Sour service vs sweet service in pipeline design and pump selection
Sour service vs sweet service in pipeline design and pump selection
(OP)
Hi there,
CSA Z662 defines sour system by considering H2s partial pressure in a pipeline.
I have crude with total Sulphur of x% mass.
Is total Sulphur % can represent H2S in crude? What is limit to consider sour liquid?
My crude includes X % mass of water. Can I assume total Sulphur and water can mix and produce H2S?
I need this info to decide pump material and design to be suitable for sour service vs sweet service.
CSA Z662 defines sour system by considering H2s partial pressure in a pipeline.
I have crude with total Sulphur of x% mass.
Is total Sulphur % can represent H2S in crude? What is limit to consider sour liquid?
My crude includes X % mass of water. Can I assume total Sulphur and water can mix and produce H2S?
I need this info to decide pump material and design to be suitable for sour service vs sweet service.





RE: Sour service vs sweet service in pipeline design and pump selection
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Sour service vs sweet service in pipeline design and pump selection
The mixture of crude oil, including the H2S percentage, shall be availble before the refinery designed, even if the crude oil goes into the process line is a mixer of serveral different oil company.
RE: Sour service vs sweet service in pipeline design and pump selection
Here are my questions:
To check if crude is considered sour by CSA, one has to calculate H2S partial pressure. Can I assue crude is not sour since alanysis specifies zero H2S; or I should consider total sulfur can be a sign that H2S can form or be causious at least? I have seen somewhere that if total sulfur in crude is more than 0.5% weight, crude should be considered as sour.But as David mentioned H2S reactions should has already been completed if that was the case and alanysis should have proved it.
Assuming crude has no H2S and assuming it is not considered sour liquid any more, should I consider stress craking corrosion when I am selecting material
Is NACE spec for pump and piping material selection applicable to sour service only?
or if we have sweet service plus total sulphur we need to meet NACE?
PLease share your thoughts
RE: Sour service vs sweet service in pipeline design and pump selection
But if the lab is certified to issue such number as reference, it is good news.
Keep some space for poor quality crude oil, when you select material, one day, high quailty crude oil will be too expensive, those plant capable to handle sour crude oil will survive.
Sour crude oil from mid-east may have a total sulfur above 2%(weight).
RE: Sour service vs sweet service in pipeline design and pump selection
You may get more responses if you were to transfer or copy this posting to the materials engineering / corrosion engineering forum ?
RE: Sour service vs sweet service in pipeline design and pump selection
You really need to talk to a materials engineer to see what the actual impact is on your particular system, but if you design for a relatively small amount of H2S it might not be so bad.
AFAIK, the key thing to consider is H2S, not total sulphur. Total sulphur is important for the "quality" of the crude and how it can be distilled and sold or require treatment to lower the sulphur so that when it gets burnt it doesn't emit SO2 in large amounts, but not for transport of the Crude itself.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Sour service vs sweet service in pipeline design and pump selection
The Sulfur you are talking about cannot be detached from Hydrocarbon molecules unless you apply high pressures, high temperatures, catalyst, and high partial pressure of Hydrogen in hydroprocessing reactors in refinery. In transportation you are far, far away from these conditions.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Sour service vs sweet service in pipeline design and pump selection
You can also see which are the common Sulfur compounds and categories found in crude oils.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Sour service vs sweet service in pipeline design and pump selection
RE: Sour service vs sweet service in pipeline design and pump selection
http://www.documentation.emersonprocess.com/groups...
It looks like NACE 0103 has further expanded on the limits stated in NACE MR 01-75.