WALTER784 said:

If you soak coal in oil, it will burn much longer and more efficient than just plain coal.

There are also many grades of coal, some of which have quite a bit of oil entrained in it during its formation. It depends on the kind of biomass that decomposed, and in what geological time epoch, which determines the makeup of the material.

I think anthracite coal is the highest overall carbon content, and is ideal for high temperature burning with almost no smoke. It is considered a clean coal because there is little material present to produce soot, and also far less ash.

Then there are the more common grades of coal, from which hydrocarbons have been extracted or chemically cracked to obtain. The Nazis used coal gasification extensively to produce fuel, which is why the Allies bombed the gas works in Romania during the war.

Britain first extracted methane and other light gaseous alkanes for gas light and heat in the 19th century as they baked coal to convert it to coke, which is the near pure carbon that is needed for iron ore smelting and steel manufacture.

How about this carbon?

FWIW

Probably not very efficient. Only the C2H5(OH) is going to burn. And the remainder is tied up in the fruity carbon based materials, diluted in a very large amount of H2O that will have a strongly endothermic effect on any combustion while vaporizing it..

You need a much higher proof distilled spirit such as Everclear 190 proof to actually get a good fire going.