In-situ study of the effect of potassium release on ash sintering behavior during the co-gasification of coal and biomass

[Display omitted] •In-situ study of potassium release and ash sintering behaviour during biomass-coal co-gasification.•Correlation between potassium release and ash sintering behaviour was studied.•The formation of KAlSiO4 and K2MgSi2O8 increases the mixed ash sintering temperature. A deep understanding of the in-situ potassium release characteristics and ash sintering behavior during the co-gasification of biomass and coal is of great significance in controlling the ash deposition, sintering, and corrosion problems during co-gasification. In this work, Laser induced breakdown spectroscopy and High-temperature stage coupled with an optical microscope system were used to investigate the potassium release pattern and the changes in slag surface morphology and melt shrinkage during in-situ co-gasification of corn stover (CS) and Zhundong coal (ZD). The mechanism of potassium release on sintering behavior was also calculated using XRD and FactSage thermodynamic simulation software. The results showed that: the addition of less than 30 % CS can effectively inhibit the release of potassium and promote the formation of potassium minerals such as KAlSiO4 and K2MgSi2O8 with Si and Al elements in the mixed ash of CS and ZD. Both the initial sintering temperature of the ash and the maximum temperature corresponding to the minimum shrinkage value increased, effectively improving the sintering behavior during the gasification. This work provided a theoretical reference for the release of potassium and controlling ash sintering behavior during the co-gasification of coal and biomass.