A continuum model of heterogeneous catalysis: Thermodynamic framework for multicomponent bulk and surface phenomena coupled by sorption
A continuum model of heterogeneous catalysis: Thermodynamic framework for multicomponent bulk and surface phenomena coupled by sorption
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DOI：
10.1016/j.ijengsci.2019.01.001
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发表时间：
2019-05
影响因子：
6.6
通讯作者：
O. Souček;V. Orava;J. Málek;D. Bothe
中科院分区：
文献类型：
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作者：
O. Souček;V. Orava;J. Málek;D. Bothe
我们推导出一个化学反应的流体混合物的非均相催化连续热力学的框架内制定的一致性模型。该模型考虑了体域中的标准输运现象，并涉及体域和边界的催化（活性）部分之间的物质传质，其中表面对应于体域输运过程发生。该模型受益于将边界的活动部分描述为体域与其外部之间的界面，这允许采用以下框架：连续介质力学与界面输运现象。涉及向量和张量的本构关系，如柯西应力，能量和熵通量和扩散通量相关的个别成分的构造在一个系统的方式，确保与热力学第二定律的兼容性。本构过程如下从本构方程的规格为合适的热力学势（自由能）的混合物在散装和边界的活性部分，并从识别的散装和表面熵生产。用统计物理的方法描述了边界的活动部分，并以此为基础导出了表面连续热力学势，所导出的模型适用于有关初边值问题的进一步数学、数值和计算分析。虽然该模型采用了一个相对简单的描述的活性部分的边界作为一个单层晶格与单网站的朗缪尔型吸附，其详细推导这里提出的其他吸附模型的结合提供了明确的指导方针。
We derive a thermodynamically consistent model of heterogeneous catalysis for chemically reacting fluid mixtures formulated in the framework of continuum thermodynamics. The model takes into account standard transport phenomena in the bulk domain and involves mass transfer of the species between the bulk and the catalytic (active) part of the boundary where the surface counterparts to the bulk transport processes take place.Concerning the balance laws on the catalytic surface, the model benefits from description of the active part of the boundary as an interface between the bulk domain and its exterior which allows to employ the framework of continuum mechanics with interfacial transport phenomena. The constitutive relations involving vectorial and tensorial quantities such as the Cauchy stress, energy and entropy fluxes and diffusive fluxes relevant to individual constituents are constructed in a systematic manner ensuring compatibility with the second law of thermodynamics. The constitutive procedure follows from the specification of constitutive equations for suitable thermodynamic potentials (free energies) of the mixture in the bulk and on the active part of the boundary and from the identification of the bulk and surface entropy productions. The active part of the boundary is described by means of statistical physics and this description then serves as a building block for the derivation of surface continuum thermodynamic potentials.The derived model is suitable for further mathematical, numerical and computational analysis of relevant initial and boundary value problems. While the model employs a relatively simple description of the active part of the boundary as a monolayer lattice with single-site Langmuir-type adsorption, its detailed derivation presented here provides clear guidelines for the incorporation of other sorption models.