Energy Sources PDF - 3rd Year

Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Introduction Energy is essential to our lives....

Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Introduction Energy is essential to our lives. Our bodies need energy to function and to perform physical activities. And the technological age in which we live needs a reliable energy supply for heating, lighting, communication, transport, food production, manufacturing goods, and so on. Because of their importance, issues such as the supply and cost of energy and the environmental impact make frequent appearances on the daily news. In this introductory chapter we consider energy consumption and the energy resources available to us. We consider the general characteristics of energy sources and the transformation of energy from one form to another to suit the end use. We also consider the role of energy storage. 1.1 Energy consumption We consume energy in maintaining our vital bodily functions, such as the operation of the heart and lungs, the maintenance of body temperature, brain function and digestion of the food we eat. Roughly speaking, in maintaining these functions we consume energy at the rate of ∼100 J/s; a power of ∼100 W. We also expend energy when we do physical work. Suppose, for example, that we climb stairs and rise at the rate of 0.5 m/s in vertical height. If our mass is 75 kg, our rate of doing work is 75 kg × 9.8 m/s2 × 0.5 m/s = 368 W. The amount of physical activity that a person does depends on their lifestyle. Suppose, however, that, averaged over the course of a 24-hour period, we consume energy at the average rate of 125 W in maintaining our metabolic rate and performing physical work. This amounts to ∼10 MJ of energy per day. This energy comes from the chemical energy stored in the food that we eat; a tin of baked beans, Figure 1.1 Illustration of the dramatic rise in annual global energy consumption that occurred between 1820 and 2010. for comparison, contains ∼1.5 MJ of energy. We also need energy to heat and light our houses, to run washing machines and refrigerators, to travel to work, to use computers, to fly to a foreign country on holiday, and so on. Furthermore, energy is needed to produce the food we eat, to manufacture and transport the goods we buy, etc. Overall, the total energy consumption per person per day in the UK is ∼450 MJ. When we consider energy consumption, it is perhaps more meaningful to use the kilowatt-hour (kWh) unit of energy. This is the energy consumed by a 1 kW electric fire in 1 hour and the conversion factor is 1 kWh = 3.6 MJ. So 450 MJ/day = 125 kWh/day, which is the amount of power consumed by Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. five 1 kW electric fires running day and night. This figure of 125 kWh per person per day is typical for a European country. In the USA, the energy consumption per person is about twice as high, while in underdeveloped countries it is considerably lower. Averaged over all countries, energy consumption is ∼60 kWh per person per day and this amounts to a total global energy consumption of ∼5 × 1020 J/year. Global consumption of energy continues to increase because of advances in technology, growth in world population and economic growth, factors that are interrelated. Figure 1.1 illustrates the dramatic increase in annual global consumption of energy that occurred between 1820 and 2010. As an example of a technological advance, James Watt patented his steam engine in 1769 and this enabled the Earth’s deposits of fossil fuels such as coal to be unlocked. This signaled a sharp increase in energy consumption, and once industrialization occurred, the rate of consumption increased dramatically; over the course of the 20th century, global use of energy increased more than 10-fold. The world’s population has also increased dramatically over the last few hundred years, rising from 1 billion in 1800 to 7.4 billion in 2016. Indeed, the curves for global energy consumption and global population follow each other quite closely. Presently, global population is increasing at a rate of just over 1% per year. The rate of economic growth is different for different countries. However, averaged over all countries, economic growth also increases at about 1% per year. Taking the various factors into account, it is predicted that the growth in global energy consumption over the next 30 years will be ∼2% per year. A complementary aspect of energy consumption is the efficiency with which energy is used. No source of energy is cheap or occurs without some form of environmental disruption, and it is important that energy is used as efficiently as possible. One particular advance can be seen in the use of electric light bulbs. It is estimated that lighting consumes about 20% of the world’s electricity. Traditional incandescent light bulbs with a wire filament are only about 5% efficient, while new types of lighting are much more efficient. LED lighting, for example is about 20% efficient. 1.2 Energy sources Energy is one of the most fundamental parts of our universe. We use energy to do work. Energy lights our cities. Energy powers our vehicles, trains, planes and rockets. Energy warms our homes, cooks our food, plays our music, gives us pictures on television. Energy powers machinery in factories and tractors on a farm. Energy from the sun gives us light during the day. It dries our clothes when they're hanging outside on a clothes line. It helps plants grow. Energy stored in plants is eaten by animals, giving them energy. And predator animals eat their prey, which gives the predator animal energy. Everything we do is connected to energy in one form or another. Energy is defined as: "the ability to do work." Work means moving something, lifting something, warming something, lighting something. All these are a few of the various types of work. But where does energy come from? There are many sources of energy. In The Energy Story, we will look at the energy that makes our world work. Energy is an important part of our daily lives. The forms of energy we will look at include: Electricity Biomass Energy - energy from plants Geothermal Energy Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Fossil Fuels - Coal, Oil and Natural Gas Hydro Power and Ocean Energy Nuclear Energy Solar Energy Wind Energy Transportation Energy Most of the energy available to us comes directly