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Elemental sulfur dew point
- Thread starter Andrea10
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It's a bit difficult to define sulfur vapor pressure, since elemental sulfur vapor consists of S, S2, S3...S8 species. Equations below are for total sulfur vapor pressure above liquid sulfur.
Recent data from T.E. Daubert et al. (1997) are shown in a graph, Figure 13, at
A curve fit to data at 400, 450 & 500 oF gives
log P(atm) = 5.515 - 3820/T(K) [note units]
At P = 0.015 atm, this gives T = 520.5 K = 247.4 oC = 477 oF.
Another source, Lange's Handbook of Chemistry, 14th Edn., page 5.37 (1992), gives
log P(Torr) = 6.84359 - 2500.12/(toC + 186.30) [note units]
Solving this equation at P = (0.015 x 760) = 11.4 Torr gives t = 245.75 oC = 474 oF in good agreement.
If your total pressure is higher than 1 atm, just solve for the higher P(sulfur).
Recent data from T.E. Daubert et al. (1997) are shown in a graph, Figure 13, at
A curve fit to data at 400, 450 & 500 oF gives
log P(atm) = 5.515 - 3820/T(K) [note units]
At P = 0.015 atm, this gives T = 520.5 K = 247.4 oC = 477 oF.
Another source, Lange's Handbook of Chemistry, 14th Edn., page 5.37 (1992), gives
log P(Torr) = 6.84359 - 2500.12/(toC + 186.30) [note units]
Solving this equation at P = (0.015 x 760) = 11.4 Torr gives t = 245.75 oC = 474 oF in good agreement.
If your total pressure is higher than 1 atm, just solve for the higher P(sulfur).
- Thread starter
- #3
Dear kenvlach,
thank you so much for your quick and detailed answer.
Hence, if I have a syngas with 1.5% mol of elemental sulfur at 5 atm absolute, dew point will be 300°C approx. But in this case liquid sulfur will be characterised by high viscosity...how do I manage that? Do I have to cool in any case my syngas down to 150-130°C (low viscosity region) hoping that sulfur will not plug my heat exchanger when it reaches dew point temperature?
Thank you in advance for your appreciated reply.
Bye!
thank you so much for your quick and detailed answer.
Hence, if I have a syngas with 1.5% mol of elemental sulfur at 5 atm absolute, dew point will be 300°C approx. But in this case liquid sulfur will be characterised by high viscosity...how do I manage that? Do I have to cool in any case my syngas down to 150-130°C (low viscosity region) hoping that sulfur will not plug my heat exchanger when it reaches dew point temperature?
Thank you in advance for your appreciated reply.
Bye!
Andrea10, the vapor pressures of liquid sulfur are tabulated in the CRC manual. Your estimated dew point for S is about right.
Indeed liquid sulfur is unusual, not to say anomalous, in its viscosity-temperature behaviour due to ring cleavage and catenation. For this reason, have you considered converting it, for example, into H2S by hydrogenation ?
- Thread starter
- #5
Hi 25362!
Thanks for your answer!
Yes...I've read about the anomalous behaviour of liquid sulfur viscosity.
My problem is that I have to produce sulfur...I mean I start from H2S and I want to evaluate its oxidation, so I can't transform sulfur back to H2S.
But as the estimated sulfur dew point is about 300°C (high viscosity region), what can I do in order not to plug my cooling system? Do I have to cool rapidly in any case my syngas down to 150-130°C (low viscosity region) hoping that sulfur will not plug my heat exchanger when it reaches dew point temperature?
Thanks in advance for your reply.
Bye
Thanks for your answer!
Yes...I've read about the anomalous behaviour of liquid sulfur viscosity.
My problem is that I have to produce sulfur...I mean I start from H2S and I want to evaluate its oxidation, so I can't transform sulfur back to H2S.
But as the estimated sulfur dew point is about 300°C (high viscosity region), what can I do in order not to plug my cooling system? Do I have to cool rapidly in any case my syngas down to 150-130°C (low viscosity region) hoping that sulfur will not plug my heat exchanger when it reaches dew point temperature?
Thanks in advance for your reply.
Bye
Off-hand I'd say you look for "sulfur condensers" in the net. One link might be:
especially pages 12+.
especially pages 12+.
Please read the report at the link in my first post. It describes the successful field test of catalytic oxidation of H2S at 180oC & 2.7 atm (absolute) pressure into S + H2O from a gas stream approximately 8000 ppm of H2S, 60% CO2, 20% CH4, and 20% ethane, propane, butane and traces of higher hydrocarbons. Process flow & equipment diagrams & photos, properties of sulfur, and details of a sulfur trap & condenser & heat traced liquid sulfur handling piping are given. Also, for commercial application, a heated coalescing filter would be used.
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