Combustion in Reducing Atmosphere?

[stevebowers]

Googling around I found this thread about Titan on a forum I'm not a member of;
http://www.unmannedspaceflight.com/index...topic=2833

The surface temperature of titan is actually well above the flash point of methane (-178C vs. -223C). Furthermore, we know now that at the surface, the concentration of methane gas is ~5%, this is within the explosion fraction range of methane of 5-15% on earth with an O2 conc. of 20% (the fact that we are dealing with gas at the surface actually negates the relevancy of methane's flash point). I also suspect that because the pressure of the atmosphere at the surface is higher than at earth's surface, the explosion fraction for methane would actually slightly extend below the 5% lower limit add to this the fact that you'd be burning it with 100% O2 instead of earth's paltry 20% and this probably pushes the explosion fraction limits even wider. The fact that the gas is very cold is irrelevant. What's -180C when you're talking about a flame temperature in the thousands of degrees? nothing. It is quite certain that you could light a flame off of a bottle of O2 at the surface and it would self sustain 'till it ran out. Even if you are uncomfortable with the closeness to the lower limit of the explosion fraction at 5%, performing a concentration of methane out of the atmosphere to a slightly higher % would be trivially easy with a semipermiable membrane and a very small amount of energy input (the amount of entropy change you'd need to concentrate it to say, 10% would be very small). The nice thing about the ability to carry liquid O2 instead of liquid hydrocarbon is the high density. a small bottle of O2 would go a long way. Even if you wanted to run some silly scheme of condensing the methane out of the atmosphere as a liquid using a cryocooling loop and then heating and burning off the purified lquid all at once (like for a rocket), this would be VERY easy and energetically inexpensive to do since you're already so close to the boiling point.