Slagging tendency analysis and evaluation of biomass and coal during co-firing

Co-firing of biomass and coal may cause slagging and fouling and impact the operational lifespan of the boilers. In this paper, eucalyptus bark (EB) and four kinds of coal were used as raw materials, and the degree of slagging was experimentally investigated by scanning electron microscope (SEM), X-ray fluorescence (XRF), and X-ray diffraction (XRD). Moreover, the technique for order preference by similarity to ideal solution (TOPSIS) method and the entropy weight (EW) method were used to establish a slagging evaluation model E-TOPSIS. The results showed that the co-firing of EB and coal caused an increase in ash particle size, particle sintering, and adhesion. XRD analysis confirmed that EB promoted the reaction of calcium compounds with quartz and enhanced the diffraction intensity of muscovite, anorthite, and calcite. The evaluation results of the E-TOPSIS showed that the slagging tendency of EB, IC, and ICEB was severe, which is aligned with the experimental results, and proves the accuracy of this method. The research results can provide a reference for predicting the slagging tendency of biomass and coal during co-firing.