FUELS PDF

the calorific value of this fuel is high to the FUELS tune of 35500 kJ/kg and is very suitable for steam generation Types of coal a. Peat...

the calorific value of this fuel is high to the FUELS tune of 35500 kJ/kg and is very suitable for steam generation Types of coal a. Peat Coal Properties the first stage in the formation of coal from wood The basis of an analysis helps to specify the contains huge amount of moisture, dried conditions under which the coal is tested. for about 1 to 2 months before it is put to - as-mined basis: the coal sample may be use freshly taken from the mine used as a domestic fuel in Europe and for - as-fired basis: it may have resided in a power generation in Russia coal pile for months, and be analyzed just in India it does not come in the categories before burning of good fuels - as-received basis: it may be examined b. Lignites and brown coals immediately after transport from the mine intermediate stages between peat and coal a. Moisture content they have a woody or often clay-like moisture content of coals ranges from appearance associated with high about 5% to almost 70% moisture, high ash and low heat contents Moisture is an undesirable constituent of Lignites are usually amorphous in coals because it reduces the heating character and impose transport difficulties value (water does not burn!) and its as they break easily. They burn with a weight adds to the transportation costs of smoky flame. Some of this types are coal suitable for local use only. b. Volatile Combustible Material (VCM) C. Bituminous coal Volatile matter is material that is driven it burns with long yellow and smoky flames off when coal is heated to 900 °C in the and has high percentages of volatile absence of air for 7 mins in a closed matter crucible. It is measured practically by the average calorific value of bituminous determining the loss of weight. It includes coal is about 31350 kJ/kg volatile carbon, combined water, net It may be of two types, namely caking or Hydrogen, Nitrogen and Sulfur. non-caking c. Mineral (Ash) content d. Semi-bituminous coal Coal contains a variety of minerals in softer than the anthracite varying proportions that, when the coal burns with a very small amount of smoke is burned, are transformed into ash. contains 15 to 20 percent volatile matter d. Fixed carbon content (FC) and has a tendency to break into small Fixed carbon is the sold combustible sizes during storage or transportation residue that remains after a coal particle e. Semi-anthracite is heated and the volatile matter is has less fixed carbon and less luster as expelled. compared to true anthracite and gives out longer and more luminous flames when The fixed-carbon content of a coal is burnt determined by subtracting the f. Anthracite percentages of moisture, volatile matter, very hard coal and has a shining black and ash from a sample. luster Since gas-solid combustion reactions ignites slowly unless the furnace are slower than gas-gas reactions, a temperature is high high fixed-carbon content indicates that it is non-caking and has high percentage the coal will require a long combustion of fixed carbon time. it burns either with very short blue flames The anthracites, which contain a high or without flames proportion of fixed carbon and are a  popular domestic heating fuel, may be difficult to ignite but they will often burn steadily for a long time with a short, Coal Utilization clean flame FC = 100 -N- VCM- Ash e. Calorific Value Calorific value, measured in British thermal units or megajoules per kilogram, is the amount of chemical energy stored in a coal that is released as thermal energy upon combustion Of the components determined by proximate analysis, only the volatile matter and the fixed carbon actually burn and liberate thermal energy TESTING ANALYSIS OF SOLID FUELS 1. Proximate Analysis determination of the thermal energy released when the coal is burned 1. Combustion involves burning the coal in air to determines the moisture, volatile liberate thermal energy (heat) combustible matter, fixed carbon and 2. Carbonization is the heating of coal to high ash content temperatures in the absence of air gives good indication about heating and 3. Conversion uses various chemical processes burning properties of coal to transform coal into gaseous or liquid fuels, 2. Ultimate Analysis called synthetic fuels This analysis of coal is a more precise MANUFACTURED SOLID FUELS way to find the chemical composition of 1. Charcoal and its Characteristics coal with respect to the elements like derived from destructive distillation of carbon, hydrogen, oxygen, nitrogen, wood, being left in the shape of solid sulfur and ash. residue Carbon and hydrogen are the principal burns rapidly with a clear flame, producing combustible elements in coal no smoke and developing heat of about On a weight basis, carbon is the predominant 6,050 cal/kg. one. It constitutes about 60% to about 95% of 2. Coke and its Characteristics the total. obtained from destructive distillation of 6 basic components of coal: coal, being left in the shape of solid - Carbon residue - Hydrogen Soft coke is obtained as the solid residue - Nitrogen from the destructive distillation of coal in - Sulfur the temperature range of 600-650°C. It - Ash contains 5 to 10% volatile matter & burns - Oxygen without smoke. Hard coke is obtained as solid residue from the destructive distillation of coal in the temperature range of 1200-1400°C. It burns with smoke and is a useful fuel for metallurgical process 3. Briquettes and their Characteristics  The term briquettes are used in respect 1. Asphalt of the dust, culm, slack and other small Asphalt is commonly used to make roads. size waste remains of lignite, peat, coke, It is a colloid of asphaltenes and maltenes etc. compressed into different shapes of that is separated from the other regular form, with or without binder. components of crude oil by fractional distillation. 