Operation of the electric arc furnace – With examples.ppt

Flicker * Lowest flicker Summary For maximum productivity (t/h) is required to operate at maximum value of active power that is compatible with the dimensions of the furnace and with the characteristics of the transformer and power circuit. The active power is the product arc voltage x current“. For a given active power, the higher the arc voltage, the greater the aggression of the arc to the walls and, in general, the lower electrode consumption. The Power ON time is proportional to the specific consumption of electrical energy and inversely proportional to the active power. A greater proportion of chemical energy reduces electrical energy consumption and indirectly reduces the Power ON time. * Large furnaces operated under normal conditions like, low downtime, scrap charge density sufficient to allow a few number of charges and high metal yield (0,89/0,90), also clean charge that reduces the amount of slag and pouring temperature of 1620/1640 ° C usually require an amount of specific energy of about 545 to 565 kWh per tonne of product (billets) or 485 to 508 kWh per tonne of metal charge. A portion of the energy supplied is of chemical origin. The specific consumption of electricity depends on the amount of chemical energy provided. If a particular furnace operates with power consumption of 565 kWh/t and are supplied 165 kWh/t of chemical energy, electrical energy consumption will be 565-165 = 400 kWh/t. It is common in steel plants to establish goals to reduce just electrical consumption, when in fact, the aim should be to seek the minimum total energy consumption (electrical + chemical). * Summary Summary To get the regulator to maintain a certain current with stable arc, the circuit must have a reactance value that depends on the voltage and current used (sine phi sinusoidal = I . X. 1.73 / V must be sufficiently high for the cosine phi does not exceed certain value, e.g. 0,85 for the period of boring down). The arc stability has no d