How is ethylene produced and why is it the most important petrochemical?

Ethylene is produced primarily by steam cracking of hydrocarbons (ethane, naphtha, or gas oil) at 750-900C with steam dilution and very short residence time (milliseconds). Products: ethylene (main), propylene, butadiene, aromatics, and fuel gas. Naphtha cracking produces more byproducts; ethane cracking is more selective to ethylene. Ethylene is the most important petrochemical because it is the building block for: polyethylene (largest volume plastic), ethylene oxide/glycol (antifreeze, PET), styrene, vinyl chloride (PVC), and many other chemicals. Global ethylene capacity exceeds 200 million tons/year. Ethylene plant (cracker) is typically the centerpiece of a petrochemical complex.