The hydrothermal carbonization of rice straw and corn stover is carried out under different K2CO3 concentrations and holding time, and the physicochemical properties of the hydrochars and liquid products are investigated. The results show that with increasing K2CO3 concentration and holding time, the hydrochar yield decreases from 35.65% to 22.86%, while the gas yield increases from 4.68% to 13.03%. Besides, the liquid products show increases in yield, pH value, electrical conductivity and NH4+-N concentration, while decreases in PO43--P concentration. With increasing K2CO3 concentration and holding time, the hydrochars show higher ash, fixed carbon, C, N content and higher heating value, while lower volatile matter, H, O content and energy conversion efficiency. When the K2CO3 concentration is 10% and the holding time is 120 min, the obtained hydrochars have abundant oxygen-containing functional groups and optimal pore structure, with the maximum specific surface area and total pore volume of 9.5321 m2/g and 0.0724 cm3/g, respectively.
Key words
biomass energy /
catalysts /
potash /
physicochemical properties /
straw /
hydrothermal
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