Study On The Catalytic Hydrogenation Of C9 Petroleum Resin

The C9 petroleum resin is an important thermoplastic resin, which is synthesized by the polymerization of C9 byproduct originates from the ethylene production. It has been widely used in adhesives, road paints, inks and rubber industries because of its outstanding viscosity, excellent miscibility with other oils and resins. However, abundant of unsaturated double bond, S2-, and Cl- present in the C9 petroleum resin, which leads to higher chromaticity and lower thermal stability, and limits its application. In order to improve its added value, the chemical modification for petroleum resin is conducted by hydrogenation, which is one of general and effective method.Firstly, taking the composition of C9 petroleum resins into consideration, the evaluation of catalyst was carried out in 5 mL continuous stirred tank reactor with high-pressure. The Ni/y-Al2O3 catalyst exhibited excellent catalytic performance. And then the univariate analysis was studied in lab scale high-pressure fixed-bed reactor, including temperature, pressure, volume ratio of hydrogen-oil, liquid hourly space velocity and the concentration of petroleum resin. Moreover, the Gardner color, softening point, bromide value of C9 petroleum resins was also characterized.Secondly, the structure properties of catalyst were determined by H2-TPR, XRD and N2 physical adsorption techniques. On the basic of characterization, the suitable reduction temperature for catalyst was 320℃, and no obvious change for the crystal phase of Ni was observed after running 30 days in the reaction. The catalyst was suitable for the hydrogenation of petroleum resins due to the narrow pore size distribution which was mainly concentrated in the 5-12 nm. In addition, the optimal reaction conditions as reaction temperature of 260℃, reaction pressure of 18 MPa, the concentration of 20 wt.%, liquid hourly space velocity of 600:1-800:1, the hydrogen-oil volume ratio of 0.6-0.8 h"1, was also determined. After hydrogenation, the resins color became very light-colored or water-white. The bromine value was declined to ca.1 g Br2/100 g, and the softening temperature was just decreased slightly.Based on the lab-scale results, the pilot-scale experiment was performed. The influence of liquid hourly space velocity and reaction temperature was further investigated. After reaction, the specific surface area and pore volume of catalyst was not changed obviously, indicating that the catalyst exhibited excellent stability. It was noteworthy that 3%-4% of hydrogen consumption and more than 95% of C9 petroleum resin yield was obtained. Finally, the ratio of new hydrogen and cycle hydrogen gas, new hydrogen gas and those sent to stripping tower, and the optimized reaction temperature in each stage (first stage:280℃, second stage:260℃) were also determined. These obtained process packet lays a foundation for the subsequent industrialization of C9 petroleum resin.