Analysis and comparison of RD and SRC involving consecutive reaction of chlorination of toluene

Compared to a conventional reactive distillation(RD)process combining reaction and separation in a single unit, the distillation column coupled with side reactors(SRC)as an advanced integrated reaction and separation technology can be applicable to the reaction system whether the conditions for reaction and separation are harmonious or mismatched. For the typical consecutive reaction system of benzyl chloride production, the mathematic models of RD and SRC were firstly established. On this basis, under the same total column stages and bottom vapor boil-up rate, process simulation was performed for the given RD and SRC processes, in which the pressures for reaction and separation were set to 101.3 kPa. The results showed that there were consistent vapor and liquid flow rates, temperature, and composition profiles in the given RD and SRC flowsheets. Furthermore, for the given RD and SRC processes operated under the same pressure of 101.3 kPa, and the SRC process, in which the pressures for reaction and separation were respectively fixed at 101.3 and 10 kPa, feed flow rate of chlorine and distribution ratio of chlorine as two critical variables deciding production capacity were optimized by minimizing total costs. Optimization results showed that consistent system performance was achieved in the RD and SRC processes operated under 101.3 kPa, while obviously increased production capacity and improved product purity were observed in the SRC process with reaction and separation operated under different pressures.