Feedstock Sources and Ethylene Yields

Updated Table with Ethylene Yields and Percentage Estimates

Definition of Source of Feedstock Categories

(1) Crude oil well alone: Feedstock derived solely from crude oil extracted from oil wells, processed without involvement of natural gas.
(2) Crude oil well and associated gas: Feedstock sourced from crude oil wells and the natural gas (associated gas) produced alongside the oil from the same well.
(3) Crude oil well and separate gas: Feedstock from crude oil wells combined with natural gas from a distinct gas cap within the same well.
(4) Crude oil well and associated gas and separate gas: Feedstock derived from a crude oil well, including its own associated gas (natural gas produced with the oil) and a separate gas cap (a distinct gas layer) within the same well.
(5) Gas well: Feedstock derived exclusively from natural gas extracted from standalone gas wells, without crude oil involvement.

Source of Feedstock	Feedstock	Process	Intermediate Products	Ethylene Yield	Estimated % of Source Used to Generate Feedstock
(1, 2, 3, 4, 5)	Naphtha	Steam Cracking	Ethylene, propylene, butadiene	25–35%	(1) 20–30%, (2) 5–10%, (3) 5–10%, (4) 5–15%, (5) 1–5%
(2, 3, 4, 5)	Ethane	Steam Cracking	Ethylene, propylene, methane	75–85%	(2) 10–20%, (3) 15–25%, (4) 15–25%, (5) 20–30%
(2, 3, 4, 5)	Propane	Propane Dehydrogenation (PDH)	Propylene, hydrogen	~1–3%	(2) 10–20%, (3) 15–25%, (4) 15–25%, (5) 20–30%
(1) Crude oil well alone	Heavy Oil (VGO)	Fluid Catalytic Cracking (FCC)	Gasoline, diesel, LPG, propylene	1–3% (up to 5–10% with ZSM-5)	(1) 10–20%
(4) Crude oil well and associated gas and separate gas	Methanol	Methanol-to-Olefins (MTO)	Ethylene, propylene	35–50%	(4) 5–15% (of gas/syngas fraction)
(2, 3, 4, 5)	Butane	Steam Cracking	Ethylene, propylene, butadiene	20–30%	(2) 5–15%, (3) 10–20%, (4) 10–20%, (5) 15–25%

Notes on Ethylene Yields

Naphtha (Steam Cracking): Ethylene yield is 25–35%, depending on naphtha type (light naphtha yields more) and cracking conditions (higher severity increases ethylene). It’s a major ethylene source globally.
Ethane (Steam Cracking): Ethylene yield is 75–85%, the highest due to ethane’s C₂ structure, which cracks efficiently into ethylene with minimal co-products.
Propane (PDH): Ethylene yield is ~1–3%, as PDH is designed for propylene (80–90%). Ethylene arises from minor cracking side reactions.
Heavy Oil (VGO) (FCC): Ethylene yield is 1–3% naturally, rising to 5–10% with ZSM-5 catalyst, which enhances light olefins. FCC prioritizes gasoline and diesel.
Methanol (MTO): Ethylene yield is 35–50%, tunable via catalyst (e.g., SAPO-34) and process conditions, balancing with propylene output.
Butane (Steam Cracking): Ethylene yield is 20–30%, lower than ethane or naphtha due to butane’s C₄ chain, yielding more butadiene and other co-products.

Notes on Estimated % of Source Used

These percentages represent the fraction of the source material (crude oil or gas) converted into the feedstock itself, not the ethylene yield. They’re based on typical industry processes (e.g., crude distillation for naphtha, gas separation for ethane).