Investigation of the slagging characteristics during co-combustion of Shenhua coal and corn stalk: Effect of deposition surface

Slagging is one of major problems in boilers especially during co-combustion of coal and biomass. In this research, a real-time digital image technique was applied to study the mechanism of Ni coating controlling the slagging during co-firing of coal and biomass in a pilot-scale furnace. According to the growth of slagging deposit, the Ni coating revealed a positive effect on reducing slagging deposit and increasing the heat flux through probe. The relative time average heat flux increased from 0.473 to 0.578 and the time average thickness of slagging deposit decreased from 3.6 to 1.1 mm, as the probe modified with Ni coating. In addition, the formation rate of initial deposit which was an important stage in growth of slagging deposit was obtained. The XRD and SEM-EDX were used to analyze the slagging deposits, in order to clarify the mitigation mechanism of slagging deposit. Alkalis and Fe compounds significant affected in the adhesion behavior. Ni coating has a positive effect on controlling the slagging deposit through affecting the content of alkalis and Fe compounds. The results contribute to deep understanding of the mechanism of Ni coating on the growth of slagging deposits during co-firing of coal and biomass.