Application of the dividing wall column to olefin separation in fluidization methanol to propylene (FMTP) process

Dividing wall column (DWC) is shown to be energy efficient compared to conventional column sequence for multi components separation, which is used for olefin separation in fluidization methanol to propylene process in the present work. Detailed design for pilot DWC was performed and five control structures, i.e. composition control (CC), temperature control (TC), composition-temperature control (CC-TC), temperature difference control (TDC), double temperature difference control (DTDC) were proposed to circumvent feed disturbance. Sensitivity analysis and singular value decomposition (SVD) were used as criterion to select the controlled temperature locations in TC, CC-TC, TDC and DTDC control loops. The steady simulation result demonstrates that 25.7% and 30.2% duty can be saved for condenser and reboiler by substituting conventional column sequence with DWC, respectively. As for control structure selection, TC and TDC perform better than other three control schemes with smaller maximum deviation and shorter settling time.