Other major countries are also in the refining business, but all is consumed within those countries itself. European countries have highest prices for petrol compared to the rest of the world as they are majorly importers of gasoline. In India petrol prices were initially subsidized, but now its prices are fixed in the open market with government control. It is in more unrefined form than sugar. It is a brown raw mass of sucrose which gets it color because of other elements found in concentration such as wood ash and bagasse.
Jaggery is commonly made from two products, that are sugar cane and date palm tree. The process of making gur is easier and more convenient than sugar, and has healthier than. Description: M. It is a kind of thermoplastic which is famous for its tensile strength. Its unique properties can stand high temperatures. Description: HDPE is a boon to developing countries like India where it is used to prevent groundwater pollution.
It can be easily molded and welded together. Due to its high chemical r. It's similar to diesel, but there is variation in chemical composition, though properties are the same.
Heating oil is the second most important by-product of crude oil after petrol, which is also heavily used worldwide.
Description: Majorly all over the world it's used as fuel for fu. It has silver white color with a shining base and golden tint in it. Nickel is said to be useful for its properties of being ductile and corrosion resistant. Nickel is extracted from two ores - magmatic sulfides and laterites.
By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers. Each of the layers is called a phase. Oil and water do not mix, instead forming two distinct layers called phases. The oil phase is less dense than the water phase and so the oil floats on top of the water.
In the vegetable soup example, one phase would be the liquid soup itself. This phase has vitamins, minerals, and other components dissolved in the water. This phase would be homogeneous. The carrots, peas, corn, or other vegetables represent other phases of the soup. The various vegetables are not mixed evenly mixed in the soup, but are spread around at random.
There are a large number of heterogeneous mixtures around us. Soil is composed of a variety of substances and is often of different composition depending on the sample taken. One shovel may come up with dirt and grass while the next shovel could contain an earthworm. Smog is another example of a heterogeneous mixture.
This murky collection of pollutants can be a mixture of water and contaminants from burning gasoline or plastics mixed with nitric oxide derivatives and ozone.
You can see that the smog distribution in the air illustrate below is not evenly spread out, but varies from one part of the atmosphere to another. Skip to main content. The importance of using alternative fuels in internal combustion engines emerges because of limited oil resources and decreasing reserves, increasing oil prices, and increasing environmental problems.
In order to reduce dependence on oil, alternative engine fuels such as vegetable oils, biofuels alcohols, biodiesel, biogas , and liquefied hydrogen gas have been of particular interest to researchers [ 1 , 2 ]. Fuel compounds containing carbon and hydrogen atoms in their basic molecular structure are called hydrocarbon-based fuels.
Hydrocarbons can be divided into two main groups, aliphatic and aromatic. Aliphatic hydrocarbons are divided into two subclasses as saturated and unsaturated hydrocarbons. The carbon atom in hydrocarbon is called saturated if it has bonded with four hydrogen atoms and unsaturated if the carbon atoms have made double or triple carbon-carbon bonds. Saturated hydrocarbons are classified as alkanes; unsaturated hydrocarbons are classified as alkenes or alkynes [ 3 , 4 ]. Hydrocarbons can be in the solid, liquid, and gas phases according to the number of carbons in the chemical structure.
Generally, hydrocarbons with carbon atoms 1—4 are in gas, 5—19 are liquid, and molecules with 20 and more carbon atoms are in the solid phase [ 5 ]. C n H m is the general closed chemical formula of liquid hydrocarbons used as a fuel in the internal combustion engines. However, hydrocarbons consist of hydrogen and carbon and also small amounts of O 2 , H 2 , S, H 2 O, and some metals containing crude oil derivatives [ 2 ].
Figure 1 gives the classification of the compounds of hydrocarbons. Classification of hydrocarbons [ 3 ]. As the number of carbon atoms in the hydrocarbon chain increases, the properties of the alkanes such as autoignition tendencies, molecular weights, and melting and boiling points increase.
Alkanes are insoluble in water because they are apolar. Among the apolar molecules such as hydrocarbons and inert gases are Van der Waals forces, in other words, London dispersion forces. Dispersion force is as a weak intermolecular force between all molecules by means of temporary dipoles induced in the atoms or molecules. The dispersion forces are commonly expressed as London forces. Electron numbers and surface area of the molecules are the most important affecting factors of the magnitude of dispersion forces.
