Procedure for Welding of Naptha Tank

at my last job i had heavy oil tank & we had box of conic wood pieces which made for a quick patch.

in your case - first' make one & close it. afterward - take your time to find solution.

Sisira, Thank you for that info. Looks like a good product.

It certainly is an excellent product, in fact not one product. There are many products in the range but metal and elastomer (rubber) range is well established in marine and Petro chemical fields.

We over here in Sri Lanka have used different Belzona products to repair and rebuild many engineering components pumps, shafts, conveyor belts etc

In fact either you can get Belzona consultants to do the job for you or you can do the job yourself after buying the materials. You do not need special training. Procedures are very straight forward.

Belzona has saved a lot of plant down time for me.

I can vouch for Belzona, I worked on a Nuclear Power Station, we used them almost contiuously for repairing steam leaks, we also had them come into a Pumped Storage Power Station I later worked on, to demonstrate how they recoverd wear in water pumps, by the use of their products. They can be found on www.belzona.co.uk

20 mm is a pretty big hole. I think if it was me, I'd have the whole tank very thoroughly inspected. You may be replacing it or conducting some extensive repairs, not just plugging that hole.

My suggestion is to make an earth dike 1 foot height around the tank to be filled with water before welding.

All the safety will help.

Regards,

Cesar Diaz

www.copcoltd.com

copcoltd@copcoltd.com

many thanks my cr4 friends. it is a wonderful experience to receive so many replies. as we do not gave the idea about the extent of seepage in the ground below the bottom plate resorting to welding is a risky affair. we experimented with welding of sample piece at our workshop and observed a temperature of 200 deg centigrade which is very near to the auto ignition temperature. immediately we will go for putty or tap and for a long term solution the idea of a temporary dyke with water is an excellent idea.

a lot of thanks once again.

pkmohapatra

You need to evaluate the reason considering following parameters before any action

1) How old is the tank?

2) API code of construction?

3) Bottom plate UT reading results, undulations if any?

4) Heat No. of plate or was it a sub standard plate or whether the hole is at any weld joint?

4) Type of Tank foundation, settlements, plumb readings etc.

5) Dia. of the tank and location of the mentioned 20 mm hole. Any thining of the botom plate owing to direct product flow from any nozzle?.

6) Corrossion or puncture due to any hard substance below? This can give you repeated problems. If it is due to corrossion, the nature, whether soil is tested for corrosive substances like sulphur?

I have succeded with Belzona in Gasoline pipelines. Selection of the same need to be compatible for Naptha. I remember this is a good product.

Hope you will follow vacuum box testing, hydrotesting etc and requisities....I would go for repeated vacuum box testing as it is easy to perform even just before commisioning of the tank.

Reg

Srijit

I have repaired literally 100's of small gas tanks in this fashion with the exhaust from a combustion motor in the "old days". These days I purge the tanks with nitrogen,co 2 or argon the same way one would purge a stainless steel pipe before welding. I can see how this would be beneficial on a big tank if you have a ready source of flue gas as long as it has been scrubbed and there are no flammables carrying over. Here at the paper mill where I work we do not do this but rely more on a good cleaning and atmospheric sniff to assure that there is no chance of a fire or explosion. The bottom line here is that if it won't sniff we don't go in or make sparks near a tank. I would encourage you to be careful welding on this tank without testing what ever you use to displace the oxygen and knowing there is no flammables to explode. Please be careful.

pipewelder

Many thanks Mr pipewelder and mr srijit and other cr4 friends. it was an excellent interaction. the problem of repairing the bottom of naptha tank was an impossible task a month ago now appears to be so easy after discussions in this forum. after examining all pros and cons now we are going for cutting the reduced thickness area with the help of a milling cutter to avoid any sort of sparks and localised heating. after removing the portion of plate dry chemical powder will be inserted upto a distance of half a meter and then going for welding of plate. all these precautions are being taken as the grond below the tank has got soaked with naptha leaked through the hole. we had used an ejector to remove the soaked naptha from the ground.

many thanks once again. i will be in touch with the forum.

pkmntpc