Concrete Code 3

[maneesha0702]

Our company is checking a roof design and tank design. The tank stores a liquid at 250 degrees Fahrenheit. Is there a ACI code for design. Can concrete be used in this scenario?

 

[Ron]

What type of liquid is in the tank? Different groups provide code input based on applicability to their interests. For instance, if it holds potable water, the AWWA has input. If petroleum, then API has codes and standards.

Does the tank have an interior coating? If so, what is it?

 

[kslee1000]

Ron:

Excellent points.

 

[maneesha0702]

The molten liquid is Sulfur. The tank does not have any coating.

 

[kslee1000]

I don't think direct contact of any chemical to concrete, or steel is advisable. Investigate suitable liners, also should be capable of handling high temp.

 

[msquared48]

Concrete cracks. Without an interior lining of some sort, the liquid will peneterate the concrete matrix. I would also seal the concrete from the outside to prevent water intrusion.

As a thought here, what elements does sulfur have an affinity for other than oxygen? Is there anything in the concrete matrix that sulfur likes to put it a different way/

Mike McCann
MMC Engineering

 

[Ron]

When sulfur mixes with water vapor, it creates either sulfurous acid or sulfuric acid, both of which are detrimental to concrete and rebar.

Coat the inside.

Not sure which code, other than building code would apply to this one.

 

[msquared48]

There you go... Seal the sucker.

Mike McCann
MMC Engineering

 

[steve1]

The OP asked about ACI codes.

ACI 350 "Code Requirements for Environmental Engineering Concrete Structures" Section 4.3 "Sulfate Exposures"

ACI 350.2R "Concrete Structures for Containment of Hazardous Materials" Chapter 5 "Liners and Coatings"

ACI 350.3 "Seismic Design of Liquid Containing Conrete Structures"

ACI 350.4 "Design Considerations for Environmental Engineering Concrete Structures" Section 4.2 "Expansion and Contaction Conditions"

 

[csd72]

Even with the seal I would look at specifying sulphate resistant cement.

 

[Ron]

csd72...good point.

 

[msquared48]

And maybe epoxy coated resteel?

Mike McCann
MMC Engineering

 

[chichuck]

I used to work for a company that did work at refineries. I helped design several sulphur pits.

Concrete is appriopriate for this type of containment. A big concern for us was bending moments in the (thick) walls due to temp gradient through the wall. (250 deg liquid sulfur inside face, moist soil outside = large through-thickness gradient = substantial bending moments in walls.) We used some sections of the aci standard for nuclear facilities, there was one section that applied to this. I forget the standard number thouigh.

On one small installation, we fixed this by applying rigid foam insuation blocks to the outside of walls with adhesive (I forget the speicif product and adhesive), then wrapped this up like a christmas package with neoprene sheets to waterproof it. (Yes the neoprene wend down first, then the foam blocks under teh base slab, we just folded the neoprene sheets up around the sides & sealed the jonts.) On all the other pits, they were much larger, we used no insulation.

Also be sure to consider the effects of overall expansion & reinforce accordingly. Remember, it will get hot and it will expand, you cant prevent that. (on one installatino we had two large pits, 20 apart with a plant roaway in between. I talked to the geotech and asked about two pits expanding toward each other, what effect would that have on the backfill between. He studied that and recommended a lower level of compaction for fill between that would allow lthe pits to expand & still allow us to build the roadway.)

I had a supervisor there who related a story about an old plant with above-ground sulfur tanks. For those, he said the sulphur pushed through cracks and it cooled and solidified near the outside face of walls, effectively sealing it off. Perhaps cracks don't cause problems.

I did all this back in the '80's, but I don't recall any difficult environmental issues for those. But looking back, I cannot understand why that didn't become a big issue.


my 2cents worth.


Regards,

chichuck