Control strategy for multi-column continuous periodic counter current chromatography subject to fluctuating inlet...

Area of Science:

• Chemical Engineering
• Chromatography
• Process Control

Background:

• Controlling continuous multi-column counter-current chromatography (CCC) systems is challenging due to fluctuations in inlet feed stream concentration.
• Standard control methods struggle to maintain consistent performance under variable feed conditions.

Purpose of the Study:

• To develop a novel control strategy for CCC systems that is independent of inlet feed concentration fluctuations.
• To improve the robustness and processing capabilities of CCC for unstable feed streams.

Main Methods:

• A new control strategy based on calculated product column breakthrough using UV sensor signals.
• The method utilizes the impurity-to-product ratio, neglecting the impurity baseline.
• In-silico simulations and experimental application to a three-column periodic counter-current chromatography (PCCC) process.

Main Results:

• The proposed method accurately calculates product column breakthrough even with highly unstable inlet feed concentrations.
• Constant column loading was achieved in each cycle using the new strategy, unlike the standard method.
• Band broadening from diffusion and dispersion identified as a limiting factor for breakthrough calculation.

Conclusions:

• The advanced calculation method significantly increases the robustness of PCCC.
• This strategy extends the capability of CCC systems to process unstable inlet streams effectively.
• The impurity-to-product ratio offers a reliable metric for breakthrough detection independent of feed variability.