Oil refinery
CategoryProduction
Overview
The oil refinery is a mid-to-late game chemical building used to process crude oil (and some alternate inputs) into the basic petroleum products required for advanced chemical production. It must be set to a specific recipe to operate; the selected recipe determines the inputs consumed, outputs produced, and the required research unlock. A visible flame appears from the refinery's chimney while it is actively working.
Available recipes and their basics:
Basic oil processing: consumes crude oil and outputs petroleum gas. Unlocks with 
Oil processing research.
Advanced oil processing: consumes crude oil and water and outputs heavy oil, light oil, and petroleum gas. Unlocks with Advanced oil processing research.
Coal liquefaction: consumes coal (and produces steam as an associated requirement in some descriptions) to produce heavy oil, light oil, and petroleum gas. Unlocks with Coal liquefaction research.
Simple coal liquefaction: consumes coal plus 
Calcite and 
Sulfuric acid and produces heavy oil. Unlocks with 
Calcite processing research.
Practical notes and behavior:
- The refinery will not operate until you assign one of the available recipes; selecting a recipe is required before processing begins.
- A refinery will halt production if any of its fluid output boxes (pipes) become full. For example, a filled heavy oil output (100.0 units shown) will prevent production of the other fluids on that recipe until space is freed. Ensure adequate piping, storage tanks, or processing (cracking) for all outputs.
- Arrange downstream processing (oil cracking, storage tanks, chemical plants) and fluid routing before enabling high-throughput operation to avoid blockages that stop the refinery.
- The chimney flame provides a quick visual indicator of activity; a missing flame indicates the refinery is idle due to no recipe set, lack of inputs, or blocked outputs.
Place refineries with access to multiple pipe connections and plan space for associated pumps, tanks, and steam/consumption lines required by alternate recipes.