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50tonElectricarcfurnace

50ton Electric arc furnace

EAF-50t电弧炉

EAF


 EAF-50t Electric Arc Furnace


The actual power consumption per ton of steel is 610-180-200-10=220 kWh


Namely, the actual electrical energy needed for melting, phosphorus removal and heating up to the tapping temperature of 50% scrap steel and 50% molten iron in the arc furnace, (1630) is 220 kWh/t (e.g. oxygen blasting50Nm3, metal charging 60%, electrical consumption 160kWh/t).


4. Main technical and economic indexes of the electric furnace.


Main technical and economic indexes of the electric furnace are shown in Table 1-5.


Table 1-5 Main technical and economic indexes of arc furnace

Type of steel

transformer capacity /MVA

Average tapping output /t

Max tapping output /t

Cycle of smelting /min

Power consumption of smelting kWh/t

Electrode

consumption

/kg/t

Amount of oxygen blasting /Nm3/t

Time of oxygen blasting /min

Structural Steel

22

55

60

68

220

<2.2

50

45


The key points to achieve the above indexes are: 1) Oxygen lance in furnace door; 2) the   secondary charging together with molten iron feeding thermal idle time should be less than 16 min.


The high-quality super high power graphite electrode shall be adopted.


II. Technical specifications and explanation of 50t electric arc furnace


1. Technical specifications for 50t electric arc furnace equipment


Technological conditions and technical parameters for 50t arc furnace


1.1                      Technological conditions and main requirements


The process flow of electric arc furnace is: 50t arc furnace + 60tLF refining furnace + continuous casting  trinity process flow. Such techniques as furnace wall burner and oxygen lance in furnace door are adopted in the arc furnace equipment and process. Carbon steel is mainly produced.

Requirements for main process technical parameters of 50t arc furnace are shown in Table 2-1


Table 2-1 Requirements for main technical parameters of 50t arc furnace

No.

Name

Unit

Parameter

Remark

1

Number of furnaces in workshop

Piece

2


2

Nominal capacity

t

50

Alternating current

3

Average tapping of molten steel 

t

55


4

Max. tapping of molten steel  

t

60


5

EBT hot heel

t

79


6

Tap to tap period  

Min

68

Mix 50% iron melt

7

Rated capacity of transformer

MVA

22


8

Burner

Piece

3

3-5 MW/piece


Requirements for main performance and technological guarantee values for the 50t arc furnace equipment see Table 2-2


Table 2-2 Requirements for main performance and process guaranteed values of 50t arc furnace equipment

No.

Items to be checked

Unit

Parameter

Remarks

1

Tap to tap period

Min

68


2

Average tapping

T

55


3

Average power factor


0.8


4

Three-phase impedance unbalanced coefficient

%

5



1.2                      Technical parameters on designing 50t arc furnace


According to Technological conditions and technical requirements, main technical parameters of 50t arc furnace see Table 2-3


Table 2-3 Main technical parameters of 50t arc furnace

No.

Name of technical parameter

Specification /requirement

Remarks

1

Nominal capacity

50t


2

Average

tapping output

55t


3

Quantity of EBT hot heel

79t


4

Internal diameter of furnace shell

Φ5200mm


5

Rated capacity of the transformer

22MVA

Self-supply by user

6

Primary voltage of transformer

34.5KV

Frequency 60Hz

7

Secondary voltage

410V-320V-170V


8

Voltage regulation mode

17 grade electric pressure regulating on load


9

Secondary rated current

39.692KA


10

Cooling mode

Forced oil circulative water cooling


11

Three-phase impedance imbalance coefficient

5%


12

Graphite electrode diameter

Φ450

Super high power electrode

13

Electrode pitch circle diameter

Φ1200


14

Electrode lifting speed

Auto: hoist 6m/min fall 4m/min

Manual: hoist 9m/min; fall 6m/min


15

Max travel of electrode lifting

3700mm


16

Tilting angle

EBT tapping 20°; slag tapping 12°


17

Furnace tilting speed

Tapping; slag tapping 01°/s; return dumping 3°/S


18

Hoisting height of furnace roof

450mm


19

Lifting time of furnace roof

Hoisting 15sfall 20s


20

Max Rotary angle of furnace roof

75°


21

Rotary time of furnace roof

Out/back 50s


22

Dimension of the furnace door

1100mm×800mm


23

Hydraulic system




Working pressure

12MPa



Working medium

Water --glycol

Shenzhen Houghton Co., Ltd.


Electrode fluctuation

Oil tank  electro-hydraulic proportional valve


24

Pneumatic system




Consumption

5m3/min



pressure

0.4Mpa


25

Water-cooling system




Flow

620m3/h



Intake pressure

0.450.55MPa



Intake temperature

35



Temperature of backwater

55


26

Requirement for water quality




PH value

78.5



Total hardness

10° DH



Suspended solid

10mg/L



Alkalinity

60mg/L



Chlorine ion

Mean 60mg/L



Sulfuric ion

100mg/L



Conductance rate

50 mille Siemens /m


27

Hoisting weight of lower furnace body

90t

The weight of refractory is included