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[MW:17764] Welding inside CO2 Absorber

By Materials & Welding
Dear All
We are having Co2 Absorber in our Ammonia plant. This equipment has been installed in 1969. The MOC of vessel is BS 1501-151-28B & is 38mm thick. Now we want to install a new modified demister set on the top of the tower. In this connection demister manufacture wants to weld a
supporting ring (10 MM thk 516 Gr. 70) and 4 nos. brackets (516 Gr. 70). As per supplier, the brackets are to be welded at top conical portion 38 mm thk. (90 Degree orientation) of the absorber. After this 10 mm thk supporting ring is also to be welded to the absorber shell.
As per the drawing of CO2 absorber, the vessel supplier M/S BHPV India have mentioned under the Note;
'NO WELDING IS TO BE DONE ON THE VESSEL AFTER HEAT TREATMENT UNLESS OTHERWISE PERMITTED BY CODE/SPECIFICATIONS".

You are requested to kindly advise regarding welding of 04 nos. brackets and supporting ring (10 MM thk 516 Gr. 70) to absorber shell (38 mm thk. BS-1501-151-28B).kindly also advises welding procedure and type of electrode to be used.

Alternately can we fix the bracket by 8mm dia bolt (4 nos per bracket) after drilling & tapping in the vessel & welding the ring with the bracket? Will it affect the design criteria of the vessel?

Thanks & Regards,

BM Ritolia
Advisor
Kanpur fertilizers & cement ltd.
Udhog Nagar,Panki ,Kanpur
Uttar Pradesh,208022 India
Mob. 07388003288
Land Line 0512-2693504

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