Steam Turbine and Power Generation Feb28

Steam Turbine and Power Generation...

Steam Turbine and Power Generation A steam turbine is a mechanical device that converts thermal energy of the pressurized steam into useful mechanical work. It is the heart of a power plant. It has a higher thermodynamic efficiency and a lower power-to-weight ratio. It derives most of its thermodynamic efficiency because of the use of multiple stages in the expansion of the steam which results in a closer approach to the ideal reversible process. Steam turbines are one of the most versatile and oldest prime mover technologies being used to drive a generator. Power generation using steam turbines has been in use for more than 100 years. A turbo generator is the combination of a turbine directly connected to a generator for the generation of electrical power. Large steam power generators provide the majority of the electric power. Steam turbines are ideal for very large power configurations used in power plants because of their higher efficiencies and lower costs. In a power plant, the steam turbine is attached to a generator to produce electrical power. The turbine acts as the more mechanical side of the system by providing the rotary motion for the generator, while the generator acts as the electrical side by employing the laws of electricity and magnetism to produce electrical power. In a steam turbine rotor is the spinning component that has wheels and blades attached to it. The blade is the component that extracts energy from the steam. A typical schematic diagram of afossil fuel powered steam turbine based  power plant for electricity generation is given in Fig 1  Fig 1 Schematic diagram for steam turbine based power generation The energy conversion process Steam has the following three components of energy components Kinetic energy –  by virtue of its velocity Pressure energy...

Terms used related to Steam...

Terms used related to Steam The terms used related to steam are given below. Absolute pressure – It is gauge pressure plus atmospheric pressure. Atmospheric pressure – It is the normal pressure of the atmosphere on the sea level at 0 deg C. Boiling point – It is the temperature (100 deg C) at which water boils. Water boils when its absolute pressure reaches the vapour pressure. Condensation – It is defined as the change in the physical state of water vapour to liquid water. It is reverse of vaporization. Condensate – It is the liquid phase produced by the condensation of steam. Density of steam – It is the mass of steam per unit of volume of steam at the given pressure and temperature. It is the reciprocal of the specific volume. Dry saturated steam – On heating the wet steam, the water particles, which are in suspension, starts evaporating gradually and at a particular moment the final particles just evaporates. The steam at that moment is called dry steam or dry saturated steam. The resulting volume is known as specific volume of dry steam. This steam does not obey the gas laws. Dryness fraction of saturated steam – It is a measure of quality of wet steam. It is the ratio of the mass of dry steam to the mass of total wet steam. Enthalpy – Enthalpy of a system is defined as the mass of the system (m) multiplied by the specific enthalpy (h) of the system and can be expressed as H = m h, where H is enthalpy in kJ, m is mass in kg, and h is specific enthalpy in kJ/kg. Enthalpy is the total amount of heat received by 1 kg of water from O deg C at constant pressure to convert it to...

Wind Power Feb14

Wind Power

Wind Power Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth’s surface, and rotation of the earth. Wind flow patterns are modified by the earth’s terrain, bodies of water, and vegetative cover. Wind energy is the kinetic energy of air in motion. This wind energy can be harvested. Wind power is the conversion of this wind energy into a useful form of energy, such as electrical power by using wind turbines, mechanical power by using wind mills, pumping or drainage of water by wind pumps and as sails to propel ships. Wind energy is a renewable or non-conventional source of energy. This is clean and non polluting energy source. It is available in large amounts in many parts of the world. It does not generate any greenhouse gasses during the production of electricity. The total amount of economically extractable power available from the wind is very high.  Axel Kleidon of the Max Planck Institute in Germany carried out a ‘top down’ calculation on how much wind energy there is, starting with the incoming solar radiation that drives the winds by creating temperature differences in the atmosphere. He concluded that somewhere between 18 TW and 68 TW (Terawatt which is one trillion watts) could be extracted. Cristina Archer and Mark Z. Jacobson presented a ‘bottom-up’ estimate based on actual measurements of wind speeds. As per this estimate there is 1700 TW of wind power available at an altitude of 100 meters over land and sea. Out of this available power, between 72 and 170 TW could be extracted in a practical and cost competitive manner. They later estimated it to be 80 TW. However research at Harvard university estimates 1 Watt/Sq m on an average and...