Thermogravimetric and kinetic analysis of bio-crude from hydrothermal liquefaction of Enteromorpha prolifera

Abstract

Bio-crude upgrading process by thermal treatment without the presence of neither catalysts nor hydrogen is a promising technique. Mechanism and kinetics of bio-crude thermal decomposition are crucial for the development of thermal upgrading process. In this paper, thermogravimetric and kinetic analysis of bio-crude from hydrothermal liquefaction of Enteromorpha prolifera was performed under non-isothermal conditions at different heating rates. A two-step reaction mechanism, a volatilization step followed by a thermal reaction step, was proposed based on the experimental results. The most probable reaction model was determined through a universal integral method, and the kinetic parameters were obtained simultaneously. At heating rate of 10 K/min, the volatilization step can be described by a 1-D diffusion model and the thermal reaction step followed apparent first-order reaction kinetics. The apparent activation energy was also estimated by using several isoconversional methods. However, further analysis proved that the basis of isoconversional method was violated.