Investigation of element migration characteristics and product properties during biomass pyrolysis: a case study of pine cones rich in nitrogen

To further understand the element migration characteristics and product properties during biomass pyrolysis, herein, pine cone (PC) cellulose and PC lignin were prepared, and their pyrolysis behavior was determined using thermogravimetric analysis (TGA). Subsequently, the PC was pyrolyzed in a vertical fixed bed reactor system at 400-700 degrees C for 60 min. The characteristics of element migration and the physicochemical properties of the pyrolysis products were analyzed and discussed. In the pyrolysis temperature range from 200 degrees C to 500 degrees C, there were two distinct weight loss peaks for PC. During the pyrolysis process, the C element was primarily retained in the biochar, while the O element mainly migrated into liquid and gaseous products in the form of compounds such as CO2, CO, and H2O. Besides, 28.42-76.01% of the N element in PC migrated into biochar. Of the three-phase products, the gases endow the lowest energy yield, while the energy of the biochar dominates the pyrolysis of the PC. Additionally, the N content and specific surface area for the PC-derived biochar obtained at 400 degrees C in a N-2 atmosphere were higher than those of the biochar derived from fiberboard.

Automated summary

This study investigated the pyrolysis behavior of pine cone cellulose and lignin, revealing that carbon element was mainly retained in biochar, while oxygen element migrated into liquid and gaseous products. Moreover, a significant portion of nitrogen element was found to migrate into biochar during the pyrolysis process.