How is the feed rate to the distillation tower adjusted automatically?
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Our plant’s distillation tower is fed with two streams, which enter the tower after being washed. Simply put, Flow A + Flow B = Total Flow C after washing. Flow rate A is subject to cascade control based on the liquid level in the reflux tank and the production flow rate, so it varies. Flow rate B is adjusted in response to the fluctuations in flow rate A; it also has control valves and flow meters, which ensure that flow rate C remains relatively stable. Failure to adjust it in a timely manner can cause fluctuations in the liquid level of the other tower. How to achieve automatic adjustment, for example, when flow rate A increases, flow rate B decreases automatically to keep flow rate C at a constant level.
In this case, an automatic control system can be used to regulate the flow rates of streams A and B, ensuring a stable total flow rate for stream C. The specific implementation steps are as follows: 1. Install flow sensors: Install flow sensors on the flow pipelines at points A and B respectively to monitor flow changes in real time. 2. Use a PID controller: Adjust the control valves for flows A and B using a PID controller. Set C flow as the control target, and A and B flows as input variables. 3. Set up a feedback loop: Feed the detection results from the flow sensor back into the PID controller, and automatically adjust the opening degree of the control valves for flow A or B based on the difference between the set value and the actual value of flow C, in order to maintain stability in flow C. 4. Set the control strategy: When flow rate A increases, the control system automatically reduces flow rate B ； When the flow rate of A decreases, the flow rate of B is increased accordingly to keep the total flow rate of C constant. 5. Monitoring and optimization: After implementation, continuously monitor the system’s operating status, and optimize the PID parameters based on the actual performance to improve control accuracy and response speed. Through the above steps, automatic balance adjustment of the feed flow rates for streams A and B can be achieved, ensuring stability of the total flow rate in distillation column C. .
This post was last edited by jlshnlhj on 2025-2-8 08:43: create a data setter to store the C flow setting value --> adder (add a negative value): C setting value – A_PV value --> B controller setpoint. Be sure to maintain consistency in physical units.
A represents backflow; when the load does not change much, the amount of backflow remains constant, and it is the production volume that is adjusted. Distillation operations rely on three key equilibria; frequently changing the reflux flow rate is not reasonable from an operational perspective.