Kinetic and Thermodynamic Analyses of Sugar Cane Bagasse and Sewage Sludge Co-pyrolysis Process

This study investigates the co-pyrolysis of sugar cane bagasse (B), sewage sludge (S), and their blends of different proportions (100% B, 70% B/30% S, 50% B/50% S, 30% B/70% S, and 100% S) through thermogravimetric analysis–differential thermal analysis at 20 °C/min. The purpose of this study to assess the synergistic effect of the addition of sugar cane bagasse into sewage sludge and investigate the co-pyrolysis process kinetics and thermodynamics by employing five major reaction mechanisms with 17 models using the Coats and Redfern method. The kinetic result indicates a synergistic effect of bagasse and sewage sludge. The active co-pyrolysis zone was divided into two reaction zones: zone I (200–400 °C) and zone II (400–600 °C). In both zones, 100% bagasse has the highest E a (F1–F3, 20.77–106.54 kJ/mol; D1–D4, 1.59–89.27 kJ/mol; N1–N4, 2.33–43.69 kJ/mol; and P0.5–Pi, 2.15–39.88 kJ/mol) and A (F1–F3, 2.22 × 10 +2 –6.4 × 10 +10 min –1; D1–D4, 3.20 × 10 +2 –3.72 × 10 +2 min –1; N1–N4, 2.33 × 10 +2 –3.20 × 10 +2 min –1; and P0.5–Pi, 2.33 × 10 +2 –3.20 × 10 +2 min –1 ) compared to 100% sewage sludge E a (F1–F3, 6.20–51.06 kJ/mol; D1–D4, 1.85–68.01 kJ/mol; N1–N4, 2.07–32.06 kJ/mol; and P0.5–Pi, 0.91–29.25 kJ/mol) and A (F1–F3, 2.66 × 10 +2 –4.0 × 10 +2 min –1; D1–D4, 2.66 × 10 +2 –4.32 × 10 +2 min –1; N1–N4, 2.06 × 10 +2 –2.66 × 10 +2 min –1; and P0.5–Pi, 2.06 × 10 +2 –2.66 × 10 +2 min –1 ) for all reaction mechanisms. Among blends in zones I and II, 70% B/30% S showed the highest E a (F1–F3, 17.15–82.77 kJ/mol; D1–D4, 4.34–89.15 kJ/mol; N1–N4, 1.83–42.44 kJ/mol; and P0.5–Pi, 2.27–39.82 kJ/mol) and A (F1–F3, 2.24 × 10 +2 –3.40 × 10 +2 min –1; D1–D4, 4.76 × 10 +2 –12 × 10 +5 min –1; N1–N4, 2.32 × 10 +2 –2.43 × 10 +2 min –1; and P0.5–Pi, 2.32 × 10 +2 –2.34 × 10 +2 min –1 ) compared to all other blends for all reaction mechanisms.