Reconsidering the calculation of hydrogen sulfide partial pressure and hydrogen sulfide solubility
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There have been many discussions on this forum regarding the calculation of hydrogen sulfide partial pressure； The partial pressure of hydrogen sulfide is relevant to the assessment of wet hydrogen sulfide environments, and it also affects the selection of equipment materials and the manufacturing processes; it is therefore a quite important parameter. I also have doubts now regarding the calculation of the hydrogen sulfide partial pressure and its solubility; this doubt has been bothering me for a long time, so I would like to raise it for discussion with everyone. In the current standards (HG/T 20581-2011 Regulations for the Selection of Materials for Steel Chemical Process Vessels), there is a statement regarding wet hydrogen sulfide environments: “The H2S partial pressure is greater than or equal to 0.00035 MPa, which corresponds to a H2S solubility in water at room temperature of greater than or equal to 7.7 mg/L.” Correspondingly, the old standard (HG 20581-1998 Regulations on the Selection of Materials for Steel Chemical Storage Vessels) states as follows: “The H2S partial pressure is greater than or equal to 0.00035 MPa, which is equivalent to an H2S solubility in water at room temperature of greater than or equal to 10 ppm.” The old vessel regulations (version 99) also cite this statement. My confusion is: how should this sentence be understood, how are the voltage division values and solubility converted, and what is the specific process? Which basic knowledge needs to be applied?
This is determined from the solubility curve of hydrogen sulfide in water.
The solubility curve of hydrogen sulfide in water generally shows the \"saturated\" solubility level, which is much higher than the values given by the two standards mentioned above； I checked the solubility of hydrogen sulfide in water; it is 0.385% (m) at 20°C and 0.298% (m) at 25°C —— Handbook of Physical Properties of Chemicals and Engineering Materials (Inorganic Volume): 84
This post was last edited by lsswyb01 on 2017-9-8 at 17:03. It’s too heavy to delete yet; editing again! The data in the two standards do not match (after unit conversion); are there other factors to consider?
I think this issue is quite important, but there aren’t many people addressing it； Is it that I didn’t explain the issue clearly, or do everyone already think this isn’t a problem at all? This problem has plagued me for a long time, and there has still been no answer!