Co‐pyrolysis characteristics of coal and sludge blends using thermogravimetric analysis

Abstract

Co‐pyrolysis characteristics of low grade coal (LGC) and sludge derived fuel (SDF) as well as their blends (L/S = 85/15, 75/25, 50/50, and 25/75) were determined at nonisothermal (10, 20, and 30°C/min) conditions in nitrogen atmosphere using thermogravimetric analyzer (TGA). The results indicated that SDF decomposed at a lower temperature than LGC and weight loss of L/S blends was lower than individual LGC or SDF. The difference of weight loss between experimental measurement and theoretical calculation reached circa 0.82 to 2.50 wt % at around 900°C, indicating that there was an inhibitive effect between LGC and SDF. In addition, textural analysis also confirmed the assumption that L/S blend char had higher surface area but less micropore. The results of kinetics analysis showed that the process could be described by two or three consecutive first order reactions, which revealed the possible mechanism of co‐pyrolysis behaviors between LGC and SDF. The estimated kinetics parameters (activation energies and pre‐exponential factors) for LGC, SDF and their blends were found to be in the range of 16.3 to 144.1 kJ/mol and 1.21 to 4.09 × 1010 min−1, respectively. Lower activation energies observed in the relevant decomposition stages indicated that the reaction became faster upon blending. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1780–1789, 2015