Enhancement of Fixed-bed Flow Reactions under Microwave Irradiation by Local Heating at the Vicinal Contact Points of Catalyst Particles
Enhancement of Fixed-bed Flow Reactions under Microwave Irradiation by Local Heating at the Vicinal Contact Points of Catalyst Particles
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DOI：
10.1038/s41598-018-35988-y
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发表时间：
2019-01-18
影响因子：
4.6
通讯作者：
Wada, Yuji
中科院分区：
文献类型：
--
作者：
Haneishi, Naoto;Tsubaki, Shuntaro;Wada, Yuji
在非均相反应体系中形成局部高温区或所谓的“热点”已被认为是使用微波加热增强化学反应的关键因素。本文报道了微波加热下催化剂颗粒间局部高温区的产生。首先，我们证明了当用微波辐射而不是电炉加热时，在磁铁矿催化剂上2-丙醇脱氢的反应速率提高了17-（250摄氏度）至38-（200摄氏度）倍。随后，微波产生的特定的局部加热的存在下，证明了使用耦合模拟的电磁场和热传递，以及在原位发射光谱。由于集中的微波电场，在催化剂颗粒的邻近接触点处产生特定的高温区域。我们还直接观察到局部高温区域的接触点的颗粒在微波加热过程中的模型碳化硅球形材料使用原位发射光谱。我们的结论是，在催化剂颗粒之间的接触点的局部加热的产生是一个关键因素，用于增强微波辐射下的固定床流动反应。
The formation of local high temperature regions, or so-called "hot spots", in heterogeneous reaction systems has been suggested as a critical factor in the enhancement of chemical reactions using microwave heating. In this paper, we report the generation of local high temperature regions between catalyst particles under microwave heating. First, we demonstrated that reaction rate of the dehydrogenation of 2-propanol over a magnetite catalyst was enhanced 17-(250 degrees C) to 38-(200 degrees C) fold when heated with microwave irradiation rather than an electrical furnace. Subsequently, the existence of microwave-generated specific local heating was demonstrated using a coupled simulation of the electromagnetic fields and heat transfer as well as in situ emission spectroscopy. Specific high-temperature regions were generated at the vicinal contact points of the catalyst particles due to the concentrated microwave electric field. We also directly observed local high temperature regions at the contact points of the particles during microwave heating of a model silicon carbide spherical material using in situ emission spectroscopy. We conclude that the generation of local heating at the contact points between the catalyst particles is a key factor for enhancing fixed-bed flow reactions under microwave irradiation.