Mass transfer and process control in randomly packed column a case study on CO2 absorption wth NaOH

摘要

This thesis studies the mass transfer performance and presents a unified approach in process modeling of a randomly packed column useful for controlling industrial scale CO2 emissions. A case study was conducted on the carbon dioxide absorption with aqueous sodium hydroxide in the packed column. The case study conducted helped in evaluating the mass transfer by using the method of transfer units, which involves the estimation of the height of transfer unit, number of transfer units, and overall gas-phase mass transfer coefficients. The process model developed was an automatic online control and uses a feedback Proportional-Integral-Derivative (PID) Controller. Internal Model Control (IMC) and Ziegler-Nichols (Z-N) tuning methods were used to tune the PID controller based on the process dynamic model and model parameters obtained from the step tests. The overall gas-phase mass transfer coefficient (K Ga) values obtained from the experimental data are comparable to the published data in the literature.