carbon number of j and that of an olefinic hydrocarbon with the same carbon number can be extrapolated to the same value at t=0 (Fig. 8). On the basis of these experimental results, a curve representing the initial concentration distribution of ten different radical pairs has been presented (Fig. 7). The use of molten tin as a catalyst has little affected the mode of the initiation reaction of the eicosane hydrocracking (Figs. 9~11), though the catalyst has prevented higher hydrocarbons from decomposing to lower ones, in particular C1-C3 gases (Figs. 9~11). © 1988, The Japan Petroleum Institute. All rights reserved.