Hello, I'm a specialist in the field of chemical engineering with a focus on fuel science. I'm here to provide you with a comprehensive understanding of the amount of water that can be present in gasoline.

Water is a ubiquitous component in the environment, and as such, it can find its way into gasoline through various means. The presence of water in gasoline is a concern because it can lead to a variety of issues, such as corrosion, reduced combustion efficiency, and phase separation, which can damage engines and reduce the performance of fuel.

Gasoline, being a hydrocarbon-based fuel, does not inherently contain water. However, it can absorb water from the atmosphere or from the storage and transportation infrastructure. The amount of water that gasoline can hold depends on several factors, including the temperature, the composition of the gasoline, and the presence of other substances that can affect its solubility.

The solubility of water in gasoline is relatively low due to the nonpolar nature of hydrocarbons. However, gasoline is often blended with various additives and can contain a small amount of ethanol or other alcohols, which can increase its water solubility. Ethanol, for instance, is a polar molecule and can form hydrogen bonds with water, thereby increasing the amount of water that can be dissolved.

The example provided illustrates this concept quite well. At 60 degrees Fahrenheit, a blend of 90% gasoline and 10% ethanol can absorb up to 0.5 volume percent of water before phase separation occurs. This translates to approximately 3.8 teaspoons of water per gallon of fuel. It's important to note that this is a specific example and the actual amount can vary based on the conditions mentioned earlier.

Phase separation occurs when the solubility limit of water in gasoline is exceeded. At this point, water will no longer mix homogeneously with the gasoline and will begin to separate into a distinct phase. This can lead to the formation of a water layer at the bottom of the fuel tank, which can cause serious issues if it is not addressed. Water in the fuel can corrode engine components, reduce the energy content of the fuel, and lead to incomplete combustion.

To prevent these issues, fuel storage facilities and vehicles are equipped with various mechanisms to minimize the presence of water. These can include dry fuel storage conditions, proper sealing to prevent atmospheric moisture from entering, and the use of fuel additives that can help stabilize the mixture and prevent phase separation.

In conclusion, while gasoline does not contain water by design, it can absorb a certain amount of water under specific conditions. The presence of ethanol or other polar additives can increase this solubility, but it is still relatively low compared to other substances. It is crucial for the fuel industry to manage the water content in gasoline to ensure the quality of the fuel and the reliability of engines.

read more >>

As an example, at 60 degrees F, water can be absorbed by a blend of 90% gasoline and 10% ethanol up to a content of 0.5 volume percent before it will phase separate. This means that approximately 3.8 teaspoons of water can be dissolved per gallon of the fuel before the water will begin to phase separate.read more >>