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Friday, November 29, 2013

Fuels and Lubricants (F&L).




Fuels and  Lubricants (F&L). Sources of FL Raw Materials. Nonrenewable Primary Energy Resources


All types of equipment and machinery have been greatly improved mechanically and designed to run under far more severe operating conditions. Fuels, lubricants, and other oil products, likewise, have been greatly improved and adapted for exacting operating requirements. The selection of the proper product for the specific application thus has become more important than ever before. The proper transportation, storage, and handling of products to ensure that they reach the point of usage with their properties unchanged from their manufacture are also important.
Since F&L derived from oil in the refining processes make up the most of all F&L used, they will be referred to and analyzed in this discipline course as the main object. According to the international standard ISO 8681 (International organization for standardization), all oil products are classified into five main classes named with alphabetic indexes (table 1).
Table 1
Classification of petroleum products according to ISO 8681
Class
Product
F
Fuel
L
Lubricants, industrial oils and related products
W
Paraffin
B
Bitumen
S
Solvents and raw material for the chemical industry

Fuel is any material or individual substance that can be burned or altered to obtain different kinds of energy for heating and/or moving objects. Fuel releases its energy through chemical reactions, such as combustion and oxidizing. An important property of a useful fuel is that its energy can be stored to be released only when needed, and that the release is controlled in such a way that the energy can be harnessed to produce work. The application of energy released from fuels ranges from heat for cooking and from powering weapons to combustion and generation of electricity.
            Fuels are usually categorized according to four main indications into groups, grades, brands and kinds:
            a) based on their origin – there are natural and synthetic (artificial);
            b) based on their chemical structure – hydrocarbon and non-hydrocarbon;
            c) based on their state of matter – gaseous, liquid and solid;
            d) based on the engine type (gasoline, diesel fuel, jet fuel, gas oil, rocket fuel).
            ISO 8216/0 sets the general classification of the oil origin fuels (table 2). 

Table 2
General classification of fuels according to ISO 8216/0

Class
Category
Title

G
Gaseous fuel. Gaseous fuel of petroleum origin consisting mainly of methane and (or) ethane
F
L
Liquefied gaseous fuel. Gaseous fuel of petroleum origin consisting mainly of propane, propene and (or) butane and butene

D
Distillate fuel. Fuel of petroleum origin except for liquefied petroleum gases and fuels. Include gasoline, kerosene, gas-oil and diesel fuel. Heavy distillates may contain a small amount of residuals

R
Residual fuel. Petroleum fuel containing residual fractions of distillation

C
Petroleum cokes. Solid fuel of petroleum origin consisting mainly of carbon, obtained through the process of cracking
           
            The work of engines, mechanisms and machines is accompanied by friction of contacting and moving surfaces. Lubricants are individual substances or materials that are used for decreasing of wear of rubbing details and decreasing the loss of power expended on friction in any mechanism.
            All lubricants are subdivided into three basic groups:
            1. The lubricants, which under normal conditions are liquids (oils).
            2. Consistent (plastic, flexible) lubricating materials (lubricating pasty greases).
            3. Solid lubricants that might be used as oil additives and grease additives, or as individual lubricants.

