Here is my suggestion on what you should do:
1) You seem to have enough information to get a budgetary grade estimate for a replacement tank. Get a cost estimate for a bare CS tank from the vendor that supplied the tank. Also ask for a number of weeks to delivery
2) Equipped with a cost estimate of a replacement tank, perform a random UT evaluation of the defective tank. The original wall thickness seems to be 8mm with a 3mm corrosion allowance. Pay particular attention to the shell-head juncture on both heads. Is there at least 5mm wall thickness left in the areas where you did the UT inspection?... Get an estimate to reweld the burst tank... Does the repair estimate exceed 50% of the cost of a new tank ?..... If it does, buy a new tank
3) Understand that you have a thin walled CS tank in Concentrated Sulfuric Acid Service and with no internal coating protection.
A 7 to 10 year life would be typical for this application ....IMHO. Even if you found a way to repair this tank, you might find more problems in the OTHER HEAD of the tank in a couple of years..You should consider the cost of a new, internally coated CS tank and the long term plant advantages of reliable tankage
4) There are several types of internal coatings that were developed specifically to protect Carbon steel from sulfuric acid. I suggest that you also investigate the various types of coatings and what they would additionally cost for a new tank. I also suggest that you get an estimate of the new extended life of the tank from the coatings vendor
Then, based on the information you get above, the best course of action should be obvious...
Please keep us informed and complete this thread ..... Tell us of your final solution
MJCronin
Sr. Process Engineer