October 1, 2009 School of the Boat - We'll stay with medical

[JTheotonio]

I'm not sure if any of your museum boats still have battery cells aboard, but if you do then this might be useful information.  The question (and only one) will remain in the medical area.  However it could fit into the ventilation system as well.  But it was important that we know and understood about the gasses that are produced from the batteries on a fleet-type submarine.  So here we go!

A Fleet-type submarine uses two very large batteries for propulsion while under water.  The battery cells discharge at variable rates as the ship is driven through the water at different speeds, and is recharged by diesel driven generators. Water from the electrolyte is hydrolyzed at the poles, in large amounts if there is a rapid rate of charge or discharge, and/or a high cell temperature.

Rapidly evolved gases then bubble to the surface, and the cell is said to be "gassing." Each of the battery wells is continuously ventilated by its own set of exhaust blowers, to forestall the buildup of high concentrations of these gases at any point in the ship.

Here is your question: What are the four main gasses that come from the battery cells as they are gassing?

[JTheotonio]

   OK this one is an important question.  Deadly gasses can form during a quick battery charge or quick discharge of the battery.  I'm hoping someone will take the time and try to answer this one.  You would not want any of these gasses forming in pockets on you boats.

Water is  H2O = so one of the gasses is easy - Hydrogen! Now you only have three more to go!    

[Lance Dean]

Oxygen?  Chlorine?

As far as I know, the Requin is the only museum sub that has her original batteries. And I'm sure they've been gutted for safety and preservation reasons.

[etkfixr]

There is also the electrolyte, sulfuric acid which has more hydrogen and sulfur, plus the lead in the plates.  You get combinations of all of that in the cell.  The electrolyte reacts with the lead to for lead oxide or lead sulfide or maybe both.  I thought chlorine only came from a sea water leak when the salt in the water reacted with the battery acid.  So, I think Hydrogen, Oxygen, Sulfur and the chlorine from a leak.  Terry

PS sorry for the long hiatus.  I was defaulted into being base commander of my subvets base when no one else wanted it.  So that plus the forty hundred other things I have on my plate.....  Terry

[JTheotonio]

Well this has been around long enough and we did have a couple of takers. All good answers and to be sure we should what out for:

1.   Hydrogen – highly explosive at 4% or higher
2.   Stibine
3.   Arsine
4.   Chlorine

2-4 are deadly if inhaled

So Terry gets some points on this one.

Antimony is added to the lead sulfate of the cathode plates to improve their durability and length of life. Hydrogenation of antimony during gassing produces stibine (SbH3), an explosive gas with a characteristic unpleasant odor, which dissociates rapidly at room temperature, and which acts toxicologically as a lower respiratory irritant and a hemolytic agent, with traces of antimony excreted in the urine.

An impurity in lead storage battery plates is arsenic, which forms arsine (AsH3) upon contact with nascent hydrogen; this gas is more stable than stibine, has a garlic-like odor and, after a delay of a day or two after exposure, causes such symptoms as malaise, dyspnea, headache, fainting, nausea and vomiting, dark urine, anemia, and jaundice. Arsine is spoken of as a "blood and nerve poison." Neither gas has been positively incriminated in the present day submarine.

And just so you know

Lead sulfide (also spelled sulphide) is a inorganic compound

Lead oxide is the chemical compound with the formula PbO.  Lead oxide occurs in two forms: red, having a tetragonal crystal structure and yellow, having an orthorhombic crystal structure. Both forms occur naturally as minerals.  Remember “Read Lead?”

[Mark Sarsfield]

So, of all of these chemicals, which ones remain behind long after the batteries are gone?  We can still smell a hint of batteries in our battery compartments.

[JTheotonio]

If the batteries are dry - probably none.  What you have is residual smell - just like the rest of the boat.    You never get rid of that wonderful diesel smell! 

I'd bet that when they took the electrolyte out of the batteries they didn't do a good job of flushing them with pure water,  So you may have some corrosion taking place where dissimilar metals are touching.

If the batteries were de-watered in place they could of spilled some of the electrolyte on the deck below the cells.   

[Mark Sarsfield]

There's some rust aboard the boat, in general, because for 30+ years there wasn't any operational air conditioning.  The slight odor in the battery wells is different than the normal diesel odor, but not much air circulation gets down there.  So, it could be a number of things.