Integrity of Horizontal Atmospheric Tank 1

[Maz07]

Hi Buddies,

We are having a CS Horizontal Atmospheric Tank (SA 510 Gr. 60) built in 1966 resting on two saddle supports. Material thickness is 6.35mm having no corrosion allowance. The ID is 2425.7mm and the service is NaOH. t(required) is calculated as 3mm. Based on the UT inspection report end of 2021, 46% readings revealed material thickness below 4mm and only 4% readings were under 3mm. The corrosion rate for the critical area is established -0.11mm/ yr and overall other parts of tank is -0.6mm/ yr. Some theoretical stresses are reported around saddle horns calculated by Finglow software PD:5500

Based on the above scenario, is it possible to repair it with some kind of inner coating or lining to make it more out of it rather replacement?

 

[Louisiana Inspector]

If replacing the tank will be the path forward, I suggest looking into an FRP replacement tank. This will eliminate your corrosion and cracking concerns.

 

[shvet]

May be the electrical tracing could be beneficial.

What is max cable temperature? How will it be controlled and ensured?

I suggest to conduct an experiment. Go to a kitchen, place a pot on a stove, fill it with water, and light it up. Put thermometer at center of a pot and wait until water on potwall becomes to boil. Compare thermometer measurement and boiling bubbles being. Then measure a distance from thermometer to potwall and compare to a distance from tank thermowell and tank wall.

And after this relocate a pot from a gas stove to an electric coil stove. Is there a difference for water a pot is heated by a flame or by a coil? If not, then will еруку be a difference for tank wall?

Think, think how this actually works. An engineer's work is to know and to think.

Tank in our case is atmospheric.

People in CSB's video thought/behaved exactly the same way as you do. In your case fragments are not likely to fly over 100 meter. What does this fact change? Does your installation become safe from this?

If you sure your situation differs than I suggest to conduct an experiment - dip your hand to a caustic puddle (any other exposed part of one's body - neck, eyes). Have you ever seen how skin peel off one's arm/leg? Have you ever taken a victim by ambulance to urgent care?

Main point is - What is the difference between people in video and you?

I think better to have AE testing in combination with UT during upcoming inspection.

Why AE? Who decided AE? What is a qualification level of this person? Has he/she proper background and experience? Was an independent expertise of this decision provided? Is this person responsible/authorized/certified for such decisions?

Who disagees ? ....... Who has better cost estimates than me ?

This is an unattainable level, o father.

 

[Maz07]

After having all the comments, replacing the tank seems better option rather investing in coating for a short term.

 

[LittleInch]

I think that's a very good decision.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[r6155]

@ shvet
This is a non-explosion atmospheric storage tank.

Regards

 

[shvet]

@r6155
Agreed, but this tank contains not a bucket of cold water, right?

 

[MJCronin]

Maz07 ...

Please keep us in the loop .... Respect us....and inform us about the details of your final solution !!!

Please complete this thread with any up-to-date cost comparisons and other details that would help others !!!

Experience with caustic and Acid system storage is an important and unique aspect of Chemical Engineering ... and should be shared with others .... We are all in this together !!

Thank You sir !!! ...... and the best of luck to you

MJCronin
Sr. Process Engineer

 

[chicopee]

If your company is strap for money, instead of purchasing a new tank, look a second hand tank but beware of past experiences and of deleterious details on inpection reports on that tank. For second hand tanks, I would research second hand Propane pressure vessels which are abundant for purchase.

 

[CuMo]

I think it's a disaster waiting to happen and the tank shall be replaced.
I have seen the aftermath of a water storage tank collapse. Who ever thinks "there is no pressure" may be right in terms of definition but boy the force of water coming out
was able to throw around half ton items like children toys and bend a steel roller shutter half a metre inwards. And we're talking only about 20 m^3 of water.
The tank failed due to corrosion.

 

[r6155]

@ CuMo :"The tank failed due to corrosion"

The tank failed due to a lack of inspection or an incorrect inspection.

Regards