By Jim Montague, Executive Editor
Some folks are still debating and waiting to see if wireless is really useful in process monitoring and control. Many others jump in with both feet and solve problems as they come up.
One of the jumpers is Western Refining's refinery near Gallup, New Mexico, which recently upgraded its tank operations and process units with a mesh networking solution and went way beyond just saving on cable.
Based in El Paso, Texas, Western is an independent oil refiner and marketer, and has a combined crude oil processing capacity of approximately 221,000 barrels/day. Its refineries and affiliates serve customers in Arizona, California, Colorado, Nevada, New Mexico, Texas, Utah and the central East Coast of the U.S. Its high-value, light products include gasoline, diesel and jet fuel.
To produce these products, however, the Gallup refinery operates in a very rocky, very windy, very dusty environment that is also at about 6,000 ft in elevation.
And, as if that weren't enough, the refinery is also located next to a 600-vehicle truckstop, whose many visitors all have powerful base radios that can create huge amounts of potential interference.
"The Gallup refinery uses a legacy TDC 3000 distributed control system (DCS), but our management also wanted to extend monitoring capabilities to remote tank farm areas," says Reginald Joseph, Western's senior process controls engineer, who recently presented Western's story at Honeywell Users Group 2010. "However, the costs of traditional wiring and conduit for monitoring outside storage units were estimated at $15,000 to $22,000 per tank. As a result, starting in 2008, we began implementing Honeywell's OneWireless. First, we completed a site survey with Honeywell to determine the project scope and challenges, and then we implemented a multi-function wireless mesh network to support a variety of applications in one network. Wireless technology was then employed for tank gauging, and it's now being introduced for high-level analog and digital indications in our process units. Monitoring data is then integrated into the existing DCS and advanced applications."
Joseph says Western Refining's primary motivations for adopting wireless include:
- Saving up to 90% of the installed cost of measurements, which usually go for cable, conduit and related construction
- Traditional wired infrastructure is largely unnecessary with wireless field devices
- Wireless reduces costs for comprehensive process monitoring
- Connects to points that are physically or economically difficult to access
- Allows easy expansion for added measurement or actuation points for simply the cost of the transmitter
- Offers robust security, predictable power management and multi-speed monitoring
- WiFi coverage is available at no additional cost.
Joseph adds that the Gallup refinery's present wireless installation includes one wireless system gateway and four redundant multi-nodes connecting 38 wireless instruments. Wireless transmitters send information to a series of multi-nodes, creating a mesh infrastructure that maximizes uptime and data security.
"At the refinery, Honeywell's XYR 5000 wireless transmitters replace outdated pneumatic devices that are used for valve positioning and process variable indication," says Joseph. "Meanwhile, optimized wireless infrastructure with narrow-band radio frequency hopping ensures maximum performance. Wireless devices transmit measurements to a base radio connected to the plant control system. These wireless transmitters break down barriers to monitoring variables in areas where traditional hardwired transmitters are too costly and difficult or time-consuming to implement. Our wireless instruments are designed for applications with no access to power, that are remote or difficult to access, that require frequent changes in instrumentation schemes or where manual readings are typically taken."
Consequently, wireless has become a desirable alternative to traditional copper wiring at Western Refining—wiring that not only adds cost, but also requires high maintenance and causes unreliability, according to Joseph. "ISA100 wireless transmitters can monitor a variety of processes and assets in hazardous and remote areas," he states. "In addition, data can be used in a variety of systems, while wireless frequency-hopping, spread-spectrum technology adds security and ensures that noise interference at any one frequency doesn't block the communications or cause security concerns. A single, scalable wireless network conserves spectrum and power, too."