It takes approximately 1.5 gallons of crude oil to make 1 gallon of gasoline. This means for every 42 gallons of crude oil, refineries can produce about 28 gallons of gasoline. The exact amount can vary based on the type of crude oil and the refining process.
Overview of Refining Crude Oil into Gasoline
Gasoline is produced by refining crude oil at oil refineries. Crude oil is a complex mixture of hydrocarbons that must be separated and purified into various fuels and petrochemical products. The key steps in refining crude oil to make gasoline include:
- Distillation – Crude oil is heated and separated into various products based on boiling point.
- Cracking – Large hydrocarbon molecules are broken down into smaller more useful hydrocarbons.
- Reforming – The octane rating of gasoline components is increased.
- Blending – The different gasoline components are combined in the proper proportions.
Various factors impact how much crude oil yields gasoline, including:
- Type of crude oil – Lighter crude yields more gasoline.
- Refinery equipment and complexity – More advanced refineries can optimize gasoline output.
- Product demand – Refineries may optimize for diesel or other products.
Typical Crude Oil Yields
The typical yield from 42 gallons of crude oil is:
- 28 gallons of gasoline
- 11 gallons of diesel
- 4 gallons of jet fuel
- 9 gallons of other products like propane, butane, asphalt
As shown, 42 gallons of crude oil yields about 28 gallons of gasoline after accounting for all the other refined products. This equates to around 1.5 gallons of crude oil required to produce 1 gallon of gasoline.
Gasoline Yield from Different Crude Oils
The gasoline yield can vary substantially based on the type of crude oil. Lighter crude oils, such as WTI from Texas, yield a higher percentage of gasoline. Heavy crude oils, such as Western Canadian Select, yield more diesel and other heavy fuels.
| Crude Oil Type | Typical Gasoline Yield |
|---|---|
| West Texas Intermediate (Light) | 45% |
| Brent Blend (Medium) | 35% |
| Western Canadian Select (Heavy) | 25% |
As shown, lighter crude can produce around 10% more gasoline compared to heavier crude when refined. This needs to be accounted for when estimating how much crude makes a gallon of gas.
Steps in Refining Crude Oil to Gasoline
Here is more detail on the key steps involved in refining crude oil into gasoline:
1. Distillation
Oil refineries use large distillation columns to separate crude oil into various fractions based on boiling points. The boiling range for gasoline is between 90-260°C. As crude is heated in the distillation tower, the gasoline compounds vaporize in this temperature range and are condensed and collected separately.
2. Reforming
The natural gasoline compounds produced from distillation have a low octane rating unsuitable for modern engines. Catalytic reforming converts low octane linear hydrocarbons into higher octane branched and aromatic hydrocarbons by breaking carbon bonds and rearranging the molecular structure.
3. Alkylation
Alkylation combines short chain light hydrocarbons together into larger gasoline boiling range molecules, creating high octane blending components. This helps boost the overall octane rating of the gasoline pool.
4. Cracking
Catalytic cracking breaks large heavy hydrocarbon molecules into smaller lighter more useful products. Fluid catalytic cracking is particularly important for maximizing gasoline yield. It converts heavy gas oils into high-octane gasoline blending components.
5. Blending
The final step is blending together all the various hydrocarbon streams from the refinery processes into finished gasoline. Components are combined in specific proportions to create gasolines with different octane ratings and seasons. Other additives like ethanol may also be added to the gasoline blend.
Factors Impacting Gasoline Yield from Crude Oil
Many complex factors impact how much crude oil gets converted into gasoline during the refining process:
Type of Crude Oil
The composition of crude oil varies substantially depending on geography. Light crude oils contain a higher proportion of gasoline boiling range hydrocarbons. Heavy crude oils contain more heavy hydrocarbons suitable for diesel and fuel oil production. Refineries optimized for light crude generally produce more gasoline.
Refinery Complexity
More complex refineries are able to convert a greater percentage of crude oil into lighter products like gasoline. They have a wider range of conversion processes like catalytic cracking and coking to produce additional gasoline. Simple refineries rely more on distillation so produce less gasoline.
Equipment and Processes
The types of equipment and processes available also impact gasoline output. Advanced reformer and cracker units boost gasoline production. Refineries continuously invest in new technology and equipment to improve gasoline yields.
Demand for Other Products
Gasoline production needs to be balanced against demand for other refined products like diesel, jet fuel, asphalts, lubricants, waxes and petrochemicals. Refineries optimize their operations based on relative profitability of producing different products. This influences crude inputs and operating conditions.
Crude Oil Cost
The input cost of crude oil affects the refinery approach. When crude prices are high, refineries focus more on maximizing liquids production. When crude prices are lower, refineries may optimize operations around petrochemicals production.
Environmental Fuel Specifications
Government environmental regulations require gasoline to meet very strict low sulfur, low emission specifications. Refineries invest in processing upgrades to produce cleaner burning gasolines that meet the latest specifications.
Historical Crude Oil Refining Yields
Refinery utilization and optimization has evolved considerably over the past century. Improvements in technology, equipment, catalysts and processes have enabled refineries to produce a higher percentage of light products like gasoline from each barrel of crude oil.
In the early 1900s, a 42-gallon barrel of crude oil yielded only around 10-15% gasoline. Refinery yields remained low prior to World War II. During the war, demand increased rapidly for high-octane aviation fuel. This accelerated refinery innovations and catalyzed improvements in gasoline production.
U.S. Refinery Yield Trends
| Year | Gasoline Yield (gal per 42 gal crude) |
|---|---|
| 1910 | 4 |
| 1920 | 8 |
| 1930 | 12 |
| 1940 | 15 |
| 1950 | 19 |
| 1960 | 20 |
| 1970 | 23 |
| 1980 | 19 |
| 1990 | 21 |
| 2000 | 24 |
| 2010 | 23 |
This table shows how processing advances over the past century have enabled refineries to steadily increase gasoline production from each 42-gallon barrel of crude oil. Yields peaked at 24 gallons per barrel in the 2000s.
Impact of Blending on Gasoline Production
In addition to refining gasoline from crude oil, modern gasoline also contains blending components from alternative sources:
- Ethanol – Ethanol is blended into gasoline at percentages of up to 10%. It is produced from corn and other plant materials by fermentation.
- Renewable Diesel – Renewable diesel is co-processed at refineries and can be blended into diesel fuel at up to 5%.
- Biofuels – Other advanced biofuels are being developed that can also supplement traditional gasoline and diesel production.
These renewable fuel blending components mean that less crude oil needs to be refined into finished gasoline and diesel. Adding 10% ethanol to gasoline effectively boosts the volume of gasoline by 10% relative to the crude oil input. Renewable fuels help reduce the dependency on petroleum.
Projected U.S. Fuel Production by Source
| Year | Petroleum (%) | Renewables (%) |
|---|---|---|
| 2015 | 95 | 5 |
| 2020 | 90 | 10 |
| 2030 (projected) | 80 | 20 |
As shown, the percentage of renewable fuels blended into gasoline and diesel is expected to increase to up to 20% by 2030. This will stretch petroleum supplies further as renewable fuel production scales up.
Conclusion
On average, it takes around 1.5 gallons of crude oil to produce 1 gallon of gasoline in oil refineries. For a typical 42-gallon barrel of crude oil, this translates to around 28 gallons of gasoline produced. The exact yield can vary from 25-45% depending on the type of crude oil and refinery capabilities. Advances in refining, blending renewables, and increased use of biofuels can help extend petroleum supplies further.