Industrial stress-test of a magnetic resonance moisture meter for woody biomass in southern European conditions

Abstract

Moisture content (MC) is the most important quality parameter for energy wood. Unfortunately, checking MC under operational conditions is difficult, because the standard method for MC measurement requires up to 48 h. The bioenergy industry needs alternative methods allowing fast and reliable MC determination, but most of the commercial devices require biomass-specific calibration models. This is an important limitation, particularly in Mediterranean areas, where mixed forest dominate and feedstock loads can include multiple species. In this study a moisture meters based on Magnetic Resonance (MR) was tested for assessing its reliability as an alternative to oven drying. For this purpose, a stress-test was performed at the premises of an energy facility in Southern Italy, using a commercial MR analyzer. Thanks to the non-destructive action on the biomass of MR technology, the MC of 350 samples was measured with both MR and standard gravimetric techniques. Results confirm the validity of the MR analyzer as an alternative to oven drying. Accuracy and precision of the machine are both satisfactory, with over 95% of values within ±2.5% of deviation and a Standard Error of Performance of 1.2%. Furthermore, the analyzer processes over 15 samples per hour, coping with frequent deliveries.