Differences between diesel, heating oil, bunker fuel and similarities (2023)

The differences between diesel, heating oil, and bunker fuel are hydrocarbons. In particular, the difference lies in the size and length of the hydrocarbons in each fuel. Hydrocarbons make up the vast majority of the components of fossil fuels, and also of biofuels. Everything else in fossil fuels and biofuels is a pollutant. As their name suggests, hydrocarbons are made up of molecules with only two types of atoms: hydrogen and carbon.

Hydrocarbons are the reason that fossil fuels and biofuels are valuable. Hydrocarbons are the reason why diesel, gasoline, heating oil, natural gas, biodiesel, etc. they ignite/burn/burn. And because there are different categories of hydrocarbons, and classes within those categories, there are different fuels.

Diesel and heating oil, including bunker oil, are heavy fossil fuels. Gasoline is a medium-heavy fossil fuel. Light fossil fuels are fuels in a gaseous state, such as methane (natural gas) and propane.

Hydrocarbon Categories: Understanding

The two categories of hydrocarbons are saturated and unsaturated. Saturated hydrocarbons are complete. They cannot accommodate additional hydrogen or carbon atoms. Unsaturated hydrocarbons are incomplete. They have space for the addition of hydrogen and carbon atoms. Because saturated hydrocarbons are complete, they are stable. Unsaturated hydrocarbons are incomplete and therefore unsaturated hydrocarbons are unstable and volatile.

Light fossil fuels -fuels in the gaseous state- have a high content of unsaturated hydrocarbons. Heavy, stable fossil fuels, such as diesel, ship oil, and heating oil, have far fewer unsaturated hydrocarbons. Gasoline is a middleweight fuel that falls somewhere in between.

Hydrocarbons in heavy fossil fuels

Gas oil and gas oil have essentially the same hydrocarbon composition. Both consist mainly of saturated hydrocarbons. “Diesel derived from petroleum constitutes about 75%saturated hydrocarbons(first of allParaffinIncludingnorte,They are like that, zcycloparaffin) y 25%aromatic hydrocarbons(Includingnaphthalenemialkylbenzol).[53] The average chemical formula for common diesel fuel is C12H24, which ranges from about C10H20 to C15H28."

Hydrocarbon classes within the saturated and unsaturated categories

Saturated vs. Unsaturated hydrocarbons is a difference between light and heavy fossil fuels. But there are also differences between fossil fuels because of the difference between hydrocarbons in these two categories. There are four classes of hydrocarbons: paraffins, naphthenes, aromatics, and olefins.

Paraffins and naphthenes are the two classes of saturated hydrocarbons. Aromatics and olefins are the two classes of unsaturated hydrocarbons.

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Paraffin A.K.A., Alkane

Paraffins are also known as alkanes. Alkanes are single chain hydrocarbons. The backbone of an alkane consists of carbon atoms. Alkanes are one of two classes of saturated hydrocarbons. The other class of saturated hydrocarbons are the cycloalkanes, also known as "naphthenes."

The difference between paraffins and naphthenes is that naphthenes have branches. And sometimes the naphthenes form a loop. Naphthene carbons typically have more than just two carbon atom bonds along the backbone of the molecule. The carbon atoms in a naphthene can have two, three, four, or five bonds with other carbon atoms. And the carbon atom at one end of the molecular chain skeleton connects to the carbon atom at the other end. A notable characteristic of naphthenes is that they are the most energy-dense hydrocarbon class of all hydrocarbon categories.

unsaturated hydrocarbons

The two classes of unsaturated hydrocarbons are aromatics and olefins. Flavorings occur naturally in crude oil. Olefins are a byproduct of crude oil refining and do not occur naturally in crude oil. Aromatics and olefins are unstable and volatile and produce the most toxic emissions. In addition, aromatics and olefins also cause greenhouse gas emissions with the highest global warming potential.

