Importance of pressure to the mean fluid temperature distribution in steam reformers for hydrogen production using microreactor technology

The mean fluid temperature data are obtained for illustrating the effect of pressure on the thermal performance of steam reformers for hydrogen production using microreactor technology. The reactor system is in the form of a catalytic coating on a substrate composed of ceramic or metal walls defining straight reforming or oxidation channels which are parallel to each other and to the axis of the reactor. Relatively high mass transfer is provided by using low hydraulic diameter channels. The reactor system offers relatively simple designs and operation. Such a reactor system is typically adiabatic in nature, meaning no heat is added in addition to the exothermic reaction heat release. The reactor system is operated using excess air and water steam. Methanol and air are mixed homogeneously and the mixture is fed directly into the oxidation channels in a specific ratio. Preferably, excess water steam is provided to the reactor to increase efficiency and to maintain operability, for example, to prevent carbon formation. The reactor provides for continuous and simultaneous reaction of two different process reaction streams in the channels defined between the walls, wherein a first process reaction stream undergoes a high temperature exothermic reaction in the first set of flow channels and a second process reaction stream undergoes an endothermic heat-consuming reaction in the second set of flow channels separated from the first set of flow channels by the heat transfer separating walls. More specifically, the reactor system includes a set of reforming channels for steam reformation of methanol and a set of oxidation channels for heating the reactor system to operating temperature. A separating wall therefore separates two adjacent reaction zones and also functions to transfer heat from the oxidation occurring at the catalyst surface in the oxidation zone directly to the reforming catalyst coated on the opposed surface. The channels are 0.7 millimeters in height and in width and 30.0 millimeters in length. The oxidation catalyst consists essentially of oxides of copper, zinc and aluminum. The reforming catalyst consists essentially of copper and oxides of zinc and aluminum. The exothermic and endothermic processes are conducted with a methanol-air equivalence ratio of 0.8 and a steam-to-methanol molar ratio of 1.17. The inlet temperature of the mixtures is 373 degrees kelvin. The gas velocity is 2.0 meters per second at the reforming channel inlets and 0.6 meters per second at the oxidation channel inlets, thereby assuring sufficient heat in the reactor.
Contributor: Junjie Chen, E-mail address: [e-mail], ORCID: 0000-0002-5022-6863, Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China

本数据集提供平均流体温度数据，用于阐明压力对采用微反应器技术（microreactor technology）的制氢蒸汽重整器热性能的影响。该反应器系统以催化涂层的形式附着于基底之上，基底由陶瓷或金属壁构成，壁内形成彼此平行且与反应器轴线平行的直形重整通道与氧化通道。采用较小水力直径（hydraulic diameter）的通道可实现较高的传质效率，且该反应器系统设计与操作均相对简便。此类反应器系统本质上通常为绝热结构，即除放热反应释放的热量外，无需额外补充热量。反应器系统通过过量空气与水蒸气进行运行。甲醇与空气均匀混合后，以特定比例直接送入氧化通道。为提升效率并维持运行稳定性（例如防止积碳），通常会向反应器通入过量水蒸气。该反应器可在壁间通道内实现两种不同工艺反应流的连续同步反应：第一组流动通道内的第一工艺反应流发生高温放热反应，第二组流动通道内的第二工艺反应流则发生吸热耗热反应，两组通道通过传热分隔壁相互隔开。更具体而言，该反应器系统包含一组用于甲醇蒸汽重整的重整通道，以及一组用于将反应器系统加热至运行温度的氧化通道。因此，分隔壁既隔开了两个相邻的反应区域，同时又可将氧化区催化剂表面发生的氧化反应所释放的热量，直接传递至对面表面涂覆的重整催化剂上。通道的高度与宽度均为0.7毫米，长度为30.0毫米。氧化催化剂主要由铜、锌与铝的氧化物组成；重整催化剂主要由铜以及锌、铝的氧化物组成。本次实验的放热与吸热反应过程中，甲醇-空气当量比为0.8，水蒸气与甲醇的摩尔比为1.17。混合气体的入口温度为373开尔文。重整通道入口处的气体流速为2.0米每秒，氧化通道入口处的气体流速为0.6米每秒，以此确保反应器内具有充足的热量。贡献者：陈俊杰，电子邮箱：[e-mail]，ORCID：0000-0002-5022-6863，河南理工大学机械与动力工程学院能源与动力工程系，河南省焦作市世纪大道2000号，454000，中华人民共和国