Mixing Regime Simulation and Cellulose Particle Tracing in a Stacked Frame Photocatalytic Reactor
Mixing Regime Simulation and Cellulose Particle Tracing in a Stacked Frame Photocatalytic Reactor
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DOI：
10.1016/j.cej.2016.12.016
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发表时间：
2017-04
影响因子：
15.1
通讯作者：
S. Nagarajan;L. Stella;L. Lawton;J. Irvine;Peter K. J. Robertson
中科院分区：
文献类型：
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作者：
S. Nagarajan;L. Stella;L. Lawton;J. Irvine;Peter K. J. Robertson
为了可持续地满足全球能源需求，必须出现生产可再生能源的非传统方法。由纤维素（通过发酵糖生产）经纤维素酶介导的生物燃料提供了传统化石燃料的替代品。为了有效地驱动光催化过程，需要有效的反应器设计，其设计受到许多关键因素的影响，例如催化剂与反应物的比率和停留时间、催化剂照射时间、系统的光穿透和分布、传质限制（混合）和产物回收。在这项研究中，我们使用COMSOL Multiphysics®模拟和评估了上述参数之一-纤维素颗粒在堆叠框架光催化反应器（SFPR）中的混合状态。在反应器的设计中，我们比较了两种混合器：一个“加号”形的磁力搅拌棒和一个8叶片Rushton叶轮。模拟结果表明，Rushton叶轮提供了一个径向混合模式，与提供0.9 m/s的流体速度的搅拌棒相比，流体速度更高，为1.2 m/s。纤维素颗粒示踪模拟证实，颗粒分散是上级的Rushton叶轮的情况下，在混合过程中产生的涡流推动颗粒的反应器的壁。由于颗粒被迫朝向壁，因此与没有混合或不适当混合的情况相比，有可能有更多的颗粒被照亮。
To sustainably meet the global energy demand, unconventional methods to produce renewable energy must emerge. Biofuels from cellulose (via fermentable sugar production) mediated via photocatalysis provides an alternative to conventional fossil fuels. In order to effectively drive photocatalytic processes an effective reactor design is required, the design of which is influenced by a number of key factors such as the catalyst to reactant ratio and residence time, catalyst illumination time, light penetration and distribution for the system, mass transfer limitations (mixing) and product recovery. In this study we use COMSOL Multiphysics® to simulate and assess one of the mentioned parameters – mixing regime of cellulose particles in a Stacked Frame Photocatalysis Reactor (SFPR). In the reactor design, we compare two mixers: a ‘plus’ shaped magnetic stirrer bar and an 8 blade Rushton impeller. The simulations reveal that the Rushton impeller offers a radial mixing pattern with a higher fluid velocity of 1.2 m/s when compared to the stirrer bar that offers a fluid velocity of 0.9 m/s. Cellulose particle tracing simulations confirm that the particle dispersion is superior in the case of the Rushton impeller as the vorticity generated during the mixing push the particles to the reactor’s walls. Since the particles are forced towards the walls, there is a probability of more particles being illuminated than in the case of no or improper mixing.