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Topic: Dual Relief Valves, Flare Systems and TMLs |
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Bukhrai |
Posted: 15-Apr-06 09:16 |
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The first question is:
Does anyone have experience or standard requesting to install dual RV’s “ Double “ in the refinery as protection and to avoid T&I cycle. Some refineries have only one RV and others they must have two RV the reasons just to avoid any S/D in other words if the unit T&I cycle is 60 months and the due date for RV testing is 36 months in this case we should install two RV to avoid the S/D Is this correct practice or there is any code/standard call for this.
The second question:
Is it mandatory to PWHT the flare system?
The third question:
What is the best way to select the TML’s “Thickness Measurements Locations”?
The fourth question:
Is there any good booklet book for inspectors to use it in the refinery as quick reference during the T&I?
Thks a lot
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Bukhari2007 |
Posted: 03-Jun-07 13:46 |
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I did not get any answera for my qestions?
Thks |
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admin |
Posted: 27-Aug-07 21:37 |
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To answer one of your questions, regarding TMLs (now referred to as CMLs in the API inspection codes):
The best way is to have an industry and unit specific experienced corrosion engineer perform a corrosion systmization and circuitization of your piping and vessels identifying corrosion systems and circuits at the PFD and P&ID levels, respectively. Color coding these documents works well. Then with a firm understanding of damage mechanisms locate CMLs (condition monitoring locations, because thinning isn't the only mechanism necessarily found in piping and equipment)on their respective circuits. More is not necessarily better if you are looking in the wrong locations and with the wrong NDE techniques and the old methods or rules of thumb using inspectors and inspection companies to pick the locations are no longer sufficient.
Further enhancements would include defining material operating envelopes for your units and using these to proactively manage the assets and adjust strategies practively. There are controllable and noncontrollable parameters to monitor. This can be as detailed as you like. When this and the practices mentioned above are leveraged and done by the same team there are some tremendous learning synergies that occur, too.
As another option, when you have documented a statistically significant number of thickness readings to satisfy the confidence level you desire, and you get good statistical curve fits, you may use this information to further optimize the number of CMLs, for thinning mechanisms that is, and use trending to alert you to mechamisms you may not have anticipated.
One of the first references i would pick up is the API RP 571 document covering damage mechanisms and NDE in refinery units. It does not replace a good, experienced corrosion engineer, though.
Regards,
Greg Alvarado, Chief Editor
Inspectioneering Journal |
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Panomsit Srirunpetch |
Posted: 18-Sep-07 04:11 |
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Bukhari,
For your second question, I understand that PWHT is not mandatory for flare system. |
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