Tuesday, October 17, 2017

gas laws - How can I light a fire in this case?


Is there any gas that contains oxygen so that it doesn't require oxygen from the environment in order to burn?


What I am trying to do is use LPG gas, which is fed through a pipe to a burner that is placed in an environment that has no air, somewhat like a vacuum. Is there any way to light the burner inside that vacuum environment?


A few wild ideas that I had included finding some gas that contains oxygen in itself. I may be wrong.


EDIT - The question doesn't end here. Please read the comments section below for any doubts that you might have. And if it isn't answered in comments section then ONLY comment.



Answer



The most convenient solution for your question can be the Hydrooxy gas (also sometimes called the Brown’s gas). Simply put its water split into hydrogen and oxygen. Hydrogen and oxygen can be combined back by ignition and can create a maximum temperature up to 2800 °C (around 600–700 °C hotter than burning hydrogen in air), which makes it a good fuel for metal welding and cutting.


Though 2:1 hydrogen and oxygen ratio is enough to produce water via combustion, but on a practical solution you will need around 3:1 to 5:1 ratio to avoid oxidizing flames. The temperature you can achieve by burning hydrogen oxygen mix varies, depending on the ratio of both gases used.



Hydrogen and oxygen can be obtained via simple electrolysis.


$$\ce{2H2O + Energy -> 2H2 + O2}$$


and combined back as


$$\ce{2H2 + O2 -> 2H2O + Energy}$$


It might be worth noting that for all practical purposes, the energy you use to split hydrogen and oxygen will always be greater than what you can get by combining them back (like what happens in every combustion engine, humans have ever created).


If you are planning to develop an actual application, there are many precautions that you would need to consider, the most important of which would be back-fire protection (a common problem with gas based welding), so that the flame doesn’t reach back into the gas tank, which of course will explode.


So goes without saying, but you might want to adopt some precautionary measures if you do use it in any practical application. Temperatures this high can seriously hurt a person even if the contact was for some milliseconds. It can also damage other materials if the flame is directed at them.


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