Natural gasoline is a liquid mixture of hydrocarbons, mainly pentanes and heavier molecules, extracted from raw natural gas during processing. Despite the name, it is not the same fuel you pump into your car. It’s a lighter, more volatile liquid that serves as a raw material for fuel blending, petrochemical production, and transporting heavy crude oil.
How Natural Gasoline Differs From Regular Gasoline
The gasoline at a filling station is a carefully engineered product, blended from dozens of hydrocarbon components and additives to meet strict performance and emissions standards. Natural gasoline is much simpler. It consists primarily of pentane (a five-carbon hydrocarbon) along with some butane (four carbons) and hexane (six carbons). It comes straight from gas processing plants with minimal refining.
Because of this simpler composition, natural gasoline has a very high vapor pressure, meaning it evaporates easily. It also has a broad boiling range of roughly 58°F to 275°F. Regular gasoline is blended to have a controlled vapor pressure suited to both summer and winter driving conditions. Natural gasoline on its own would be too volatile for most engines in warm weather and doesn’t contain the heavier components needed for proper combustion across a range of driving conditions.
Where Natural Gasoline Comes From
When natural gas is pulled from underground, it isn’t pure methane. The raw gas contains a mix of heavier hydrocarbons collectively known as natural gas liquids, or NGLs. These include ethane, propane, butane, and pentanes-plus (the industry term for natural gasoline). Processing plants separate these heavier components from the methane using techniques like cryogenic cooling, absorption, or membrane filtration.
Once the mixed NGLs are removed from the gas stream, they go through fractionation, a process that sorts them by weight. The mixed liquid is heated and passed through a series of distillation towers. Lighter components like ethane boil off first and are collected at the top of the first tower. The heavier remaining liquid moves to the next tower, where propane separates out, and so on. Natural gasoline, being the heaviest NGL fraction, is typically what remains at the bottom of the final tower.
Major Uses of Natural Gasoline
Fuel Blending
Refineries blend natural gasoline into finished motor gasoline to boost volume and adjust certain fuel properties. However, its high vapor pressure limits how much can be added, especially in summer when evaporative emissions regulations are strictest. Research from the National Renewable Energy Laboratory found that natural gasoline can also be blended with ethanol to make flex-fuel (E85-type blends). In those applications, the ethanol content needs to be at least 74% by volume during summer to keep vapor pressure below regulatory limits. In winter, the threshold drops, allowing more natural gasoline in the mix. Sulfur content also matters: to meet current EPA standards, the natural gasoline blendstock needs to contain 20 parts per million of sulfur or less.
Diluent for Heavy Crude Oil
Extra-heavy crude oil and bitumen, the kind produced from oil sands in Canada and heavy oil belts in Venezuela, are too thick to flow through pipelines on their own. Producers thin them by adding a lighter liquid, called a diluent, and natural gasoline is one of the most common choices. In Venezuela’s Orinoco heavy oil belt, roughly one barrel of diluent is needed for every three to four barrels of extra-heavy oil produced. That ratio gives a sense of just how much natural gasoline and similar light liquids the heavy oil industry consumes.
Petrochemical Feedstock
Natural gasoline can be fed into steam crackers, the industrial furnaces that break hydrocarbons apart at high temperatures to produce ethylene, propylene, and other building-block chemicals. These chemicals go on to become plastics, synthetic rubber, antifreeze, and thousands of other products. Because natural gasoline is rich in pentane and hexane, it yields a different product slate than lighter feedstocks like ethane, producing more of the heavier petrochemical byproducts that have their own market value.
Handling and Safety Risks
Natural gasoline is significantly more dangerous to handle than regular gasoline. Its flash point is below 0°F, meaning it can ignite under virtually any normal temperature condition. The National Fire Protection Association gives it a flammability rating of 3 out of 4. It is a clear, colorless to amber liquid with a petroleum-like odor, and its vapors are heavier than air, so they can travel along the ground and collect in low-lying areas like basements or drainage ditches before reaching an ignition source and flashing back to the original spill.
It floats on water and doesn’t dissolve, making spills on waterways particularly tricky. Water spray is often ineffective for fighting natural gasoline fires. Storage and transport require eliminating all ignition sources, grounding all equipment, and keeping the liquid out of sewers, confined spaces, and waterways. Vapor-suppressing foam is the standard response for reducing evaporation from a spill.
Natural Gasoline vs. Other NGLs
Natural gasoline sits at the heavy end of the NGL spectrum. Here’s how the main NGL products compare:
- Ethane (2 carbons): Almost entirely used as petrochemical feedstock to make ethylene. A gas at room temperature.
- Propane (3 carbons): Sold as heating fuel and barbecue gas, also used in petrochemical production. Stored under pressure as a liquid.
- Butane (4 carbons): Used in lighter fluid, as a gasoline blending component, and as petrochemical feedstock. Liquid under modest pressure.
- Natural gasoline / pentanes-plus (5+ carbons): Liquid at normal conditions without pressurization. Used for fuel blending, as a diluent, and as petrochemical feedstock.
The key practical distinction is that natural gasoline remains liquid at atmospheric pressure and normal temperatures, which makes it easier and cheaper to store and transport than propane or butane, both of which require pressurized containers. That liquid-at-room-temperature quality is exactly what makes it so useful as a diluent for heavy oil: it can be piped and blended without special pressurization equipment.