Automated Simultaneous Process Control for Continuous Protein Purification
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Solution Overview
Problem
In continuous protein purification processes, maintaining specific pH and conductivity levels while managing the fill level of intermediate surge tanks is challenging due to interdependent process characteristics and occasional interruptions in the input stream, requiring an advanced automated control strategy to maintain tight operation limits.
Innovation Solution
Implementing a method for automated simultaneous control of multiple process characteristics using a combination of feed forward regulation and feedback control, with subsystems for controlling multiple actuators influencing the same conditioning volume, allowing for real-time adjustments of pH, conductivity, and fill level management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple actuators are controlled simultaneously to adjust pH and conductivity in a surge tank, then process characteristics can be maintained within acceptable ranges, but the complexity of the control system increases
Solution Approach 1:
The control system is segmented into multiple independent control loops, each responsible for a specific process characteristic (pH, conductivity, fill level). Each loop independently controls its designated actuator based on sensor feedback, avoiding the complexity of coordinating multiple actuators simultaneously while maintaining precise control of each parameter
Solution Approach 2:
The system performs preliminary detection and calculation for each actuator before actuation. Sensors continuously monitor process characteristics, the control system calculates required adjustments in advance, and actuators are commanded sequentially based on pre-computed values, simplifying the control logic while maintaining precision
2Manufacturing precision
If tight operation limits are maintained for all process characteristics, then product quality is ensured, but the system becomes less adaptable to input stream interruptions
Solution Approach 1:
The system employs continuous feedback control where sensors monitor process characteristics and feed this information back to the control system. When interruptions occur, the feedback mechanism detects deviations from setpoints and automatically adjusts actuators to restore tight operation limits, thereby maintaining both precision and adaptability
Solution Approach 2:
The control system dynamically adapts its behavior based on real-time conditions. During normal operation, it maintains tight control limits; when interruptions are detected, it dynamically adjusts control parameters and actuator responses to handle the abnormal situation while striving to return to tight control once normal conditions resume
3Manufacturing precision
If pH and conductivity set agents are added to adjust process characteristics, then the next unit operation requirements are met, but the fill level of the surge tank becomes difficult to control
Solution Approach 1:
The control of fill level is segmented into a separate control loop independent of pH and conductivity control. A dedicated sensor monitors fill level and a separate actuator (such as a discharge pump or valve) is controlled based on fill level measurements, while pH and conductivity control use their own actuators. This segmentation prevents the fill level from becoming difficult to control when chemical agents are added
Solution Approach 2:
The surge tank fill level acts as an intermediary variable that mediates between the addition of set agents and the output stream requirements. By independently controlling the fill level through a separate feedback loop, the system uses the fill level as a buffer to accommodate the volume changes caused by adding pH and conductivity set agents without compromising the quality of the output stream
Data Source
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AI summary
Described herein is a method and a system for automated simultaneous control of at least two process characteristics of a continuous production process with at least one fluid stream, at least two unit operations, at least one process control system and at least one conditioning volume.