These tensile forces directly affect the boiling point of these materials. The alkanes may exist in a straight chain, branched chain, and cyclic form depending on the arrangement of the carbon atoms. Van der Waals forces are more effective than branched ones because the molecular surfaces of the straight-chain alkanes are more in contact with each other. Thus, the boiling point of the straight-chain alkanes having the same molecular weight is higher than the branched ones.
In other words, as the branching increases, the boiling point decreases, because the branched structure makes the molecule tighter. However, the increasing of branching has led to the surface area of the molecule to become narrow, and the boiling point decreases with the reduction of Van der Waals forces between itself and neighboring molecules. The ignition tendencies of straight-chain alkanes are generally higher than the branched chain ones due to it being more easily broken down.
Unlike straight-chain molecule structures, branched chain and ring structures have higher ignition resistance. Therefore, straight-chain alkanes are more suitable for use as diesel fuel rather than as gasoline fuel. However, alkane isomers which are of the same closed formula but with different branched chains and rings are more suitable for use as a gasoline engine fuel since they have higher engine knocking resistance.
The property that defines whether the fuel ignites spontaneously is called the octane number. In other words, it is defined as ignition resistance. Straight long chain fuels generally have a lower octane number, whereas branched structures have a higher octane number.
To summarize this briefly, the octane number is usually inversely proportional to the chain length of the molecules of the fuels. The shorter the chain structure of the fuel molecules, the higher the octane number. The octane number is directly proportional to the branched side chain components.
Besides, having a ring molecular structure of fuels leads to high octane numbers. Alkanes are present in solid, liquid, and gaseous form according to their carbon number. The carbon number 1—4 is present in gas, 5—25 in liquid form, and more than 25 in solid form.
Alkanes contain less than 4 carbon atoms in their natural gas and petroleum gases, 5—12 atoms in gasoline, 12—20 atoms in diesel fuels, and 20—38 atoms in lubricating oils [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Figure 2 shows the molecular structure of the first four alkanes. The molecular structure of the first four alkanes [ 8 ].
Another type of alkanes is cyclic structures which demonstrate as the general formula C n H 2n. Two hydrogen atoms are missing from normal alkanes because their structures are cyclic-shaped and in closed form. Cycloalkanes are difficult to break up because of their closed cycle structure and have higher ignition resistance than straight-chain alkanes. However, they are also suitable for use as both petrol and diesel fuel due to that they have lower ignition resistance than branched ones.
Thermal values of naphthenes are lower than alkanes and higher than aromatics [ 2 ]. Figure 3 shows the cyclic molecular structure of cyclohexane. The cyclic molecular structure of cyclohexane [ 5 ]. Alkenes are unsaturated hydrocarbons that have double bond between carbon atoms shown as the general formula C n H 2n.
Many isomers are formed by displacement of the double bonds of alkenes. Alkenes have high ignition resistance. Alkenes are less resistant to oxidation than alkanes so that they can easily react with oxygen. Thus, oxygen causes to be gummed to alkenes and consequently block the fuel pipeline.
For this reason, it breaks down more difficult than alkanes with a single sigma bond. Alkenes can be used as fuel for gasoline engines due to high ignition resistance. Besides, it can be used as a diesel fuel by increasing autoignition temperature. Carbon atoms of alkenes are not fully saturated with hydrogen. Therefore, alkenes can be more easily associated with elements such as hydrogen, chlorine, and bromine due to it being more chemically reactive than alkanes and naphthenes.
With this reactive structure, they are used as raw materials to obtain better quality fuels by methods such as hydrogenation, polymerization, and alkylation. While alkenes are present in very small amounts in crude oil, generally they can be obtained by thermal and catalytic cracking methods which are heat or catalyst by means of large molecular product decomposition.
Alkenes are present in large quantities in the gasoline obtained by these methods. The high ignition resistance of the alkenes makes them a good gasoline engine fuel, but they can also be diesel engine fuel by increasing the ignition tendencies [ 1 , 2 , 3 , 5 , 9 ].
