Induction Furnace and Important Operational Aspects Feb14

Induction Furnace and Important Operational Aspects...

Induction Furnace and Important Operational Aspects   The development of the induction furnace for steel making has been a boon to the small steel producers. These furnaces are easy to install, operate and maintain. These furnaces are smaller in heat size with a low cost investment and preferred by lower capacity steel plants. In these furnaces, steel is produced by melting the charge material using the heat produced by electromagnetic field. The induction furnace consists basically of a crucible, inductor coil, and shell, cooling system and tilting mechanism. The crucible is formed from refractory material, which the furnace coils is lined with. This crucible holds the charge material and subsequently the melt. The choice of refractory material depends on the type of the charge and basically consist of either acidic, basic or neutral refractories. The inductor coil is a tubular copper coil with specific number of turns. An alternating current (AC) passes through it and magnetic flux is generated within the conductor. The magnetic flux generated induces eddy currents that enable the heating and subsequently the melting process in the crucible. The shell is the outer part of the furnace. This houses the crucible and the inductor coils, and has higher thermal capacity. It is made of rectangular parallelepiped with low carbon steel plate and joined at the corners by edge carriers from angular pieces and strips of non-magnetic metal. The cooling system is normally a through one way flow system with the tubular copper coils connected to water source through flexible rubber hoses. The cooling process is important because the circuit of the furnace appears resistive, and the real power is not only consumed in the charged material but also in the resistance of the coil. This coil loss as well as the loss...

Delegation of Power

Delegation of Power  Delegation of power (DOP) is also known as ‘Delegation of Authority’ (DOA). It is one of the vital processes for any organization. It is inevitable along with the expansion and growth of the organization. Delegation means assigning of certain responsibilities along with the necessary authority by the management of the organization to the employees. Delegation does not mean surrender of authority by the management. It only means transfer of certain responsibilities to the employees and giving them the required authority, which is necessary for the discharge of the responsibility properly. DOP is defined in many ways. Some of the definitions are given below. “Delegation means assigning work to the others and giving them authority to do so” “Delegation takes place when one person gives another the right to perform work on his behalf and in his name and the second person accepts a corresponding duty or obligation to do that is required of him. “Delegation is the dynamics of management, it is the process a manager follows in dividing the work assigned to him so that he performs that part which only he, because of his unique organizational placement, can perform effectively, and so that he can get others to help him with what remains. “Delegation is the assignment of responsibility or authority to another person (normally from a manager to a subordinate) to carry out specific activities. It is one of the core concepts of management leadership.” “Delegation of authority can be defined as subdivision and sub-allocation of powers to the subordinates in order to achieve effective results.”  Characteristics of delegation of power The following are the characteristics of DOP. It involves transfer not surrendering of authority. It is a process of sharing work, granting authority and creating accountability. Delegation takes...

Transmission of Electric Power Mar06

Transmission of Electric Power...

Transmission of Electric Power Transmission of electric power is a process by which the electric power produced at power plants is transported in bulk quantities over long distances for eventual use by consumers. Electric power is sent from generating power plants to the end consumer by transmission lines. Transmission lines, when interconnected with each other, become transmission networks. This transmission network along with power stations and substations is known as ‘transmission grid’ or simply ‘grid’. A typical transmission grid is shown in Fig 1. The transmission networks which are interconnected at the national level are known as ‘National grid’. Energy is usually transmitted within a grid with three phase alternating current (AC). Due to the involvement of large quantity of electric power and due to the properties of electricity, transmission involving long distances normally takes place at high voltage (33 kV or above). Electric power is usually transported to a substation near the consuming point which is either a populated area or an industrial complex. At the substation, the high voltage electric power is converted to lower voltages suitable for consumer use, and then transported to the end users through low voltage electric distribution line Fig 1 Typical transmission grid Transmission efficiency and transmission losses Transmitting electricity at high voltage reduces the fraction of energy lost to resistance, which varies depending on the specific conductors, the current flowing, and the length of the transmission line. For a given amount of power, a higher voltage reduces the current and thus the resistive losses in the conductor. Transmission efficiency is improved by increasing the transmission voltage using a step-up transformer which has the effect of reducing the current in the conductors, whilst keeping the power transmitted nearly equal to the power input. The reduced current flowing through the conductor reduces the losses...

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...

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...