Heat exchanger & Distillation Tower (and other oil-related questions)

I’ve progressed in my playthrough to the point of dealing with oil, and my main stopping point is DT (Distillation tower) and how to get it going. Basically, how does heat exchanger work? Or rather, how to supply it with energy? Secondly, while I was pumping oil I was expecting to see all different kinds of it (very heavy, heavy, etc.), yet the only type of it I was getting is, basically, plain oil. Is it because I was using BC pump, or is there an extra step to separate all those oils from “just” oil?
P.S. I wouldn’t have needed to post this thread if I had video- or written tutorials, too bad Bear makes his tutorials kind of all over the place and Wiki doesn’t provide much mid- to late-game info. If there are other sources of information, I’d be very glad if you’d list them.

  1. Pump in Lava, Hot Coolant or similar and get out Power?
  2. Those Oil Types are raw resources, not inbetween Products. You can find them in the World but they are just different flavors of regular Oil.