Recommendations for the Disposal of Chemical Agents and Munitions (1994) / Chapter Skim
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Appendix C: Use of Activated Carbon Adsorption Systems for Exhaust Gas Cleaning
Appendix C: Use of Activated Carbon Adsorption Systems for Exhaust Gas Cleaning
Pages 148-153
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From page 148... ...
Industnal gas filtration processes commonly employ several sequential vertical beds of charcoal, each several inches thick. They have gas velocities of ~ foot per second or less to ensure essentially complete removal (adsorption)
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From page 149... ...
For low concentrations of high molecular weight contaminants, such as agents and dionns, this time can be designed to be on the order of several months. This duration easily allows adequate tune for chemical analyses between the beds to certify contaminant removal and to determine breakthrough upstream of the final bed with adequate tune for bed replacement or other remedial action.
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From page 150... ...
beds. GAS FLOW ~ ILL 1 1 Breakthrough at second bed Final Bed - ' 1 1 1 1 2 ~ 3 4 5 6 Bed Number Contaminant concentration profiles in a series of charcoal If a pulse of high agent concentration occurred, it would also be captured, and the leading edge of the pulse would then migrate through the bed at about the same speed as the wave from lower concentrations, as long as it did not exceed ache storage capacity of the bed.
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From page 151... ...
As the exit gas temperature is increased, the adsorptive capacity of the charcoal decreases, time to breakthrough decreases, and the probability of hot spots or fires is increased. The optimum temperature will then depend on the specific application.
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From page 152... ...
Fires can also be initiated rapidly if a major upstream process upset should occur, such as the failure of power to the quench, wet scrubbing, and/or cooling water supply pumps. Without corrective action, such a failure would rapidly-inject into the carbon beds a high-temperature gas stream with sufficient residual oxygen to cause a fire.
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From page 153... ...
The water would merely block the interstitial passages In the carbon granules, preventing further gas adsorption. It would not likely block the bulk gas flow through the much larger void spaces between the charcoal granules.
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