Control Valve Solutions for Pressure Swing Adsorption
Keep PSA units operating reliably without unplanned interruptions.
Keep PSA units operating reliably without unplanned interruptions.
Pressure swing adsorption units are notoriously abusive on control valve assemblies, mostly due to the high stroking frequency—often exceeding hundreds of thousands of cycles per year—and tight shutoff requirements of Class V or Class VI to maintain industrial gas purity and efficiency. Choosing Fisher valves for these applications can help you avoid unplanned interruptions, extend the time between planned maintenance, and improve product purity.
Emerson offers a breadth of extensively tested and proven-reliable Fisher control valve assemblies to help extend the lifecycle of high-cycle applications and maintain purity. Fisher control valve assemblies are accepted by several of the world’s leading licensors for use in their high-cycle applications because they were validated through lab testing and field trials.
Control valve shutoff is a major concern because it affects purity. If leakage causes contamination from one PSA bed to another, industrial gas purity can be compromised. Fisher sliding-stem and rotary control valves are premier performers in achieving tight shutoff in high-cycle applications.
Valve diagnostics in Fisher FIELDVUE digital valve controllers can detect performance changes by monitoring seat load and friction. When coupled with ValveLink™ software, FIELDVUE instruments alert the user of shutoff integrity deterioration. Predictive diagnostics allow scheduling of service before quality suffers.
Special GX actuator diaphragm material helps reduce common problems such as air oxidation, thermal aging, low temperature embrittlement, and loss of retention. Unlike a piston actuator, the GX spring-and-diaphragm actuator does not have a large diameter sliding seal that is subject to wear. The double-sided diaphragm within the actuator helps eliminate mechanical wear-induced failure.
The 2052 spring-and diaphragm actuator was designed for long service life under load conditions. It has no O-rings to wear, an inherent position on air failure, low actuator pressures for operation, and double-sided diaphragms. Designed for 1,000,000 cycles under load conditions, you can forget about leakage, failure, and poor control.
Linkage-less, non-contact FIELDVUE digital valve controllers are paired with Fisher control valves to achieve precise positioning accuracy and fast response to process changes, which can directly increase PSA unit efficiency, catalyst life, and profitability. With no linkage to wear, loosen, corrode, or vibrate, FIELDVUE digital valve controllers can handle harsh environments and nonstop cycling. FIELDVUE digital valve controllers offer integral 4-20 mA position feedback for explosion-proof or non-explosion-proof applications.
Emerson’s cycle testing lab was designed to represent the PSA process as accurately as possible, including a large volume tank to provide process pressure in high capacity to all of the control valve assemblies being tested.
Each control valve assembly tested is comprised of standard option parts—including valve seats, packing, actuator springs, and diaphragms—and is controlled with a Fisher FIELDVUE digital valve controller.
The valve is subjected to pressure drops, while the actuator stroke time is controlled so that the 0–100% and 100–0% strokes occur in under two seconds. In addition to counting cycles, pressure taps have been installed allowing for seat leak testing as cycles accumulate.
The use of Fisher FIELDVUE digital valve controllers allows for monitoring of diagnostic and performance data such as friction, spring rate, and bench set. This information gives a detailed picture of what is happening inside the valve as cycle counts reach and exceed 1,000,000.
