sulfuric acid unloading and storage station 2

[mae1133]

I am working on a plant in NY that requires 93% sulfuric acid, so part of the plant is the design of the tanker truck unloading station to fill a 6000 gallon tank that will be located in an adjacent building. Can anyone point me in the right direction for codes and requirements for the transfer, handling and storage of this acid? Thanks

 

[SuperSalad]

You'll want a filter as the hookup location for the incoming material. Stainless is acceptable, but it'll go bad, PTFE lined equipment and piping is a good idea. Kynar is a good material for the filter as it holds up well to wide temperatures and is acid resistant. I forget the micron rating, but I want to say its about 5. The filter at that point is important though because tanker liners come apart over time and you'll end up with residues in your storage tank if you don't filter it right out of the truck.

For some technical details, I would suggest NorFalco's handbook: NorFalco: Sulfuric Acid Handbook

They do a pretty good job of laying it out in that brochure. The storage and handling section is on page 24 and goes into details of some of the basic safety requirements with PPE and emergency equipment. You'll need to check into NY's DEP for specific local requirements for handling and storing it, but you'll likely need to report quantities annually for a couple different environmental and safety programs; like TRI, Right-to-Know, discharge prevention programs. etc.

Also make sure you have containment for the tank. The building may serve as that if there is not exit point in case of a tank rupture or spill, but you'll need to be very much aware of that. In NJ, we have DPCC plans for discharge prevention containment and countermeasure. It is an intensive program centered around preventing release to the surrounding environment, but I'm not sure what NY has in place for that function.

Either way, if you have specific questions to follow this up, I'll be happy to help if I can.

Andrew H.

http://www.MotoTribology.com

 

[MJCronin]

I have worked on Sulfuric Acid unloading and Storage systems in the past ....

Some things to consider:

1) Your 6000g tank seems a little small, IMHO...... According to many H2SO4 guidelines, the tank capacity should be 1.5 times the standard tanker volume plus two weeks usage. This rule usually gets you to approximately a 7-8,000 gallon tank.

2) Concentrated Sulfuric acid storage tank design should be in accordance with NACE International (National Association of Corrosion Engineers) SP 0294-2006 standard. Pay particular attention to corrosion allowance, tank inlet pipe placement, tank overflow and tank tank venting. There are many specific tank and system recommendations in this Standard and they are the resultant of many years of experience

3) Consider safety shower placement and location when sizing the tank and unloading facilities. Federal and State Safety shower regulations have changed a lot in the past ten years (regarding water temperature, shower time and alarm indication) so be aware ...

4) Consider administrative procedures for tanker truck driver hook-up and delivery early in the project. how will delivery be handled ?

5) Place the Storage tank in it's own separate coated containment. If there is a transfer pump, locate it on a tall pedestal inside of containment

6) If acid usage will be modest, consider an elevated horizontal axis tank and no transfer pump

7) DO NOT use a FRP/CPVC/PVC/Plastic tank if the acid is to be air-offloaded from a tanker truck

An excellent detailed guideline can be found here:

https://info.veolianorthamerica.com...industrial/sulfuric-acid-push-information.pdf

Respect us ........ and keep us posted as your details become final

MJC

MJCronin
Sr. Process Engineer

 

[MJCronin]

More information here:

https://www.eng-tips.com/viewthread.cfm?qid=103747

https://www.eng-tips.com/viewthread.cfm?qid=464582

https://www.eng-tips.com/viewthread.cfm?qid=453674

https://www.eng-tips.com/viewthread.cfm?qid=455432

MJCronin
Sr. Process Engineer

 

[dogtop]

mae1133,

This link might be informative:

http://www.sulphuric-acid.com/techmanual/Storage/tcloading.htm

HTH



dogtop
An Inversion of Top Dog

 

[0707]

About this matter you get no concrete answers here, this is a complex matter which involves licencors, safety, and political environmental rules, which cannot be answered in a forum thread, like this.

luis

 

[georgeverghese]

Use only dry air or dry inert gas as the blanketing medium in the storage tank to avoid corrosion in the tank. Design the relief system at the tank for gas blowby scenario in case the truck tank is offloaded with high pressure dry air; else avoid this scenario altogether with an offloading pump rather than using compressed air. Use breakaway hose couplers with unique connectors for this service in case there are other fluids also being offloaded from this same location. Ask for high integrity SIL-3 high level protection at the onsite tank.

 

[pierreick]

Hi,
Consider the resources attached .
Pierre

 

[pierreick]

Hi,
One more resource.
Pierre

 

[MJCronin]

I disagree with some of the comments above...

Neither dry air or nitrogen is necessary for 93% Sulfuric Acid tank blanketing. Use a large vent, open to the atmosphere, as detailed in the Veloia document I referenced. A 3" NPS vent would be right for a tank of this volume.

The Veolia guideline was based on an earlier DuPont document which was the industry standard for decades.

A State and Federally approved "Secondary Spill Containment System" of concrete or plastic must be considered for the Truck Offloading Station.

https://www.polystarcontainment.com/concrete-vs-containment-pads/

MJCronin
Sr. Process Engineer

 

[TiCl4]

I'll have to partially disagree with MJCronin here.

I worked at facility that had a sulfuric acid tank (98%, not 93%) that was designed and installed by people who were, let's say, very knowledgeable about the DuPont guidelines MJCronin referenced for sulfuric acid storage. The tank had no blanketing gas - it was, as MJCronin has suggested, open to atmosphere through a vent. It was also an oldish tank for this service, probably better than 20 years, though I don't know for sure.

