Modeling study on devolatilization of coal particle in fluidized bed under pressurized oxy-fuel combustion

作     者：Li, Lin Duan, Lunbo Wu, Wanqiang Sun, Guang 

作者机构：Key Laboratory of Energy Thermal Conversion and Control Ministry of Education Southeast University Nanjing 210096 China 

出 版 物：《Meitan Xuebao/Journal of the China Coal Society》 (Journal of China Coal Society)

年 卷 期：2022年第47卷第11期

核心收录：

学科分类：080702[工学-热能工程] 08[工学] 0807[工学-动力工程及工程热物理] 

基　　金：国家自然科学基金资助项目（51922027） 中国博士后科学基金（2021M700766） 

主　　题：Fluidized beds 

摘      要：Pressurized oxy-fuel combustion is considered one of the most promising CO2 capture technologies, which has gradually attracted the attention of academia and industry in recent years. However, due to the difficulty of the pressurization experiment, the combustion process is like a black box, and the acquisition of combustion information is not rich, the combustion mechanism of coal under pressurized oxy-fuel conditions is not sufficient. In this work, the influence mechanism of O2/CO2 and O2/N2 atmospheres on the devolatilization process of a single coal particle was studied by establishing the devolatilization model. The model considered the heat transfer and the temperature gradient inside the coal particle. The model used the unsteady one-dimensional particle model to describe the drying and devolatilization processes of the single coal particle. The results showed that the model has good applicability, and the error between the calculated and experimental results was less than 20%. The sensitivity analysis of the model showed that the specific heat capacity of bed material and fuel, fuel size, fuel density, fuel moisture content and total heat transfer coefficient between bed material and fuel have a great influence on the drying time. The specific heat capacity of bed material, transfer coefficient, fuel density and size greatly influence the devolatilization time. The specific heat capacity of bed material, heat transfer coefficient, fuel density and fuel size are the main factors affecting the peak value of temperature gradient inside and outside the particle. With the increase of pressure and bed temperature, the heat transfer between coal particle and bed material increased, which also brought lower drying time and devolatilization time and increased the peak temperature difference between inside and outside the particles. Compared with N2 atmosphere, the drying time and devolatilization time decreased slightly under CO2 atmosphere, and the temperature difference between inside and outside particles increased. With the increase in fluidization number (w), the heat transfer between particles and bed was strengthened, and the drying and devolatilization processes were shortened. © 2022 China Coal Society. All rights reserved.