[PSUBS-MAILIST] scrubber humidity

[Sean T. Stevenson via Personal_Submersibles]

Hank, the scrubber chemical reaction requires water to dissociate the compounds in the scrubber media. The reactions actually occur in aqueous solution at the granule surfaces. Most scrubber media contains some amount of water by weight as supplied, and in addition to isolation from atmospheric CO2, scrubber media ships in sealed containers to prevent it from drying out completely. As long as you are keeping your cabin humidity in the recommended range between 30% and 70% RH, humidity shouldn't be an issue as far as scrubber performance. The other thing to consider is the scrubber's temperature.  The chemical reactions are more efficient at higher temperature, and if your scrubber is cold at the beginning of a dive, it will take some time to warm up to an efficient operating range. Fortunately, the scrubbing reaction itself is exothermic, which helps. Be aware though that a very warm scrubber will drive relative humidity down within the scrubber bed, so if you have quite dry cabin
air to start with, a warming scrubber can drive the humidity out of the efficient operating range.

Sean


On May 17, 2015 3:07:16 PM MDT, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
>Hello,
>Is it normal for my scrubber to perform poorly until the humidity level
>inside the sub rises?
>Hank
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