The current military respirator provides protection from contaminants using a cartridge packed with adsorbent activated carbon particles treated with metal salts to provide protection from toxic gases. However, the user of this respirator is subject to a physiological burden as a result. One component of this burden is the pressure drop, which makes breathing through the respirator filter difficult, with the burden becoming more severe at higher breathing rates. This project investigates the reduction of pressure drop and hence burden in respirator cartridges by using adsorbent hollow fibres. These are made up of adsorbent powder held together with a polymer binder to replace the conventional adsorbent particles. Adsorbent hollow fibres have a number of advantages,including lower pressure drop, the ability to operate in any orientation, no special filling requirements and customisability against emerging threats, such as toxic industrial chemicals. Dynamic challenges were performed using ammonia, hydrogen sulphide and cyclohexane as candidate gases, as each typifies a particular category of toxic industrial chemicals. Adsorbent hollow fibres were customised by treating with metal salts, metal organic frameworks and pore forming agents, and by replacing the hollow fibre polymer binder with a novel microporous polymer. In addition, the pressure drop of these adsorbent fibres was compared to granular beds. Pressure drop was then modelled usingthe Hagen-Poiseuille equation, and the breakthrough time was modelled with the Wheeler-Jonas equation, enabling the prediction of pressure drop and breakthrough time for new designs of adsorbent hollow fibre cartridges.
|Date of Award||21 Feb 2015|
|Supervisor||Semali Perera (Supervisor)|