pH Control
Description
This experiment involves the control of a liquid-phase reactor to neutralize acid-base streams. As in all control situations, the initial approach is to understand and analyze the reactor dynamics followed by the design and implementation of a control scheme. A buffer stream can also be introduced into the reactor as a disturbance. You have the potential to control several reactor parameters: liquid flows (in and out), reactor volume, reactor stirring, etc. There are any of several control schemes that can be implemented, from simple PID to MIMO. You are to choose a scheme, collect appropriate data on dynamics, implement the scheme, and evaluate the resulting controlled dynamics.
Suggested initial experiment
Develop a correlation between the buffer stream value position and the buffer stream flow rate that allows a desired buffer flow rate to be established manually. Determine operating conditions that provide a neutral pH. Use the PI tuning parameters for the acid, base, outlet flow and level controllers obtained by the previous group. Collect dynamic process data by introducing various step changes in the acid, base and buffer flow rates. Develop a dynamic model of the pH neutralization system based on the concept of reaction invariants. Simulate the dynamic model for step changes in the acid, base and buffer flow rates and compare the simulation results to the corresponding experimental data. Assess the quality of the dynamic model.