Another difference between light and heavy fossil fuels is the size of the hydrocarbons they contain. The molecules and molecular chains of light fossil fuels are short and small. Those that run on heavy fossil fuels are long and tall.

Hydrocarbon molecules and molecular chain sizes

As expected, light fossil fuels are made up of smaller molecules and chains of molecules than heavy fossil fuels. And again, unsaturated hydrocarbons make up a larger portion of the hydrocarbons in light fuels. Heavy fossil fuels have a higher proportion of large and long saturated hydrocarbon molecular chains.

The longer the chains of hydrocarbon molecules in a fuel, the higher the density of the fuel. However, the longer the chains of hydrocarbon molecules in a fossil fuel, the more difficult it is to achieve combustion efficiency. So while there is more energy in heavy, dense fossil fuels, more energy is wasted. The problem with diesel, heating oil and bunker oil is that a high percentage of their hydrocarbons do not burn.

Achieving the same combustion efficiency typical of light fuels when burning heavy fuels requires more heat and more advanced technologies. The combustion efficiency of diesel, heating oil and fuel oil is one of the biggest differences. And the efficiency of combustion is a property of hydrocarbons.

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The biggest difference between diesel and heating oil is the size of the hydrocarbons, not the classes of hydrocarbons.

Diesel: types of hydrocarbons, sulfur content and cetane number

Unlike gasoline and diesel hydrocarbons, diesel hydrocarbons and heating oil are very similar. In fact, in many cases they are almost the same. The hydrocarbons that make up diesel fuels "are more or less similar to the heating oils used for heating (#1, #2, and #4 heating oils)," the company said.US Department of Health and Human Services. Diesel and heating oil are made up of mixtures of aliphatic and aromatic hydrocarbons. “Aliphatic alkanes (paraffins) and cycloalkanes (naphthenes) are saturated with hydrogen and make up about 80-90% of heating oils. Aromatics (eg, benzene) and olefins (eg, styrene and indene) account for 10-20% and 1% of heating oils, respectively.”

The hydrocarbon composition of diesel and heating oils is very similar. However, there are different types of diesel. The differences in diesel qualities depend on two things. The amount of impurities, especially sulfur, is a difference between fuel grades. The second is the cetane number of the different grades.

regular diesel vs. low sulfur

Sulfur is the diesel pollutant of greatest concern to those concerned with the environmental and health impacts of diesel emissions. In its natural state, sulfur is neither toxic nor a significant pollutant. But when sulfur is oxidized to form sulfur oxides, the molecules become dangerous both for the environment and for the health of humans, flora and fauna.

Sulfur oxides are one of two diesel fuel emissions responsible for creating acid rain. USAEnvironmental protection agencyexplains: “Acid rain is formed when sulfur dioxide (SO2) and nitrogen oxides (NOX) are released into the atmosphere and carried by wind and air currents. SO2 and NOX react with water, oxygen, and other chemicals to form sulfuric and nitric acids. These are then mixed with water and other materials before falling to the ground. While a small portion of the SO2 and NOX that cause acid rain comes from natural sources like volcanoes, most of it comes from burning fossil fuels."

Due to acid rain, emissions regulators around the world collectively mandate the use of low sulfur diesel in most commercial and passenger vehicles.

In terms of sulfur content, there is a significant difference between normal sulfur and low sulfur. EITHERExplanation from the US Department of Energy., “ULSD is a clean burning diesel fuel that contains 97% less sulfur than low sulfur diesel (LSD). The ULSD was developed to allow the use of improved emission control devices that reduce diesel emissions more effectively, but can be damaged by sulfur."

Low or high cetane diesel

The cetane number of diesel is similar to the octane number of gasoline, but in reverse. Octane additives increase the resistance to compression combustion of gasoline. cetane additivesto reducethe resistance to combustion by compression of a fuel. Both cetane and octane are measures of how much pressure a fuel can withstand before it will self-ignite. Regular gasoline (gasoline without octane additives) is usually low pressure and requires higher resistance.

