电站锅炉粉煤灰漂珠富集模拟研究

Simulation study on fly ash floating bead enrichment in power station boiler

粉煤灰中的漂珠具有很好的工业再利用价值,常规湿法分选漂珠的方法因提纯溶剂的消耗量较大,导致成本较高。本文提出一种在旋风分离器底部送入灰气混合物,上部送入辅助风形成旋流进而富集漂珠的方法,采用欧拉-拉格朗日模型对富集装置内的气固两相流展开数值模拟,验证该方法的可行性;研究芯管高度、底部灰气混合物入射速度及上部辅助风送入速度对富集效果的影响。研究发现,该方法在芯管高度为3 000 mm,上部辅助风送入速度为3.0 m/s,底部灰气混合物入射速度为7.5 m/s条件下,富集后的漂珠质量分数可提升45%。该方法在提高湿法分选前的漂珠质量分数,降低湿法分选的成本方面有明显效果。

Floating beads in fly ash have good industrial reutilization value. The conventional wet separation method for floating beads sorting consumes a large amount of purification solvent, leading to higher costs. Against this problem, this article proposes a method, in which the ash gas mixture is fed at the bottom of the cyclone separator, and the auxiliary wind is fed at the top to form a cyclone separator, thus to enrich the floating beads. Moreover, the Euler-Lagrange model is used to perform numerical simulation on the gas-solid two-phase flow in the enrichment device to verify the feasibility of the method. The influences of the height of the core tube, the incident speed of the bottom ash gas mixture and the feed speed of the upper auxiliary air on the enrichment effect are studied. The results show that, when the incident speed of the bottom gas mixture is 7.5 m/s, the core tube height is 3 000 mm, and the upper auxiliary air feed speed is 3.0 m/s, the mass fraction of the enriched floating beads increases by 45%. This method has obvious effects in improving the mass fraction of floating beads before wet sorting and reducing the cost of wet sorting.