Abstract
Commercial fire escape masks (FEMs) use packed bed filters to remove gaseous and vaporous toxic components in the event of building fires. Packed bed filters incur a high pressure drop and commercial masks have no method to remove environmental (fire) or process (reaction and adsorption) heats. Here we derive a computationally efficient numeric model based on a bi-linear driving force (LDF) model to investigate the purification of gas streams in a square channelled monolith filter containing an impregnated activated carbon (AC) section to adsorb and react toxic components, and a section consisting of shape stable phase change materials (SS-PCMs) to absorb heat. The modelled test gas mixture contained an adsorbing component, cyclohexane, and a reacting component, carbon monoxide, permitting the combined effects of heat generation, heat absorption, component reaction and component adsorption to be studied for a novel filter. The bi-LDF model was validated against a three-dimensional model and provided excellent accuracy at significantly reduced computational time ca. 99.7%. Additionally, the bi-LDF model was used to optimise the dimensions and configuration of the filter, specifically finding an optimal channel diameter, d ch, to wall thickness, t w, aspect ratio of d ch=1.3t w. The optimal configuration consisted of an initial 2.0 cm long impregnated AC section followed by a 2.5 cm SS-PCM section at the outlet, providing 18 min of thermal protection whilst preventing cyclohexane vapour breakthrough for 21 min. Pt/TiO 2 was confirmed to be a viable CO oxidation catalyst with a minimum weight fraction within the impregnated monolith of 2.5 wt%. The success of this work represents a step change in FEM design and more widely in air purification devices where heat absorption is important.
Original language | English |
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Article number | 132775 |
Journal | Chemical Engineering Journal |
Volume | 430 |
Issue number | Part 2 |
Early online date | 8 Oct 2021 |
DOIs | |
Publication status | Published - 15 Feb 2022 |
Bibliographical note
Funding Information:This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) grant EP /L016516/1 for the University of Bath Centre for Doctoral Training, the Centre for Sustainable & Circular Technologies. This research made use of the Balena High Performance Computing (HPC) Service at the University of Bath.
Publisher Copyright:
© 2021
Keywords
- Bi-linear driving force
- CO oxidation
- Fire escape masks
- Monoliths
- Phase change materials
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry
- General Chemical Engineering
- Industrial and Manufacturing Engineering