How to save power in the production process of intermediate frequency induction furnace
Intermediate frequency induction furnaces are widely used due to their advantages of less investment, quicker results and convenient operation.
Luoyang Huatong Medium Frequency Furnace According to the production characteristics of induction furnace and my many years of practical experience in production, from the aspects of improving production efficiency, increasing the melting speed, reducing the melting time, this paper discusses the power saving methods of the induction furnace production.
First of all, reasonable ingredients
The scientific management of concrete materials is of great significance to improve the production efficiency of intermediate frequency furnace induction furnace and reduce energy consumption. First of all, you must master the chemical composition of the various charge materials. You must carefully and reasonably calculate the ingredients and use the reasonable mix of various charge materials to ensure that the main chemical components in the molten steel meet the requirements. Delaying the smelting time due to adjusting the composition, preventing scrap of the molten steel due to unqualified components, increasing material consumption and power consumption. For this reason, the charge must be properly classified according to the chemical composition, the impurity content, and the size of the block, cutting large and long scrap steel, and conditions for light and thin materials to be packed to ensure smooth feeding and reduce melting time. The block size of the charge should be adapted to the frequency of the power source. The frequency of the power source used in the induction furnace decreases with the increase of the furnace capacity. Therefore, large-capacity induction furnaces can use large pieces of charge, and small-capacity induction furnaces use small pieces of charge.
The distribution of induced current in polymetallic conductors is subject to the skin effect. The induced currents in the charge and molten steel are sequentially weakened from the surface to the center following the skin effect. The distance from the point where the current strength decreases to 36.8% of the surface current strength to the conductor surface is called the current penetration depth. The induced current in the charge is mainly concentrated in the depth layer, and the heat to strengthen the 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 increases, the heat lost to the surrounding medium by the charge increases, thereby reducing the thermal efficiency. If the penetration depth layer and the geometrical size of the charge are properly matched, the time required for heating is short and the thermal efficiency is high.
The research on cylindrical metal materials shows that the total efficiency is highest when the ratio of the diameter d of the cylindrical shape and the penetration depth Δl is 35.
Extending the continuous smelting time The unit power consumption has a great relationship with the smelting method. The working method of the furnace can be divided into three cases:
1) Continuous smelting: three continuous operations per day;
2) Intermittent smelting: two shifts or one shift operation per day. During non-operation period, the molten iron in the furnace is insulated by the insulation power;
3) Intermittent smelting: after the completion of the daily operation, all the nets are apparent. When operating in the above three cases, the unit energy consumption of continuous smelting is the lowest, followed by intermittent smelting, and the highest is intermittent smelting. Therefore, if possible, centralized continuous smelting should be arranged as far as possible. Increase the number of smelting furnaces as much as possible to extend the continuous smelting time and reduce power consumption. The total tonnage of molten iron that can be expected during the service life of the silicon furnace lining is evaluated according to the following empirical formula: N = K (G2L) 1/3
In the formula: Ⅳ_Total tonnage of molten molten iron, T; GL——furnace capacity, kg;
K——constant; cold material melts once a day, K = l_3 ～ l 8; cold material melts once a week (6h-7h for daily operation), K = 2.8—4.6
The cold material is melted once a week (over 18 hours per day). K = 6.O-9.0.
It can be known 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 cold furnace. The larger the IV. The longer the furnace life. The lower the consumption of molten iron material and energy consumption per ton of molten iron. As an example, the batch smelting of cast steel is about 100 minutes. The smelting time of the first furnace is about 100 minutes. Then, the smelting time of the hot furnace is about 80 mln. The cold furnace smelting time is 30 minutes longer than that of the hot furnace. Heating with 60% power is equivalent to 18min at 100% power. Then, when 5 furnaces are smelted at one time, the total melting time is about 422 mlR, and the multi-use time of the cold furnace is 18/422 = 4.2%. When 10 furnaces are smelted at one time, the total melting time is about 722 min. The time spent in the cold furnace is 18/722 = 2.4%. In comparison, the 10-time melting time of a 10-melting furnace is reduced by 18% compared to the 5-time cooling furnace of a melting furnace. That is, the power can be saved by 18%. The continuous smelting furnace has many times and long time. When the output is constant, the number of melting times of the cold furnace is small. Because of the high and low temperature, the chance of cracking on the furnace pair is small, which is also conducive to extending the life of the furnace lining.