PWHT and NDT requirement for SPENT CAUSTIC LINES

[mpk mpk]

Dear Experts,

 

We have 2” sch 160 &  4” sch 80  C/S Piping welding ,whether  we need to conduct PWHT  for these lines or no need ,  because as per standard  CAUSTIC service lines need PWHT. but in our package the service fluid is SPENT CAUSTIC  and I want to know what is the required  percentage of NDT  for these service lines,

Please send suggestion & if any specific documents..

Thank you,

MPK

[jignes...@linde-le.com]

Dear MPK,

Spent caustic is the waste industrial  caustic solution, that has become exhausted and no longer useful (spent). It is made of Sodium hydroxide or potassium hydroxide, water and contamination. The common and dangerous  contamination is  H2S  in it.  

Various process licensors have technology for effective and environmental disposal of spent caustic and guidelines for material selection as well as for PWHT also.

Refer the pipe class generated for spent caustic line, for PWHT  & NDT requirements.

PWHT is dependent on concentration of Caustic and design temp.  In normal case, % caustic is < 5.0 % and temp. varies  from RT to 130 -140 Deg C.

Since, H2S would contamination;  this would fall in category M services as per ASME B 31.3.

With Best Regards,

Jignesh R Rana
Manager - Materials Technology, QA/QC & Standards

Linde Engineering India Pvt. Ltd.
'Linde House'
Opp: VUDA Office, VIP Road, Karelibaug,Vadodara - 390018, India.
Tel.: +91 265 3056789, Fax: +91 265 2335213 , Mobile:  +91 90999 86019
jignes...@linde-le.com, www.linde-india.com

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Thank you,
MPK

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