Study on the effect of molten ash on the combustion process for biomass

In this study, the high temperature visual test system (HTVTS) and high temperature thermogravimetric test system (HTTTS) were set up to observe the formation process of ash, thereby analyzing the mechanism of biomass melt combustion. Then, the effect of the molten ash on the combustion process was investigated. Results show that during the combustion, once the local temperature of the biomass particle is higher than the ash melting temperature, the generated ash could be melted and contracted into a spherical shape by the surface tension. The molten ash located in the interior of the biomass particle adhere to the char surface, thereby preventing the contact between char and oxygen. The molten ash located on the surface of biomass particle could drop down from the surface of biomass particle. When the conversion rate is higher than 45%, the effect of molten ash on the reaction rate becomes more obvious.