or indirectly from the Sun. The Sun gets its energy from nuclear fusion reactions that heat its core to a temperature of ∼107 K. Energy is transported to the Sun’s surface and maintains the surface at a temperature of ∼6000 K. The hot surface acts as a blackbody radiator emitting electromagnetic radiation and it is this radiation or sunlight that delivers solar energy to the Earth. The total solar power that falls on the Earth is enormous, ∼1.7 × 1017 W, which is about 25 MW for every person in the world. Sunlight provides us with energy in various ways. Photosynthesis is the process by which plants and other organisms use sunlight to transform water, carbon dioxide, and minerals into oxygen and organic compounds. Fossil fuels that we burn, including oil, coal and natural gas, were formed over millions of years by the action of heat and pressure on the fossils of dead plants. Bioenergy comes from biofuels that are produced directly or indirectly from organic matter, including plant material and animal waste; an example is rapeseed oil, which produces oil for fuel. Wood also fits into this category and, indeed, burning wood is by far the oldest source of energy used by humankind. Hydroelectric power, wind power and wave power can also be traced back to the Sun. Solar energy heats water on the Earth’s surface, causing it to evaporate. The water vapour condenses into clouds and falls as precipitation. This fills the reservoirs of hydroelectric plants, and the potential energy of the stored water provides a supply of energy. The Sun’s warming of the Earth’s surface produces winds that circulate the globe and which can be used to drive wind turbines. The winds also produce ocean waves whose kinetic energy can be harvested. More directly, solar energy can be captured by solar water heaters or alternatively by photovoltaic devices, which convert sunlight into electrical energy directly. The Sun even plays a role in the formation of the tides, which result from the motions of the Moon, Sun and Earth. The rising and falling tides contain potential and kinetic energies that can be harvested. We also get energy from human-induced nuclear reactions. So far, nuclear power has exploited fission reactions of heavy, radioactive elements such as uranium. However, as we will see, nuclear fusion of light elements such as deuterium and tritium has great potential as an energy source of the future. Finally, the Earth itself is a source of energy called geothermal energy. This is stored as thermal energy beneath the Earth’s surface. It results from the processes involved in the formation of the Earth and from the decay of radioactive elements within its crust and appears, for example, as hot water springs in various regions of the world. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. The annual consumption of energy with respect to energy source varies from country to country and from year to year. However, to get an impression of energy consumption by energy source, Figure 1.2 shows the data for the USA in 2014. We see that 81% of energy consumption came from fossil fuels, while nuclear energy and renewable sources provided the remainder. The energy sources listed above are called primary energy sources. Electricity, on the other hand, is described as a secondary energy source, as it derives from the conversion of energy from a primary source. Electricity has significant advantages as an energy carrier. It can be conveniently transported and distributed via a national grid, and for many energy needs it is easier to use than the primary energy source itself. The other important secondary energy source is hydrogen gas, which can be burnt or used in fuel cells. Figure 1.2 Annual energy consumption for the USA in 2014, by energy source – 81% of energy consumption came from fossil fuels, while nuclear energy and renewable sources provided the remainder. 1.3 Fuel Fuel is a substance which, when burnt, i.e. on coming in contact and reacting with oxygen or air, produces heat. Thus, the substances classified as fuel must necessarily contain one or several of the combustible elements: carbon, hydrogen, Sulphur, etc. In the process of combustion, the chemical energy of fuel is converted into heat energy. To utilize the energy of fuel in most usable form, it is required to transform the fuel from its one state to another, i.e. from solid to liquid or gaseous state, liquid to gaseous state, or from its chemical energy to some other form of energy via single or many stages. In this way, the energy of fuels can be utilized more effectively and efficiently for various purposes. 1.4 CLASSIFICATION OF FUELS Fuels may broadly be classified in two ways, i.e.  according to the physical state in which they exist in nature – solid, liquid and gaseous, and  according to the mode of their procurement – natural and manufactured. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. None of these classifications, however, gives an idea of the qualitative or intensive value of the fuels, i.e. their power of developing the thermal intensity or calorimetric temperature under the normal condition of use, i.e. combustion of fuels in mixture with atmospheric air in stoichiometric proportion. A brief description of natural and manufactured fuels is given in Table 1.4. Table 1.4 Natural and Manufactured Fuels Natural Fuels Manufactured Fuels Solid Fuels Wood Tanbark, Bagasse, Straw Coal Charcoal Oil shale Coke Briquettes Liquid Fuels Petroleum Oils from distillation of petroleum Coal tar Shale-oil Alcohols, etc. Gaseous Fuels Natural gas Coal gas Producer gas Water gas Hydrogen Acetylene Blast furnace gas Oil gas 1.5 Renewable and non-renewable energy sources Energy sources can be classified as either renewable or nonrenewable. We define a renewable source as one in which the energy comes from a natural and persistent flow of energy that occurs in the environment. Hydroelectric energy, solar energy, wind energy, wave energy, tidal energy and geothermal energy are renewable sources and so is bioenergy, so long as the trees and crops are replaced. Nonrenewable sources are finite stores of energy, such as coal and oil, and nuclear fuels such as uranium. These non- renewable sources are not sustainable in the longer term. The distinction between renewable and non-renewable energy sources is illustrated in Figure 1.5. Closely associated with renewable energy sources is sustainability. Figure 1.5 Illustration of the distinction between renewable and nonrenewable energy sources, using the examples of solar energy and energy from the fossil fuel oil. Solar energy flows continuously from the Sun, while reserves of oil are finite. