Typically 0.2–0.3 t per tonne of crude processed — a mid-size 10 Mt/yr site emits 2–3 Mt CO2/yr, mostly from fired heaters and hydrogen production.
From our guide: Decarbonizing Oil refining — full context, charts and sources there.
Boilers, kilns, heat exchangers, valves and steam lines lose energy continuously. Inzonex makes patented (UK GB2508992.1) removable modular insulation — snap-fastened covers engineered per temperature tier, not generic off-the-shelf jackets: