Key attributes of high-performance valves

New approaches to monitoring, controlling and engineering valves are improving process reliability and performance, and reducing the cost of operations and maintenance. At the same time, valve technologies are being tailored to specific environmental and application requirements, and scaled to unusual sizes.

Wireless position sensor:Manually monitoring valve positions and inspecting valves for maintenance are risky tasks in hazardous environments and costly in remote locations. A wireless valve position sensor from Honeywell alleviates these concerns. The XYR 6000 valve position sensor, based on Honeywell’s Micro Switch CX series analog sensor, supports real-time remote monitoring in harsh environments. Using Honeywell’s OneWireless mesh network system, the sensor sends signals from distant or dangerous plant locations to be monitored to more convenient locations.

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Certified for hazardous locations and with the sensor in explosion-proof packaging, the XYR 6000 is suitable for monitoring valve positions and positioner condition to prevent leaks, product contamination and unintended fluid mixing. It can trigger tank overflow alarms and emergency response associated with safety shower and eye bath notifications. Electronically tagging valves in the system allows maintenance schedules to be targeted to those that are damaged or degraded. Avoiding the need to install communications cables and power lines provides further cost and labor efficiencies.

Smart positioner: A new milestone in large-valve positioner accuracy was reached earlier this year at a natural gas compression station in Uzbekistan. Dresser Masoneilan, working with joint venture partner DS Control Technologies in Novgorod, Russia, integrated its Smart Valve Interface II Advanced Performance (SVI II AP) positioner with the station’s largest valve — a 56-by-36-by-56-inch, ANSI 150 measurement AST ball valve. Valve control accuracy for this type of application typically ranges from 1% to 3%, but the double-acting SVI II AP positioner delivered a 0.3% accuracy rate.

Dresser Masoneilan’s SVI II AP positioner expands upon the predecessor SV II positioner’s performance and adds the ruggedness and durability of marine-grade components. Its onboard control algorithm positions the valve rapidly, and its one-button auto-tuning and ability to self-calibrate and self-tune simplify installation and setup. The positioner’s high precision derives from measuring nine tuning variables, whereas most positioners tend to use fewer tuning inputs.

Digital control valve: Size also matters in the petrochemical industry. The largest ever Fisher 42-inch anti-surge valve is targeted for an olefin plant at the Saudi Kayan petrochemical complex in Al Jubail Industrial City, Saudi Arabia. The five-meter, 11,000-kg valve with Fisher technology will be used for surge protection in stage one of the project’s cracked gas compressor system. Emerson’s anti-surge valve includes a FieldVue DVC6000 series digital valve controller with performance diagnostic (PD) capabilities and optimized digital valve (ODV) technology to control stroking, deceleration, resolution and overshoot. Its high-seal graphite packing prevents fugitive emissions.

Emerson will supply 780 Fisher digital control valves for the project to provide predictive process and valve performance monitoring and enable proactive maintenance. The plant, scheduled to start up in 2010, is expected to have an annual production capacity exceeding six million tons.

Intelligent control system: An integrated smart control valve that combines process sensors, microprocessor controls and a digital positioner offers an economical alternative to conventional control systems. StarPac 3 is the third generation of Flowserve’s Valtek StarPac smart control valves. Among the enhancements in the StarPac 3 are USB and infrared interfaces, explosion-proof housing and enhanced positioner functions.

The process control system has full proportional-integral-derivative (PID) control. Using minimal system lags for tighter control, the PID controller can react to process upsets and return to setpoint faster than traditional control-loop systems. Other reported advantages include a small footprint, low installed cost, quick response time, repeatability and accuracy. The StarPac 3 can be used as a standalone control valve or integrated into a system.

Polymer material: Alternative materials are passing the test in the industrial gas sector. Hale Hamilton engineered a new line of actuated stop valves with a polymer seat that provide improved performance and greater tolerance to contamination than conventional hard-seated valves. The ASV 156 adiabatically shock-tested valves are designed for high-pressure cylinder filling systems for industrial oxygen, hydrogen and inert gases, and can be in-line or manifold-mounted.

E-mail Contributing Editor Sheila Kennedy, managing director of Additive Communications, at [email protected].