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Sustainable development can be broadly defined as living, producing and consuming in a manner that meets the needs of the present without compromising the ability of future generations to meet their needs. Renewable sources are much more compatible with sustainable development than non-renewable sources. Fossil fuels, although non-renewable, have the advantage that their energy densities are high, i.e. they yield a large amount of energy per unit mass or per unit volume. For example, a liter of oil contains 35 MJ of energy. Moreover, the output of a power plant using fossil fuels is controllable. However, the burning of fossil fuels produces substantial amounts of pollution and increases the concentration of CO2 in the atmosphere, which enhances the greenhouse effect. Nuclear fuels have an even higher energy density. In fact, their energy density is ∼106 times greater than that of a fossil fuel and, again, the output of a nuclear reactor can be controlled. But, of course, nuclear power presents its own challenges, including the long-term storage of spent nuclear fuel. In general, renewable energy sources produce less atmospheric pollution than fossil fuels and do not emit CO2 gas directly, the exception being the burning of biofuels. Furthermore, because they extract their energy from natural flows of energy that are already compatible with the environment, they produce minimum thermal pollution. They may also offer the possibility of a country becoming self- sufficient in energy. A disadvantage of some renewable sources is that they produce energy intermittently; solar cells need the Sun and wind turbines need the wind. Hence, the energy they deliver cannot be controlled in the same way as, say, a nuclear power station. However, this disadvantage is mitigated by the use of energy storage. Renewable energy is also usually more expensive than that obtained from fossil fuels, and renewable energy plants may have a significant impact on the local environment. For example, a hydroelectric plant can greatly affect the local ecology and may also cause the displacement of local inhabitants. At present, renewable sources contribute a much smaller fraction of global energy than do fossil fuels, although this fraction is expected to increase significantly in the future; presently, for example, renewable energy accounts for roughly a fifth of global electricity production. 1.6 CHARACTERISTICS OF ENERGY RESOURCES 1.6.1 Solid Fuels and Their Characteristics Solid fuels are mainly classified into two categories, i.e. natural fuels, such as wood, coal, etc. and manufactured fuels, such as charcoal, coke, briquettes, etc. (Table 1.4). The various advantages and disadvantages of solid fuels are given below: Advantages (a) They are easy to transport. (b) They are convenient to store without any risk of spontaneous explosion. (c) Their cost of production is low. (d) They possess moderate ignition temperature. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Disadvantages (a) Their ash content is high. (b) Their large proportion of heat is wasted. (c) They burn with clinker formation. (d) Their combustion operation cannot be controlled easily. (e) Their cost of handling is high. 1.6.2 Liquid Fuels and Their Characteristics The liquid fuels can be classified as follows: (a) Natural or crude oil, and (b) Artificial or manufactured oils. The advantages and disadvantages of liquid fuels can be summarized as follows: Advantages (a) They possess higher calorific value per unit mass than solid fuels. (b) They burn without dust, ash, clinkers, etc. (c) Their firing is easier and also fire can be extinguished easily by stopping liquid fuel supply. (d) They are easy to transport through pipes. (e) They can be stored indefinitely without any loss. (f) They are clean in use and economic to handle. (g) Loss of heat in chimney is very low due to greater cleanliness. (h) They require less excess air for complete combustion. (i) They require less furnace space for combustion. Disadvantages (a) The cost of liquid fuel is relatively much higher as compared to solid fuel. (b) Costly special storage tanks are required for storing liquid fuels. (c) There is a greater risk, particularly, in case of highly inflammable and volatile liquid fuels. (d) They give bad odour. (e) For efficient burning of liquid fuels, specially constructed burners and spraying apparatus are required. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.6.3 Gaseous Fuels and Their characteristics Gaseous fuels occur in nature, besides being manufactured from solid and liquid fuels. The advantages and disadvantages of gaseous fuels are given below: Advantages Gaseous fuels due to erase and flexibility of their applications, possess the following advantages over solid or liquid fuels: (a) They can be conveyed easily through pipelines to the actual place of need, thereby eliminating manual labour in transportation. (b) They can be lighted at ease. (c) They have high heat contents and hence help us in having higher temperatures. (d) They can be pre-heated by the heat of hot waste gases, thereby affecting economy in heat. (e) Their combustion can readily by controlled for change in demand like oxidizing or reducing atmosphere, length flame, temperature, etc. (f) They are clean in use. (g) They do not require any special burner. (h) They burn without any shoot, or smoke and ashes. (i) They are free from impurities found in solid and liquid fuels. Disadvantages (a) Very large storage tanks are needed. (b) They are highly inflammable, so chances of fire hazards in their use is high. 1.7 THE FORM AND CONVERSION OF ENERGY According to the kind of energy they deliver, we can broadly divide sources into the following categories: thermal energy sources, mechanical energy sources and photovoltaic sources. 