Concentration measurement of biomass/coal/air three-phase flow by integrating electrostatic and capacitive sensors

This paper describes an integrated instrumentation system for the volumetric-concentration measurement of biomass/coal/air three-phase flow in a pneumatic conveying pipeline. The system combines electrostatic sensors with capacitive sensors and incorporates data fusion techniques. As the electrostatic sensor is more sensitive to dilute pulverized coal and the capacitive sensor is more sensitive to biomass particles, both sensor techniques are integrated for the concentration measurement of biomass and pulverized coal in biomass/coal/air three-phase flow. First, the flow regime is identified through the Hilbert marginal spectrum of the electrostatic sensor output signal. Then, under certain identified flow regimes, the dual regression analysis method is applied to work out the biomass concentration and the pulverized coal concentration. The experimental result indicates that the fiducial error of the system is less than 5%, and the resolution is about 1%.