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Asset maintenance and reliability are topics regularly covered in trade publications, around the water cooler, and in budget planning sessions. For those that walk the plant floor, however, those same terms are more often than not a reminder of a jarring phone call at 2:00 AM or a mid-day emergency stoppage associated with some catastrophic […]
Control problems range from malfunctioning valves to clogged heat exchangers along with most everything in between. Identifying such problems efficiently and isolating their source is typically a tedious task. This is especially true as production and maintenance staff find themselves faced with shifting priorities and mounting responsibilities that demand more and more of their attention. […]
A 25 MW combined-cycle cogeneration plant at the University of Connecticut supplies electricity to the entire UConn campus with three natural gas combustion turbine generators and one high pressure steam turbine generator. Low pressure steam is used to provide building heat in the winter and to drive refrigeration compressors for chilled water cooling in the […]
Real-time performance monitoring to identify poorly or under-performing loops has become an integral part of preventative maintenance. Among others, rising energy costs and increasing demand for improved product quality are driving forces. Automatic process control solutions that incorporate real-time monitoring and performance analysis are fulfilling this market need. While many software solutions display performance metrics, […]
The manner in which a measured process variable responds over time to changes in the controller output signal is fundamental to the design and tuning of a PID controller. The best way to learn about the dynamic behavior of a process is to perform experiments, commonly referred to as bump tests. Critical to success is […]
Two of the most popular architectures for improving regulatory performance and increasing profitability are 1) cascade control and 2) feed forward with feedback trim. Both architectures trade off additional complexity in the form of instrumentation and engineering time for a controller better able to reject the impact of disturbances on the measured process variable. These […]
Evolving Best-Practices Through Simulation-Based Training: Training The Field Operator Of The Future
Simulators are widely recognized as essential to process control training as they facilitate the propagation of a companys standard operating procedure (SOPs). According to process industry estimates, nearly $8 Billion in annual losses are due to human error. A significant part of these losses are attributed to inadequate or ineffective training. Simulation software permits trainees to […]
By Bob Rice1 and Doug Cooper The control objective for the pumped tank process is to maintain liquid level at set point by adjusting the discharge flow rate out of the bottom of the tank. This process displays the distinctive integrating (or non-self regulating) behavior, and as such, presents an interesting control challenge. The process […]
By Bob Rice1 and Doug Cooper Integrating (or non-self regulating) processes display counter-intuitive behaviors that make them surprisingly challenging to control. In particular, they do not naturally settle out to a steady operating level if left uncontrolled. To address this distinctive dynamic character, we modify the controller design and tuning recipe to include a FOPDT […]