1.7.1 Thermal energy sources Fossil fuels are a store of chemical energy that is a form of potential energy associated with the chemical bonds of the molecules of the fuel. Burning the fuel breaks these bonds and releases energy, mostly in the form of thermal energy. Nuclear fission reactions release potential energy that is stored in the nuclei that undergo fission and this energy becomes converted into thermal energy in the core of the reactor. In both cases, the thermal Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. energy is converted into mechanical energy by a steam turbine, which is a type of heat engine. A fundamental aspect of the conversion of thermal energy into mechanical energy is that it is governed by the laws of thermodynamics, and these limit the efficiency of the conversion process. For example, the efficiency of a conventional, coal-fired power plant for converting thermal energy into mechanical energy may be ∼35%. Alternatively, thermal energy can be used to heat buildings directly, thus avoiding thermodynamic limitations. Here, the thermal energy is transported as steam through large-diameter insulated pipes, and such district heating is common in some countries. 1.7.2 Mechanical energy sources These sources deliver mechanical energy directly, as in the case of a wind turbine. The wind causes the blades of a turbine to rotate and the rotation of the turbine shaft delivers mechanical energy directly. Hence, the thermodynamic limitations of thermal to mechanical energy conversion are avoided. Nevertheless, methods of extracting mechanical energy from a particular source also have inherent limitations to their efficiency. In the case of a wind turbine, we will see that the maximum efficiency of a turbine for extracting energy from the wind is 59%. 1.7.3 Photovoltaic sources Photovoltaic solar cells have the advantage that they convert sunlight into electrical energy directly so again the thermodynamic limitations of thermal to mechanical energy conversion are avoided. However, as we shall see, there are a number of factors that limit the efficiency of solar cells. In practice, the efficiency of a commercial solar cell for converting solar energy into electrical energy is ∼20%. The efficiency with which a particular source of energy can be transformed from one form to another is described as the quality of the source. Waste hot water from a manufacturing process at 60◦C would be described as low quality. This is because at this relatively low temperature the efficiency of a heat engine to convert the thermal energy of the water into mechanical energy is very low, less than 12%. On the other hand, electricity has high quality. For example, it can be converted into mechanical energy by an electric motor with very high efficiency, ∼95%. 1.7.4 Energy storage Energy has to be provided when it is needed. Some energy sources, such as nuclear power stations and hydroelectric plants can provide a continuous supply of energy. On the other hand, sources such as wind turbines and solar cells produce energy intermittently; these sources may not generate enough energy when it is needed or, alternatively, they may generate excess energy. Energy storage systems allow the excess energy to be stored and used at a later time. And with increasing use of intermittent renewable sources, energy storage is becoming increasingly important. It is also the case that demand for energy varies substantially throughout the seasons and throughout the day; it tends to peak in the morning and afternoon, and fall to a minimum during the night. Power stations should ideally be operated at a fairly constant output level and close to where they operate most efficiently. But it does not make economic sense, and is a waste of energy, to have a power supply system whose capacity exceeds peak demand. Stored energy can supply the extra energy when required. So energy storage is able to even out variations in both supply and demand. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.8 Liquid Fuels (Petroleum) Definition: Petroleum is thick, flammable, yellow to dark brown or greenish liquid and solid hydrocarbons that occur naturally in deposits beneath the surface of the earth; it is also called as crude oil. The word petroleum comes from the Latin word ‘Petra’ which means rock and ‘oleum’ which means oil, the name inherited for its discovery from the sedimentary rocks. It is used mostly for producing fuel oil, which is the primary energy source today. Petroleum is also the raw material for many chemical products, including solvents, fertilizers, pesticides and plastics. Oil in general has been used since early human history to keep fires ablaze, and also for warfare. Its importance in the world economy evolved slowly. In the search for new products, it was discovered that, from crude oil or petroleum, kerosene could be extracted and used as a light and heating fuel. Petroleum is often considered the lifeblood of nearly all other industry. For its high energy content (Table 1.1) and ease of use, petroleum remains as the primary energy source. Table 1.8 Common measuring units used to describe common energy sources. 1.8.1 Origin of Petroleum: The origin of petroleum is one of the interested topics in the past and in the current research. Different theories and researches have been discussed the origin of petroleum, but the most accepted theories are explained as in bellows: 1.8.1.1 Biogenic Theory: Most geologists view crude oil, like coal and natural gas, as the product of compression and heating of ancient vegetation over geological time scales. According to this theory, it is formed from the decayed remains of prehistoric marine animals and terrestrial plants. Over many centuries this organic matter, mixed with mud, is buried under thick sedimentary layers of material. The resulting high levels of heat and pressure cause the remains to metamorphose, first into a waxy material known as kerogen, and then into liquid and gaseous hydrocarbons in a process known as catagenesis. These then migrate through adjacent rock layers until they become trapped underground in porous rocks called reservoirs, forming an oil field, from which the liquid can be extracted by drilling and pumping. 150 m is generally considered the “oil window”. Though this corresponds to Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. different depths for different locations around the world, a ‘typical’ depth for an oil window might be 4-5 km. Three situations must be present for oil reservoirs to form:  A rich source rock,  A migration conduit, and  A trap (seal) that forms the reservoir. The reactions that produce oil and natural gas are often modeled as first order breakdown reactions, where kerogen breaks down to oil and natural gas by another set of reactions. 