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Is there an expiration date on propane?

  1. Dec 8, 2011 #1
    I am stumped!!!! I have three different big burners for cooking. I have a very old tank of propane......like 20 years old. It still has propane as I can feel it's heavy than the empty tank and when I shake it, I can hear liquid inside.

    But I connect to the burners.....two new and one old. They are slow. I tried three different regulators( I even bought and return one) thinking the regulator is plugged. I have no luck. I need to get this going for Chinese cooking in Christmas. I don't know what to do. Is there an expiration date on propane? Does it get old and lost pressure?

    I tried open the valve on the tank and seems plenty of pressure come out and it smell bad( propane). But I cannot imagine 3 bad burners, three bad regulators. Just seems there is not enough pressure to push out to the burner!!!!

    Any suggestion would be very helpful. If there is a better place for this post, please move me.

    Thanks

    Alan
     
  2. jcsd
  3. Dec 8, 2011 #2

    lisab

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    Is there a way to determine if there is any gas coming out of the burners at all?

    Please don't get your face close and sniff, if there is any chance the gas could suddenly ignite :surprised.
     
  4. Dec 8, 2011 #3

    Evo

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    Get a new can of propane.
     
  5. Dec 8, 2011 #4

    Q_Goest

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    Hi yungman,
    That's interesting. I'm no expert on propane but I'm curious to understand why propane would be 'old'. Propane is a mix of various hydrocarbons but it's mostly C3H8. The remainder consists of various other hydrocarbons both lighter and heavier. I was wondering if the lighter hydrocarbons leaked out, say through the valve, if the pressure of the tank would change at all. The pressure will be the saturation pressure. So I checked a database I have and it doesn't look like the pressure should change substantially, even if all the lighter hydrocarbons were to leak away which suggests there shouldn't be any problem with low pressure or lighting it.

    You've tried 3 different regulators but there is still only 1 cylinder valve on the tank. My guess is the cylinder valve is plugged for some reason, and the most likely reason I can think of is bugs. There are various types of bees that like to make nests in round, tubular structures like the outlet of valves. We have a hell of a problem with "mud daubers" in some parts of the country. I've seen them build nests in the outlets of small valves and the valves end up mostly or completely plugged. You might try blowing them out but I've seen mud dauber nests hold back many hundreds of psi, which is more than the propane cylinder, so I wouldn't hold out much hope of blowing out one of their nests. In fact, I can't remember a single one we've blown out with just a few hundred psi, and I can think of a handful. I remember one case where we put something like 3000 psi behind it and it finally blew out like a gun shot! lol

    If the cylinder valve is blocked by some kind of insect nest, there might not be anything you can do other than try to pick it out with a bit of wire. The nests can be as hard as cement - maybe someone can think of a way to dissolve them but I don't know enough about what those nests are made of.
     
  6. Dec 8, 2011 #5
    Thanks for all the reply. I did tried to have the tank with nothing hooked up and open the valve. Seems like it has plenty of pressure as the gas gushing out strongly. Tonight, I did tried puting the regulator and the hose along with no burner hooked to the tank and open the valve of the tank, it was a weak stream but gas do come out. As I said, I swapped regulators already and it didn't help.

    I took my old burner apart, checked all the jets, I use a guitar string to poke through all the holes to show they were not plugged. In fact everything were clean. I use my mouth to blow from the inlet and proof that I can blow air through each of the path. It does need to blow hard, as the holes are small, but nothing blocked.

    I did tried to blow through the inlet of a new burner, it felt the same as the first one that you can blow through but with resistance. So the two burner I tested were consistence.

    Also I notice the old burner has a pilot light that used to be very touchy that I had to turn it down or else it would have so much gas coming out that it will blow out the frame. I tested with mouth and it had the least resistance, gas can flow easily through. But when I lighted the pilot, it was still weak.

    In my book, all the burners work, but the tank seems ok!!! Now what?
     
  7. Dec 8, 2011 #6

    AlephZero

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    If you haven't used the propane tank for 20 years I'm guessing you haven't been using the burners on propane. Are they designed for propane or natural gas? Natural gas burners won't work properly on propane because the fuel/air ratio will be wrong. Some burners are user-adjustable to burn either gas.
     
  8. Dec 8, 2011 #7
    Two of the burners are brand spanking new!!! They are designed for propane as they come with the propane fittings. The problem is the weak stream. It burn very low. They are all big burners like 60,000BTUs, not the wimpy little ones you see in regular stove. My old burner that I just took apart to checked used to work, the frame actually wrap around an 18" wok.

    Everything else are triple proofed except the propane tank!!! But it's full!!!
     
    Last edited: Dec 8, 2011
  9. Dec 8, 2011 #8
    maybe the amount of gas in the tank is so low that it doesn't evaporate fast enough to generate sufficient flow and pressure? i would try another tank, a full one. maybe the old tank is even contaminated with water.
     
  10. Dec 8, 2011 #9

    Evo

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    I'm thinking water.

    Buy a new tank!!! They're cheap!!
     
  11. Dec 8, 2011 #10

    dlgoff

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    You probably don't have propane but a blend of propane and butane.

    propane-butane-mix-vapor-pressure-diagram.png

    http://en.wikipedia.org/wiki/Butane
     
  12. Dec 8, 2011 #11
    Thanks for all the replies, The tank was quite full. I have an empty tank and there is a big difference in weight. I venture to say it has at least 10 lbs in a 20 lbs tank. When I shake it, I can hear the liquid swashing around. I used this same tank in the early 90s and it worked. Last time I used it, it was like 10 years ago, it's the same tank and I never finished it. So I don't think the problem is original composition of butane and propane................Well unless the propane part leaked out through the years leaving the butane part in the tank.