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Direct diesel, on the other hand, is usually very resistant. This means that a diesel direct diesel engine will not start in cold weather and low temperatures. Increasing the octane number and weakening the pressure resistance of diesel makes engines run cooler more easily.

The cetane number of diesel is simply a measure of the API gravity or weight of the diesel. “A low-density fuel contains fewer BTUs and therefore delivers less power for a diesel engine. A typical gravity for #2 diesel fuel is in the 32 to 34 range compared to a high cetane number fuel, which typically has a gravity rating in the 36 to 38 range and is more like a No. 1 diesel fuel,” he explains.GrowMark Incorporated.

Although the hydrocarbons in diesel and many types of heating oil are minimal, there is a big difference between those found in diesel and other types of heating oil, especially fuel oil.

Fuel oils: types and qualities, including fuels for ships

During the distillation of crude oil, the light, medium and heavy hydrocarbons are separated, that is, they are “fractionated”. As the temperature of the oil in a crude oil distillation tower increases, the hydrocarbons vaporize. Light hydrocarbons vaporize at lower temperatures than heavy hydrocarbons. After vaporization, the hydrocarbons are placed in storage tanks.

Vaporized distillates are separated into gas, naphtha, kerosene, light diesel, and heavy diesel (distillate fuel oil).

But there are also hydrocarbons in diesel that are so heavy that they don't evaporate. Instead, they turn on automatically when the temperature gets too high. Hydrocarbons that do not distill are residues. Waste heating oil is produced from waste. Since there are distillate fuel oils and residual fuel oils, it is clear that not all fuel oils are created equal.

Fuel oil classes

The two types of heating oil fall into several classes. In the United States and North America there are a total of six classes: heating oils number 1 to number 6. The United Kingdom divides heating oils into eight classes, four distillate classes and four residue classes.

There are two characteristics that distinguish the different classes of heating oil. The first is the minimum flash point. The second difference between fuel oils is the minimum and maximum kinematic viscosity.

Flash point of different classes of fuel oils

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Flash point is the temperature at which an organic compound, in this case fuel oil, gives off enough vapor to ignite in air. For example, heating oil number 1 has a flash point of approximately 109 degrees Fahrenheit. Heating oil number 6 has a flash point of around 150 degrees Fahrenheit.

The flash point plays a role in the combustion properties of a fuel. The flash point is an indicator of the compressive strength of a fossil fuel. When a gas is compressed, heat is generated. When exposed to enough heat, fossil fuels ignite automatically. The higher the flash point of a fuel, the more pressure it can withstand before self-igniting.

Another difference between fuel oils is their kinematic viscosity.

Kinematic viscosity of fuel oil classes

Kinematic viscosity is a measure of the fluidity of a fuel. Amanda Ranowski of CSC Scientific Company explains: "Kinematic viscosity is a measure of a fluid's inherent resistance to flow when subjected to no external force other than gravity." Kinematic viscosity is a symptom of fuel density. And fuel density is a measure of how much energy is in a fuel on a volume scale.

But while high fuel density is generally considered a positive attribute, high kinematic viscosity is often a negative trait. Since fuels with high kinematic viscosity do not flow quickly, their use in internal combustion engines is difficult. Ideal fuels for internal combustion engines have a high density and low kinematic viscosity.

Bunker fuel has the highest kinematic viscosity of any fuel oil and the highest flash point.

Key Difference Between Diesel Fuel, Heating Oil, and Bunker Fuel

In terms of chemical composition, diesel, heating oil and bunker fuel differ in the size of the hydrocarbon. Of the three, diesel contains the smallest and shortest hydrocarbon chains. Bunker fuel has the largest and longest chains of hydrocarbon molecules. Heating oil from #1 to #5 is in the middle.

The other differences between diesel, heating oil and fuel oil are their flash points and their kinematic viscosities. The flash point and kinematic viscosity of diesel are the lowest of the three heavy fuels. Bunker fuel has the highest flash point and kinematic viscosity of all heavy fossil fuels.


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