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3 Monitoring and control (1 questions)
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A closed-loop control system for a chemical reactor temperature control would typically involve the following components:
| Temperature Sensor |
| Controller (e.g., PID controller) |
| Actuator (e.g., Heater/Coolant Valve) |
Block Diagram:
+-----------------+ +-----------------+ +-----------------+
| Temperature |----->| Controller |----->| Actuator |
| Sensor | | (PID Algorithm) | | (Heater/Valve) |
+-----------------+ +-----------------+ +-----------------+
^ |
| |
+----------------------------------------------+
|
| Setpoint (Desired Temperature)
|
Function of each component:
- Temperature Sensor: Measures the reactor temperature and provides a feedback signal to the controller.
- Controller: Compares the measured temperature to the setpoint and calculates the control signal needed to adjust the actuator. A PID (Proportional-Integral-Derivative) controller is commonly used.
- Actuator: Adjusts the reactor temperature by adding heat (e.g., by opening a heater) or removing heat (e.g., by opening a coolant valve).
Potential Sources of Error and Mitigation:
- Sensor Error: Inaccurate temperature readings can lead to incorrect control actions. Mitigation: Use a high-quality, calibrated temperature sensor. Implement sensor redundancy (multiple sensors).
- Actuator Lag: The actuator may take time to respond to the control signal. Mitigation: Use a controller with a suitable tuning to compensate for lag. Consider using a faster actuator.
- Disturbances: External factors (e.g., changes in ambient temperature, changes in reactant flow rate) can affect the reactor temperature. Mitigation: Design the controller to be robust to disturbances. Implement feedforward control to anticipate disturbances. Use a temperature jacket to maintain a more stable environment.
- Controller Tuning: Incorrectly tuned controller parameters can lead to instability or poor performance. Mitigation: Use appropriate controller tuning techniques (e.g., Ziegler-Nichols method). Implement adaptive control to adjust controller parameters online.