WirelessHART™ network with Rosemount® wireless temperature transmitters ensures chamber walls are not damaged
Emerson Process Management’s Smart Wireless network with Rosemount® wireless transmitters is being used to enable thermal monitoring of biomass gasification pre-combustion chambers at the Elektrownia Stalowa Wola S.A. power plant located in the city of Stalowa Wola, Poland. New temperature data is being transmitted over a WirelessHART™ network to operators to ensure that the ceramic walls of the chamber are not damaged by stress fractures through overheating.
Biomass gasification (a method for extracting energy from many different types of organic materials) is a process where biomass materials are processed to create a carbonised solid and gas, both of which are used as fuel for electricity generation.
Both power and heat is produced by the Elektrownia Stalowa Wola gasification system using forest waste wood (including chips and dust) and other biomass material from agriculture. The organic waste passes through a 9m long by 3.5m diameter rotating pre-combustion chamber where it is heated using natural gas to a temperature between
280 – 360°C. The carbonised particles that are produced are burnt in a fluidised bed which releases energy for steam generation. The pre-combustion chamber is made from a ceramic material which is protected from damage by a layer of insulation.
Elektrownia Stalowa Wola S.A. (part of Tauron Energy) wanted to further safeguard the equipment by measuring the temperature of the chamber walls so that they could be alerted to any potential problems. Should temperatures go beyond 350°C, an alarm is triggered and the operator can adjust the amount of air going into the chamber or reduce the heating of the biomass. If required, the fuel for the chamber can be shut down completely. Should the operator not react in time, the system can shut down automatically.
Two sensors have been installed within the insulation material to provide the temperature measurements of the chamber walls. Because the pre-combustion chamber rotates, a slip ring assembly would be required to connect the sensors. However, dirt, carbon dust, and other forms of contamination build up in this area which can lead to flash over (arcing between the rings or to ground) and damage the connections between the lead and the rings. “With every day usage creating the potential for high contamination we were concerned about the long term reliability of a slip ring solution. Wireless was the natural alternative and Emerson’s WirelessHART devices also meet the EX requirements,” said Miroslaw Lysikowski, Instrumentation & Control Manager, Elektrownia Stalowa Wola S.A.
Two Rosemount WirelessHART temperature transmitters have been installed on the rotating chamber delivering measurements from the sensors every 30 seconds. This provides the operator with the information needed to protect the chamber from overheating. A further transmitter has been installed nearby and acts as a router, strengthening the self-organising wireless network by providing an extra route for signals to pass through. The device also measures the ambient temperatures.
The sensors and transmitters were installed by Elektrownia Stalowa Wola during a routine shut down period, taking just two days to complete. Emerson’s AMS™ Wireless SNAP-ON™ application was used to validate the network and is now used to manage the wireless network and identify any potential trouble spots.
Measurement data from the sensors is sent via a Smart Wireless gateway to the existing Emerson Ovation® expert control system that controls the biomass gasification process. Start-up of the wireless network took only a matter of hours including installing the Modbus TCP/IP cabling that connects the gateway to the control system.
“We are extremely happy with the final solution, which has proven to be very reliable,” continued Lysikowski. “Looking to the future, we expect to use these new measurements for process monitoring and will also be working with Emerson to further expand the use of wireless technology.”
Elektrownia Stalowa Wola S.A. is currently considering increasing the number of measurements on the rotating chamber to increase its knowledge of the process. The wireless temperature measurements will then be used as part of the control of the burning process.
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