Measuring the Immeasurable
Croda Inc., an international specialty chemicals manufacturer, uses wireless temperature transmitters from Emerson mounted on chemical tank cars to send minute-by-minute readings to a central host, improving process performance and boosting overall safety.
Because the tank cars are moved frequently, hard-wiring of temperature sensors was impractical. Previously, an employee had to climb to the top of each car once a day to check the temperatures and record each reading. This was a time-consuming procedure that, during wet or icy conditions, presented a fall potential. With wireless, operators are alerted to any unexpected temperature rise in the tank cars, while saving about $15,000 per year in reduced maintenance.
The wireless solution not only saves us time and money, since plant personnel no longer have to monitor those tank cars daily, it has also greatly enhanced the overall safety of the plant and our personnel, says Denny Fetters, instrument and electrical designer for Croda. No matter where a tank car is positioned on-site, the quality of the transmissions is unaffected, and the signals integrate seamlessly into our control system.
Making the Infeasible Practical
At PPG Industries Lake Charles, La., facility, wireless temperature transmitters monitor the temperature profile of the plants steam headers. The applications had always been desired, but difficult to implement, according to Tim Gerami, PPG senior design engineer. PPG engineers also wanted to use wireless for some of the redundant measurements they really needed for plant optimization and asset management.
WIRELESS ADAPTER TO LIBERATE HART DIAGNOSTICS
There were others where the wireless part looked good, Gerami notes, but it was just point-to-point, rather than mesh. It would work, but it limited the number of devices in a given plantmaybe 50 per radio, 16 channels. That would be difficult in a plant. You need more than a hundred transmitters and several hundred eventually. A mesh network has the potential to be virtually unlimited.
Gerami makes the game-changing nature of wireless clear. Its an enabler for things you wouldnt ordinarily do, he says.
A Revolutionary Plant Design
Wireless instrumentation, together with Emersons DeltaV digital automation systems, now are making it possible to do exactly thatprovide a wireless-enabled, united information system on a unified network throughout the plant. This capability makes possible entire plant designs not feasible just a few short years ago.
One major life sciences company designed a multi-story plant in a building with twelve-inch thick reinforced concrete floors and walls. Modular process equipment can be moved around and reconfigured at will, and because instrumentation communicates wirelessly, reconfiguration requires no re-instrumentation. Indeed, one gateway installed on the third floor maintains communication with all the field devices on all four floors and on the roof of the building.
"An Era Well Begun"
Looking to the future was one of the reasons to try out the use of wireless sensors, says Ruud van Dijk, TAQA Energy engineering manager, of his companys successful test of Emerson Smart Wireless technology at its natural gas production site in Alkmaar, The Netherlands. Basically, there was no room for more wires at the site in Bergermeer, and connecting new sensors would have entailed breaking open some hundred meters of paving to install extra wires. This is expensive and time-consuming.
Of course we already have years of experience with wireless data transfer in office environments, adds John Pietersz of TAQAs metering and control department. But it is a different matter on the processing level. This world is very reluctant when it comes to introducing new technology.
The TAQA team determined that it needed the flexibility and robust reach of the self-organizing mesh network architecture of Smart Wireless. In the case of the Smart Wireless system, this radius is 200 meters, Pietersz says. It already leaves a lot of elbow room, but what is special about the solution is that the sensors can pass on each others signals. This means that you can apply sensors far outside the initial radius of 200 meters without having to install extra base stations. Future expansions will then only require the purchase of a transmitter, which will naturally also yield economic advantages.