FOSSIL FUELS &ALTERNATIVE ENERGY SOURCES презентация

FOSSIL FUELS & ALTERNATIVE ENERGY SOURCES HASEEB HAKKIM 4TH YEAR CHEM MAJOR IISER MOHALI

OUTLINE

FOSSIL FUELS ► Fossil fuels are basically any carbon based substance that is used by mankind as a source of energy. They are formed by natural processes such as anaerobic decomposition of buried dead organisms. ► Fossil fuels contain high percentages of carbon and include coal, petroleum, and natural gas . They 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. ► Fossil fuels are of great importance because they can be burned (oxidized to carbon dioxide and water), producing significant amounts of energy per unit weight. ► Fossil Fuels are a nonrenewable resource because they were formed from the remains of plant and animal matter from over 65 million years ago. Once they are gone, they are gone forever!

FOSSIL FUEL COMBUSTION Burning fossil fuels is responsible for environmental issues that are high on the political agenda these days. Examples are greenhouse gas accumulation, acidification, air pollution, water pollution, damage to land surface and ground-level ozone. The principal air pollutants resulting from fossil fuel combustion are the following: (a) carbon monoxide (b) the oxides of sulfur, SO2 and SO3 (represented as SOx) (c) the oxides of nitrogen, NO and NO2 (NOx) (d) ‘particulates’, consisting primarily of very fine soot and ash particles. ► Carbon monoxide (CO) is a product of incomplete combustion of any fuel. It is both a highly poisonous gas and the principal constituent of photochemical smog. ► Sulfur oxides arise during combustion from oxidation of sulfur in sulfur containing fuels (some coals and some petroleum-based products). The principal product is sulfur dioxide: S (in fuel) + O2 --> SO2 When it is released to the atmosphere, it can react with oxygen in the air to form sulfur trioxide: 2 SO2 + O2 --> 2 SO3

► Particulate Matter emissions (soot and fly ash) are also a concern because they can contribute to long-term respiratory problems. Many of these particles are extremely small, of the order of 10 micrometer or less, and they are thus suspended in the air we breathe. After inhaling them, they get trapped in the very thin air passages inside the lungs. Over a period of years this reduces the air capacity of the lungs. Reduced air capacity leads in turn to severe breathing and respiratory problems. Chronic asthma or emphysema can result, as well as increased general susceptibility to respiratory diseases. ► Particulate Matter emissions (soot and fly ash) are also a concern because they can contribute to long-term respiratory problems. Many of these particles are extremely small, of the order of 10 micrometer or less, and they are thus suspended in the air we breathe. After inhaling them, they get trapped in the very thin air passages inside the lungs. Over a period of years this reduces the air capacity of the lungs. Reduced air capacity leads in turn to severe breathing and respiratory problems. Chronic asthma or emphysema can result, as well as increased general susceptibility to respiratory diseases.

ALTERNATIVE ENERGY SOURCES

DIFFERENT ALTERNATIVE ENERGY SOURCES

SOLAR ENERGY “I’d put my money on the sun and solar energy. What a source of power! I hope we don’t have to wait ‘til oil and coal run out before we tackle that.” - Thomas Edison

PASSIVE SOLAR HEATING

ACTIVE SOLAR HEATING

SOLAR WATER HEATING

HYDROELECTRIC ENERGY A hydroelectric plant uses the flow of water from a higher to a lower elevation to generate power. Hydroelectric plants provide about 20% of the world’s electricity.

IMPOUNDMENT POWER PLANT The most common type of hydroelectric power plant is an impoundment facility. An impoundment facility, typically a large hydropower system, uses a dam to store river water in a reservoir. Water released from the reservoir flows through a turbine, spinning it, which in turn activates a generator to produce electricity. The water may be released either to meet changing electricity needs or to maintain a constant reservoir level.

PUMPED – STORAGE POWER PLANT

DIVERSION POWER PLANT A diversion plant, sometimes called a run-of-river facility, in most cases does not use a dam. The plant diverts some of the river water through a canal or penstock, where the flow powers a turbine. These plants rely entirely on the flow of the river to produce electricity. There is no dam to artificially raise the height of the water. A diversion plant depends solely on the landscape to create the head.

GEOTHERMAL ENERGY Magma rising from the mantles brings unusually hot material near the surface. Heat from the magma, in turn, heats any groundwater. This is the basis for generating geothermal energy.

Geothermal energy can be used in a direct or indirect way. The choice is determined by the available temperature, the presence of a reservoir, the intended purpose and the economic context. DIRECT USE Direct uses of geothermal energy is appropriate for sources below 150C. It includes : • Space heating • Air conditioning • Industrial processes • drying • Greenhouses • Aquaculture • Hot water • Resorts and Pools • Melting snow

SPACE HEATING   Where temperatures are insufficient to meet the space heating requirements of residential or commercial buildings, Geothermal heat pumps can be used to boost the temperature to desired levels. Space heating is provided by means of pumped wells or through the use of down hole heat exchangers.