2. Diesel LIQUID FUELS any fuel that can be used in a diesel Advantages engine. (a) They possess higher calorific value per unit higher density than gasoline and is mass than solid fuels. simpler to refine from crude oil (b) They burn without dust, ash, clinkers, etc. commonly used in transportation (c) They are easy to transport through pipes. 3. Fuel Oil Disadvantages any liquid petroleum product that is (a) The cost of liquid fuel is relatively much higher burned in a furnace to generate heat as compared to solid fuel. Fuel oil is also the heaviest commercial (b) Costly special storage tanks are required for fuel that is produced from crude oil storing liquid fuels. The six classes of fuel oil are: (c) There is a greater risk of tire hazards, - distillate fuel oil particularly, in case of highly inflammable and - diesel fuel oil volatile liquid fuels. - light fuel oil - gasoil - residual fuel oil Petroleum or crude oil - heavy fuel oil a basic fossil fuel Residual fuel oil and heavy fuel oil are known It is a dark greenish brown, viscous commonly as navy special fuel oil and bunker mineral oil, found deep in earth's crust fuel; both of these are often called furnace fuel oil. It is mainly composed of various 4. Gasoline hydrocarbons (like straight chain paraffins, It is mainly used as fuel in internal cycloparaffins or napthenes, olefins, and combustion engines, like the engines in aromatics) together with small amounts of cars. organic compounds containing oxygen Gasoline is a mixture of paraffins, nitrogen and sulfur naphthenes, and olefins, although the specific ratios of these parts depends on Classification of Petroleum the refinery where the crude oil is 1. Paraffinic Base Type Crude Petroleum processed. This type of petroleum is mainly Gasoline is called different things in composed of the saturated hydrocarbons different parts of the world. Some of these from CH4 to C35H72 and a little of the names are: petrol, petroleum spirit, gas, napthenes and aromatics. The petrogasoline, and mogas. hydrocarbons from C18H38 to C35H72 are 5. Kerosene sometimes called waxes. Kerosene is collected through fractional 2. Asphaltic Base Type Crude Petroleum distillation at temperatures between 302° It contains mainly cycloparaffins or Fahrenheit and 527° Fahrenheit. napthenes with smaller amount of It is a combustible liquid that is thin and paraffins and aromatic hydrocarbons. clear. 3. Mixed Base Type Crude Petroleum Kerosene is most commonly used as jet It contains both paraffinic and asphaltic fuel and as heating fuel hydrocarbons and are generally rich in 6. Liquefied Petroleum Gas semisolid waxes Liquefied Petroleum Gas is a mixture of gases that are most often used in heating Main Products of Petroleum appliances, aerosol propellants, and refrigerants.  Different kinds of liquefied petroleum gas, distribution between about 8 and 16 or LPG, are propane and butane. carbon numbers; wide-cut or naphtha- type jet fuel 7. Lubricating Oil (including JetB), between about 5 and 15 Lubricating oils consist of base oils and carbon numbers additives Mineral oils are manufactured by special processes called: solvent solvent extraction, extraction, catalytic dewaxing, hydrocracking, and isohydromerization. Different lubricating oils are classified as paraffinic, naphthenic, or aromatic. 8. Paraffin Wax Paraffin wax is a white, odorless, tasteless, waxy solid at room temperature. It is an excellent electrical insulator, second only to Teflon, a specialized product of petroleum. Paraffin wax is used in drywall to insulate buildings 9. Bitumen Bitumen, commonly known as tar, is a thick, black, sticky material. used in paving roads and waterproofing roofs and boats also-made into thin plates and used to soundproof dishwashers and hard drives in computers 10. Petrochemicals Petrochemicals are the chemical products made from the raw materials of petroleum These chemicals include: ethylene, used to make anesthetics, antifreeze, and detergents; propylene, used to produce acetone and phenol; benzene, used to make other chemicals and explosives; toluene, used as a solvent and in refined gasoline; and xylene is used as a solvent and cleaning agent. 11. Jet fuel Jet fuel is a type of aviation fuel designed for use in aircraft powered by gas- turbine engines. It is clear to straw-colored in appearance. Jet fuel is a mixture of a large number of different hydrocarbons. The range of their sizes (molecular weights or carbon numbers) is restricted by the requirements for the product, for example, freezing point or smoke point. Kerosene-type jet fuel (including Jet A and Jet A-1) has a carbon number