Co-pyrolysis of Different Coal Types with Biomass: Performance and Efficiency Evaluation by Thermogravimetric Analysis

In this study, the effect of co-pyrolysis of lignite and asphaltite, which are fossil energy sources with significant reserve potential in Turkey, with biomass sources such as walnut shell and hazelnut shell used as renewable energy sources on product efficiency and quality was investigated. The pyrolysis behavior of lignite, asphaltite, two types of biomass, lignite-biomass and asphaltite-biomass mixtures were investigated by non-isothermal thermogravimetric analysis (TGA) to evaluate the influence of biomass type, biomass mixturing ratio and pyrolysis temperature on co-pyrolysis behavior. Pyrolysis experiments were carried out at three different temperatures (400, 460, and 520°C), first with the raw samples and then with mixtures at weight ratios of 25%, 50% and 75%. Possible synergistic effects were investigated by determining the mixture ratios and temperatures with the highest solid, liquid and gaseous product yields by analyzing the pyrolysis conversions. It was observed that the calorific values obtained before the pyrolysis process showed a significant increase after the process was applied. Increasing the amount of biomass added to lignite resulted in a 13.87% increase in calorific value and a positive synergy effect was indicated. Additionally, the addition of biomass to lignite and asphaltite reduced ash content and sulfur content.