Catalyst testing in a multiple-parallel, gas-liquid, powder-packed bed microreactor
Catalyst testing in a multiple-parallel, gas-liquid, powder-packed bed microreactor
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DOI：
10.1016/j.apcata.2009.06.010
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发表时间：
2009-08-31
影响因子：
5.5
通讯作者：
Kreutzer, Michiel T.
中科院分区：
文献类型：
--
作者：
van Herk, Daniel;Castano, Pedro;Kreutzer, Michiel T.
报道了用粉末催化剂的三相推流微反应器获得本征动力学的方法。我们的测试反应是联苯在铂-钯/氧化铝催化剂上的加氢反应。我们比较了在我们的微型反应器和标准加氢高压罐中获得的反应速率。该反应器由六个内径为2.2 mm、最大催化剂床长为200 mm的平行反应管组成，两相在床上缓慢流动比只运行一种液体或一种气体需要更多注意。我们在这项工作中的主要贡献是强调流体动力学异常的影响，最重要的是气体和液体的滞留区，这些异常发生在稀释剂和催化剂分布不均匀的反应器塔中。这种填料的不规则性导致不同管子之间的换算水平有很大差异。相反，使用适当的方式均匀地装载固体，我们可以在每个反应堆管中得到相同的结果。这些动力学常数的值与我们在高压灭菌器中得到的值是相同的。众所周知，太多的稀释会导致转化率的损失，这一效应比气固体系中的影响更强。我们可视化了二维反应器模型中的流动模式，并在分离床中发现了这样的停滞区。在这里描述的特定条件下，按比例缩小连续填充床反应器以可靠地测量气-液-固反应的催化动力学是可能的。(C)2009爱思唯尔B.V.保留所有权利。
The use of a three-phase plug-flow microreactor with powder catalysts to obtain intrinsic kinetics is reported. Our test reaction is the hydrogenation of biphenyl over a Pt-Pd/Al2O3 catalyst. We compare reaction rates obtained in both our microreactor and a standard hydrogenation autoclave. The reactor design consists of six parallel reactor tubes with an inner diameter of 2.2 mm and a maximum catalyst-bed length of 200 mm.Co-flowing two phases very slowly over the bed needs more care than running only a liquid or a gas. Our main contribution in this work is to stress the impact of hydrodynamic anomalies, most importantly stagnant zones of gas and liquid, which occurred in reactor columns where diluent and catalyst were unevenly distributed. Such packing irregularities caused huge variations in conversion levels from tube to tube. In contrast, using a proper way to load the solids evenly, we could get the same results in each reactor tube. The values of these kinetic constants were identical to the ones we obtained in the autoclave. The well-known effect that too much dilution causes loss of conversion is found to be stronger than that in gas-solid systems. We visualized flow patterns in a 2-dimensional reactor mock-up and found such stagnant zones in segregated beds. Scaling down a continuous packed-bed reactor to reliably measure catalytic kinetics for gas-liquid-solid reactions is possible under specified conditions described herein. (C) 2009 Elsevier B.V. All rights reserved.