Thermochemical Conversion Behavior of Turkish Lignite/Poppy Capsule Pulp Blends in N-2 and CO2 Atmospheres

In this study, Thermogravimetric Analyzer coupled with Fourier Transform Infrared Spectroscopy (TGA-FTIR) was used for the determination of the thermochemical conversion reactivity of two different types of Turkish lignite coal (Tuncbilek and Orhaneli-Gumuspinar) and poppy capsule pulp (PCP) mixtures under pyrolysis conditions at nitrogen (N-2) and carbon dioxide (CO2) atmospheres. Activation energies (E-a) and pre-exponential factors (A) were determined according to Coats-Redfern method and first-order reaction model. In CO2 atmosphere, all samples exhibited an extra weight loss around 800 - 850 degrees C, different from the N-2 atmosphere, due to the reactive nature of CO2 during thermal decomposition. FTIR analysis confirmed this finding, at high temperatures CO formation were observed in the CO(2 )atmosphere. In all mixtures, the third zone experimental decomposition temperature is lower than that obtained theoretically in N-2 atmosphere, showing that there might a synergistic interaction between the PCP and the lignite samples. The Ea of PCP/Tuncbilek lignite mixtures are smaller than the Ea of their parent components indicating synergy in N-2 and CO2 atmospheres. However, initial and maximum decomposition temperatures for the parent components remain unchanged for these mixtures. Moreover, especially at temperatures higher than 600 degrees C, the Ea for biomass/lignite mixtures found lower than the theoretical values, due to the possible synergistic interactions between PCP and coal samples. According to FTIR analysis, CO, CH4, CHn and ether/amine components were detected. Gaseous pyrolysis product compositions were highly dependent on temperature, and gas species formation was consistent with the weight loss of samples.