Hot, High and Heavy Enough

By monitoring interior and exterior temperatures, wireless instrumentation from Emerson Process Management, Austin, Texas, helps personnel assess the condition of a boiler that produces superheated steam at a Total Petrochemicals site in Carling Saint Avold, France. The site uses steam cracking to produce ethylene, propylene, methane and styrene, as well as polyethylene and polystyrene molding resins. In the process, petroleum mixes with either gas oil or naphtha in a cracking oven utilizing high pressure, superheated steam at 800 degrees Celsius (1472 degrees Fahrenheit). Internal and external temperature differentials enable personnel to calculate the consumed life fraction of the boiler wall, which experiences continuous and unpredictable erosion. The result helps determine when the boiler may need replacement.The installation uses eight of Emerson’s Rosemount 648 wireless temperature transmitters on the boiler, 50 meters (164 feet) above the ground. An Emerson Smart Wireless Gateway on a roof around 300 meters (980 feet) away receives the data. From this gateway, data reaches the control room via a third-party distributed control system (DCS).Wireless believers"Our plant is more than 30 years old," says Jerome Uszes, electricity control & regulation maintenance manager, Total Petrochemicals. "With the rising cost of copper and aging wiring, finding alternative methods to carry data is becoming essential.  We believe in wireless technologies, and Emerson provided a solution that meets our needs."The installation was complete 10 days after the initial order of the instrumentation, and it avoided the need for roughly 1 kilometer (3,280 feet) of new wiring. The system employs mesh networking, in which every instrument-based transmitter in the network can automatically act as a router to overcome interruptions between a given sensor and the gateway; the system simply routes messaging around the problem path. Three more wireless instruments work in areas between the boiler and the gateway. In addition to their primary sensing functions, these additional devices reinforce the wireless mesh network by providing additional paths to the gateway if needed.Total Petrochemicals, part of the Total group, is the fifth largest petrochemical company in the world and produces a range of basic petrochemicals.