A percolation model of fly ash formation during the combustion of non-uniform porous char
发布时间：2025-04-30
点击次数：
- 发布时间：
- 2025-04-30
- 论文名称：
- A percolation model of fly ash formation during the combustion of non-uniform porous char
- 发表刊物：
- Combustion and Flame
- 摘要：
- An improved percolation model has been introduced to predict the particle size distributions (PSDs) of produced residue during pulverized coal char combustion. A three-dimensional cluster of interconnected sites representing a single char particle is constructed at a given size. These sites are classified into surrounding gas, macropores, carbon, or ash. Non-uniform porous char structures and the melting performances of the ash particle have been considered to approach the most realistic scenario. The char fragmentation and ash coalescence process is simulated by checking the connectivity and proximity of occupied sites. The effects of char particle sizes are addressed by using char PSD data as the input to the model. The numerical results were compared with the measured PSDs of fly ash and show a good agreement. The effects of porous char structure and included minerals on the sizes of produced particles during combustion are further investigated. The simulation results indicate that the mean sizes of produced particles initially decrease (N<0.7) and then increase with char consumption. The char fragmentation behavior dominates in the preliminary and middle stages of char burning, while the ash coalescence is the primary behavior in the char burnout stage. The mean sizes of produced particles increase with the lower char porosity and the higher extent of pore aggregation. The size difference between PM20 and PM20+ increases when the macropores are repositioned to be aggregated. The mean sizes are positively related to the ash content and ash coalescence parameter in the middle and late stages of char burning.
- 合写作者：
- Liu Siqi, Niu Yanqing*, Shang Yimin, Zhu Guangqing, Hui Shi’en
- 卷号：
- 251
- 页面范围：
- 112720
- 是否译文：
- 否
- 发表时间：
- 2023-05-01