The utilization of hydrogen is gaining increasing attention due to its high heating value and environmentally friendly combustion product. The supercritical water circulating fluidized bed reactor is a promising and potentially clean technology that can generate hydrogen from coal gasification. Cyclone is a vital part of the reactor which can separate incomplete decomposition of pulverized coal particles from mixed working fluid. This paper aims to gain in-depth understanding of the cyclone separation mechanisms under supercritical fluid by computational fluid dynamics (CFD). Although the amount of supercritical carbon dioxide in mixed working fluid is minor, it obviously influences the flow fields and separation efficiency of a cyclone. The simulation results suggest that both the decreasing content of supercritical carbon dioxide and adding the extra dipleg cause the promoting performance of cyclones. Research findings could refine the design of supercritical fluid–solid cyclones.

氢气的热值高、燃烧产物环保，因此越来越受到重视。超临界水循环流化床反应器是一种很有前景的清洁技术，可以从煤气化中产生氢气。旋风分离器是反应器的重要组成部分，它可以将不完全分解的煤粉颗粒从混合工质中分离出来。本文旨在通过计算流体动力学（CFD）深入了解超临界流体下的旋风分离机制。混合工质中超临界二氧化碳的含量虽然微乎其微，但对旋流器的流场和分离效率有明显的影响。模拟结果表明，降低超临界二氧化碳含量和增加额外的浸入管都会导致旋风分离器的性能提升。研究结果可以改进超临界流体-固体旋流器的设计。