Emerson’s Smart Wireless network at Dyno Nobel ammonium nitrate facility combines pump protection with process monitoring

The new WirelessHART™ network, comprising 20 new Rosemount® wireless temperature transmitters and 20 new Rosemount wireless discrete switches plus dual-element temperature sensors and high-temperature switches, extends about 1500 feet from end-to-end. The transmitters are connected by a self-organizing wireless mesh network to one Smart Wireless Gateway which relays the data to a DeltaV™ digital automation system for monitoring, alarming, and trending purposes. The wireless discrete switches transmit system “fault” and high temperature “trip” signals from the temperature switches to the DeltaV console, where operator graphics display temperature and switch data for each pump along with a wireless network overview and status screen for operations and maintenance personnel.

If the discharge temperature of a pump rises beyond the safe operating setpoint, a high alarm is issued by the DeltaV system. If the temperature continues to rise, the DeltaV system issues a high-high temperature alarm to notify operators that the temperature at that pump is reaching a dangerous level. If the temperature rises still further, the local high temperature switch shuts the pump off before it reaches the critical temperature at which the ammonium nitrate could begin to decompose. Operators are alerted to a safety trip fault by a signal from the discrete wireless switch.

Emerson’s AMS™ Suite predictive maintenance software sends predictive diagnostics generated by the smart field devices to operations and maintenance so a high temperature alarm condition can be addressed before a safety trip is required. In addition, the AMS Wireless SNAP-ON™ application aids in planning, installation, and diagnostics of the wireless network. All of the devices on this network were powered up and commissioned in just one day in July, 2009.

According to Dyno Nobel plant operations manager Sam Correnti, “All the factors of security, reliability, ease of installation, and ease of use were considered in our selection of this technology and our confidence in the solution.”

Having this wireless network in place offers some unique advantages that the company plans to exploit in the future, Correnti said. For example, safety shower flow alarms will soon be added, and planning is underway for additional temperature and pressure monitors in another area of the plant.

In addition to the Smart Wireless solutions already installed at Dyno Nobel, Emerson offers a wide range of wireless field instrumentation and plant operations equipment, including Fisher® position monitors, Rosemount® analytical and Machinery Health™ Management devices, and SmartStart® services.