Online Water Content Determination in Wood Chips Using a Microwave Sensor

The water content is an essential parameter for assessing the quality of solid biofuels. In terms of economic, technical and environmental aspects a continuous determination of the solid fuel water content is sought. This article investigates the use of microwave technology for the continuous measurement of fuel water content. For this purpose, a microwave sensor was evaluated with five different types of wood chips (forest residues, beech, pine, and ash). The results of the online measurements showed a strong correlation with the reference method r < 0.9 for most materials. This means that continuous water content determination of wood fuels using microwave technology is fundamentally possible.