21000kVA SUBMERGED ARC FURNACE TECHNICAL PROPOSAL.pdf

8/11/2019 21000kVA SUBMERGED ARC FURNACE TECHNICAL PROPOSAL.pdf

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Add: No.2-1803 Soubao Business Center, No.16 South-West Third Ring Road, Beijing, China.. PC100068

[email protected] TEL: 0086-10-57011358 FAX:0086-10-56298980

21000KVA SUBMERGED ARC

FURNACE TECHNICAL PROPOSAL

Beijing Bidragon Machinery Co.,Ltd

2014.9.5


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Summary

When technological parameters just conform to production of high carbon

ferromanganese, then it would not guarantee the production of silicon manganese,but conversely it could, however it could slightly affect the technical index of high

carbon ferromanganese, so this technical proposal is mainly base on the production

parameters of silicon manganese, also can produce high carbon ferromanganese.

This technical proposal has considered the technology of non-flux smelting for high

carbon ferromanganese, and the recycle problem of rich-manganous slags. The

produced products include silicon manganese, high carbon ferromanganese,

rich-manganous slags.

The trademark, raw materials requirement, technical and economical indexes for two

types of products are as follows:

I. Production technology

I. The trademark of high carbon ferromanganese and silicon manganese

Trademark and chemical component of high carbon ferromanganese

Trademark

Chemical component /%

Mn CSi P

S1 Batch 2 Batch

IGrade

IIGrade

FeMn75C7.5 75.0 7.5 1.5 2.5 0.20 0.33 0.03

FeMn70C7.0 70.0 7.0 2.0 3.0 0.20 0.38 0.03

FeMn65C7.0 65.0 7.0 2.5 4.5 0.20 0.40 0.03

Trademark and chemical component of silicon manganese

Trademark

Chemical component%

Mn Si

PS

C

FeMn64Si27 60.067.0 25.028.0 0.5 0.10 0.15 0.25 0.04

FeMn67Si23 63.070.0 22.025.0 0.7 0.10 0.15 0.25 0.04FeMn68Si22 65.072.0 20.023.0 1.2 0.10 0.15 0.25 0.04


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FeMn64Si23 60.067.0 20.025.0 1.2 0.10 0.15 0.25 0.04

FeMn68Si18 65.072.0 17.020.0 1.8 0.10 0.15 0.25 0.04

FeMn64Si18 60.067.0 17.020.0 1.8 0.10 0.15 0.25 0.04

FeMn68Si16 65.072.0 14.017.0 2.5 0.10 0.15 0.25 0.04

FeMn64Si16 60.067.0 14.017.0 2.5 0.20 0.25 0.30 0.05

II. Raw materials requirement

The raw materials are the basic foundation for smelting finished product, and the

qualified raw materials are important conditions for guarantee product quality, so the

raw materials must conform to technical requirement.

2.1 Raw materials requirement of high carbon ferromanganese

The raw materials for smelting high carbon ferromanganese: manganese ore,

rich-manganous slags, coke,lime, fluorite and electrode paste.

No. NameQualified lumpinessmm Physical and chemical properties

1Manganeseore

5100 10mm


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1Manganeseore

5100 10


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5 Dolomite kg 350400

6 Fluorite kg 100150

7 Power consumption kW.h 46004800

8Recovery rate ofmanganese

% 8385

IV. The output theoretical calculation

4.1. 21000kVA high carbon ferromanganese furnace output theoretical

calculation

Q=24CosPsk1k2k3W

=240.76210000.950.980.952900

117t/d

Note: QDaily output per furnacet/ d

h---- Production time per day 24h/d

CosPower factorcalculated by 0.76

PS----- Rated powerKVA

K1Coefficient of fluctuationPrimary voltageK1=0.95

K2Utilization factor of transformer powerK2=0.98

K3Time factorOperation rateK3=0.95

WPower consumptionW=2900 KWh

4.2. 21000kVA silicon manganese output theoretical calculation

Q=24CosPsk1k2k3W

=240.78210000.950.980.954200

83t/d

Note QDaily output per furnacet/ d

h------ Production time per day 24h/d

CosPower factor0.78

PS---- Rated powerKVA


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K1Coefficient of fluctuationPrimary voltageK1=0.95

