pH Process: Most process plants generate a wastewater efflu-ent that must be neutralized prior to discharge or reuse. About 90% industrial wastewater pH processes are still controlled by On-Off con-trol, resulting in chemical reagent wastes, equipment corrosion, and environmental pollution. Statistics show that a poorly controlled pH process can cost tens of thousands of dollars in chemical usage each month, not counting the penalties imposed by violating EPA or local discharge codes.

pH Control:A pH process is extremely nonlinear. The pH value versus the reagent flow has a loga-rithmic relationship. Away from neutrality, the process gain is rela-tively small. Near neutrality, where pH=7, the process gain can be a few thousand times higher. It is impossible for a fixed controller like PID to control this process.

MFA Flare Control System: The flare vent gas consists of waste gas from multiple streams and purge gas. Its heating value is measured with an online calorime-ter. CyboCon MFA control soft-ware is installed in a PC interfacing to a DCS through OPC. A special Anti-delay Feedforward MFA controller controls the heating value in real-time by manipulating natural gas flow. The trends show a typical condition where the waste gas flow (gray) swings causing heating value to change while MFA takes quick control actions (red) to assure HV is in control.

pH Real-Time Model: Before implementing a pH control system, it is wise to study and understand the pH process you have so that proper solutions, equipment, and software can be acquired and installed.
CyboSoft’s Real-Time pH Process Modeling and Control Simulation Software is a useful tool for such studies and includes: (1) pH process diagram, (2) a strong-acid-strong-base pH model, (3) a strong-acid-weak-base pH model, (4) a weak-acid-strong-base pH model, (5) a weak-acid-weak-base pH model, (6) MFA control simula-tion for the 4 pH processes using an MFA pH controller, (7) PID control simulation for the 4 pH processes, (8) On-Off control simulation for the 4 pH processes, (9) graphical interface with control faceplates and real-time trends, (10) Lab-VIEW diagrams, and (11) pH process model description, MFA controllers used, and recommended control strategy.

Solution:You can test your pH controller using the pH process model. The control results can be compared with the MFA pH control results obtained in MFA control simulation. You may take the results, estimate the chemical reagent savings, and present the ROI to get the budget for the proper pH controller or control software to improve pH control and achieve all the benefits.

MFA Control Products: You may use: (1) CyboCon MFA Control Software, (2) CyboCon CE MFA Control Instrument, (3) MFA Control Toolset for LabVIEW Software, and (4) Embedded MFA controllers.

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