(337d) Membrane-Based Thermocatalytic Destruction of Chemical Warfare Agents

The possibility of use of chemical weapons has increased in recent years, both as a result of potential terrorist attacks as well as of ongoing international conflicts. The successful application of a flow-through catalytic membrane reactor (FTCMR) as an individual protection (IP) system for the destruction of dimethyl methylphosphonate (DMMP), which is known as a chemical precursor (and used to simulate its characteristics) for Sarin (GB), a toxic chemical warfare agent (CWA) was previously investigated and reported by this group¹. As part of the study, the effect of the DMMP concentration in the feed on its complete combustion in the FTCMR was investigated. The studies indicate that the protection (complete conversion) time is a function of the DMMP concentration, with longer times observed for the lower concentrations, and shorter protection times associated with the higher concentrations.

In this current study, the focus is on collective protection (CP) applications. As part of this effort multi-tubular membrane bundles are developed and rendered reactive for the proposed application. The current efforts involve the development and testing of a 1 cfm multi-tubular FTCMR unit, with the eventual goal the development and testing of a 200 cfm full-scale CP system.

In addition, a novel hybrid system is being developed that combines the FTCMR with a surface-flow membrane system (SFMS)². The main advantage of this hybrid system, combining the SFMS (capable of the physical removal of a large fraction of the CWA from contaminated air streams) and the FTCMR (which completely oxidizes the remaining amount) is the continuous CWA destruction for extended time periods which are appropriate for both IP and collective protection (CP) applications. As part of this effort, we also investigate the performance of the SFMS. Experimental and modeling investigations indicate that a high removal rate can be achieved with a proper choice of (feed rate/membrane surface area) and the sweep ratio. The performance of the combined system is currently under investigation, and experimental results and the modeling of the system performance will be presented at the meeting.

References:

1.  Motamedhashemi, M.M.Y., Egolfopoulos, F.N., and Tsotsis, T.T., “Application of a Flow-Through Catalytic Membrane Reactor (FTCMR) for the Destruction of a Chemical Warfare Simulant,” J. Membrane Sci., 376, 119, 2011.
2. Lee, H. C., Monji, M., Parsley, D., Sahimi, M., Liu, P., Egolfopoulos, F., and Tsotsis, T., “Use of Steam Activation as a Post-Treatment Technique in the Preparation of Carbon Molecular-Sieve Membranes,” Ind. Eng. Chem., Res., dx.doi.org/10.1021/ie300261r, 2013.