To ensure the safety of biomass plants, an early detection system for the heating of biofuels is advisable. This is exactly what a large district heating plant in southern Sweden has implemented using innovative JUMO technologies.
Text & images by JUMO
Biomass, which consists of wood, plant residues, and waste, is an important component of renewable energy and helps to reduce the use of fossil fuels. However, its storage poses a major fire protection risk. Ultimately, biochemical processes can lead to dangerous temperature increases and spontaneous combustion. This is all the more problematic given that biomass fires cannot be extinguished with water and are difficult to fight.
Task
The greatest heat buildup occurs at the core of the biomass due to oxygen supply, biological decomposition, and moisture. That is why early detection of excessive heat buildup is particularly important at that point. Since commercially available thermal imaging cameras are usually limited to acquiring surface temperatures, they often reach their limits when objects are heated in deeper layers. Consequently, an alternative monitoring system is required that alerts the plant user at an early stage in the event of an emergency. That way, counter measures such as restacking the material with a wheel loader can be implemented. This helps prevent dangerous spontaneous combustion and ensures the safety of the entire plant.
Solution approach
This fire protection system for biomass plants was implemented by the JUMO Wtrans B, which is a head transmitter with wireless data transmission. It is available in different standard lengths to suit the size of the biomass stack. The sensor, which can be used either as a lance or in a screw-in version, can be easily inserted into the core of the stack using its sturdy handle. It is made of stainless steel so that it is resistant to cellulose acids and high temperatures. This feature ensures a long operating life and a high degree of reliability. Customized lengths are available upon request for special requirements.
The signal from the fire protection sensor is transmitted wirelessly and almost interference-free at a radio frequency of 868.4 MHz to the JUMO Wtrans receiver T01, which supports up to 16 sensors. A range of over 2 km can be achieved due to the optimal placement of the antenna and antenna amplifier. Low battery levels are indicated by the receiver at an early stage, so that functional reliability in the monitoring system is always ensured.
Centralized monitoring and evaluation
For large plants which require more than 16 sensors, the receiver can be replaced by the JUMO variTRON 300 modular PLC. It enables the operation of up to 32 sensors and can also be expanded.
The measured values can be transferred directly to the JUMO Cloud or JUMO smartWARE SCADA, thus enabling quick and easy browser-based access to all process data. As a result, even larger biomass plants with numerous stacks in a central location can be easily monitored in a single dashboard.
Project outcome
The new fire protection system ensures early detection of overheating in all biomass stacks. These include biofuels such as wood chips, pellets and sawdust, agricultural products such as straw, hay, grain, and peat as well as waste from waste centers. The system ensures safe operation, prevents fires, and minimizes energy loss as well as negative environmental impacts. In addition, time and resources are saved because the stacks no longer have to be restacked preventively, but only when dangerous overheating occurs. Continuous monitoring is made possible by reliable wireless transmission and flexible sensor integration, which supports the sustainable and efficient use of biomass.
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