    I might just go buy another tank or fill the second tank that is empty. It light up and all, just very weak on the big burner. One of the stove have a small burner like the normal kitchen stove. It actually burn quite normal as it is small. Just when come to the huge 60000 BTU one, then it just wimp out.
     
    Last edited: Dec 8, 2011
  13. Dec 9, 2011 #12

    S_Happens

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    FYI- To me, propane has a copper(ish) smell. I'd actually have to look up the purity of commercial propane, but I'm referencing 97-100%.

    I'm still betting the problem is your regulators. Have you ever used large burners like the ones you just purchased? Your regulator may be incorrect/undersized for these new burners. You say you replace them, but that's not enough to rule them out. If you replace an incorrect piece of equipment with exactly the same wrong piece, then you don't know anything.

    Are your regulators fixed or adjustable? What color are they (this lends itself typically to whether they're high or low pressure)? Did the regulator(s) come with the burner(s), or did you already have it?

    If you really want to figure out the problem then you want to get the other tank filled and use it with the exact setup you have now. If it works then you can investigate the old tank further (or simply empty and refill it). If the new tank doesn't work, then you can focus back in on the regulators. I'm going to assume for now that it's not the main valve from the tank since you claim it is clean and provides more propane flow than the regulator(s).

    Give the exact details of your setup (again maybe, I'm not going BACK though). Are you using one regulator and multiple burners, one regulator and burner at a time, or something else?
     
  14. Dec 9, 2011 #13
    Yes, I use those big burners before with the same tank long time ago. One regulator comes with the new burner so my guess is it work for the burner......I hope. I am going to either fill my other empty tank or buy a new one. I just don't want to go and few another tank while I still have one that is over half full. For me to use it up, it's might be years!!!!

    BTW, is there any restriction of letting the propane out into the air.....like pollution? Or I should hook up to a burner and let it slowly burn empty?
     
  15. Dec 10, 2011 #14

    S_Happens

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    Although you sort of answered my question by stating that one regulator came with the burner itself, you didn't give the specific information that I asked for. It's much easier for someone new to come in, get the details, and answer the question if you don't try to corral them into exactly the same dead end that you are in.

    If the regulator is non-adjustable (and new and clean) then the best assumption is that it should work (new parts can be faulty, but when troubleshooting at that point you start with other more likely problems). If it's adjustable, then that could be the entire issue, which is why I asked. Most propane regulators are non-adjustable, but I live in an area where adjustable ones are very common due to local industry.


    As far as venting propane, all the regulations I am familiar with are specific for workplaces. By doing a quick search I can't find anything. Personally I'd rather burn it than just vent it.
     
  16. Dec 10, 2011 #15

    AlephZero

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    The physics and chemistry work the same everywhere. The main difference is probably the amount of insurance cover involved.

    The "standard" procedure may be different in different countries, but in the UK the customer doesn't usually own portable gas cylinders. You pay a one-time charge as part of the initial "refilling agreement" (which covers 50 years of refills, for one of the major UK suppliers). The supplier doesn't normally refill your cylinder "while you wait", they just exchange it for a full one. So disposing of any unused "old" gas or worrying about the condition of the cylinders is not the customer's problem.
     
  17. Dec 10, 2011 #16

    S_Happens

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    The question the OP asked was about venting propane to the atmosphere, meaning they want to know if they can simply open the valve on the tank and release it without burning it.

    My answer was that all I am only familiar with OSHA, TCEQ, and my former company's regulations for releasing VOCs to the atmosphere. I don't know of any specific regulations for a private person on their own property.

    Getting propane filled in the US is very similar. You can own your own bottle and specifically have it filled or you can exchange tanks. I imagine they tanks also fall under the same 5 year pressure testing regulations. The next time I go outside I'll check mine.
     
    Last edited: Dec 10, 2011
  18. Dec 15, 2011 #17
    Well, I solved the problem. I bought a brand spanking new tank, fill the propane and it work.

    The problem with the new tank is it does not work with the fitting of the old burner. I think they put in new device such that the fitting has to push in to open the valve. You can vent the old tank by just opening the valve at the top of the tank. You can't do this on the new tank. Because of this, the old fitting that connect the tank to the burner don't work because it does not have to tip to push into the fitting to open the valve.

    So now I have the complete set of new burner and tank working, but my old burner is still sitting there. I guess I can go and fill the old tank for that.

    I think it makes a lot of sense that the propane gas is a mix of propane and butane. In the last 20 years, the propane must had escape leaving the butane. That could be the reason why I got flame but it was very weak before.

    Now my next question is how to safely dispose of the two old tank as they are 20 years old and the rubber rings inside must be old and I don't think it is good to use it anymore.
     
  19. Dec 15, 2011 #18

    S_Happens

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    Well, the new tank fittings do indeed have a check valve, which is why you can't just vent it. I never had a propane tank before they changed the regulations in 2000, so that's all I was hand on familiar with.

    Typically the problem is the other way around. People go to the new style fittings and open up the valve to the burner before opening up the valve on the tank. This keeps your flow restricted just like trying to open the tank to the atmosphere.
     
  20. Dec 19, 2011 #19
    I did my Chinese cooking today with the burner and it is not strong enough. I need to resort back to the old burner and I don't have a regulator that work with the new tank. I am going to buy a new one tomorrow. The question is how do I look for a regulator such that I can get one that support a really really large burner? I am talking one that can support over 60000btu.
     
  21. Dec 19, 2011 #20

    lisab

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    Maybe a restaurant supply store would carry such an item? They definitely use "industrial strength" equipment that isn't available at mainstream kitchen stores.

    Just curious...what are you cooking? :biggrin:
     
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