Investigation on caloric requirement of biomass pyrolysis using TG–DSC analyzer

Abstract

The caloric requirement of biomass pyrolysis has an important influence on the course of the thermal conversion. However, precise data are difficult to achieve by the current calculation method because of the complexity of the process. A new method for achieving the caloric requirement of the process by integrating the differential scanning calorimetry (DSC) curves was proposed after the simultaneous thermal analyzer (TG-DSC) and DSC curves were investigated. Experiments were conducted for wheat straw, cotton stalk, pine and peanut shell on a Netsch STA 449C analyzer. Powder samples were put into a platinum crucible with a lid on a high accuracy DSC-cp sample holder in the furnace and then heated from ambient temperature up to the maximum temperature of 973 K at the heating rate of 10 K/min in the analyzer. The product gases were swept away by 25 ml/min nitrogen. Mass changes (TG) and calorimetric effects (DSC) were recorded and analyzed. The process was investigated in detail through comparison of the DTG (differential thermogravimetric) and DSC curves of wheat straw. After the water influence in the DSC was eliminated, the relationship of the caloric requirement with the temperature of the aforementioned dry biomass was obtained by integrating the DSC curve. The results showed that 523 kJ, 459 kJ, 646 kJ and 385 kJ were required, respectively, to increase the temperature of 1 kg of dried wheat straw, cotton stalk, pine and peanut from 303 K to 673 K.