组合流化床燃烧器烧焦管内固含率的径向分布研究

Study on radial profiles of solid fraction in coke-burning riser of a compound fluidized bed combustor

在组合流化床燃烧器的冷态实验装置上,以空气-石英砂颗粒为流化介质体系,在烧焦管内表观气速(ug)为3.156～5.989 m/s,颗粒循环强度(Gs)为40.8～229.4 kg/(m2.s)的条件下,采用光纤颗粒浓度测量仪对烧焦管内床层径向局部位置的固含率(εs)进行了测定。结果表明,烧焦管内εs沿床层径向呈中心稀边壁浓的环-核形分布形态,呈现出非均一的相结构;εs随ug的升高而减小,且随Gs的升高而增大,这种影响规律在烧焦管的边壁区比中心区更为显著。根据实验数据关联出截面平均固含率不变条件下的径向局部εs的计算式,所得计算值与实验值基本吻合。

The radial local solid fraction （68）in a large- scale compound fluidized bed coke- burning riser was experimentally measured by using the particle concentration fiber probe. The medium system used was the air - sand particles. The superficial gas velocity（ug） in the coke- burning riser ranged from 3. 156 m/s to 5. 989 m/s, and the particle circulating flux（G8） varied between 40.8 kg/（ m2 · s） and 229.4 kg/（ m2 ·s）. The results showed that the radial distribution of 8, in the coke - burning riser displayed the core -annulus pattern, which demonstrated that the heterogeneous phase structure existed in the riser, the dispersed particle dilute phase in the core region, and the particle cluster dense phase in close to the riser wall region. 8s decreased with increasing u, but increased with increasing Gs. The variation of ε8 with the operating conditions was more remarkable in close to the riser wall region than in the core region. The experiential model of εs was obtained by fitting the experimental data at given cross - sectional averaged solid fraction. The model predicted values agreed well with the experimental data.