Acid Storage Tank floor plates.

[gertv]

Good day Gentlemen,

I am currently working in Africa on a project (SAP Plant)
I have a problem with Acid storage tank Diameter 25.600m & Height 11.200m
Volume 5600 m³ (Cubes) (Carbon steel Tank)
On The bottom plate that gets welded to bottom annular plate API states 6mm gap between the plates with backing stip.
But with the installation of the first side wall plate the floor plates moved and now there is a gap between 20mm & 29mm over a length of 11 meters.
Is there a welding procedure for this big gap, as the heat input & HAZ is a very big concern for me?
Or must I get welding procedure from AIA.

Any advice on this matter will be appreciated.

Regards,
Gert.

 

[fegenbush]

What is the type and concentration of the acid? What is the welding process that you are attempting to use to fill the gap, submerged arc welding?

 

[gertv]

Good day Fegenbush,

The Acid is Sulphuric Acid, concentration 96 to 99%

The welding Process is SMAW Electrodes LH 7018

Regards,

Gert

 

[fegenbush]

I think the gap will be manageable with the correct welding process. Since you are using a manual process, large diameter E7024 electrodes may be something to consider. They will be able to use fewer passes and thus reduce the overall heat input and HAZ. With this concentration of sulfuric acid, there is minimal concern for corrosion provided the tank is not continually mixed.

 

[gertv]

Thank you for the information