Emerson Wireless network for Polish biomass power plant
7 Apr 2010
Austin, Texas – 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 SA power plant in Stalowa Wola, Poland.
Both power and heat are 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 carbonized particles that are produced are burnt in a fluidized 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 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, according to an Emerson statement. The system, it added, can shut down automatically if the operator does not react in time.
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.
Two wireless 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. Another transmitter has been installed nearby and acts as a router, strengthening the self-organizing 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.
