Chemical Reaction from CO2/ Water/H2S, H2 permeating damaging diaphram when calibrating wedge meter

[elquesifilma]

Dear Fellow Eng-tips technical experts,

I am trying to figure out what chemical reaction occers that frees up Hydrogen molecules in the following process

I have a wedge meter transmitter that we are experience hydrogen premeation from our process of CO2 fluid which contains H2S and produced water. The H2 permeates through the diaprahm and then re combines as H2 gas on the other side, when the unit is in service and under pressure the gas molecules stay compressed, when the unit is taken out and recalibrated the gas expans and can cause damage to the isolating diapgram if we have significant gas trapped. We are looking into gold plating to block the hydrogen atoms so it does not get to the isolation diaphragm

I would appreciate any help regarding the chemical reaction

 

[lloydbrown]

According to HSC Chemistry, H2S can react with water to form hydrogen and H2S5O3. That is possible but more likely the hydrogen results from metallic corrosion.