Computational investigation of transport phenomena in adsorption bed

Date

2023-9

Author

Önder, Sılay

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The world's rising level of energy usage with increasing population has become a high-priority issue with the depletion of energy sources. Nowadays, researchers concentrate on developing environmentally friendly energy technologies and utilizing available waste heat sources. Chemical heat pump systems are a promising way of sustainable waste heat recovery because of their large storage capacity, long-term reactant and product storage, and reduced heat loss. Adsorption-based chemical heat pumps have further useful advantages in this category. Yet, there are still many practical issues that are ongoing research areas. One of the main disadvantages is the poor heat and mass transfer characteristic of the packed bed systems and the low thermal conductivity of the adsorbent. Therefore, improving the poor heat and mass transfer characteristics of the packed adsorption bed in the design step is crucial. Several modelling approaches are available in the literature for packed bed systems. However, conventional pseudo-homogeneous and heterogeneous models are insufficient to capture all the complex phenomena happening due to local porosity distribution. In this study, a theoretical and computational model to simulate the ethanol/activated carbon pairing adsorption bed was developed using particle-resolved Computational Fluid Dynamics approach. First, the reactor bed was 3D-modelled and then simulated. Random packing structure of the bed was generated by Discrete Element Method using commercial Altair EDEM software and the cylindrical reactor was packed with spherical particles. Then the mesh generation for 3D geometry packed with spherical particles was performed using commercial preprocessor ANSYS ICEM CFD software. Contact point treatment studies were conducted to avoid skewness and achieve good-quality mesh for CFD simulations. ANSYS Fluent software was used for the CFD simulations of the developed mesh model. Multiscale modelling of the bed was performed based on continuity, momentum, energy equations and adsorption model. This study thoroughly explains the transport properties of both the intra-particle and the interstitial fluid region in a randomly packed adsorption bed with small tube-to-particle diameter ratio. The procedure can be utilized for the design of catalyst particles and reactors for randomly packed adsorption beds.

Subject Keywords

Modelling, CFD, adsorption, packed bed

URI

https://hdl.handle.net/11511/105604

Collections

Graduate School of Natural and Applied Sciences, Thesis