C9 Petroleum Resin Hydrogenation Catalyst Research And Continuous Process Development

C9 petroleum resins are obtained by simple polymerisation of reactive C9 fraction monomers（vinyltoluene,alpha-methylstyrene,dicyclopentadiene and indene）.C9 petroleum resins without any post-processing typically contain large amounts of unsaturated bonds and heteroatoms such as sulfur and nitrogen,are yellow to amber in color,and have poor thermal stability,which limits their use in a wide range of applications such as inks and coatings.Hydrotreating of unsaturated bonds and heteroatoms in C9 petroleum resins is an effective way to improve their physical and chemical properties,expand their range of applications and increase their added value.Due to the cross-linked molecular structure,high spatial site resistance and high activation energy of unsaturated bonds in C9 petroleum resins,the design and synthesis of hydrogenation catalysts with high activity,excellent stability and fine structure is a great challenge.In this work,the Ni/Si O₂ catalysts for the hydrogenation of C9 petroleum resins are prepared by co-precipitation.The effects of co-precipitation temperature,surfactant type and amount and other factors on the catalytic performance of Ni/Si O₂ catalysts were investigated,and the structure and appearance of the catalysts were characterised and analysed by X-ray diffraction,low temperature nitrogen adsorption and scanning electron microscopy.Optimal catalysts were selected for hydrogenation of C9 petroleum resin,process conditions were optimized,the dynamics of the hydrogenation reaction were investigated,and design of the C9 petroleum resin multi-kettle tandem continuous hydrogenation processThe effect of reaction conditions and material selection on catalyst activity has been investigated in the preparation of catalysts by co-precipitation.High-speed shear was selected as the preferred stirring method,and the effects of precipitation reaction temperature,shear rate,aging time,surfactant type and amount,and sodium water glass modulus on catalyst performance were subsequently investigated.The specific surface area of the catalyst rose from150.41 m²/g to 472.06 m²/g when the precipitation temperature rose from 50℃to 70℃.The specific surface area decreased to 390.87 m²/g when the precipitation temperature continued to rise to 90℃.The structure and catalytic performance of the catalysts prepared at 70℃were found to be optimal.The catalytic activity of the catalysts prepared at different ages gradually decreases with increasing age,as evidenced by the rise of the Gardner chromate value from 0.2to 4.7.On switching from normal stirring to high-speed shear,the surface of the prepared catalysts shows a distinct pore structure and the double bond conversion rate increases from68.33%to 84.51%.When the high-speed shear rate is increased from 300 r/min to 900 r/min,the double bond conversion rate increases from 85.28%to 96.53%.The addition of polyvinylpy-rrolidone resulted in a three-fold increase in the specific surface area of the catalyst,with double bond conversions exceeding 94%.This increase was significantly greater than that observed with the other two surfactants.The optimum process conditions were 70℃precipitation temperature,900 r/min shear rate and no aging,sodium water glass with a modulus of 1 as the silica source,and polyvinylpyrrolidone at 1%surfactant addition.The specific surface area and pore volume of the catalysts synthesised under the optimum process conditions were 472 m²/g and 0.71 cm³/g respectively,with an average pore size of 4.71 nm and a morphology of honeycomb irregular spheres composed of nanosheets,and obtained C9 hydrogenated petroleum resin has a Gardner’s chroma of less than 1,a softening point of 113.52℃,a double bond conversion rate of 96.53%.Optimized catalysts were used for the catalytic hydrogenation of C9 petroleum resin to investigate the effect of reaction temperature,hydrogen pressure,reaction time,and solvent ratio on the hydrogenation of C9 petroleum resin.The optimum hydrogenation reaction conditions were obtained with a reaction temperature of 270℃,a hydrogen pressure of 6 MPa,a reaction time of 2 h and a mass ratio of C9 petroleum resin to D40 solvent of 1:2.The hydrogenation activity of the catalyst did not significantly decrease after 7 cycles,with a double bond conversion rate of over 95%.The pore structure and morphology,as well as other characteristics of the catalysts,did not change significantly before and after hydrogenation,suggesting that the catalysts were optimised in various ways to achieve excellent activity and life-time.The hydrogenation of C9 petroleum resin saturates the olefins and benzene rings,the removal of S,Br,Cr and other ions is greater than 99%and the Gardner chroma decreases from 18 to 0.2,according to characterisation by infrared and other techniques.The optimised catalyst was used for the kinetics of the hydrogenation reaction in C9 petroleum resin,using the double bond conversion in C9 petroleum resin as an indicator.The effects of internal and external diffusion were first eliminated at a stirring rate of 400 r/min and a catalyst particle size of 400 mesh to ensure that the reaction itself was a velocity controlled step in the dynamics of the hydrogenation reaction.The relationship between the double bond concentration of C9 petroleum resin and the reaction time was determined at different reaction temperatures,and the kinetic equations were constructed by nonlinear fitting of the C9 petroleum resin double bond concentration as a function of reaction time at different reaction temperatures,and a power series model was chosen.With the help of the differential ethod the reaction stage was calculated to be 1.12 and the rate constant K was also obtained for different reaction temperatures.Combining the Arrhenius formula gives a pre-finger factor A=8.53×10¹⁰ min^-1 and a reaction activation energy E_a=127.44 k J/mol.The kinetic equation was obtained as r=8.53×10¹⁰0)^-15328.71/c_A¹.¹² and R²=0.99,with good fitting accuracy,indicating that the kinetic equation can better describe the reaction process.A catalyst scale-up production process was designed based on the laboratory catalyst preparation process,and the catalyst was successfully prepared and evaluated in both the laboratory small test and pilot test for catalytic performance,with the double bond conversion rate above 96%and the Gardner chromosity of hydrogenated products is less than 0.5,and macro kinetic data on the reaction time and double bond conversion rate of C9 petroleum resin were collected in a 2 m³pilot intermittent reactor.A continuous hydrogenation process for C9petroleum resin was designed,the process unit consisted of a high-pressure pump,dosing kettle,pre-heater,high pressure reactor,catalyst separation system and hydrogen cylinders,with multiple reactors in series,anti-corrosion material inside the reactors and piping connections between the reactors and with other units.Based on the macro kinetic data collected from the pilot plant,the volume and contact time of each reactor in the continuous hydrogenation process were calculated to be 1.5 m³ and 23.26 min,based on a capacity of 8000 tonnes per year and a96%double bond conversion rate requirement,and at the same double bond conversion requirement and labour cost,the continuous process can increase the capacity at least three times the capacity compared to the intermittent pilot process.