H2S % to ppm conversion

For oil / gas industry it is stated as 1 % H2S (Hydrogen Sulfide) = 10000 ppm H2S. Can u tell me the calculation for this?

[JohnS]

Originally Posted by srd_2111

For oil / gas industry it is stated as 1 % H2S (Hydrogen Sulfide) = 10000 ppm H2S. Can u tell me the calculation for this?

"Percent" = parts per hundred.
one million divided by one hundred isten thousand. Both the numerator and denominator of one part per hundred are multiplied by ten thousand yielding 10000 parts per million. (or move the decimal four places )

H2s from mg/nm3 to ppm ,0.1

Is there a difference between mole percent H2s and Percent H2s in a gas stream? If I have 9.36 mole percent H2s, what is the percent H2S in gas stream and also PPM in gas stream. Would that be 9360 PPM? Thanks

[JohnS]

Originally Posted by Unregistered

Is there a difference between mole percent H2s and Percent H2s in a gas stream? If I have 9.36 mole percent H2s, what is the percent H2S in gas stream and also PPM in gas stream. Would that be 9360 PPM? Thanks

Percentages and ppm in gases are normally based on molar ratios (solids are usually mass ratios, liquids may be mass, volume or even mass/volume).

So it is 9.36%; however 1% = 10000 ppm (1% of one million parts), so 93600 ppm.

Mole weight of gas mixture 17.57 g/mol
H2S 20ppm in volume

How much mol % of H2S in the mixture? Thanks!

[JohnS]

Originally Posted by Unregistered

Mole weight of gas mixture 17.57 g/mol
H2S 20ppm in volume

How much mol % of H2S in the mixture? Thanks!

20 ppm or 0.002%. By Dalton's Law of Partial Pressures the fraction by molar ratio, partial pressure, or volume would be the same.

Originally Posted by JohnS

20 ppm or 0.002%. By Dalton's Law of Partial Pressures the fraction by molar ratio, partial pressure, or volume would be the same.

Just like that? Could you elaborate a bit more?

How about below calculations:
-----------------------------------
Gas Mixture: 17.57 g/mol
H2S: 34.08 g/mol; 20ppm in volume (2E-5)

Per mole Gas mixture = 17.57g
H2S = 2E-5 x 34.08 g = 6.8E-4 g
Mol % = 6.8E-4 / 17.57 *100% = 3.87E-3 % = 0.00387%

Originally Posted by JohnS

20 ppm or 0.002%. By Dalton's Law of Partial Pressures the fraction by molar ratio, partial pressure, or volume would be the same.

And Dalton's Law of Partial Pressures is only applicable for Ideal Gas. In my convertion, the P & T of mixture is 50 barg and 30C, respectively.

What is the answer then? THX

[JohnS]

Originally Posted by Unregistered

And Dalton's Law of Partial Pressures is only applicable for Ideal Gas. In my convertion, the P & T of mixture is 50 barg and 30C, respectively.

What is the answer then? THX

Since both the mixture and the H2S occupy the entire volume, what does percent (or ppm) by volume actually mean? It customarily is considered to be the ratio of the number of molecular entities hence it is the molar ratio.