Furnace draft/excess-air tuning, steam-trap and insulation programmes — typically 3–6% of fuel. On a 1 Mt HVC site that's tens of thousands of tonnes of CO2 per year.
From our guide: Decarbonizing Petrochemicals — 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:
