hydrogen permeation monitoring in hydrogen processing(cracking) unit

[Frank007]

In hydrogen processing(cracking) unit,hydrogen permeation is not avoidable,how can I evaluate the risk of faliure on equipments or pipelines?
Is there an online-monitoring method now?Any clues will be appreciated.Thanks in advance.

 

[Goahead]

Which materials are used? What is the hardness? What are the temperatures involved?
In the Cd or Cr electroplating practice of steels there is an empirical hardness limit (about 40HRC) over which plating is strongly discouraged because of the danger of hydrogen embrittlement of the base metal.
Regards,

http://www.welding-advisers.com/

 

[unclesyd]

I’ve never used this equipment but my buddies are talking about it. I have no results good or bad as of now. There is the portable HydroSteel 6000 and permanent mount HydroSteel 7000.
Might be worth a look as a addition to other inspection methods.

http://www.ionscience.com/Pages/Hydrosteel6000.htm

 

[liberoSimulation]

You would monitor metal skin temperature by pyrometer equipment that is used by operator thru peep doors of cracking heaters.

Hope this would help

 

[Frank007]

Thank you guys,now answer Goahead's questions:
the materials mainly are Cr-Mo steels such as 2.25Cr1Mo,3Cr1Mo in lower temperature sites and austenitic steels such as 321,347 in higher temperatures sites.Sometimes the based metal are Cr-Mo steels with austenitic overwelds.Temperature is about 350-450? in reactors and lower temperatures in other sites.
Hardness depends on specific materials.

Appreciate unclesyd and liberoSimulation's help again.Is there anyone else who knows something about field monitoring with an instrument?Any information will be great.

 

[SJones]

Forgive me for asking, but if you (attempt to) measure hydrogen permeation, what, exactly, will the results tell you? The first step in assessing the risk of failure will be to have a thorough survey of the materials in the system, right down to the full certification, in order to determine whether there is any potential susceptibility to hydrogen damage. Then you would need to assess the likelihood of failure given the process conditions and the stress regimes experienced by the system. Take a look at API 571, sub-clause 4.5.6 as a starting point.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[Frank007]

Thank you,SJones
I mean if hydrogen concentration in materials exceed some value,it will probably cause failure.Doesn't this method work?
At present,are there any methods to monitor materials hydrogen damage in high temperature hydrogen service?
I'm a junior corrosion engineer.Thanks in advance.

 

[SJones]

The hydrogen you measure will have permeated through the material and, therefore, won't be in the material. An assumption will have to be made about how much hydrogen has been trapped. The principal line of defence against damage is to select the correct materials and ensure that they have been supplied and installed to the correct specifications.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdo/

 

[liberoSimulation]

Think of on line monitoring by Metal Skin Temperature Transmitters that to be installed at the coil surface for measuring the skin metal temperature.
Once the max metal temperature (Below Design Metal Temperature with some margin) is reached after sometime, you stop H2 feed.
I have seen fire-heaters with such monitoring tool that indicates the performance of the heater with respect to coils skin temperatures.

Cheers