Research And Simulation Of Mixed-C₄ Oligomerization Catalytic Distillation Process

The production of mixed-C4 olefin is large and increasing year by year, but the chemical utilization ratio is very low. It is very significant to develop a new processing technic of butene to produce high value-added fine chemical products in the development and utilization of olefin resource. This paper combined the catalytic distillation with the mixed-C4 oligomerization and examined the influence of operation factors through experiment. Based on the experiment, the paper chose a mathematical model to simulate this catalytic distillation process and compared the simulation results with the experiment results. And the simulation was proved to be feasible.The paper studied the operational status changes over time by carrying out the catalytic distillation experiment and found that the system went into steady state after 180min. In the steady state, the operation factors, such as the tower bottom temperature, reflux ratio, feed location and rate, which would influence the conversion and selectivity of the process, were examined. It was found that when the bottom temperature rose, the conversion would increase but the dimer-selectivity changed in shape of a parabola. When the reflux ratio increased, the conversion increased too but the dimer-selectivity declined. If the feed rate increased, the result would be reverse of the reflux ratio's. The change of feed location influenced the conversion not so much, but if the feed location was at the bottom of the reaction section, the dimer-selectivity would decrease. And it was disadvantageous for the process if the reflux temperature was very low. Taken together, the optimum process conditions were as follows: tower bottom temperature 110℃, feed rate 10 ml/min, feed location in the middle or the top of reaction section, reflux ratio and reflux temperature not too low.Based on the experiment, this paper simulated the process with the non-equilibrium stage rate model. It was found that the change of variables in line with the experimental operation. Under the given conditions, the simulation results were compared with experimental results in good agreement. At the same time the program was investigated by changing the feed rate, reflux ratio, feed location and other factors. The average error of simulation results was within 10% and the results agreed with the experimental laws well, indicating non-equilibrium rate model could be applied to the simulation of mixed-C4 Oligomerization catalytic distillation process.