Co-Pyrolysis Characteristics of Coal and Sludge Blends Using Thermogravimetric Analysis

摘要

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 noniso-thermal (10, 20, and 30℃/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℃, 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 micro-pore. 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 × 10~(10) min~(-1), respectively. Lower activation energies observed in the relevant decomposition stages indicated that the reaction became faster upon blending.