Effect of the Heating Rate on the Supercritical Water Gasification of a Glucose/Guaiacol Mixture

Abstract

We herein report the effect of the feedstock heating rate on the supercritical water gasification of a glucose/guaiacol mixture. In the study, glucose was employed as a model compound for cellulose and guaiacol was employed as a model compound for lignin. A mixture of glucose (0.34 wt %) and guaiacol (0.16 wt %) was fed into a laboratory-scale continuous reactor at 600 °C and 25 MPa through a preheater, where the feedstock heating rate could be controlled. Feedstock flow rates of 1 and 2 g/min were employed along with preheaters of three different lengths (i.e., 0.45, 0.9, and 1.8 m). We found that longer preheaters resulted in slower heating rates at the same feedstock flow rate. Studies into the effect of the feedstock heating rate on the gasification efficiency indicated that a high heating rate enhanced the carbon gasification efficiency even for a glucose/guaiacol mixture. However, when the heating rate reached ∼25 K/s, a decrease in the carbon gasification efficiency was observed. This may be due to glucose and guaiacol interacting in a manner similar to that of cellulose and lignin. Finally, the preheater length had no apparent effect on the product gas composition.