The only issue that was ever found during inspections was slight metal corrosion/loss around the normal operating liquid level. The moisture from the atmosphere would locally dilute the acid at the gas-liquid interface, causing an increased aggressiveness towards the carbon steel.

The recommendation in the reference MJCronin provided for mild steel goes down to 93% sulfuric. If moisture is absorbed into your storage tank, it will drop the local concentration at the liquid top below 93%, and may result in increased corrosion. You are on the borderline of concentration recommendation for mild steel, so you may be more susceptible to moisture intrusion than a typical 98% application. Thus, a simple open vent may not be the best idea.

As an alternative to the two options presented thus far (vent to atmosphere and dry gas blanket), this tank could simply have the vent line pull air through a desiccant pot. That would serve to keep moisture out of the tank without requiring a blanketing gas, and may provide better life than an open vent.

 

[chrysa1975]

I totally agree with 0707. However NACE SP0391 and NACE SP0294 are relevant. I have also used dogtop reference website and has helped me in the past.
A simple google search revealed

https://www.sulphurinstitute.org/pub/?id=478a5ef2-c710-c5b3-ec9e-62947fac411e

Last but not least, the national and / or governmental guidelines shall be strictly followed.

 

[georgeverghese]

If you have no choice but to use compressed air to force out the acid out from the truck tank, then the only safe option to avoid overpressure in the downstream storage vessel is to ask for a storage vessel with the same mechanical design pressure as the HP air used as the motive medium at the trailer truck tank.

 

[MJCronin]

Some more comments:

1) Tank desiccant dryers are an option to be considered by the owner for sulfuric acid tank vents. They are not necessary in all circumstances, IMHO.... They require maintenance of course.... Tank overpressure or excess vacuum must be considered in the original tank specification

https://www.drytechinc.com/tank-vent-dryers/

2) If the tank is made from carbon steel with a 0.125 to 0.25 inch corrosion allowance, dryers are of minimal benefit. If the tank is located in an arid area, there is little moisture to be removed from the atmosphere. The threat of an internal wall thinning in one specific area for a 93% carbon steel tank implies that the level of the tank rarely changes. My understanding of the OP is that he was installing a new system that would be repeatedly and frequently refilled.

3) Internal tank wall thinning, when it occurs, does not show up immediately. I would incorporate an inspection as part of a three or five year plan... IMHO, internal tank wall thinning is not as much of a threat as (CS)piping failure on the acid outlet piping.... I have worked on multiple systems where "hydrogen grooving" has caused piping failure which damaged equipment and required replacement

http://vgoinc.com/wp-content/uploads/2015/07/Case-Study-Sulfuric-Acid-Supply-Line.pdf

4) I am still a fan of the "tried and true" gooseneck vent which has been used on hundreds and hundreds of installations

5) Unlike love, Sulfuric acid Tanks and systems do not last forever. I would expect a CS tank to require replacement every 12 to 20 years. Plastic tanks may require more frequent replacement. Carbon steel piping systems will probably require replacement every 8 to 12 years

6) All of the comments I have made above only apply to systems storing and transferring NEW OR VIRGIN SULFURIC ACID !!!.... Tanks and systems storing used or spent or "waste" sulfuric acid may pose SIGNIFICANT FIRE OR EXPLOSION HAZARDS !!!..... There have been many accidents where "hot work" was being done nearby waste water or waste acid venting systems

A remarkable (Spent)sulfuric acid tank explosion and fire occurred in 2001 at the Motiva Enterprises Refinery
Delaware City, Delaware, July 17, 2001 -----1 Killed, 8 Injured

https://www.csb.gov/assets/1/17/csb...tin_embargoed_until_10_a_m__3_4_101.pdf?14329

https://www.yumpu.com/en/document/v...igation-report-us-chemical-safety-and-hazard-

Also

https://www.eng-tips.com/viewthread.cfm?qid=315366

MJCronin
Sr. Process Engineer

 

[TiCl4]

I always appreciate your posts, MJCronin. Your experience and insight is always informative, and you put all of that into responses.

 

[hacksaw]

Remember spent acid is more than dangerous, given the dissolved gases present, and must be treated as a toxic substance.

We always used bubbler pipes on the acid tanks, carefully designed and laidout, so the tank purge (dry instrument air) was built in to the measurment. The loss of level transmitter signal meant you lost the tank purge too.

 

[shvet]

1/ I had been working on a chemical unit where H2SO4 was processed. 92.5-98% H2SO4 was stored in 4x50m3 CS horizontal cylindrical vessels vented to atmosphere, vessels were ~30 years old. I can not recall a problem with corrosion caused by atmospheric moisture. May be this is because H2SO4 was consumed continuously.
2/ Note that hydrogen accumulation and explosion inside of H2SO4 equipment is a well-known hazard.
3/ NACE 6G197/SSPC-TU2 can help in case of concrete secondary containment.
4/ Be sure that workplaces (e.g. local panels and instrumentation), pathways and vulnerable eqipment (e.g. cables) are not exposed to possible drips of H2SO4. H2SO4 piping should be placed at outside part of a piperack, no pipes should be located beneath, crossing with a road/pathway should be protected by a shed/apron.
5/ Protecting cover is required for possible sources of a acid&caustic leakage as per local codes.