Pressure control of fully heat-integrated pressure-swing distillation system using hot-vapor bypass

Fully heat-integrated pressure-swing distillation system is often more economically viable; however, the dynamic behavior of this system is subject to the effect of floating-pressure in the high-pressure column, making the control of this process a challenge. The most common way to control the pressure in distillation columns is by manipulating the coolant flow rate, but this strategy cannot be used in the heat-integrated pressure-swing distillation because of the coupling between reboiler and condenser. Therefore, this study evaluates the use of hot-vapor bypass to control the pressure of the high-pressure column of the pressure-swing distillation process applied to the separation of azeotropic acetonitrile-water system. Disturbances to the fresh feed flow rate and feed composition were performed. The scheme with dual pressure control presented the lowest average value of the IAE. Moreover, all configurations have shown satisfactory results in controlling the products' composition with an offset of less than 0.013%.