Calculation method of electric arc furnace grafit elektrod consumption
The grafit elektrod is the last part of the short network of electric arc furnace power supply. Through the end of the grafit elektrod, a strong electric arc is generated to melt the charge and heat the molten steel. That is, the electrode is the central hub that converts electrical energy into heat. The electrode is subjected to high temperature when working, and the furnace gas is oxidized. As well as the effects of collapse and impact, especially the connection of the two electrodes, the resistance is higher and the conductivity is lower than other places, and it is easy to trip, oxidize, fall off, and break, which causes great consumption of electrodes and prolongs the smelting time. Reduced productivity.
The normal consumption of the electrode is divided into front-end consumption and side-side consumption, which can be calculated by the following formula:
Normal electrode consumption: CE=Cγ+Cs
Front end consumption: Cγ=Vγ·/W, Vγ=Kγ·I2/dnγ
In the formula: — Electric furnace power supply time, h;
W———Electric furnace tapping weight, t;
Vγ———the front end consumption speed of the electrode, kg/h;
Kγ-front-end consumption constant (for AC arc furnace, Kγ=0.0361 and n usually take 0.58);
I-arc current intensity, kA;
dγ—The diameter of the front end of the electrode, m.
Side consumption: Cs=Vs·/W, Vs=3Ks·S
In the formula: — Electric furnace smelting cycle, h;
W———Electric furnace tapping weight, t;
Vs———The consumption speed of the electrode side, kg/h;
Ks———oxidation consumption rate, kg/(m2·h);
S————The oxidation surface area in the electrode furnace, m2.
At present, in the production process, the electrode consumption model has been widely recognized. Wang Mingli and others believe that once the smelting process is stabilized, the current supplied has the greatest impact on the electrode unit consumption, and according to the model, the 60 t EAF current on the electrode consumption and smelting time is obtained. The impact of this is shown in Table 1.
Table 1 The influence of current on electrode unit consumption and smelting time
It is generally believed that the two concepts of net consumption and gross consumption coexist in calculating electrode consumption in the smelting process. Net consumption refers to the technical consumption of electrodes consumed by high-temperature sublimation, oxidation, and reaction in the smelting process; gross consumption is the net consumption and gross consumption. The sum of losses caused by not participating in smelting, that is to say, the aforementioned grafit elektrod consumption model is only technical consumption, which is classified as net consumption. Gao Zhanbiao and others believe that the steel industry mainly uses the following two methods to calculate grafit elektrod consumption at this stage.
(1) Yield method
The production method is based on the amount of molten steel (finished products) produced in a certain period of time, and the consumption of grafit elektrod minus the remaining amount on the furnace during the same period.
Gross consumption per ton of steel grafit elektrod
Net consumption per ton of steel grafit elektrod:
In the formula: MZ———the total consumption of electrodes (input amount-remaining amount on the furnace), kg/t;
MC———The pure consumption of the electrode (input amount-remaining amount on the furnace-loss amount), kg/t;
MG—The amount of finished molten steel, t.
(2) Electricity consumption method.
The electricity consumption method is based on the cumulative amount of electricity consumption for pure heating time in a certain period of time, and the input amount of grafit elektrod in the same period is subtracted from the remaining amount on the furnace as the consumption (the LF furnace is calculated based on the electricity consumption and electrodes per 1 °C of heating. ).
Electrode consumption per kilowatt hour
In the formula: MC———the pure consumption of the electrode (input amount-remaining amount on the furnace-loss amount), kg/t;
QH—The cumulative amount of electricity consumption during pure heating time, kW·h.
At this stage, when calculating the electrode loss, iron and steel companies generally include the amount of loss due to not participating in the smelting process at the same time. This can more fully reflect the center of gravity and key points of the loss in the electric arc furnace steelmaking production process, so as to find The deficiencies in the process parameters should be resolved.