K2Utilization factor of transformer powerK2=0.98

K3Time factorOperation rateK3=0.95WPower consumptionW=4200 KWh

V. Brief introduction of production process

5.1 High carbon ferromanganese production process flow diagram

The qualified raw materials and auxiliary materials, including manganese ore,

rich manganese slag, lime, reducing agent, flux, electrode paste, etc., are transported

to factory area after wagon balance by trucks, and separately stored in relevant raw

materials storage yard, all kinds of raw materials are mixed together according to the

Manganese ore CokeLimeRich-manganese s lag

Automatic burdening and weigh

Belt conveyor charging

21000KVA high carbonferromanganese

furnace

Electrode paste

Cooling water

35KV power source

Iron output

Casting ingot

Finishing

Packaging and leave factory

Chimney

Air cooler

Preprocessor

Draught fan

Slag output

Dust remover

Continuous casting machine


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formula of smelting alloy, then elevated to the platform of 27m delivered by belt

conveyor, the rotary distributor deliver the mixed materials to lower stock bin, and fall

into furnace through blanking pipe.

The furnace burden are charged into semi-closed submerged arc furnace,35KV

power source are lead into furnace through three-phase electrode by transformer, the

voltaic arc heat generated between electrode and furnace burden are transferred to

furnace chamber, through voltaic arc heat and resistance heat, so the mixture of

manganese ore and rich manganese slag can reduce to high carbon ferromanganese,

during the whole process of smelting, the voltage classes and current intensity of

electrode are decided by smelting technical parameters, the value of voltage and

current in different times, that means the input power to furnace is different, the

electrode is inserted in furnace burden, and the gas escape from the surface of

materials. The voltaic arc keep not exposed, the blending furnace materials are feed

into furnace following with the declining of charge level, that will keep certain height of

in-furnace charge level, and there is a flat cone shape around electrode, the reduced

high carbon molten ferromanganese store to certain level, use opener to open

furnace mouth and release molten iron and slag, remove the slag in alloy, then pour

into ingot in mould. The alloy ingots are delivered to finished products warehouse

after cooling and crushing. The electric furnace must supply power under stipulated

power supply standard. The electric furnace can tap iron once every 2.5 hours, and

output 9~10 batches per day, the output is about 13 ton. The winch will pull the ladle

car to casting workshop, the crown block hoist the ladle after 20 minutes of cooling,

and pour molten ferromanganese into ingot mould. The cooled alloy are levered, and

hoisted to iron container and put into storage.

The smelting and pouring are triple-shift work system, the annual work time are 330

days. The high carbon ferromanganese tap dry slag, which overflow from ladle to slag

tanks, the slag and iron are transported out after one batch, the crown block hoist the

slag ladle and pour into continuous casting machine.

It is necessary to sample and analyze the output iron every time, the analysis result

must be offered to furnace supervisor.

The smoke enter into dust discharge flue through smoke absorption hood, and

arrange bag type dust collector beside or behind the plant workshop, the smoke dustenter into dust collector after pre-processor, the effluent concentration after treatment


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can conform to stipulated emission standard.

The circulating cooling water is supplied by pump station, and the cooling water flow

back to water tank because of natural drop after entering furnace, then which is

supplied to front furnace by pump after natural cooling in tank.

5.2. Silicon manganese production process flow diagram

The qualified raw materials and auxiliary materials, including manganese ore,

rich manganese slag, silicon, reducing agent, flux, electrode paste, etc., are

transported to factory area by trucks after wagon balance, and separately stored in

relevant raw materials storage yard, all kinds of raw materials are mixed together

Manganese ore CokeSiliconRich manganeseslag

Automatic burdening and weighing

Belt conveyor charging

21000KVA Silicon

manganese furnace

Electrode paste

Cooling water

35KV power source

Iron tapping

Casting ingot

Finishing

Packaging and leave factory

Chimney

Air cooler

Preprocessor

Draught fan

Water s lag output

Dolomite

Dust collector


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according to the formula of smelting alloy, then elevated to the platform of 27m

delivered by belt conveyor, the rotary distributor deliver the mixed materials to lower

stock bin, and fall into furnace through blanking pipe.

