Study on the heat transfer and chemical reactions during pyrolysis of Cellulose, Xylan and Lignin

Temperature and heat of reactions have been measured during fast pyrolysis of biomass powder packed bed. For cellulose powder, temperature at the center of the bed, TC, increased monotonously with time due to thermal conduction for TC < 500K. The temperature increased slowly with time due to endothermic decomposition of cellulose for 500 K < TC < 600 K. On other hand, exothermic behaviors for xylan powder and lignin one were significantly observed at TC > 500 K and at TC > 600 K, respectively. The heats of reactions were measured by differential scanning calorimetry (DSC). For Cellulose powder, endothermic and exothermic signals were observed at 560 K < T < 607 K and at 607 K < T < 638 K, respectively. For Lignin powder has two endothermic peaks at 491 K < T < 495 K and 503 K < T < 549 K while the exothermic signal was observed at 549 K < T < 682 K. For Xylan powder, endothermic and exothermic signals were observed at 371 K < T < 477 K and at 477 K < T < 602 K, respectively. Furthermore, numerical simulation of fast pyrolysis of cellulose powder packed has been conducted.