1.8.1.2 Abiogenic Theory: 1. In 1866, Berthelot proposed that carbides are formed by the action of alkali metal on carbonates. These carbides react with water to give rise to large quantities of acetylene, which in turn is converted to petroleum at elevated temperatures and pressures. For example, one can write the sequence as follows: 2. Mendalejeff proposed another reaction sequence involving acetylene in the formation of petroleum. He proposed that dilute acids or hot water react with the carbides of iron and manganese to produce a mixture of hydrocarbons from which petroleum could have evolved. The reaction sequence according to the proposal of Mendelejeff is: These postulates based on inorganic chemicals, though interesting, cannot be completely accepted for the following three reasons: 1. One often finds optical activity in petroleum constituents, which could not have been present if the source of petroleum were only these inorganic chemicals. 2. Secondly, the presence of thermo-labile organic constituents (biomarkers) in petroleum cannot be accounted for in terms of origin from these inorganic chemicals. 3. It is known that oil is exclusively found in sedimentary rocks, which would not have been the case if the origin of oil could be attributed to processes involving only these inorganic chemicals. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. In 1911, Engler proposed that an organic substance other than coal was the source material of petroleum. He proposed the following three stages of development: 1. In the first stage, animal and vegetable deposits accumulate at the bottom of island seas and are then decomposed by bacteria, the water-soluble components are removed and fats, waxes and other fat-soluble and stable materials remain. 2. In the second stage, high temperature and pressure cause carbon dioxide to be produced from carboxyl- containing compounds, and water is produced from the hydroxyl acids and alcohols to yield a bituminous residue. There can also be a little cracking, producing a liquid product with a high olefin content (petro petroleum). 3. In the third stage, the unsaturated compounds are polymerized to naphthenic and/or paraffinic hydrocarbons. Aromatics are presumed to be formed either by cracking and cyclization or decomposition of petroleum. The elements of this theory have survived; the only objection to it is that the end products obtained from the same sequence of experiments namely, paraffin and unsaturated hydrocarbons differ from those of petroleum. 1.8.2 Three situations must be present for oil reservoirs to form: Petroleum is a relatively common constituent of the shallower parts of the Earth’s crust, but useful quantities are found only within the areas of petroleum systems, where they reside in concentrations called accumulations or fields. What are the elements? o A source rock, a sediment relatively rich in organic material (kerogen) which, when heated to a certain temperature through burial can yield significant quantities of volatile hydrocarbons (oil and gas). o A reservoir rock, sediment with sufficient pore space between the grains to allow oil and gas to reach a suitable concentration. Typical reservoirs include sandstones and limestones, where the pore space may constitute up to 30% of the rock. o A seal to prevent the leakage and loss of oil and gas from the reservoir; this is usually a clay or other impermeable rock type. o A structure to collect and hold the concentration below the Earth’s surface This will usually be a convex- upwards fold in the sedimentary layers called a trap. The accumulation of oil and gas depends on the upward movement or migration of hydrocarbons from the source rock through the sediment pore space into a reservoir sealed in a trap structure. This occurs under the influence of buoyancy. A sufficiently thick pile of sedimentary rocks is required to allow buried kerogen to generate its hydrocarbons – petroleum Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. systems are therefore limited to sedimentary basins – and that all the essential elements must be present and have the appropriate relationship to each other. In general, oil reservoir could be divided into two types: Conventional reservoir Unconventional reservoir 1.8.3 Composition of the crude oil: Hundreds of different crude oils (usually identified by the geographic origin) are processed, in greater or lesser volumes, in the world’s refiners. Each crude oil is unique and is a complex mixture of thousands of compounds. Most of the compounds in crude oil are hydrocarbons (organic compounds composed of carbon and hydrogen atoms). other compounds in crude oil are small (but important) amounts of (hetero-element). Most notably sulfur, as well as nitrogen and certain metals (e.g. Nickel, Vanadium, etc.). The compounds that make up crude oil range from the smallest and simplest hydrocarbon molecules –CH4 (methane) to large complex molecules contains up to 50 or more carbon atoms (as well hydrogen and hetero-element). The physical and chemical properties of any given species or molecules depends on not only the number of carbon atoms in the molecule but also of the chemical bonds between them. Carbon atoms readily bond with one another (and with hydrogen and heteroatoms) in various ways-single bonds, double bonds and triple bonds –to form different classes of hydrocarbons. Paraffin, aromatics and naphthenic are natural constituent of crude oil, and are produced in various refining operations as well. Olefins usually are not present in crude oil; they are produced in certain refining operations that are dedicated mainly to gasoline production. Aromatic compounds have higher C/H to hydrogen ratio than paraffin. The heavier more dense the crude oil the heavier the crude oil, due to the chemistry of oil refining. The higher C/H ratio of crude oil the more intense and costly the refinery processing required to produce the given volumes of gasoline and distillate fuels, thus the chemical composition of the crude oil and its various boiling range fraction influence the refinery investment requirements and refinery energy use. The two larger component in of total refining cost. The proportion of the various hydrocarbon classes, their carbon number distribution and the concentration of hetero-elements in a given crude oil determine the yield and qualities of refined products that a refinery can produce form the crude and hence the economic value of the crude. Different crude oils require different refinery facilities and operations to maximize the value of the product salts that they yield. