Waste-to-Energy Plant Uses Wireless Sensors to Monitor Key Parameters

May 10, 2012
Hitachi Zosen Inova AG (www.hz-inova.com), a company with 350 employees in Switzerland, is among the world’s leading experts in the generation of energy using waste as fuel.

More than 500 waste-to-energy plants throughout the world show the company’s abilities in planning, engineering and commissioning complex systems. Hitachi Zosen Inova recently tested a new solution for process monitoring: a modular wireless-mesh sensor network platform from Paradox Engineering (www.pdxeng.ch).

The monitoring of process parameters is of major importance after the start up of a new plant, when systems have to be optimized. Distances within the plant are often long, which makes the troubleshooting and testing of operations complex and time consuming, and operating conditions are extreme: high temperatures, thick concrete walls, steam, etc. Hitachi Zosen Inova conducted a test to verify the reliability of Paradox Engineering’s PE.WSNi industrial sensor network in the plant in Lausanne.

The Hitachi Zosen Inova solution involved one PE.WSNi gateway and three nodes, one I/O module with two 4-20mA channels connected to radiation pyrometers, three I/O modules with two 4-20mA connections to four thermometers, one flow sensor, one pressure sensor, and one I/O module with two 4-20mA channels connected to two thermometers.

According to Gianni Minetti, CEO at Paradox Engineering, “The PE.WSNi node was installed in the waste bunker and attached to two microwave radar level measurement devices via 4-20 mA transmitters. The PE.WSNi gateway was installed in the plant control room, which was separated from the bunker through a thick concrete wall. The gateway stored one-minute level measurements of the waste level in the feed hopper.  In this test phase, data were downloaded into .csv format and used, firstly, as indicators of the system reliability and secondarily for statistics and monitoring.”

Minetti said the expectations of Martin Steiner, Hitachi Zosen Inova R&D project manager, and of Urs Hugentobler, manager of project engineering tools, “related to swift and easy systems monitoring and cost reduction, as well as to be able go beyond local data collection to get to a next level of data penetration and measurement.”

After a smooth installation phase, the test gave positive results, said Minetti. The only obstacle was the two 4-20mA analog input channels on the I/O module that were not galvanically separated. To overcome this, it was enough to pay particular attention to the connection of external power supplies, and the problem was solved using a second 24V supply.

Steiner says, “For troubleshooting and optimization, PE.WSNi allows us to monitor important parameters of the system in a very easy way. It allows us to reduce the costs for experimental installations for R&D projects, enabling us to avoid cables and local data collection.”

After the successful first testing phase, Hitachi Zosen Inova has decided to implement a second test. PE.WSNi will be integrated with Hitachi Zosen Inova’s data analysis tool, called Pamela, which will study how to mitigate fouling in waste-to-energy boilers. This time, the analysis will consider data from thermocouples, flow sensors and pressure sensors—a more complex set of information and a more challenging working environment. 

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