Study on the co-pyrolysis characteristics of lignite and biomass and the evolution law of related gaseous products

Biomass is a kind of clean and renewable organic fuel. The development and utilization of biomass can effectively solve the problems of environmental pollution and energy. At present, the research on co-pyrolysis of biomass and low-rank coal has attracted extensive attention from scholars. In order to analyze the synergetic effect of the co-pyrolysis of biomass components and lignite, this paper took cellulose and the Mengdong lignite as the research object, and used the thermogravimetric infrared spectrometer (TG-FTIR) as the experimental method to study the pyrolysis kinetics characteristics (heating rates of 10, 25 and 50℃/min) of cellulose and lignite separately and the blends at different mixing ratios. The results show that the addition of cellulose can increase the pyrolysis activity of the mixture, and make the weight loss rate significantly increase. At the same time, distributed activation energy model (DAEM) can be applied to the calculation of activation energy of cellulose-lignite mixture. The experimental activation energy of the cellulose-lignite mixture under different mass conversion rates is lower than the theoretical activation energy, indicating that the addition of cellulose can reduce the reaction energy barrier during the co-pyrolysis process. In addition, the peak temperature (400-420℃) of small molecule gases (CH₄, CO₂, and CO) during the co-pyrolysis process is consistent with the gas evolution temperature of cellulose, and the amount of gas evolution is significantly higher than the theoretical value. With the increase of the proportion of cellulose in the mixture, the difference between the actual amount of gas precipitated and the theoretical amount shows a trend of first increasing and then decreasing, and when the mixing ratio of cellulose and lignite is 6:4, the gas release of mixture C/L (6:4) is the highest. Therefore, the cellulose component of biomass has a positive synergistic effect on the copyrolysis process.