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Table 1.8.3 Overall tank Composition of Petroleum Elements Percentage by weights Carbon 84-87 Hydrogen 11-14 Sulfur 0.06-0.4 Nitrogen 0.1-2.0 Oxygen 0.1-2.0 1.8.4 Volumetric Calculation: 1. Recovery factor (RF) The fraction of the oil or gas we can produce is a function of the recovery process and is called the recovery factor (RF). Drive mechanism has the greatest geological impact on recovery factor. Narrowing the range in recovery factor is a matter of estimating how much difference pore type and reservoir heterogeneity impact the efficiency of the drive mechanism. Table 1.8.4 show the range recovery percent for mechanism of primary recovery Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 2. Oil reserve calculation Where: IOIP: initial oil in place Oil well: The well is basically a hole drilled from surface to the oil reservoir. A typical oil well will have: 1. Casing– for hole stability, 2. Tubing– for channeling oil and gas to the surface, 3. Well head – for surface control of pressure and oil flow 4. From a well, together with the oil flow, gas is always expected and sometimes they are accompanied with water as well. Thus in summary oil well is: Oil well is an instrument, which a driller taps it, brings oil from the ground to the Earth’s surface. The oil itself, according to the US Department of Energy, exists as small droplets in the pores of rocks. There are many types of well: 1- Injection well: an injection well is one in which a worker might inject water or gas into the well to stimulate oil production. 2- Appraisal well: the purpose of an appraisal well is evaluation. According to the Oil Gas Glossary, oilrig workers use this type of well to run buildup tests. 3- Satellite well: this type of well is one that an offshore drilling unit digs to produce hydrocarbons that well diggers cannot otherwise produce from development wells from a platform rig. 4- Flowing well: flowing well refers to a well that produces oil naturally without the aid of a pump. The Disadvantages of the drilling oil well: Exploring and drilling for oil may disturb land and ocean habitats in many ways: 1) Dust particles left from drilling may coat the surrounding areas. 2) Flames from burning the natural gas found in oil fields cause air pollution. 3) Oil spills, accidents, and dumping of oil barrels and produced water lead to devastating ecological and health consequences that can last for decades. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.8.5 Physical and Chemical Properties of Liquid Fuels: Liquid fuels like furnace oil and Low Sulfur Heavy Stock (LSHS) are predominantly used in industrial application. The various properties of liquid fuels are given as follows: 1.8.5.1 Density: This is defined as the ratio of the mass of the fuel to the volume of the fuel at a reference temperature of 15°C. Density is measured by an instrument called hydrometer. The knowledge of density is useful for quantity calculations and assessing ignition quality. The unit of density is kg/m3 in the SI unit system. Easily the formula of Density: 𝑚𝑎𝑠𝑠 (𝑚)   𝑣𝑜𝑙𝑢𝑚𝑒 (v) 1.8.5.2 Specific Gravity (SG): This is defined as the ratio of the weight of a given volume of oil to the weight of the same volume of water at a given temperature. The density of fuel, relative to water, is called specific gravity. The specific gravity of water is defined as 1. Since specific gravity is a ratio, it has no units. The measurement of specific gravity is generally made by a hydrometer. Specific gravity is used in calculations involving weights and volumes. The specific gravity values of various fuel oils are given in Table 1.8. Table 1.8 Specific Gravity of Various Fuel Oils Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.8.5.3 Viscosity: The viscosity of a fluid is a measure of its internal resistance to flow. Viscosity depends on temperature and decreases as the temperature increases. Any numerical value for viscosity has no meaning unless the temperature is also specified. Viscosity is measured in Stokes / Centistokes. Sometimes viscosity is also quoted in Engler, Saybolt or Redwood. Each type of oil has its own temperature - viscosity relationship. The measurement of viscosity is made with an instrument called Viscometer. 1.8.5.4 Flash Point: The flash point of a fuel is the lowest temperature at which the fuel can be heated so that the vapor gives off flashes momentarily when an open flame is passed over it. The flash point for furnace oil is 66 o C. 1.8.5.5 Pour Point: The pour point of a fuel is the lowest temperature at which it will pour or flow when cooled under prescribed conditions. It is a very rough indication of the lowest temperature at which fuel oil is readily pumpable. 1.8.5.6 Specific Heat: Specific heat is the amount of kcals needed to raise the temperature of 1 kg of oil by 1oC. The unit of specific heat is kcal/kg Co. It varies from 0.22 to 0.28 depending on the oil specific gravity. The specific heat determines how much steam or electrical energy it takes to heat oil to a desired temperature. Light oils have a low specific heat, whereas heavier oils have a higher specific heat. 1.8.5.7 Calorific Value: The calorific value is the measurement of heat or energy produced, and is measured either as gross calorific value or net calorific value. The difference being the latent heat of condensation of the water vapor produced during the combustion process. Gross calorific value (GCV) assumes all vapor produced during the combustion process is fully condensed. Net calorific value (NCV) assumes the water leaves with the combustion products without fully being condensed. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Fuels should be compared based on the net calorific value. The typical Gross Calorific Values of some of the commonly used liquid fuels are given below: Fuel Oil Gross Calorific Value (kCal/kg) Kerosene - 11,100 Diesel Oil - 10,800 L.D.O – 10,700 (Light diesel oil (LDO)) Furnace Oil - 10,500 LSHS - 10,600 (Low Sulphur heavy stock (LSHS)) 1.8.5.8 Sulphur Content: The amount of Sulphur in the fuel oil depends mainly on the source of the crude oil and to a lesser extent on the refining process. The normal sulfur content for the residual fuel oil (furnace oil) is in the order of 2-4 %. Typical figures are: Fuel oil Percentage of Sulphur Fuel Oil Percentage of Sulfur The main disadvantage of sulfur is the risk of corrosion by sulfuric acid formed during and after combustion, and condensing in cool parts of the chimney or stack, air pre heater and economizer. 