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Hi Everyone, I have a high pressure water boiler leaked after very short upset in the boiler feed water pH: the pH was around 3 to 4! Has anybody come across such thing? What might be the causes? The steam condensate makeup is demineralized water (pH of demin water is within range). No leak of...

Hi Everyone, I have a length of piping (material falls under P No. 1 in ASME B31.3) that I am currently reviewing the corrosion circuits associated with them. I have noticed that SSC is defined as a possible damage which I tend to agree because the service is sour, but upon reviewing NACE...

Hi Everyone, Does anybody know how ECE model deals with H2S? i.e. if H2S is present does it multiply the CO2 corrosion rate with a certain factor and gives the overall corrosion rate? I want to understand how it deals with slightly sour and very sour systems (pCO2/pH2S > 500 and pCO2<pH2S <...

Hi Everyone, Has anyone got any experience of using oil wetting agents to prevent water from stripping out from oil/crude and hence preventing MIC? Any references is well-appreciated. Regards, Corroneer

Hi, One major oil company mandates the use of coating and chemical treatment! I guess their argument is that the corrosion inhibitor will work on coating failures and welds as the CP will do for the coating holidays! which is not proven as far as I know. I do not consider internal coatings as a...

I am looking for a document that outlines the best practice for injecting the different chemicals in a pipeline. We have corrosion inhibitor, biocide, and oxygen scavenger that have to be injected in the pipeline. What is the first chemical to inject, the second and the last? Regards, Corroneer

https://nickelinstitute.org/media/1702/highperformancestainlesssteels_11021_.pdf What is the border line between considering an alloy a higher stainless steel (like alloy 825) and a nickel alloy (like alloy 625)? Thanks, Corroneer

Hi Everyone, Is anyone aware of any effect of methanol on the FBE coating of the pipings? What about other hydrate inhibitors (e.g. Mono Ethylene Glycol)? Appreciate if you can cite some references. Regards, Corroneer

Hi Everyone, I am trying to understand the extreme value theorem used in pitting corrosion where a limited number of UT or MFL measurements can be used to: 1) calculate the "current" extreme value based on the limited inspection data. 2) calculate the probability that in "x" years you will...

Hi Everyone, I remember that I have read somewhere that the most corrosive case in CO2-H2S environment is when the ratio of the partial pressures is 1. Is this true? If yes, any reference please? Regards, Corroneer

Hi Everyone, I am looking for a reference that clearly shows that taking a sample from a line/vessel under pressure will yield wrong pH measurements because of degassing. Regards, Corroneer

Dear All, Do you agree that the severity region graph (in part 2) is of little practical use? I do not think I have ever used them in materials selection using the 2003 and later editions! If it is CS, then the limit the hardness and HIC follow TM0284 … etc. If it CRA, then follow what is the...

Hi Everyone, We are designing a new gas vessel (it will separate liquids from the gas). The partial pressure of H2S is > 100 KPa. We do not have proper pH values, but the optimum working pH for the vessel is between 6 and 7. The operator confirmed that the pH can go lower than this (again no...

Is anybody aware of the difference in performance, and price, between cladding (as of sheets) vs thermal spraying of the same alloy? I am inclined towards thermal spraying due to much better adhesion. I guess it would be cheaper as well. The service is wet sour gas. Any thoughts? Regards...

Hi All, Does anybody has experience with either, or both, of the following: 1. Partial re-tubing of the heat exchanger with a higher alloy, i.e. corroded tubes to be upgraded to CRA while keeping the intact ones and replace them as needed in the coming shut-downs? 2. Internal coating of heat...

Is anybody aware of cracking of galvanized steel (not welded to stainless steels) structure because of fire? API 571 4.5.5 lists carbons steel as an affected material.

Hi everybody A quick question about calculating the chemical availability. How would you know that you are pumping the required dosage for a pump that is not connected to the DCS? The only way I can think of is to do the pump performance test (1-min test) every day. Or, less preferably to me...

Hi All, I would like to ask if anyone has experience with the performance of lined CS pipes in very sour gas service (>15% H2S). As you know the pipes are welded (no seamless for such diameters, 36 in)? What would you recommend? Any standards or papers discussing such thing? Regards, A

Is anybody aware of a document similar to the Energy Institute one that outlines the corrosion threats in the upstream O&G industry? Preferably with the threats shown on the PFD's as per the EI one. Regards, A

A newly (few months old) welded 625 spools with matching filler showed corrosion of the weld and the HAZ (couple of inches on both sides of the weld). This happens for all the welded joints on the pipe. The pipe is offshore. I suspect that no pickling and passivation was done for the welds. I...