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ALTERNATIVE FUELS Lecture 5, Fuel Tech-ll - Copy.pptx

  1. Conventional and non-conventional Energy  Conventional sources of energy (e.g. coal, petroleum and natural gas) are non-renewable sources of energy. Non- conventional sources of energy (e.g. solar and wind energy) are renewable sources of energy.
  2. overview World energy consumption has been steadily increasing for a variety of reasons which include;  Enhancements in quality of life  population increase  industrialization  rapid economic growth of developing countries  increased transportation of people and goods There are many types of fuel available worldwide, the demand for which strongly depends on application and use, location and regional resources, cost, “cleanness” and environmental impact factors, safety of generation and utilization, socioeconomic factors, global and regional politics, etc. The energy utilization cycle consists of three phases: generation, distribution, and consumption, all of which must be closely balanced for an ideal energy infrastructure. Any shortage would immediately affect the entire cycle as a limiting factor. Further, based on the supply and demand principle, the consumer price of this fuel type would undoubtedly rise. Even a breakdown in the transportation system of a certain fuel type would affect the consumer market directly, and consequences such as fuel shortage and price hike would be realized at least for a limited time in the affected region. Study suggest that if exploited at the same rate, the coal reserve will deplete in the next century, and petroleum deposits will deplete in the coming few years. So it is important for us to engage in research and development of alternative fuels so we may not face scarcity of natural resources in the future.
  3. Needs for Alternative Fuels 1. Diminishing reserve of conventional fuels 2. To reduce environmental pollution 3. To protect against global warming 4. To reduce import cost and improve nations economy 5. Meeting the current global energy demanding
  4. Needs for Alternative fuels 1. Diminishing reserve of conventional fuels The traditional fuels including petroleum would be depleted after sometimes, because that are not renewable 2. To reduce environmental pollution The use of alternative fuels considerably decreases harmful exhaust emission (such as carbon dioxide, carbon mono oxide , particulate matter and sulfur dioxide) as well as ozone-producing emission
  5. Needs for Alternative fuels 3. To protect against global warming According to a commonly accepted scientific theory, burning fossil fuel was causing temperature to rise in the earth atmosphere (global warming). Though global warming continues to be just a theory, a lot of people across the globe are of the belief that discovering sources of cleaner burning fuel as an essential step towards enhancing the quality of our environment.
  6. Needs for Alternative fuels 4. To reduce important cost and improve nations economy The majority of oil field located in middle east are associated with problems, both political and economic, so the production rate is uncertain and may or may not meet the demand. This cause rise in price abruptly. On the other hand the feed stock for alternative fuels are renewable and can be and can be produce locally with less expenses. This interns means saving of money in the long time. 5. Meeting the current global energy demand Every day an increase in demand of energy has create large gap between demand and supply.
  7. Properties of alternative fuels Key properties for alternative fuels to be considered are;  Combustion and Performance: heat of combustion, heat contents for Stoichiometric mixture, octane number(SI engine), Cetane number(CI engine), boiling points, flammable limits  Emission: chemical composition and nature, adiabatic flame temperature  Storage and Handling: Boiling points, volumetric energy, density, vapour pressure, flammability limits
  8. Properties of alternative fuels  Volatility: volatility is one of the main characteristics properties of petro/gasoline which determines its suitability for use in an SI engine. Since gasoline is a mixture of different hydrocarbons, volatility depends on the fractional composition of the fuels. The usual practice of measuring the fuels volatility is the distillation of the fuels in a special device at atmospheric pressure of known vapour.  Starting and Warm up: a certain part of the gasoline should vaporize at the room temperature for easy starting of engine. As the engine warm-up, the temperature will gradually increases to the operating temperature.
  9. Properties of alternative fuels  Antiknock Quality: abnormal burning or detonation in Si engine combustion chamber causes a very high rate of energy release, excessive temperature and pressure inside the cylinder adversely affects its thermal efficiency. therefore, the characteristics of the fuels used should be such that it resist the tenancy to produce detonation and this properties is called its antiknock property  Gum Deposits: reactive hydrocarbon and impurities in the fuel have tendency to oxidize upon storage and form liquid and gummy substances. A gasoline with high gum contents will cause operating difficulties such as sticking values and piston rings carbon deposits in the engine, gum deposits in the manifolds, clogging of carburetors jets and enlarging of the valve stems , cylinders and piston.
  10. Properties of alternative fuels  Sulfur Contents: Hydrocarbon fuels may contain free sulphur, hydrogen sulphide and other sulphur compounds which are objection able for several reasons. The sulphur is a corrosive element of the fuel that can corrode fuel lines, carburettors and injection pumps and it will unite with oxygen to form sulphur dioxide that, in the presence of water at low temperatures, may form sulphurous acid . The presence of sulphur can reduce the self- ignition temperature, then promoting knock in the SI engine  Viscosity : CI engine fuels should be able to flow through the fuel system and the strainers under the lowest operating temperatures to which the engine is subjected to. SI Engine: Higher Octane number is required (above 86-94) CI Engine: Above 45 Cetane number is preferred 18
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