I came up with a concept for how a dragon could breathe fire. However, I haven’t figured out some crucial details, which I need help with.

The dragon would capture the methane gas produced by its digestion. Then, it would pump this gas out through its throat, igniting it with a pilot light in the back of its mouth.

Now, what I haven’t figured out is, how would the dragon ignite the pilot light? And for the pilot light’s fuel, would it use methane as well, or should it synthesize some other flammable substance?