Petroleum refining processes and operations can be separated into five basic areas:
- Fractionation (distillation) is the separation of crude oil in atmospheric and vacuum distillation towers into groups of hydrocarbon compounds of differing boiling-point ranges called “fractions” or “cuts.”
- Conversion Processes change the size and/or structure of hydrocarbon molecules. These processes include:
- Decomposition (dividing) by thermal and catalytic cracking;
- Unification (combining) through alkylation and polymerization; and
- Alteration (rearranging) with isomerization and catalytic reforming.
- Treatment Processes to prepare hydrocarbon streams for additional processing and to prepare finished products. Treatment may include removal or separation of aromatics and naphthenes, impurities and undesirable contaminants. Treatment may involve chemical or physical separation e.g. dissolving, absorption, or precipitation using a variety and combination of processes including desalting, drying, hydrodesulfurizing, solvent refining, sweetening, solvent extraction, and solvent dewaxing.
- Formulating and Blending is the process of mixing and combining hydrocarbon fractions, additives, and other components to produce finished products with specific performance properties.
- Other Refining Operations include:
- light-ends recovery;
- sour-water stripping;
- solid waste, process-water and wastewater treatment;
- cooling, storage and handling and product movement;
- hydrogen production;
- acid and tail-gas treatment;
- and sulfur recovery.
- Auxiliary Operations and Facilities include:
- light steam and power generation;
- process and fire water systems;
- flares and relief systems;
- furnaces and heaters;
- pumps and valves;
- supply of steam, air, nitrogen, and other plant gases;
- alarms and sensors;
- noise and pollution controls;
- sampling, testing, and inspecting and laboratory;
- control room;
- maintenance; and
- administrative facilities.