Dynamic Simulation of the CO ₂ Cryogenic Separation Process

This study develops steady‐state and dynamic models of a CO 2 cryogenic separation process using Aspen HYSYS, focusing on control and operational robustness. The sensitive tray in the purification tower is identified using slope and sensitivity criteria, and PID controllers are applied with parameters tuned by empirical and relay autotuning. A representative steady‐state period shows that key variables, including flow rates, air release, liquefier cold load, reboiler heat load, subcooler cold load, CO 2 recovery, and outlet temperatures, remain constant for up to 5 h, confirming stable operation. Dynamic performance is analyzed under typical disturbances, including a 10% increase in feed flow rate, a 2% increase in feed CO 2 content, and a 10°C increase in feed temperature. Results indicate that increasing feed flow rate causes the strongest system‐wide transients and the largest impact on energy consumption. A 2% increase in CO 2 content has minimal effects, while feed temperature mainly affects condenser/reboiler thermal behavior. This work establishes an integrated framework for steady‐state validation, sensitive‐tray identification, disturbance‐response analysis, and energy sensitivity assessment, providing valuable guidance for CO 2 cryogenic separation units.