Now, I'm not sure whether it is your mod or Angel's PetroChem that's causing this issue, but I'm making both parties aware regardless: BioTech appears to be the only 'major' mod that still has issues converting from the sulfur / advanced oil processing technologies to the PetroChem ones, which was supposedly fixed in PetroChem version 0.1.5. Upon Load-up I merely receive this message during the loading of prototypes phase:

Error Util.cpp:57: Error in assignID, technology with name 'advanced-oil-processing' does not exist.

Now yes, I am clearly aware that PetroChem is a beta mod, but again, as this issue was supposedly patched already I wanted to bring this to your attention as there may be a simple tweak on your end you can do so both these mods...play nice together. As it stands I had to take this mod out of my pack, and I love this mod. X_X

EDIT: PetroChem got back to me, he believes he has a fix, I'll test it when it goes live and get back to ya.

At this moment I'm still having issues for getting up and running with Angel's stuff. It's gonna take a little longer to figure that out.

No worries. Again, there's apparently another fix coming out in petrochem 0.1.6 that should solve the problem, it seems to be something on angels end and not yours. I wouldn't sweat it. ^^

FIXED. Apparently it was something on angels petrochem's end, as 0.1.6 came out not long ago, tested it with biotech and no problems occurred. Now we can all sleep easier. ^^