Abstract: Due to the ash has an inhibitory effect on activity of oxygen carrier in coal-fueled CLC(chemical looping combustion) technology,a new method of separating oxygen carrier and ash respectively by double-stage cyclone separator was proposed in this paper. The RSM(SSG) turbulence model and the particle stochastic trajectory model were both adopted,and the phase coupling was also considered. The numerical simulation was carried out for optimizing the double-stage cyclone separator in CLC facility. According to the simulation result,the size and structure of separator inlet was mainly analyzed and optimized,and the separation performance was verified by experiments. The simulation and experimental results of final optimization model both showed that more than 90% of CaSO₄ oxygen carriers return to furnace from dust removal port of first stage separator. The CaSO₄ loss rate was reduced. About 50% of ash particles were separated from dust removal port of second stage separator,only about 13% with the air discharge from the exhaust port. Dust-returning rate was effectively reduced and the clean exhaust gas was relatively released. The results are significant to the efficient operation of coal-fueled CLC facility.

Key words: chemical looping combustion (CLC), double-stage cyclone separator, granular flow, numerical simulation, optimization

摘要： 由于煤化学链燃烧技术中煤灰对载氧体活性具有较强抑制作用,本文提出了通过双级串联旋风分离器分别对载氧体及煤灰进行分离的新方法,并应用雷诺应力RSM(SSG)湍流模型以及DPM颗粒随机轨道模型,考虑气固两相的相间耦合,对煤化学链燃烧装置中的双级旋风分离器进行了数值模拟,根据模拟结果对一级、二级分离器进口尺寸及结构形式进行了优化,并通过实验对分离性能进行了验证。优化后模型的模拟及实验结果均表明:相比原模型,优化模型中90%以上的CaSO₄载氧体从一级分离器排尘口返回炉膛,降低了载氧体流失率;约50%的煤灰颗粒从二级分离器排尘口分离,仅13%左右的煤灰随气流从其排气口排出,有效降低炉膛返灰率,保持载氧体活性,并实现排气的相对清洁。最后指出本文研究结果对煤化学链燃烧装置的高效运行具有重要的参考价值。

关键词: 化学链燃烧, 双级旋风分离器, 颗粒流, 数值模拟, 优化