Analysis on organic compounds in water leachate from biomass

Abstract

Water washing on biomass can effectively remove K, Na and Cl, which will cause serious problems such as fouling, slagging and corrosion during thermal conversion processes of biomass. But amounts of leachates remain to be disposed. Investigating the organics release will be helpful to the leachate disposal. In this study, four types of biomass are water washed at different temperatures. The organic species and DBP (di-n-butyl phthalate) concentrations in leachates are determined by GC-MS. The results show that organics tend to release in the high-temperature region (60–90 °C). At 90 °C, 80% of organic matters in the wheat straw leachate are AR (aromatic hydrocarbons) and AL (alkanes, cycloalkanes and heterocyclic hydrocarbons). The organics distributions in the rice hull leachate are relatively uniform, compared with other leachates. The DBP concentrations in four leachates at 90 °C are lower than that at 30 °C because of its volatility. DBP concentrations in rice hull and corn stalk leachates show a trend of “reduction−increase”, with minimum values of 0.0001 and 0.001 mg L−1 at 60 °C, respectively. Whereas in the sorghum stalk leachate, a tendency of “increase−reduction” is observed. The corresponding content achieves the maximum value of 0.024 mg L−1.