Or in other words: is it possible to convert heat into kinetic energy if you only have one environment and not two with different temperatures?
No
See the Laws of thermodynamics: esdb.bg
are you asking about a running engine?
No. Heat, like mass, can be converted to work by letting it fall from a higher to a lower level. If there is no lower level to fall to there is no energy to be extracted. You can extract energy from water up in a lake by letting fall to a lower level but you cannot extract energy if you cannot let it fall.