1.8.5.9 Ash Content: The ash value is related to the inorganic material in the fuel oil. The ash levels of distillate fuels are negligible. Residual fuels have more of the ash-forming constituents. These salts may be compounds of sodium, vanadium, calcium, magnesium, silicon, iron, aluminum, nickel, etc. Typically, the ash value is in the range 0.03-0.07 %. Excessive ash in liquid fuels can cause: Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. Fouling deposits in the combustion equipment. Ash has erosive effect on the burner tips, causes damage to the refractories at high temperatures and gives rise to high temperature corrosion and fouling of equipment. 1.8.5.10 Carbon Residue: Carbon residue indicates the tendency of oil to deposit a carbonaceous solid residue on a hot surface, such as a burner or injection nozzle, when its vaporizable constituents evaporate. Residual oil contains carbon residue ranging from 1 percent or more. 1.8.5.11 Water Content: Water content of furnace oil when supplied is normally very low as the product at refinery site is handled hot and maximum limit of 1% is specified in the standard. Water may be present in free or emulsified form and can cause damage to the inside furnace surfaces during combustion especially if it contains dissolved salts. It can also cause spluttering of the flame at the burner tip, possibly extinguishing the flame and reducing the flame temperature or lengthening the flame. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.9 Solid fuel refers to various forms of solid material that can be burnt to release energy, providing heat and light through the process of combustion. Solid fuels can be contrasted with liquid fuels and gaseous fuels. Common examples of solid fuels include wood, charcoal, peat, coal, Hexamine fuel tablets, wood pellets, corn, wheat, rye, and other grains. Solid fuels are extensively used in rocketry as solid propellants. Solid fuels have been used throughout human history to create fire and solid fuel is still in widespread use throughout the world in the present day. 1.9.1 Types of solid fuels  Wood Wood fuel can refer to several fuels such as firewood, charcoal, wood chips sheets, pellets, and sawdust. The particular form used depends upon factors such as source, quantity, quality and application. In many areas, wood is the most easily available form of fuel, requiring no tools in the case of picking up dead wood, or few tools. Today, burning of wood is the largest use of energy derived from a solid fuel biomass. Wood fuel can be used for cooking and heating, and occasionally for fueling steam engines and steam turbines that generate electricity. Wood may be used indoors in a furnace, stove, or fireplace, or outdoors in a furnace, campfire, or bonfire. As with any fire, burning wood fuel creates numerous by-products, some of which may be useful (heat and steam), and others that are undesirable, irritating or dangerous. There is debate as to whether burning wood can be considered carbon neutral, as technically the wood cannot release more carbon than was sequestered during its growth, although this does not take account of other impacts such as deforestation and rotting has on the carbon footprint. When harvested in a sustainable fashion wood is usually considered to be a renewable solid fuel. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng.  Peat Peat fuel is an accumulation of partially decayed vegetation or organic matter that can be burnt once sufficiently dried. It is used widely in the country districts of Ireland and Scotland where alternatives are absent or expensive. It has a relatively low calorific value, even after essential drying. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng.  Coal Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. Throughout history, coal has been used as an energy resource, primarily burned for the production of electricity and heat, and is also used for industrial purposes, such as refining metals. Coal is the largest source of energy for the generation of electricity worldwide, as well as one of the largest worldwide The extraction of coal, its use in energy production and its byproducts are all associated with environmental and health effects. Variations such as smokeless coal can be formed naturally in the form of anthracite, a metamorphosed type of coal with a very high carbon content that gives off a smokeless flame when set alight. It is an important type of smokeless fuel. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng.  Coke Coke is a fuel with few impurities and a high carbon content, usually made from coal. It is the solid carbonaceous material derived from destructive distillation of low-ash, low-sulfur bituminous coal. Cokes made from coal are grey, hard, and porous. While coke can be formed naturally, the commonly used form is man-made. The form known as petroleum coke, or pet coke, is derived from oil refinery Coker units or other cracking processes. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng.  Smokeless fuel Solid fuels which produce little smoke or volatiles are made from powdered anthracite coal and supplied in the form of briquettes usually for domestic use either in stoves or open fireplaces. The fuel is replacing coal as a fuel for open fires because of the reduction in particulate emissions and its increased efficiency. Smokeless fuel burns at a higher temperature and more slowly than a coal fire. The term also includes charcoal, made by restricted combustion of dry wood, is also widely used for open air barbecues with food cooked on an open fire.  Municipal waste Municipal solid waste commonly known as trash or garbage in the United States and as rubbish in Britain, is a waste type consisting of everyday items that are discarded by the public. It can be burnt to create electrical energy by careful control of the waste stream. With the correct technology it can also be gasified and converted to a viable fuel source. However, this is technology heavy and can only be used where the waste is known not to contain toxic materials. