Creating Super Heated Steam: Igniting Paper at 300°C

[PeteGt]

I searched for this and get conflicting results. I have setup a demonstration that has a erlymeyer flask with a one hole stopped and water on top of a heating mantle. I then have a copper tube comming out of the hole in the stopper going into about 5-1"diameter coils and then finally comming out to an opening.

I boil the water and then ehat the coils with a propane burner...these coils get really hot and red in fact. My thermocouple says the temperature of the steam at the end is about 300 degrees celcius. However i cannot actually get the paper to ignite, it only chars and possibly make little red embers.

Any ideas on how to make it actually ignite? Am I doing something wrong?

thanks

 

[rocketboy]

Hi,

Although I do not know the answer to your question, I am interested in hearing more about the demonstration you are setting up. What is the purpose/question that the experiment is demonstrating/answering?

Is it just the steam that is touching the paper? Perhaps a fuel is needed for the heat to act upon to create a flame, I'm not sure though.

 

[Q_Goest]

Any ideas on how to make it actually ignite?

er... hold it closer to the propane burner? :tongue2:

You need oxygen to make something burn, that's why it only chars. Not enough O2. The water vapor is displacing the air. Try injecting some oxygen into the water vapor stream. If you only use air, the oxygen in the flow stream is going to be highly diluted, so that might now work. You might also try just heating one side of the paper so the opposite side is exposed to air only.

Caution: Whenever using pure oxygen, I'd suggest using as much copper and bronze material as possible. Even stainless steel can burn in the presence of pure oxygen at a high enough O2 pressure.

 

[PeteGt]

Sorry I have not replied lately, I have been busy getting ready for the school year.

Rocketboy- I'm merely trying to show my kids the idea that "steam" is not that cloud they see when they breathe on a cold morning or the cloud that comes outta the shower. It's a demonstrationg to ahve them think that gases can be heated up too and don't just stay at one temperature. It gives the WOW effect, which is always good to see. The steam is generated in a flask that i stopper with a one holed opening into a copper tube and coil it...by doing that and then heating the coils the steam is then being heated more and more, and when i hold a piece of paper up to the end of it it chars and creates embers just from the steam hitting it.

Q_Goest-I'm glad you said that, I have had the idea in the back of my mind cause i belw on it one day thinking that was the issue and saw the embers glow even hotter. Injecting O2 might be an issue...i'm not sure if I have a source of O2 that would be suffcient enough...Could always setup a Hydrogen Peroxide decomposition reaction...that might do enough.


Thanks for all your help!

Pete

 

[Q_Goest]

How about a small medical oxygen cylinder such as used for home care? Look up 'oxygen' in your yellow pages, or look under medial supplies. You might also get an oxygen cylinder from a welding supply store. Generally you can rent these for a few bucks. Oxygen cylinders are also available in Sears, look in the tools section.

 

[Danger]

Hi Pete;
You could also investigate snagging a small nitrous oxide bottle from a speed shop. The ones made for motorcycles are not as large as the automotive variety. I recall as well that a few decades ago you could buy little pellets of 'solidox' that release oxygen when burned. They were used in a particular type of oxy-propane torch that my friend had.

 

[FredGarvin]

Just be damned careful when dealing with pure oxygen.

 

[Danger]

Just be damned careful when dealing with pure oxygen.

Too true! I've never seen a picture of Pete, but if he's got kids he probably can't afford to lose any more hair.

 

[PeteGt]

I still have all my hair, but It's been close sometimes. Haha.

found a bottle of oxygen and it worked great, it went right up. I was thinking of using hydrogen peroxide and maganese oxide (catalyst) to make Water and Oxygen in the flask and boil that through the coil...wonder if that'd be enough oxygen to set it off?

pete

 

[LURCH]

I've seen this experiment done with a strait length of copper tube; perhaps you're losing too much heat as the steam in the coil moves repeatedly toward the heat source and then away from it again. Maybe even some phase transitioning going on inside the tube?

 

[paul k]

Pete GT this is an old topic by the date on your post but if you revisit the idea but add a second coil around the first coil that is open at both ends you can heat both atmospheric air and the superheated steam pipe at the same time with the same flame therefore no heat loss at the potential point of ignition ( paper) on the one end of the air coil (intake side) install a valve so that you can regulate the amount of air introduced. At the opposite end have the end of this air coil in line with the superheated steam line to induce a venturi effect which is what you need to pull the heated air into the stream for ignition of the target. Bernoulies principle works wonders in all different applications from a carburetor on a vehical to precice chemical injection systems in mass production lines, etc etc. The extra copper coil does not have to be the same size as the steam coil, it can be slightly smaller and it is a safer, cheaper method to the issue than pure O2! You should be able to fine tune the rate of cumbustion with the valve at the intake side of the air coil. The concept of heating the air maintains the temp at the source of ignition rather than cooling it as the introduction of a compressed gas will do. If you do decide to try this method let me know how you make out and for the copper pipe you may be able to scrounge some from a plumbing or heating outfit that has an end of a coil from a previous job. Refridgeration use copper a lot for central air applications so they would be worth checking out as well