Interest has surrounded the use of adsorbent hollow fibres (HF) as an alternative to existing adsorption technology, such as packed beds, because of their comparatively low pressure drop and efficient sorption cycles. The aim of this research was to improve the understanding of the transport phenomena within adsorbent HF, in order to optimise their design for VOC abatement based on breakthrough performance. Computational models of HF’s with circular, trilobal and clover shaped bores were developed, with a single and multichannel design based on a circular bore and n-butane was used as the model VOC. Computational fluid dynamics (CFD) were applied to resolve the conservation equations involving continuity, momentum and species transport. Convective and diffusive transport were assumed within the fibre bore whereas in the porous media transfer occurred by diffusion and adsorption, modelled using the Langmuir isotherm. The dimensions of HF’s and operating conditions were obtained from experimental work in our group. The pressure drop in the HF’s were found to be significantly lower than in packed bed. In terms of breakthrough and equilibrium times, the order of performance is smaller multichannel fibres > circular > clover > trilobal. Parametric studies showed that the most significant impact on breakthrough and equilibrium times results from varying the effective diffusivity of gas in the porous media, the Reynolds number in the bore and the Langmuir constant. Further considerations are required for financial weight, structural integrity and regeneration in order to confirm usage in industrial applications.
|Publication status||Published - 2016|