Environmental Science/Sulphur calculation


Dear Sir,
How do i can exactly calculate the sulphur content in a sour gas. if the gas capacity is 30 mmscfd with the system design of 0.12% H2S content.

It depends on how the Sulfur Content is measured, whether by weight or by volume.
Since you specified the measurement is about 30mm scfd, that indicates temperature and pressure, but the remaining question is what's in the gas stream besides H2S?  Usually, "sour gas" is a term reserved for petrolum gases, and they have higher molecular weight than Methane or Natural gas ( one in the same thing). You need to find out the average molecular weight of the gas,and for the sake of argument, I'll assume that it is all ethane or C2H6 which has an average density of 1.24 gm/cm3 and a molecular weight of 30.07 gm/ Mole. The Mol Wt. of H2S is 30.0908
One mole is 22.7L and there are 28.3168 L/ ft3.  Now there is a slight temperature conversion problem because a mole is defined at 0C and STP is often at 68F (or 20C). The gas laws indicate that the volume of the 22.7L is multiplied by 293/273 for the volume to correct it for temperature, and that gives 24.363 L as the volume of 30.07 gm of ethane at 20C. Since most gases are set by weight, the revised Mol wt of the gas is 30.07*0.9988+0.0012*30.0908 or about 30.1 gm
Now there are 28.316/24.363 about 1.1225 mol/Cubic foot. 1,000,000 cubic feet of gas at STP will weigh 1.225*10E6 moles *30.1 grams/mole * 1 pound/453.6 grams  or about 81,288.5 lb of  mixed gas, of which 0.0012 is H2S or 97.54 lb of H2S per 1,000,000 Cubic feet.
I assume you can do the multiplication by 30.

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David L. Russell, PE


I`m a Chemical,Civil and Environmental Engineer and have a number of projects in all phases of the environment. I have worked in the chemical industry and am active in professional societies, and am currently on an industrial wastes committee for the Water Environment Federation, and have taught courses in remediation in the US and abroad. I have written one book on Remediation of petroleum Contaminated Sites, and have a second book on PRACTICAL WASTEWATER TREATMENT to be published by John Wiley in September, 2006. I've also written over 30 articles on various elements of environmental problems and cleanup. Most Recently, I have addressed a NATO Scientific and Techical Conference on Ecoterrorism, and have worked with the same group on remediation of sites contaminated with Chemical Warfare Agent materials and othe materials as well. . I can answer q`s about Chemical and Environmental Engineering, land development, air pollution, water pollution, soil and water cleanup, combustion, international environmental problems, industrial processes chemical processes. Civil and Environmental and Chemical Engineering. Overall, I have over 35 years of experience in this area. Note: I do not answer homework questions


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