WirelessHART™ network uses Rosemount® wireless temperature transmitters attached to a rotating kiln to deliver continuous information for instant response to process changes, enabling better heat control
AUSTIN, TEXAS (December 15, 2009) – Emerson Process Management’s Smart Wireless network using the WirelessHART™ communications standard is contributing to process improvements at the Calgon Carbon Corporation plant in Blue Lake, California. The network provides continuous temperature measurements from a rotating catalyst kiln where spent carbon particles are reactivated. As the world’s largest manufacturer and supplier of granular activated carbon, Calgon Carbon operates several reactivation plants to prepare carbon for reuse by removing chemicals picked up in previous filtering of air, gases, water, and other liquids.
The reactivation process involves passing recycled carbon through the kiln where it is dried and chemicals it has absorbed are “cooked off” at temperatures ranging between 1400oF and 1800oF. Measuring the temperature at each zone in the kiln is important to ensure proper heat transfer for each step in the process. For this reason, six Rosemount® wireless temperature transmitters were recently installed to monitor temperatures in the kiln and transmit a steady stream of data, giving operators more information for controlling heat levels in each zone.
The effects of process changes on heat transfer are now readily apparent, and trending can be used to improve process efficiency. This was not possible previously with the limited amount of information generated every two hours through manual viewing of readouts on devices connected to thermocouples in the kiln.
The new wireless transmitters mounted on raised platforms on the surface of the kiln were simply connected to the existing thermocouples, and the WirelessHART self-organizing mesh network was set up with a single Smart Wireless gateway. The six transmitters monitor temperatures in five zones of the kiln and at the outlet, communicating data reliably from the rotating kiln to the gateway, which then integrates the measurements in a host PLC.
According to site manager Jeremy Dolan, “We used WirelessHART because of the ease of installing the network, the reduced cost of installation, and the ability to communicate in spite of the constant rotation of the kiln. Non-wireless methods were too expensive, and other wireless line-of-sight systems could not handle the kiln’s movement.”
Dolan said that by contrast other carbon reactivation plants employ a conduit through the center of the kiln with thermocouple “spiders” going out into each zone. He called this method “very expensive to install and difficult to maintain.”
In addition to the Smart Wireless solutions already installed at Calgon Carbon, 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 native wireless interfaces to AMS® Suite predictive maintenance software, DeltaV™ digital automation systems, and SmartStart® services.