# Mercaptan?



## jim r king (Sep 30, 2020)

Hello all, 
Looking for advice. I have picked up a 250 gallon propane tank, valves are out and looking to start working on it. Problem is I live in a residential area and have neighboring homes on all 4 sides. im looking to fill the tank w water and detergent but am concerned that I’m going to have to haul this liquid mess out of my yard 5 gallons at a time as to not stink up the hood. 
thought about filling it 80% now and let it freeze this winter and cut into it frozen and haul off the ice..
questions ... if I put in the water and detergent and let it set for 5 months  will this help with the smell? 
if I open the valves up will it smell this bad in say 6 months? How long to evaporate out of the tank on its own? 
Reading online and suggested mixing and bleach but also creates hydrochloric acid. I really don’t want that in my yard either. 
I can’t dump 250 gallons of this in my yard , neighbors will go nuts. 
thoughts? 
this is my second propane tank build but the first one dident stink this bad as the valves were out a long time. 
thanks in advance, Jim


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## indaswamp (Sep 30, 2020)

Put a charcoal filter over top as you fill it with water, it'll suck up the odors....


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## jim r king (Oct 1, 2020)

indaswamp said:


> Put a charcoal filter over top as you fill it with water, it'll suck up the odors....


Thanks for the idea!!


indaswamp said:


> Put a charcoal filter over top as you fill it with water, it'll suck up the odors....


 Thanks for the reply, sounds like that would work for the displaced air / gas that’s currently in the tank, 
Any thoughts on how bad the smells are from the water that is released during cutting ?


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## WaterRat (Oct 1, 2020)

Addition of hydrogen peroxide and baking soda (1qt peroxide to 1/4cup baking soda) will neutralize the mercaptan. Adding detergent - dish washing soap  - will dissolve the neutralization product... but you'll need quite a lot for a 250gal tank and agitation could be an issue but it seems like time may do the work for you.  You may have to repeatedly mix the peroxide/soda and add as it is only active for a short time. I'd pre-dissolve the soda in minimal water, add the peroxide and mix well then pour into the tank. Wear goggles, the reaction could be vigorous and you don't want peroxide in your eyes!

Just thinking out loud.... if you put the mix (for this you could dilute in equal amount of water in theory) in a long hose sprayer and were able to spray the walls directly, that may really work better than dumping into a whole lot of water....


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## jim r king (Oct 1, 2020)

WaterRat said:


> Addition of hydrogen peroxide and baking soda (1qt peroxide to 1/4cup baking soda) will neutralize the mercaptan. Adding detergent - dish washing soap  - will dissolve the neutralization product... but you'll need quite a lot for a 250gal tank and agitation could be an issue but it seems like time may do the work for you.  You may have to repeatedly mix the peroxide/soda and add as it is only active for a short time. I'd pre-dissolve the soda in minimal water, add the peroxide and mix well then pour into the tank. Wear goggles, the reaction could be vigorous and you don't want peroxide in your eyes!
> 
> Just thinking out loud.... if you put the mix (for this you could dilute in equal amount of water in theory) in a long hose sprayer and were able to spray the walls directly, that may really work better than dumping into a whole lot of water....


thanks for


WaterRat said:


> Addition of hydrogen peroxide and baking soda (1qt peroxide to 1/4cup baking soda) will neutralize the mercaptan. Adding detergent - dish washing soap  - will dissolve the neutralization product... but you'll need quite a lot for a 250gal tank and agitation could be an issue but it seems like time may do the work for you.  You may have to repeatedly mix the peroxide/soda and add as it is only active for a short time. I'd pre-dissolve the soda in minimal water, add the peroxide and mix well then pour into the tank. Wear goggles, the reaction could be vigorous and you don't want peroxide in your eyes!
> 
> Just thinking out loud.... if you put the mix (for this you could dilute in equal amount of water in theory) in a long hose sprayer and were able to spray the walls directly, that may really work better than dumping into a whole lot of water....


