Classic distributed control systems typically remain only in high-availability refining and power applications, but their strategies and capabilities persist in descendants and todays sophisticated networks.
To make the most of diagnostic equipment used in chemical processing, technicians must stretch their knowledge of control valves and related diagnostic equipment that keeps tabs on valve health and safety.
Design provides improved reliability in a polymer-precursor batch reactor. Sensors must respond quickly and survive a harsh environment. Poor probe reliability can make the difference between a process that makes money and one that doesnt.
Control's Béla Lipták continues his series on control of distillation processes, this time focusing on managing reboiler flow, temperature, feed rate, loading and reflux for economy, stability and safety.
ControlGlobal.com contributor David W. Spitzer provides a look from a process automation perspective at how magmeters and Venturi meters are vying with ultrasonics for clean and dirty water applications.
Handling slurries (a mix of solids and liquids), should be based on experience and experiments, not theory. Much of the knowledge obtained from pneumatic conveyors and fluidization systems can be used in understanding slurries.
Author: Thomas R. Blackwood, Healthsite Associates
This article looks at six technologies mechanical floats and displacers, differential pressure, capacitance, ultrasonic, radar, and guided wave radar that are used most often for automated control, and provides practical guidance for choosing among them.
Author: Jerry Boisvert, Siemens Energy & Automation
When it comes to selecting and sizing control valves and positioners, this article not only helps you pick the right one for the right job, but also includes a valuable valve selection chart you can download!
Some U.S. oil refineries repair their centrifugal pumps every three years while other refineries enjoy an average repair interval of 10 years. Learn about the highest-performing refineries and other petrochemical companies that have significantly reduced pump failures, and how you can obtain the same results.
Theres more to boiler level control than measuring level and adjusting a feedwater valve. Improved measurements and inverse response are just a few of the influences on operating boilers in a reliable manner.
The more energy prices rise, the more heat integration saves. However, heat integration steps can present complex control problems. Slip-ups in putting control systems in place can make operations nearly impossible. That certainly was the case at one unit using heat recovery.
Author: Andrew Sloley, contributing editor and Carolyn K. Hawley, VECO USA
Profibus-PA and Foundation Fieldbus both reduce cabling cost by sharing wiring among several field instruments. They also save money by reducing the number of instrument interface cards required to connect field instruments to the control system. However, they all save money by being able to use the same field transmitter for a wide range of measured variables.