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng.  Rocket propellant Solid rocket propellant consists of a solid oxidizer (such as ammonium nitrate) bound with flakes or powders of energy compounds (such as RDX) plus binders, plasticizers, stabilizers and other additives. Solid propellant is much easier to store and handle than liquid propellant. It also has a higher energy density so it does not require as large of a space for the same amount of stored energy. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.9.2 Coal and Their Characteristics It is commonly adopted view that coal is a mineral substance of vegetable origin. Over 30% of coal output is consumed by railways; another similar proportion is used by industry including iron and steel works. This leaves barely 40% of coal mined for use of the power supply undertakings. 1.9.2.1 Analysis of Coal To ascertain the commercial value of coal certain tests regarding its burning properties are performed before it is commercially marketed. Two commonly used tests are: Proximate analysis and Ultimate analysis of coal. Calorific value of coal is defined as the quantity of heat given out by burning one-unit weight of coal in a calorimeter. Proximate Analysis of Coal This analysis of coal gives good indication about heating and burning properties of coal. The test gives the composition of coal in respect of moisture, volatile matter, ash and fixed carbon. The moisture test is performed by: Heating 1 gm of coal sample at 104 ⁰C to 110 ⁰C for 1 hour in an oven and finding the loss in weight. The volatile matter is determined by: Heating 1 gm of coal sample in a covered crucible at 950 ⁰C for 7 minutes and determining loss in weight, from which the moisture content as found from moisture test, is deducted. Ash content is found by: Completely burning the sample of coal in a muffled furnace at 700Co to 750Co and weighing the residue. The percentage of fixed carbon is determined by difference when moisture, volatile matter and ash have been accounted for. The results of proximate analysis of most coals indicate the following broad ranges of various constituents by weight: Table 1.9.1 the Results of Proximate Analysis of Most Coal The importance of volatile matter in coal is due to the fact that it largely governs the combustion, which in turn governs the design of grate, and combustions space used. High volatile matter is desirable in gas making, while low volatile matter for manufacturing of metallurgical coke. Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. The Ultimate Analysis of Coal This analysis of coal is more precise way to find the chemical composition of coal with respect to the elements like carbon, hydrogen, oxygen, nitrogen, Sulphur and ash. Since the content of carbon and hydrogen that is already combined with oxygen to form carbon dioxide and water is of no value for combustion, the chemical analysis of coal alone is not enough to predict the suitability of coal for purpose of heating. Table 1.9.2 the Results of Ultimate Analysis of Most Coal Analysis of coal on dry and moist base: When an analysis is given on a moist fuel basis, it may be readily converted to a dry basis by dividing the percentages of the various constituents by one minus the percentage of moisture, reporting the moisture content separately. How to change the moist base to the dry base: Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.9.2.2 Calculations of Heating Value from an Ultimate Analysis The first formula for the calculation of heating values from the composition of a fuel as determined from an ultimate analysis is due to Dulong, and this formula, slightly modified, is the most commonly used to-day. Other formulae have been proposed, some of which are more accurate for certain specific classes of fuel, but all have their basis in Dulong’s formula, the accepted modified form of which is: Heat units in Btu. per pound of dry fuel = Coal Composition Calculation: # Example 1: Consider a Pittsburgh seam coal that contains 77.2% C, 5.2% H, 1.2% N, and 2.6% S, 5.9% O, and 7.9% ash by weight. The ultimate analysis is generally reported on an "as received basis, including the moisture in the chemical analysis. The molar composition may be determined by dividing each of the mass percentages by the atomic weight of the constituent. For convenience in stoichiometric calculations, the composition is then normalized with respect to carbon: The total number of moles of gaseous combustion products per mole of C is: Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department Mr. Hesham J. alnoor 3RD YEAR DEP.: Fuel & Energy Technologies Eng. 1.10 Heating Value of Gaseous Fuels The heating value of gaseous fuels may be calculated by Dulong’s formula with terms to represent any carbon monoxide present. Such a method, however, involves the separating of the constituent gases into their elementary gases, which is oftentimes difficult and liable to simple arithmetical error. As the combustible portion of gaseous fuels is ordinarily composed of hydrogen, carbon monoxide and certain hydrocarbons, a determination of the calorific value is much more readily obtained by a separation into their constituent gases and a computation of the calorific value from a table of such values of the constituents. The table (1.10) gives the calorific value of the more common combustible gases, together with the theoretical amount of air required for their combustion. Table 1.10 Weight and calorific value of various gases at 32⁰F and atmospheric pressure with theoretical amount of air required for combustion ft3(air) ft3(air) Gas Symbol ft3(gas)/Ib Btu/Ib Btu/ ft3 Required/ Required/ Ib (gas) ft3(gas) Hydrogen H 177.90 62000 349 428.25 2.41 Carbon CO 2.81 4450 347 30.60 2.39 Monoxide Methane CH4 22.37 23550 1053 214.00 9.57 Acetylene C2H2 13.79 21465 1556 164.87 11.93 Olefiant C2H4 12.80 21440 1675 183.60 14.33 Gas Ethane C2H6 11.94 22230 1862 199.88 16.74 # Example 1 Assume a blast furnace gas, the analysis of which in percentages by weight is, Oxygen = 2.7, Carbon monoxide = 19.5, Carbon dioxide = 18.7, Nitrogen = 59.10. Calculate the heating value of this gas and air required to burn one bound of it? Address: Southern Technical University – Engineering Technical College/Basrah – Fuel and Energy Department