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srd_2111
06-02-2008, 02:47 AM
For oil / gas industry it is stated as 1 % H2S (Hydrogen Sulfide) = 10000 ppm H2S. Can u tell me the calculation for this?

JohnS
06-02-2008, 03:43 AM
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 :) )

Unregistered
11-21-2011, 02:50 AM
H2s from mg/nm3 to ppm ,0.1

Unregistered
03-08-2012, 04:39 PM
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
03-09-2012, 02:57 AM
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.

Unregistered
03-09-2012, 07:08 AM
Mole weight of gas mixture 17.57 g/mol
H2S 20ppm in volume

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

JohnS
03-09-2012, 11:27 AM
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.

Unregistered
03-09-2012, 05:15 PM
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?

-----------------------------------
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%

Unregistered
03-09-2012, 05:32 PM
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
03-10-2012, 02:16 AM
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.

JohnS
03-10-2012, 02:22 AM
Just like that? Could you elaborate a bit more?

-----------------------------------
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%

What you have calculated is percent by mass. It is still 20 µmol/mol. Your first line is 1 mole of mixture, and its mass. The 2 nd line is 20 µmol of H2S and its mass. What yo have calculated is 38.7 µg/g or ppm by mass.

Unregistered
03-13-2012, 07:07 PM
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.

---- From Wikipedia----

Dalton's law is not exactly followed by real gases.

"Those deviations are considerably large at high pressures."

In such conditions, the volume occupied by the molecules can become significant compared to the free space between them. Moreover, the short average distances between molecules raises the intensity of intermolecular forces between gas molecules enough to substantially change the pressure exerted by them. Neither of those effects are considered by the ideal gas model.

---- what does the quoted sentence mean?

JohnS
03-14-2012, 02:51 AM
---- From Wikipedia----

Dalton's law is not exactly followed by real gases.

"Those deviations are considerably large at high pressures."

In such conditions, the volume occupied by the molecules can become significant compared to the free space between them. Moreover, the short average distances between molecules raises the intensity of intermolecular forces between gas molecules enough to substantially change the pressure exerted by them. Neither of those effects are considered by the ideal gas model.

---- what does the quoted sentence mean?

It means the total pressure won't be what you expect from the ideal gas law.
Ideal Gas Law: PV = nRT
Real Gas Law PV = ZnRT
Z is the compressibility factor. Since the volume is the volume of the vessel, Z defines the departure of pressure from ideality. There are other equations of state for gases that attempt to predict or calculate Z, or it can be looked up as a function of pressure and temperature.

It does not alter the fact that ppm is gases is specified as molar fractions even if people incorrectly call it a volume ratio -- both gases occupy the whole chamber. The partial pressures may not be in accord with the molar ratio (Dalton's Law of Partial Pressure may break down).

Unregistered
07-26-2012, 04:41 AM
for oil / gas industry it is stated as 1 % h2s (hydrogen sulfide) = 10000 ppm h2s. Can u tell me the calculation for this?

1/100=10000/1000000

Unregistered
01-29-2013, 08:54 PM
for oil / gas industry it is stated as 1 % h2s (hydrogen sulfide) = 10000 ppm h2s. Can u tell me the calculation for this?

100 ppm of h2s is equal to how much percent of h2s

JohnS
01-30-2013, 02:02 AM
100 ppm of h2s is equal to how much percent of h2s

0.01%. Percent are just parts per hundred and differ from parts per million by a factor of 10000.