Migration behavior of chlorine during co-gasification of Shenmu coal and corn straw

The addition of biomass such as straw in the coal gasification process is one of the strategies for clean and efficient utilization of coal with decreasing CO 2 emissions. However, the abundance of chlorine and alkaline metals contained in the corn straw is the key factor to aggravate the corrosion, deposition, and slagging of the co-gasifier. The effects of temperature (700–900 °C), residence time (2–12 min) and the addition ratios of corn straw on the migration behavior of Cl are studied during co-gasification of Shenmu coal and corn straw. The results show that the released amount of Cl from coal increases with the increase in gasification temperature and the extension of gasification time, while the amount of Cl in the coal gasification residue decreases initially and then stabilizes. On the other hand, the released amount of Cl from the corn straw increases with the increasing temperature and the extension of time below 800 °C, but both the temperature and time extension show limited effect on the released amount of Cl above 800 °C. It is also identified that the migration and volatilization behavior of Cl is related to the mass proportions of coal and biomass during the co-gasification process. When the addition ratios of corn straw are 16.7% and 50%, the released amount of Cl from the coal-biomass mixtures can be inhibited, while the released amount of Cl can be promoted when corn straw is added to coal-biomass mixture at the ratio of 37.5%.