It converts just under a red belt of coal into 450 plastic/m. The only circuitry is a pump before the heavy cracking which activates if heavy > 10k. The rest functions non-stop and the ratios are fairly good apart from the overcapacity of heavy:
You need to prime it with one or more barrels of heavy oil, but after that it should work and always keep some heavy oil in buffer. Input is from the left, but it is easy to switch that around.
If you build this near your nuke plant you can remove the steam engine in the top right, but it doesn't really help that much compared to the coal intake of the refineries, and it is nice to keep the unit isolated.
(Adding prod3 modules would make this setup a lot more coal efficient (about 2 coal : 1 plastic instead of the current 4:1), but of course that also changes the design and ratios a lot and I don't have prod3 modules yet in my current base
)production statistics
