Advanced pH Measurement and Control

Advanced pH Measurement and Control: Digital Twin Synergy and Advances in Technology details system design, installation, maintenance and ongoing improvement, including a special focus on how digital twins and first-principles charge balance contribute to innovation, operability, productivity, reliability and maintainability. It offers insights into key principles and advances in electrode technology and diagnostics, including a simple and largely untapped method for computing titration curves that match laboratory curves, as well as guidance on selecting and implementing the best control valves and strategies.

The extraordinary sensitivity and rangeability of pH used for measuring and controlling hydrogen concentration introduce many challenges in managing the nonlinearity in the control loop and the precision needed for the control valve. This, combined with pH's critical role in maintaining cell health in biological processes, as well as in the production of clean water, food, pharmaceuticals and chemicals, makes the best pH control system particularly important and challenging. Despite these challenges, the outcomes can lead to significant reductions in equipment costs and, more importantly, substantial improvements in system reliability and performance.

Finally, the appendices cover fundamental principles and provide guidance on using new PID features to reduce project costs and maximize process efficiency, capacity and safety.

Gregory K. McMillan, CAP, has more than 50 years of experience in industrial process automation, with an emphasis on the synergy of dynamic modeling and process control. He retired as a Senior Fellow from Solutia and a senior principal software engineer from Emerson Process Systems and Solutions. He was also an adjunct professor in the Washington University Saint Louis Chemical Engineering department from 2001 to 2004. McMillan is the author of numerous ISA books and columns on process control, and he has been the monthly Control Talk columnist for Control magazine since 2002. He started and guided the ISA Standards and Practices committee on ISA-TR5.9-2023, PID Algorithms and Performance Technical Report, and he wrote "Annex A - Valve Response and Control Loop Performance, Sources, Consequences, Fixes, and Specifications" in ISA-TR75.25.02-2000 (R2023), Control Valve Response Measurement from Step Inputs. McMillan's achievements include the ISA Kermit Fischer Environmental Award for pH control in 1991, appointment to ISA Fellow in 1991, the Control magazine Engineer of the Year Award for the Process Industry in 1994, induction into the Control magazine Process Automation Hall of Fame in 2001, selection as one of InTech magazine's 50 Most Influential Innovators in 2003, the ISA Life Achievement Award in 2010, and the ISA Mentoring Excellence award in 2020. He has a BS in engineering physics from Kansas University and an MS in control theory from Missouri University of Science and Technology, both with emphasis on industrial processes.

Christopher Stuart is a senior software engineer in the Process Simulation Development group at Emerson Process Systems and Solutions. He holds a bachelor of science degree in chemical engineering with a biochemical emphasis from Missouri University of Science and Technology. Stuart's research interests are in efficient algorithms for thermodynamic calculations and dynamic simulations.

Dean Cook is the Mimic product manager in the Process Simulation Development group at Emerson Process Systems and Solutions. He holds a bachelor of science degree in physics from Western Illinois University, has 30 years of experience developing dynamic simulation software, and continues to drive toward improving training and process optimization for a wide range of industries.

Zachary Sample is a digital enterprise consultant in Marketing/Business Development for Emerson Process Systems and Solutions. He has over 10 years of experience delivering cross-industry simulation solutions in various roles ranging from technical implementation and engineering to project management and consulting. In these roles, he has had a passion for helping process companies better leverage simulation to improve automation and operational performance. He has a bachelor of science degree in chemical engineering from Missouri University of Science and Technology and a master of science degree in chemical engineering from North Carolina State University.