thanks for the info. I’ll try it out. 
ive been experimenting a bit with the setup to determine if I’m going all in. 
I dumped 8-10 gallons of water in the tank. Moved it around a bit and pulled it back out. 
collected around5 gallons. 
I see the oils are at the top and have separated somewhat from the water. From doing this I have decided I am going to fill the tank full of water and let it sit for a week or so. Let all the oils come to the top. I have two threaded holes at the top so after it separates I should be able to hook a garden hose and a blow off tube and push out all of the oil. 
I know there will be some residual left in the water but I’m thinking I can get a bunch of the oils out of the tank this way. that would allow me to pull the oils off and discard them without crapping up my yard. 
I will add the detergent or peroxide baking soda mix after I pull the oils out as to keep the oils separate from the water.
Right now I have my 5 gallon of water pulled from the tank. I mixed that with 80 mL of bleach. 
that would be a close approximate to a gallon of bleach mixed into 250 gallons of water.
Planning to let that sit for 24 to 48 hours and see what it smells like. 
i’ll try another batch with the Peroxide baking soda . 
certainly is easier to learn on 5 gallons than dumping complete 250 into the yard. Fortunately I live on a hill with woods in the back but still want to be conscious of what I’m dumping.


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## kmmamm (Oct 5, 2020)

I store my build tanks in an outside lot right side up with valves removed and find it takes 5-6 months for tanks setting in the open to air out.  Even then I occasionally catch a small whiff of captan.   An old builder I knew used to  rig-up a small fan to blow fresh air into his tanks for a couple months.  He did it primarily to clear residual LPG, and avoid the mess of rinsing before cutting, but it did help to dissipate the captan.   He lived in town and would rig a timer to run the fan only late at night until just before dawn...when the majority of his neighbors were asleep.   Issues like these make me glad I live on a farm and don’t have to deal with close neighbors.


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## jim r king (Oct 6, 2020)

kmmamm said:


> I store my build tanks in an outside lot right side up with valves removed and find it takes 5-6 months for tanks setting in the open to air out.  Even then I occasionally catch a small whiff of captan.   An old builder I knew used to  rig-up a small fan to blow fresh air into his tanks for a couple months.  He did it primarily to clear residual LPG, and avoid the mess of rinsing before cutting, but it did help to dissipate the captan.   He lived in town and would rig a timer to run the fan only late at night until just before dawn...when the majority of his neighbors were asleep.   Issues like these make me glad I live on a farm and don’t have to deal with close neighbors.


Thanks for the good info and yes


kmmamm said:


> I store my build tanks in an outside lot right side up with valves removed and find it takes 5-6 months for tanks setting in the open to air out.  Even then I occasionally catch a small whiff of captan.   An old builder I knew used to  rig-up a small fan to blow fresh air into his tanks for a couple months.  He did it primarily to clear residual LPG, and avoid the mess of rinsing before cutting, but it did help to dissipate the captan.   He lived in town and would rig a timer to run the fan only late at night until just before dawn...when the majority of his neighbors were asleep.   Issues like these make me glad I live on a farm and don’t have to deal with close neighbors.


Thank you for the information, that was exactly what I was looking for. 
The amount of time it would take if the tank just sat open.
I filled the tank full of water and dawn dish soap yesterday. It was windy outside and I filled it slowly over 5 hours as to keep the smells at bay. Was planning to let this sit till this weekend. I did some sample tests adding bleach to a few gallons I pulled off and that definitely helped with the smell. Looks like after about 3 days in the bleach the smell was mostly gone. 
i’m not going to add bleach to the tank for safety reasons. After reviewing and reading on those tank explosions in Virginia (mercaptan + bleach +aluminum+ sealed Steel container= hydrogen bomb) I decided it would be best to siphon off the water into a open top plastic tub. 
after the water has been siphoned end of the tub I will add the bleach and let it sit for three days before dumping. 
I think that should work out well to get rid of the smell as well as not blowing myself up. 
I figured I would run a couple of these water fills before cutting into it.


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## kmmamm (Oct 6, 2020)

That is a pretty labor intensive process, but it will work and most importantly,  will keep peace in the neighborhood.  if you completely filled the tank so that water was flowing out of the valves, I guarantee all of the lpg gas was displaced and the tank is safe to cut.  You will still have some captan to deal with, but the explosive element will be gone.


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## jim r king (Oct 8, 2020)

kmmamm said:


> That is a pretty labor intensive process, but it will work and most importantly,  will keep peace in the neighborhood.  if you completely filled the tank so that water was flowing out of the valves, I guarantee all of the lpg gas was displaced and the tank is safe to cut.  You will still have some captan to deal with, but the explosive element will be gone.


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## jim r king (Oct 8, 2020)

purchased a lel propane gas meter with a led display that shows ppm. 
for $30 with shipping I couldent come up with a reason not to buy it. 
hoping to cut into this bad boy soon. 
insides soaking in water and detergent.


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