Distillation process optimization for styrene production from a styrene-benzene-toluene system in a Petlyuk column

• The Petlyuk column presents advantages in comparison with the conventional system.
• The Petlyuk system eliminates the condenser and the boiler of the first column.
• The Petlyuk column reduces energy consumption and improves the final product.
• A reduction of 741.1 kW energy consumption was obtained for styrene generation.

The conventional way to produce styrene is ethyl-benzene dehydrogenation, which generates benzene and toluene as byproducts. In general, the separation of these three components is made through successive reactor product distillation, first removing benzene and, then, separating toluene from benzene. The main problem with the use of conventional distillation columns is excessive energy consumption in comparison with modern separation methods. This work simulates the conventional distillation system and the coupled column system (Petlyuk), in order to compare the benefits obtained on energy economy. The results show that, while the energy consumption to feed the boilers in the conventional distillation system is 2295 kW, for the Petlyuk system the energy consumption was 1554 kW, representing energy economy of 32.3%. Moreover, with application of this method higher purity was obtained for toluene, from 76.19% to 99.67%, and for styrene, from 99.71% to 99.98%.