What are the main environmental emissions from a refinery?

Refinery emissions include: Air emissions - SO2 (from sulfur in fuel and flare), NOx (from combustion), CO2 (greenhouse gas from combustion), VOCs (volatile organic compounds from storage and fugitives), particulates (from FCC regenerator and combustion). Water emissions - oily water, dissolved hydrocarbons, sulfides, ammonia, phenols. Solid waste - spent catalyst, tank bottoms, sludge. Emission controls: sulfur recovery units (Claus process) to minimize SO2, selective catalytic reduction for NOx, vapor recovery from tanks, wastewater treatment plants, and flare gas recovery systems. Refineries must meet increasingly stringent environmental regulations. Environmental management is a major operational focus.