Cannot load this mod; probably due to ItemPrototype replacement in 2.1.20.
"Replaced ItemPrototype::fuel_category with ItemPrototype::fuel_categories." (from 2.1.20 changelog)

Full error message below (translated):

Failed to load mods: Error while loading item prototype "carbon" (item): ItemPrototype::fuel_category was removed. Please use ItemPrototype::fuel_categories.
Modifications: Bob's Metals, Chemicals and Intermediates mod › Angel's Petrochemical Processing

Mods to be disabled:
- bobplates (3.0.1)
- angelspetrochem (2.1.2)