Investigation of dust resistivity for a fractioned biomass fly ash sample during poor combustion conditions with regard to electrostatic precipitation
D. Steiner, C. Lanzerstorfer - Investigation of dust resistivity for a fractioned biomass fly ash sample during poor combustion conditions with regard to electrostatic precipitation - FUEL, Vol. 227, No. 1, 2018, pp. 59-66
It is well known that dust resistivity and particle size play a major role in electrostatic precipitation processes. In this work, an ash sample from an electrostatic precipitator downstream an industrial biomass boiler operated under poor combustion conditions was air classified into 5 particle size fractions. Those fractions were then analysed regarding chemical composition, loss on ignition, particle size distribution and dust resistivity. Furthermore, scanning electron as well as optical microscope images were taken to investigate particle structure and shape.
Diverse types of particles were found in the different fractions, varying from unburned coal particles to inorganic sand-like particles. It was also found that chemical composition as well as resistivity varied significantly with different size fractions. During resistivity measurements, fluctuating voltage and current values were recognized, similar to what can be seen during the back-corona phenomenon, but found at medium resistivity values.