There are some time, we posted an article on scanned tests on the Makhonine fuel. This article is available this page.
This article was difficult to read the texts were therefore transcribed into text more readable:
To recap, the Makhonine fuel is a fuel made from coal liquefaction (even of poor quality), it's a bit of Fischer-Tropsch before time (test date from 1926). In addition to being very economical and completely independent of oil, fuel was also very good physicochemical property including a fire focus / high flash (infinflammable at room temperature) and a density close to that of water.
Its use allowed, apparently, also (compared to the time of essences) fuel savings of 30%.