DISTRICT HEATING  

SPACE COOLING Given the proper circumstances, natural hot water may be used to space cool, too! Absorption refrigeration is a cooling process that is efficiently employed to cool areas of human occupancy. Geothermal absorption refrigeration units create "cold" by making use of a well known physical phenomena: the boiling temperature of a liquid depends on pressure; and heat is "robbed" from the environment when a liquid boils. The use of geothermal space cooling wiII depend upon the location, temperature, production (flow) rates and chemical quality of hot water in prospective geothermal reservoirs.

INDIRECT USE : GENERATION OF ELECTRICITY  

DRY STEAM POWER PLANT Steam is used directly from the wells to drive a turbine generator. Wastewater from the condenser is injected back into the subsurface to help extend the useful life of the hydrothermal system. Resource temperature range : 220°C to 320°C.

FLASH STEAM POWER PLANT Flash plants take super heated water out of the ground, allowing it to boil as it rises to the surface, then separates the steam from the water  in a surface vessel (called a steam separator) and uses the steam to turn a turbine generator. The remaining water and steam are then injected back into the source from which they were taken. Resource temperature range : 200°C to 300°C.

BINARY CYCLE POWER PLANT  In binary cycle geothermal power plants, pumps are used to pump hot water from a geothermal well, through a heat exchanger, and the cooled water is returned to the underground reservoir. A second "working" or "binary" fluid with a low boiling point, typically a Butane or Pentane hydrocarbon , is pumped at fairly high pressure  through the heat exchanger , where it is vaporized and then directed through a turbine. The vapor exiting the turbine is then condensed by cold air radiators or cold water and cycled back through the heat exchanger.  1- Wellheads , 2 - Ground surface , 3 -Generator  4 - Turbine, 5 -Condenser, 6 - Heat exchanger , 7  - Pump   Resource temperature range : 120°C to 190°C.

WIND POWER Wind Power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electrical power, windmills for mechanical power, wind pumps for water pumping or drainage, or sails to propel ships. It is predicted that by 2030, wind energy will supply at least twice the electricity it does now.

WIND POWER PLANT A wind turbine or wind power plant is a device that converts kinetic energy from the wind into electric current . Modern wind turbine generators are highly sophisticated machines, taking full advantage of state-of-the-art technology, led by improvements in aerodynamic and structural design, materials technology and mechanical, electrical and control engineering and capable of producing several megawatts of electricity. A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades. The rotor is connected to the main shaft, which spins a generator to create electricity. The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed. The kinetic energy of a moving body is proportional to its mass (or weight). The kinetic energy in the wind thus depends on the density of the air, i.e. its mass per unit of volume. In other words, the "heavier" the air, the more energy is received by the turbine.

OCEAN ENERGY Ocean energy or ocean power refers to the energy carried by ocean waves, tides, salinity, and ocean temperature differences. The movement of water in the world’s oceans creates a vast store of kinetic energy, or energy  in motion. This energy can be harnessed to generate electricity to power homes, transport and industries.

WAVE ENERGY Waves are caused by a number of forces, i.e. wind, gravitational pull from the sun and moon, changes in atmospheric pressure, earthquakes etc. Waves created by wind are the most common waves. Unequal heating of the Earth’s surface generates wind, and wind blowing over water transfers energy and thus generates waves.

FLOATING DEVICE METHOD

TAPERED CHANNEL METHOD As a wave enters the collector, the surface of the water column rises and compresses the volume of air above it. The compressed air is forced into an aperture at the top of the chamber, moving past a turbine. As the wave retreats, the air is drawn back through the turbine due to the reduced pressure in the chamber.

TIDAL ENERGY

Open-cycle OTEC uses warm surface water directly to make electricity. The water from the surface is put into a near vacuum. A near vacuum is a container which has had most of the air sucked out of it. This allows the water from the surface to turn into steam, because when water is in a near vacuum its boiling temperature is lower.

OCEAN THERMAL ENERGY CONVERSION (OTEC)

BIOMASS ENERGY

CONCLUSION Most of the world still relies very heavily on fossil fuels, but slowly but surely, attention is being diverted to alternative energy. The most important aspects of most alternative energy sources is that they promise clean, pollution-free energy. Energy use in the future will not be dominated by a single source.

REFERENCES http://www.energysavers.gov/renewable_energy/ocean/index.cfm/mytopic=50009 http://www.consumerenergycenter.org/homeandwork/homes/construction/solardesign/direct.html http://www.climatehotmap.org/ Bertani R., 2005: World geothermal power generation in the period 2001–2005. Geothermics, 34,651–690. http://www.wbdg.org/media/pdf/mh1003_19.pdf http://www1.eere.energy.gov/biomass/initiative_sheet.pdf

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