Effect of pyrolysis heating rates on fuel properties of molded charcoal: Imitating industrial pyrolysis process

• Published in: Renewable energy Vol. 197; pp. 257 - 267
• Main Authors: Ni, Liangmeng, Feng, Zixing, Zhang, Tao, Gao, Qi, Hou, Yanmei, He, Yuyu, Su, Mengfu, Ren, Hao, Hu, Wanhe, Liu, Zhijia
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2022
• Subjects: Bamboo; Chinese fir; Energy properties; Heating rate; Molded charcoal; Molded charcoal; Chinese fir; Heating rate; Bamboo; Energy properties
• ISSN: 0960-1481; 1879-0682
• DOI: 10.1016/j.renene.2022.07.132

To investigate the relationship between fuel properties and pyrolysis heating rates (PHRs) of molded charcoals (MCs), biomass briquettes (manufactured by 70% bamboo and 30% wood blends) were pyrolyzed using various PHRs based on industrial production stages (preheating, primary pyrolysis, and carbonization stage). Proximate and ultimate analyses, as well as thermogravimetric and kinetics analyses, were performed for MCs. Results showed that PHRs had a significant effect on the quality and yield of MCs at the primary pyrolysis stage. Based on the production efficiency and energy performances, the PHRs were suggested to 5 °C/min, 1 °C/min, and 5 °C/min for preheating, primary pyrolysis, and carbonization stages. The higher heating value, energy enrichment factor, calorific value improvement, energy yield, and fuel ratio of optimal MCs were 34.02 MJ/kg, 1.777, 1.716, 71.65%, 55.27, and 11.51, respectively. The MCs had a minimum activation energy of 98.57 kJ/mol. The findings of this study will be useful in understanding and standardizing the manufacturing process of MCs. [Display omitted] •The industrial production process of molded charcoal has been imitated.•Pyrolysis heating rate influences the preheating and carbonization stages slightly.•High pyrolysis heating rate affects the primary pyrolysis stage primarily.•High combustion heating rate decreases the activation energy.•Combustion heating rate has a greater effect on Ea than pyrolysis heating rate.