Water from heat exchangers at the Gävlebukten plant is carefully monitored prior to its return to the sea. Small internal leaks may result in the discharge of hazardous chemicals into the local environment. Any leak of acids, bases, or salts will raise the electrical conductivity of the water and is easily detected using a conductivity sensor. A renovation project within the utilities section meant that I/O supporting existing instrumentation was to be removed. Korsnäs Gävle therefore needed an alternative way to transmit the required measurements to the main control room.
“Initially we considered installing new cable runs, but the process would have taken too long and would have delayed the planned renovation project,” said Peter Hallenberg, Project Leader Process Automation, Korsnäs Gävle. “The application presented a great opportunity for us to install and evaluate Emerson’s Smart Wireless technology, which takes advantage of the IEC 62591 (WirelessHART®) communication standard.”
The Smart Wireless solution that Korsnäs Gävle installed includes a Rosemount® Analytical 6081-C transmitter connected to a conductivity probe. The transmitter sends the measurement data via a Smart Wireless Gateway to the existing control and data acquisition systems, where it is used to ensure compliance with the environmental monitoring legislation.
Korsnäs Gävle also needed to establish new continuous monitoring of emissions from aerated basins and ponds. Twenty-two new sensors measuring pH, dissolved oxygen, and water temperatures had to be installed and connected to the central monitoring system. There were no available cable runs, and new cable infrastructure presented a considerable challenge and cost at €200 per metre.
To meet this challenge, Korsnäs Gävle installed six Rosemount wireless transmitters, each with four available inputs, to relay data from the analytical sensors. The wireless instruments provide the necessary data to meet the environmental requirements.
“Less than two months after ordering the Smart Wireless devices, the whole system was fully operational. That is very fast for implementing 30 new measurement points,” said Hallenberg.
“Now that the network is in place we have also found that adding additional devices becomes very simple.”
Specifically, Korsnäs Gävle has installed seven Rosemount 648 wireless temperature transmitters to automate the monitoring of water temperatures in wastewater pits that feed the aerated basins and ponds. A further eight Rosemount wireless transmitters will be installed to identify plugged filters on two wood chip digesters within the main processing section of the plant.
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