Mexican lead foundry avoids plant shutdowns while saving $12,000 in installed cost compared to wired network
AUSTIN, TEXAS (April 28, 2010) — Met-Mex Peñoles has improved its sulfur dioxide emissions data collection with Smart Wireless field instrumentation solutions from Emerson Process Management. Installation of the Smart Wireless solution on a 50-meter stack at its lead foundry in Torreon, Mexico cost $12,000 less than the cost to install a traditional wired network.
Met-Mex management had committed to the community that the plant would reduce SO2 atmospheric pollution caused by stack emissions, and the plant also needed to provide better quality reporting to the environmental agency.
Prior to the installation, the plant estimated the amount of sulfur emissions coming from stack based on a number of sources. Emissions were inferred using the opacity meter and an SO2 analyzer on the stack along with an annual flow measurement taken by a contractor who would climb to the top of the stack. This person was exposed to extreme heat and emissions during the measurement.
All calculations were done manually and this data was not entered into the plant control system. Plant management needed more accurate emissions measurement to improve the quality of reporting to the environmental agency. They also wanted the data to be available to the control system.
To meet these requirements, Met-Mex installed a Smart Wireless network and field instruments including a Rosemount® Annubar flowmeter onto the stack at 25 meters above ground with a Rosemount wireless DP flow transmitter to measure stack gas flow, as well as a Rosemount wireless pressure transmitter, and two Rosemount wireless temperature transmitters. The reliable, self-organizing network sends data every five seconds to a Smart Wireless Gateway, which is installed outdoors approximately 65 meters away.
The gateway is integrated with the plant’s DeltaV™ digital automation system. Plant staff use Emerson’s AMS™ Suite predictive maintenance software to manage the new devices, including configuration, diagnostic checks, and monitoring alarms and alerts.
“The new data allow us to take preventative actions within our processes to reduce emissions instead of shutting down the plant to avoid fines,” said Juan Manuel Perez, smelter plant instrumental department chief, Met-Mex Peñoles. “A plant shut down can cost up to $100,000 an hour.”
Met-Mex chose wireless for the stack flow project because of its convenience and avoidance of expense, time, and difficulty of installing wired monitors on the stack, which is subject to extreme heat as well as the elements. The plant had successful experience with Emerson instrumentation, making adoption of wireless versions a confident choice.
“The equipment is working reliably and has reported on-time and precise information to the gateway and DeltaV system,” Perez said. “The information is also shared with the control systems over the Peñoles plant broadband communications network, and is being used to support reporting and reductions of SO2 emissions.”
Met-Mex intends to expand its wireless network by installing more devices to tap into additional data from nearby processes, making further operational improvements, and expects this will bring total installed cost savings to $40,000 compared to installing wired instrumentation. In addition to the Smart Wireless solutions already installed at Met-Mex, 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 DeltaV™ or Ovation™ digital automation systems, and SmartStart® wireless services.