Fast Determination of Fuel Properties in Solid Biofuel Mixtures by Near Infrared Spectroscopy

Analytical Methods for the Rapid Determination of Solid Biofuel Quality

“…Currently, several well‐investigated methods are available for the rapid determination of M in solid biofuels, such as capacitive measurement 60, 61, 230, TDR 60, 61, 126–128, electrical resistance 60, 61, 234, 236 infrared drying (gravimetric) 60, 256, NIRS 60, 86–96, 241, 242, microwave‐, or radio wave methods 60, 80, 120–125. Usually, most of these methods do not require any special sample preparation such as milling or grinding of the material and can be applied directly when fuels are delivered to the plant.…”

“…In particular, capacitive measurement, infrared drying and NIR spectroscopy have been investigated in detail in various studies in recent years 60, 61, 86–96, 241, 242. They usually show medium to good results in terms of instrument precision compared to the reference method (ISO 18134‐1 to ‐3) 13–15.…”

“…Due to the wide penetration depth into the sample and the particularly high sensitivity of the moisture measurement, NIRS is especially useful in rapidly analysing M in solid biofuels 60, 86–96, 241. However, instruments require a good calibration to the respective biofuel for precise M determination using NIRS methods (likewise capacitive methods).…”

“…Various approaches for the rapid determination of A and Q in solid biofuels were investigated in recent studies using, e.g., NIRS 1, 86–88, 91–97, 102, Laser applications 207, 208, 210, or X‐ray method 184. Most of the tested devices are already available on the market but mainly for other sectors and not especially for solid biofuels.…”

“…show potential for future studies 102. Various studies investigate the usability of IR methods to measure different parameters of solid biofuels like the carbon content or plastic contaminations 62–64, 72, 92–98. Kip et al evaluated the development of spectrometers and showed that they are increasingly robust and less susceptible to vibrations.…”