Thermochemical Behaviour of Red Algae Kinetics and Mechanism of the Pyrolysis

摘要

The present work assesses a possible process for treating red algal in an environmentally friendly way. It is based on the pyrolysis of these algals for energetic valorization to evaluate its bioenergy potential. The pyrolytic and kinetic characteristics of red algal as a model for algal biomass were evaluated and compared at heating rates of 5, 10,20 and50°C min-1 from 0 to900 °C in an inert atmosphere. The DTG curves showed three distinct stages of degradation; dehydration, devolatilization, and residual decomposition. The kinetic analysis was established by the isoconversional methods of Friedman (FR), Flynn-Wall-Ozawa (FWO), and Vyazovkin (VYA) methods) to estimate activation energy, the master-plot methods were introduced to establish kinetic models. Activation energy values were shown to be 227± 8, 214 ± 2 and224,2 ± 3 kJ mol-1as calculated by FR, FWO, and VYA methods, respectively. The devolatilization stage of redalgal could be described by the Third-order equation (n = 3). It is shown that the isoconversional kinetic methods provide reliable kinetic information suitable for adequately choosing the kinetic model which best describes the thermal decomposition of red algal. The composite differential method was used to obtain the following kinetic triplet: g(x)= Ea=221,6kj/mol, R=0.99.