Similar to explosives, the more thoroughly mixed it is the more energetic the reaction. Pouring LOX over charcoal and soaking charcoal in LOX are very different (the first ignites vigorously, the latter explodes like a stick of dynamite). http://www.popsci.com/diy/article/2009-09/most-dangerous-way...
That's right, wet hay bales can and will spontaneously combust. It sounds counter-intuitive, but wet hay bales are more dangerous than dry hay bales, because hay actually heats up as it dries. As the hay gets hotter, it starts giving off flammable gas. The heat it is generating combined with the gas it is giving off means they could light on fire at any moment if they've been stored before fully drying.
And where is hay commonly stored? In a barn, with an attached grain silo. And that grain silo is sometimes full of fine dust. Which, like flour, can easily explode at the smallest spark or flame.
This phenomenon is easy to exploit actually. Laying out "sheet mulch" with 9-12" of hay on top of an opaque layer (typically newspaper or cardboard) can greatly accelerate the production rate of soil and repair degraded soils. No tilling or digging required, the mulch retains water and cuts down evaporation, and weeds are smothered by the opaque layer. This yields high quality produce without fertilizer and with a minimum of labor. The late Bill Mollison of permaculture design describes it here (@21m): https://vimeo.com/142711756
In the interest of public wellbeing, from now on I shall restrict my vocabulary on HNews to Python keywords only.
As noted earlier by schiffern, charcoal has a huge surface area, and carbon fiber has a different structure with much less surface area.
But, I'd still expect it to burn very nicely in the presence of concentrated oxygen.
Carbon fiber, is solid fibers about 5-7 microns thick and of arbitrary length. The fiber is embedded in a matrix, typically of epoxy. A typical ratio for a high-performance part would be about 64% carbon fiber and 36% epoxy. If built properly, the epoxy or other matrix material will completely encapsulate the carbon, including a thin coating on the surfaces.
That said, the first thing I'd want to do in the presence of 100% liquid oxygen is to coat the entire carbon composite to ensure that the composite and the oxygen stay apart. The epoxy itself is an organic compound, and the thickness of the coating is at most a few hundred microns (you have to be very careful sanding the surface to prep it for a more durable coating, or you'll get into the carbon).
Source: I'm a carbon fiber designer and fabricator.
https://www.youtube.com/watch?v=0tcP9SLKEG4
Given the right conditions, carbon+oxygen is carbon+oxygen, usually resulting in a combustion.
This is the first thing that pops up when you google 'carbon composite':
https://en.wikipedia.org/wiki/Carbon_fiber_reinforced_polyme...
I had a vision of a massive porous mass of carbon (a la water filters and the like) storing all that lox, but it seems not to be the case.
Because with that conceptualization, it seems like an inherent risk to store liquid oxygen in a charcoal container on a rocket ship.