Relationships between char reactivity and char structure from a suite of organic model compounds

Abstract

In order to better understand the impact of the carbon structure of char on its combustion reactivity, 14 types of organic model compounds were pyrolyzed under temperatures of 530 °C, 800 °C and 1028 °C at heating rates of 10 °C/min and 65 °C/s, respectively. The carbon structure and the oxidation reactivity of the produced char were determined by respective Raman spectroscopy and thermogravimetric analysis (TGA) methods. The relationships between different reactivity indexes and Raman spectral parameters have been assessed. The results reveal that changes in pyrolysis temperature and heating rate would result in certain evolution of the graphitization degree of char. Good correlations have been discovered between the Raman spectral parameters (AD/AALL, AGL/AALL, A(S+R+SL+VR+VL)/AD, and A(GR+VL+VR)/AD) and the combustion characteristic temperatures (Ti, Tb, T50, and Tmax). From the correlations above, Raman spectral parameter A(GR+VL+VR)/AD is found to be the best correlated to the char combustion characteristic temperature Tb with R2 of around 0.76.