            Natural resources such as coal, petroleum, oil and natural gas take thousands of years to form naturally and cannot be replaced as fast as they are being consumed. Eventually natural resources will become too costly to harvest and humanity will need to find other sources of energy. At present, the main energy sources used by humans are non-renewable as they are cheap to produce. Natural resources, called renewable resources, are replaced by natural processes during a reasonable amount of time. Soil, water, forests, plants, and animals are all renewable resources as long as they are properly conserved. Solar, wind, wave, and geothermal energies are based on renewable resources. Renewable resources such as the movement of water (hydropower, including tidal power; ocean surface waves used for wave power), wind (used for wind power), geothermal heat (used for geothermal power); and radiant energy (used for solar power) are practically infinite and cannot be depleted, unlike their non-renewable counterparts, which are likely to run out if not used wisely.
            A non-renewable resource is a natural resource which cannot be produced, re-grown, regenerated, or reused on a scale which can sustain its consumption rate. These resources often exist in a fixed amount, or are consumed much faster than nature can recreate them. Fossil fuel (such as coal, petroleum and natural gas) and nuclear power are examples. In contrast, resources such as timber (when harvested sustainably) or metals (which can be recycled) are considered renewable resources
            Fossil fuels are fuels generally thought to be formed by natural resources such as anaerobic decomposition of buried dead organisms. Fossil fuels range from volatile materials with low carbon:hydrogen ratios like methane, to liquid petroleum to nonvolatile materials composed of almost pure carbon, like anthracite coal. It is generally accepted that they are formed from the fossilized remains of dead plants and animals by exposure to heat and pressure in the Earth's crust over hundreds of millions of years.
Fossil fuels are easy to transport, store, and use, and they have very high energy capacity per unit of mass.
            It was estimated that in 2007 primary sources of energy used by mankind consisted of
            petroleum 35,0%,
            coal 27,0 %,
            natural gas 23,0%,
amounting to an 85 % share for fossil fuels in primary energy consumption in the world.
Non-fossil sources in 2007 included
            hydroelectric 6,0 %,
            nuclear 8,0 %, and geothermal, solar, tide, wind, wood, waste
amounting 1 percent.
           
World energy consumption has been growing about 2.3% per year.
            Petroleum is by far the most commonly used source of energy, especially as the source of liquid fuels, and its use is projected to continue at least at the current levels for at least two decades .

            Figure 1.1. Trends and the projected trend for the use of fossil fuel resources and other fuel resources until 2020.

            Fossil fuels are non-renewable resources because they take millions of years to form, and reserves are being depleted much faster than new ones are being formed. The production and use of fossil fuels raise environmental concerns. A global movement toward the generation of renewable energy is therefore under way to help meet increased energy needs.
           
Total fuel reserves of the Earth are estimated at the level of 12,5 trillion tons of equivalent fuel (1 kg of equivalent fuel = 29,4 MJ/kg (~7000 kcal);
1 kg of wood = 19,5 MJ/kg,
1 kg of coal = 33 MJ/kg,
1 kg of oil = more than 50 MJ/kg.
However only 3,5 trillions tons of these resources may be extracted and used with modern technological methods.
           
Hydrocarbon Sources for FL production

            Most of FL are produced using petroleum as a main raw material. Oil is refined in different processes to produce large variety of derived products.
            Petroleum products may also be supplied in whole or in part from natural gas.       Crude oil emerging from the well is accompanied by a large volume of natural gas, about 100 m3 of gas per barrel of oil on the average (1 barrel = 158.94 L). The quantity of natural gas produced per barrel of oil decreases with the age of the oil field. More than two-fifths of the gas obtained from oil wells is returned to the ground to maintain the pressure in the oil pools and thus increase the ultimate oil recovery.
            Though natural gas is predominantly methane, it contains other saturated hydrocarbons and gasoline vapors. The liquids extracted from gas constitute an important supplement to our petroleum resources. Today they are about one-tenth the volume of the crude oil taken from the ground.  The heavier hydrocarbons are recovered and sold as liquefied petroleum gas (LP-Gas), natural gasoline, solvents, and raw materials for the manufacture of plastics and chemicals, among other uses.
            Petroleum is the cheapest but not the only possible source of liquid fuels. Petroleum substitutes can be obtained from oil sands (also called tar sands), large beds of which are found in Canada and Venezuela. These sands are basically a mixture of sand, clay, water, and a form of petroleum called “bitumen,” which is very viscous and dense material.
            Coal, which is almost pure carbon, can be changed to liquid fuels by combining it chemically with hydrogen. This process today is also more costly than the production of these fuels from petroleum. Processes are available to recover the oil from the shale but at a cost today which generally speaking is higher than the cost of producing petroleum from wells.  Shale oil recovery and hydrogenation of coal are now economical in some European countries which are located far from crude-oil supplies in the ground.  

taken from Mykola Zakharchuk

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