A study on benzene release during water washing of biomass

Abstract

AbstractWater washing can effectively remove Na, K, and Cl in biomass, which can cause fouling, slagging, and corrosion during thermal conversion process of biomass fuels. However, it is necessary to dispose the leachates appropriately after water washing. Characterization of organic matters in leachates should be performed first, which is beneficial to find an effective way to dispose the leachate. In this study, four biomass materials are washed with the deionized water at 30°C, 60°C, and 90°C. The release of toluene and styrene is studied. The results show that yields of organic matters for corn stalk and wheat straw are the highest relatively, of which the eventual values are 8% and 15%, respectively. Less toluene and styrene are released at 30–60°C than that at 90°C for wheat straw. But the release of toluene and styrene in rice hull leachate shows the opposite trend. The concentration of styrene in leachates reaches a minimum value at 60°C. The corresponding values are 0.017 mg L−1 for wheat straw and 0.15 mg L−1 for rice hull. But none is detected in corn stalk and sorghum stalk leachates. In addition, variations of toluene and styrene concentrations are obviously different with different washing temperatures.