variation of h2s contend on natural gas transport

[ograte]

I´m Electrical Engineer and I´m Working on a POWER PLANT PROJECT for a Petroleum Company, using a Natural Gas Combined Cycle (NGCC) arrangement, of about 500 MW. We are planning the use of natural gas supplied from a remote area, an the concentration of h2s in the natural gas, measured at the supply point 150 miles away from the POWER PLANT, is 10 ppmv. I´m not familiar with the chemicals knowledge to analize the perfomance of the natural gas in the Pipeline, and i have a few questions about this. I appreciate the help, any one can give me about this suject. My questions are:
1-There is any possibility of chemical reaction between the pipe-line material and the h2s contained in the natural gas?
2-Can we use the concentration measured at the supply point, 150 miles away from the Power Plant, to especified the quality of the natural gas at the Power Plant site?
Thanks for your help.----->>>ograte

 

!_ H2S can react with carbon steel in the pipeline to form FES. The FES film is passive and protect the pipeline of furthur corrosion. The reaction does not need water as is the case with CO2. The prezence of CO2 and water forms H2CO3 which will wash away the FES film and prepare the pipe surface for furthur corrosion . However whith 10 ppmv of H2S in the gas and even CO2 the pipe corrosion is not a matter of concern unless water is not present , ie; the gas is dehydrated. The other risk which is very dangerous is the H2S stress corrosion cracking which is addressed in NACE MR 01. For your case this is not a concern also because of small amount of H2S. I think the pipeline operating pressure is in the normal range ie less than 1400 psig.
2-Measurement of H2s at upstream can adequately show the H2S amount at the downstream facility. As said above the FES film once formed is passive and protect the pipe that is no furthur reaction of H2S with pipe and the concentration of H2S remains unchanged. Conversion of H2S to other sulfur compound like COS and CS2 in the presence of CO2 with the pipeline condition is not possible. You may check yhis by use of Tutweiller test apparatus which is simple and not costly.