A Novel Process for Styrene Monomer Production with CO₂ Utilization and Membrane Process

In this paper, the process of toluene methylation to produce styrene monomer replaced the conventional process of ethylbenzene dehydrogenation with two fix bed reactors and a H_SOD membrane for separation of H₂O from the formaldehyde. It is observed that optimization of reactors used in the proposed process will increase the production of final outputs, so by optimizing the formaldehyde synthesis reactor, by adjusting the temperature near 150 °C and the pressure at 600 kPa, the reactor conversion rate would reach 98.80%, and with optimization of the styrene production reactor by adjusting the temperature to 300 °C and the pressure at 300 kPa, the reactor conversion rate reaches 99.09%. It is also observed that the steam injection is eliminated and consequently CO₂ and by-products production decreases down to zero, while the cost of process reduces by 69.81%. In the fractionation section, it is proposed that separation of reaction products would be performed by H_SOD membrane for the formaldehyde/H₂O mixture and the three-phase separator (V-100) would be responsible for separation in styrene monomer/H₂O mixture.