Figure 4 shows the molecular structure of some alkenes. The molecular structure of some alkenes [ 5 ]. Alkynes are unsaturated hydrocarbons due to all carbon atoms not having enough bonds with hydrogen. The simplest and most known compound is acetylene C 2 H 2. Alkynes may also be referred to as acetylene derivatives. Alkenes are more reactive than alkanes and naphthenes because they are unsaturated. Thus, they can be more easily reacted with elements such as hydrogen, chlorine, and bromine to form a compound [ 3 , 5 , 9 ].
Figure 5 gives the molecular structure of some alkenes. The molecular structure of some alkynes [ 5 ]. At the end of the nineteenth century, organic compounds were divided into two classes as aliphatic and aromatics. Aromatic compounds are bonded to each other by aromatic bonds, not single bonds. In other words, aromatics are also called arenes. Just as there are different types of fossil fuels and biofuels, there are different types of hydrocarbons.
The qualities of each category, class, and specific hydrocarbon determine fossil fuel types. Gasoline, diesel, propane, methane, jet fuel, bunker fuel, fuel oil, ethanol, and biodiesel each have a different combination of hydrocarbons. But though there are different categories, classes, and specific hydrocarbons, every hydrocarbon consists of only two types of atoms.
As the name implies, hydrocarbons are made from bonds between hydrogen and carbon atoms. The bonds between carbon and hydrogen determine hydrocarbon category, class, and type. So too does the number of carbon and hydrogen atoms bonds in a molecule or molecule chain. Just as different combinations of hydrocarbons determine fuel type, different carbon and hydrogen bond combinations determine hydrocarbon types.
The category, class, and combination of hydrocarbons determine fossil fuel type. Fossil fuel type is a measure of two qualifiers: fuel weight and fuel density. Fuel weight and fuel density are different measurements of fuel qualities and both fuel weight and fuel density are consequences of one variable with two variables. First, weight and fuel density are consequences of hydrocarbon molecule size.
By extension, the structure of hydrocarbon molecule chains plays a role in weight and density. The size, length, and pattern of the hydrocarbons determine the weight and fuel density of a fossil fuel. Second, fuel weight and energy density are consequences of the carbon-to-hydrogen ratios of the hydrocarbons molecules in a fossil fuel. The greater the number of carbon atoms in relation to hydrogen atoms, the greater the weight and density of a hydrocarbon. The larger and longer the hydrocarbon molecules in a fossil fuel, the heavier the fossil fuel.
The smaller and shorter, the lighter the fossil fuel. As one would expect, gas-state fossil fuels like methane and propane have small, short molecules and molecule chains. Heavy fossil fuels like diesel and bunker fuel contain large, long-chain hydrocarbon molecules.
Gasoline is a medium weight of fossil fuel. Additionally, the number of hydrogen atoms attached to the carbon molecules in the backbone of a hydrocarbon also plays a role in weight and energy density. Carbon molecules are heavier than hydrogen molecules — every element on the periodic table is heavier than hydrogen. So, the higher the number of carbon atoms in relation to hydrogen atoms in a hydrocarbon, the heavier the hydrocarbon.
So, the heaviest, most energy-rich hydrocarbons are those that have size and density. The largest and longest and hydrocarbon molecule chains have the greatest weight and density. And, those that have the highest carbon-to-hydrogen ratios have the greatest weight and density. Gasoline has greater weight and density that gas-state fossil fuels like natural gas — methane — and propane. Fossil fuels like diesel and kerosene have greater weight and density than gasoline.
With respect to molecule chain size and length and carbon-to-hydrogen ratio, gasoline is somewhere near the middle of the spectrum of fossil fuels. There are hundreds of hydrocarbons in gasoline. But, each type of hydrocarbon falls into one of two categories: saturated or unsaturated.
Saturated hydrocarbons are the most stable. Saturated hydrocarbons are those with carbon backbones with no space to take on more hydrogen or carbon atoms. There are three types of saturated hydrocarbons. They can be linear, branched, or loops. Branched saturated hydrocarbons that are looped have the name cycloalkanes. Like saturated hydrocarbons, unsaturated hydrocarbons can be linear, branched, or loop.
But, unsaturated hydrocarbons can easily take on additional hydrogen atoms. Unsaturated hydrocarbons, as a result, are unstable. Because of their stability, saturated hydrocarbons burn with a clear, clean flame.
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