We used the stereolithography printing technique to fabricate a toroidal fluidised bed (TORBED) at the smallest scale ever achieved (50 mm diameter with 10 mm annular width). In toroidal fluidisation, most of the kinetic energy of the fluidising gas is used to induce swirling of the particle bed meaning higher gas velocities can be used without entrainment. The end-goal of this research is to use this ‘mesoscale-TORBED’ for screening adsorbents for CO₂ capture, where the intensified heat/mass transfer rates can potentially minimise the troublesome scalability issues encountered in standard packed beds, a consequence of gradient effects. Here, we have performed a comprehensive parametric study to understand the influence of bed loading, gas volumetric flow rate, gas temperature and gas humidity on the swirling bed formations of activated carbon pellets in order to identify appropriate conditions for sorbent screening. We show that desirable ‘uniform packing’ occurs across a broad range of operating conditions and identify the lower bed loading limit as 1200 mg. Other observed bed formations included collapsed, maldistributed and entrained states that caused gas bypassing of the particle bed. At the lowest air flow rate studied (27 L/min), the bed was either in the collapsed state or not swirling at all, whilst swirling was readily observed at the intermediate and high air flow rates (35.5 L/min and 44 L/min respectively). Humidity and air temperature had minimal influence over the flow patterns.

我们使用立体平版印刷技术以最小的规模（直径50毫米，环形宽度10毫米）制造了环形流化床（TORBED）。在环形流化中，流化气体的大部分动能用于引起颗粒床的涡旋，这意味着可以使用更高的气体速度而不会夹带。这项研究的最终目标是使用这种“中尺度-TORBED”筛查CO ₂吸附剂捕集，因为传热/传质速率的提高可以最大程度地减少由于梯度效应而在标准填料床中遇到的麻烦的可扩展性问题。在这里，我们进行了一项全面的参数研究，以了解床载量，气体体积流量，气体温度和气体湿度对活性炭颗粒旋流床形成的影响，从而确定合适的吸附剂筛选条件。我们表明理想的“均匀包装”可在很宽的操作条件范围内发生，并确定床的下限为1200 mg。其他观察到的床层形成包括塌陷，分布不均和夹带状态，导致气体绕过了颗粒床。在研究的最低空气流量（27升/分钟）下，床处于塌陷状态或完全不回旋，而在中等和高空气流速（分别为35.5 L / min和44 L / min）下很容易观察到回旋。湿度和空气温度对流态的影响最小。