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

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. (C) 2016 Elsevier B.V. All rights reserved.