To the OP: I haven't checked but, is there a reason to not make SF from Petroleum? Less efficient i presume?

Good question. The ratio of Heavy and Petrol to SF is 2 to 1, however Light oil to SF is 1 to 1, which meanS light is the more efficient method preserving crude.

As a side note if you ...

Dumb question, how do you only use 1/4 of a chemical plant? Do you make 4 pipes and only assign one to the chem plant in question?

What I mean by this is that one chemical plant can process 48 Heavy oil per min, and 12 is a quarter of what it can handle. Therefore, you can have up to 4 refineries ...

So I have done the math on oil for optimal production of Solid Fuel (SF) and Petroleum Gas (PG). In order to get my own head around the numbers, I converted all the processing times to resources/min. These numbers assume you can provide your refineries with as much crude as they can handle ...