How to save more electricity in the induction melting furnace production process
Induction melting furnaces are widely used because of their low investment, quick effect and convenient operation.
Based on the production characteristics of induction furnaces and our many years of production practice experience, our company has explored the power-saving ways of induction furnace production from medium-frequency furnaces by improving production efficiency, increasing melting speed and reducing melting time.
First of all, reasonable ingredients
The scientific management of the charge material is of great significance for improving the production efficiency and reducing energy consumption of the induction furnace of the intermediate frequency furnace. First of all, we must master the chemical composition of the various charge materials used, and carry out careful and reasonable calculation of the ingredients to make reasonable use of various materials. The main chemical components in the molten steel meet the requirements, and the content of harmful impurities is as small as possible and does not exceed the standard. Delaying the smelting time by adjusting the composition, eliminating the scrapping of molten steel due to unqualified components, increasing material consumption and power consumption. To this end, the charge must be properly classified according to chemical composition, impurities and block size, cutting large and long scrap steel, and conditionally coping with light and thin materials to ensure smooth feeding and reducing melting time. The size of the charge should be adapted to the frequency of the power supply. The power frequency of the induction furnace is reduced as the capacity of the furnace increases. Therefore, a large-capacity induction furnace can use a large charge, and a small-capacity induction furnace uses a small charge.
The distribution of induced currents in multi-metal conductors obeys the skin effect. The induced current in the charge and the molten steel is obeyed by the skin effect and is attenuated from the surface to the center. The distance from the point where the current intensity is reduced to 36% of the surface current intensity to the surface of the conductor is called the penetration depth of the current. The induced current in the charge mainly concentrates into the depth layer, and the heat of the enhanced hot material is mainly supplied from the surface layer. In order to obtain the same temperature across the entire cross section of the charge, as the heating time is extended, the amount of heat lost from the charge to the surrounding medium increases, and the thermal efficiency decreases. If the penetration depth layer and the charge geometry are properly matched, the heating takes a short time and the thermal efficiency is high.
Studies on cylindrical metal materials have shown that the total efficiency is highest when the ratio of the diameter d of the cylinder to the depth Δl of the penetration is 35.
Extending the continuous smelting time The single unit of electricity consumption has a lot to do with the smelting method. The working mode of the furnace can be divided into three cases:
1) Continuous smelting: three consecutive daily operations;
2) Intermittent smelting: two shifts or one shift per day. During non-operational period, the molten iron in the furnace is insulated with insulation power;
3) Intermittent smelting: All are cleaned after daily completion. Obviously, in the above three cases, the continuous smelting power consumption is the lowest, the intermittent smelting is the second, and the intermittent smelting is the highest. Therefore, centralized smelting should be arranged as much as possible under conditions. Try to increase the number of smelting furnaces as much as possible to extend the duration of smelting and reduce electricity consumption. The total tonnage of molten iron that can be expected to be achieved during the service life of the silicon lining is evaluated according to the following empirical formula: N=K(G2L) 1/3 of the formula: IV_total molten tonnage, T; GL——furnace capacity ,kg;K——constant; the cold material melts once a day, K=l_3~l 8; the cold material melts once a week (6 h to 7 h per day), K=2.8-4.6: weekly cold The material is melted once (more than 18 hours per day). K=6. O-9.0.
It can be seen from the above formula that when the furnace capacity is constant, N is proportional to K, that is, the longer the melting cycle of the furnace. The bigger the IV. The longer the furnace life. The consumption and energy consumption per ton of molten iron liquid is lower. Taking 1.5 t refining and casting steel intermittent smelting as an example, the smelting time is roughly the first furnace smelting time is about 100 min. After that, the furnace is smelted by about 80 mln, and the furnace is smelted for 30 minutes longer than the hot furnace smelting. If this time is heated by 60% power, which is equivalent to 100% power for 18 minutes, then when the furnace is smelted for 5 times, the total time of smelting About 422 mlR, the time of cold furnace multi-use accounted for 18/422=4.2%. When 10 furnaces were smelted once, the total melting time was about 722 min. The time spent on the cold furnace accounted for 18/722 = 2.4%. Compared. The time for smelting 10 furnaces is reduced by 18.8% compared with the time when the furnaces are more than 5 furnaces. That is, energy can be saved by 8%. A continuous smelting furnace has many times and a long time. When the output is constant, the number of cold furnace smelting is small. Due to the high and low temperature, the furnace has less chance of cracking, which is also beneficial to extend the life of the lining.
