Our practice when considering stock ERW for offhsore pressure containing service is to have a third party inspection outfit double check the seam weld using UT to an N5 notch criteria. We also do two weld line charpy test sets per heat to verify weld has min API body toughness.
To calculate the rate you would need both the corrosion current in the connected and polarized condition as well as the anode surface area. Bur basically large cathode (old steel) small anode (new steel) = trouble. I have seen 2-3mm/yr from such situations.
Normal B7 bolts can crack if the LPG (shellside?) is sour. Is it sour? Did the bolts fail in a brittle fasion, without elongation? Was bolt hardness checked?
I think the issue is how was the starting bar made? May have been made using good practices and there will not be a problem. Could have been made with less good practices. Some examples would be:
Low reduction ratio - May still have coarse grains, hydrogen cracks from casting...
I think what he is asking is what dewpoint he needs to achieve in dehydration to assure no water can drop out. Fr that he needs access to a process engineer who can run an equation of state simulator. Generally, a good TEG plant can do the job for CO2 pipelines.
Modification has no formal and consistent meaning. It really means one or more compositional elements will fall outside the approved values in 5L, or an additional element is being added that is not normally present.
Have to ask the owner of the specification requirement what they mean.
My...
Union Oil Lamont - Look it up
http://www.twi.co.ir/download/case_studies/180%20-%20Union%20oil%20amine%20absorber%20tower.pdf
Eng-Tips is not a responsible technical authority.
Hire a an experienced consultant. This is not a service to mess with.
Elgiloy is a good choice. We would not use X750 in 17% H2S. Several failures of X750 can be found in NACE papers.
We also have had one Elgiloy spring failure in highly sour service. We think it was over cold worked and was near strain exhaustion as new.
Who checks hardness of thin flat...
Sam,
How did this get resolved? Wellheads have chokes to take the pressure drop so that other valves don't have to have full stellite. It makes no sense to ask for more than the seating area of the ball to be stellite coated. On the wellhead gate valves, only the sealing surfaces are...
The issue is the pipe mill is not required to test to a high percentage of SMYS and so may be a lot lower than field hydrotest pressure. Users should supplement 5L requirments and be specific about what % of SMYS they require the pipe mill to test at.