The furnace burden are charged into semi-closed submerged arc furnace,35KV

power source are lead into furnace through three-phase electrode by transformer, the

voltaic arc heat generated between electrode and furnace burden are transferred to

furnace chamber, through voltaic arc heat and resistance heat, so the mixture of

manganese ore and silicon can reduce to silicon manganese alloy, during the whole

process of smelting, the voltage classes and current intensity of electrode are

decided by smelting technical parameters, the value of voltage and current in different

times, that means the input power to furnace is different, the electrode is inserted in

furnace burden, and the gas escape from the surface of materials. The voltaic arc

keep not exposed, the blending furnace materials are feed into furnace following with

the declining of charge level, that will keep certain height of in-furnace charge level,

and there is a flat cone shape around electrode, the reduced high carbon molten

ferromanganese store to certain level, use opener to open furnace mouth and release

molten iron and slag, remove the slag in alloy, then pour into ingot in mould. The alloy

ingots are delivered to finished products warehouse after cooling and crushing. The

electric furnace must supply power under stipulated power supply standard. The

electric furnace can tap iron once every 2.5 hours, and output 9~10 batches per day,

the output is about 10 ton. The winch will pull the ladle car to casting workshop, the

crown block hoist the ladle after 20 minutes of cooling, and pour molten

ferromanganese into ingot mould. The cooled alloy are levered, and hoisted to iron

container and put into storage.

The smelting and pouring are triple-shift work system, annual work time are 330 days.

The water slag overflow from ladle to slag tanks, then flow into slag groove, flush into

slag tank at the end of groove, then transported to slag yard by submerged chain

conveyor.

It is necessary to sample and analyze the output iron every time, the analysis result

must be offered to furnace supervisor.

The smoke enter into dust discharge flue through smoke absorption hood, and

arrange bag type dust collector beside or behind the plant workshop, the smoke dustenter into dust collector after pre-processor, the effluent concentration after treatment


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can conform to stipulated emission standard.

The circulating cooling water is supplied by pump station, and the cooling water flow

back to water tank because of natural drop after entering furnace, then which is

supplied to front furnace by pump after natural cooling in tank.

VI. Workshop layout

6.1 Unit set submerged arc furnace smelting span

This span is multi-story factory, there is arranged with electrical room in the north of

factory, and one set 21000KVA submerged arc furnace: the span of transformer is

7.5m36m, smelting area span is 15m36m, casting area span is 24m36m,the

space between center line of silicon manganese furnace and lateral axial line is 6m,

all the platforms are arranged are shown in the following table:

No.Level ofplatform(m)

Main equipment Remarks

1 0.00121000kVA Submerged arc furnace proper, 2 baffles of ironoutput mouth,2 opener and mutegun, ladle car, slag ladle car,steel rail, vertical winch, iron ladle, slag ladle.

2 +7.00Operation platform, smoke hood, short-net, holder, blankingtube, in-furnace cooling water, high and low voltage cabinet

2thfloor

3 +11.00 Transformer 2.5floor

4 +16.00Electrode steel suspension platform, hydraulic system,pneumatic system

3thfloor

5 +21.00 Electrode paste charging platform 4thfloor

6 +27.00 Materials feeding bin, rotary belt conveyor 5thfloor

7 +34.00 10t single beam crane Roof

In order to improve the labor environment in workshop, the electric furnace apply low

smoke hood water cooled smoke discharge, at the both ends of workshop arrange

hatches of 2.5m2.5m can elevate to 7m and 27m platform for delivery of electrode

paste and electrode shell.

6.2. Casting area span This span is single layer plant, the occupied area is

24m36m=864 , and equipped with 1 set electric overhead travelling crane of

Q=32/10tLk=22.5mJc=40%,the standard height of rail level is +13.00m. Besides

pouring work zone, there is reserved ladle engineering work zone at both ends of

workshop. 1 set furnace is equipped with 5 set ladles and 6 set slag ladles. 1 set

furnace is equipped with one whole set of ingot mould, the finished products are


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delivered by flat cars to storage house.

VII. Finished products warehouse, maintenance shop, control lab, material

depot

7.1 Finished products warehouse: this warehouse is for crushing, finishing and

storage of alloy products delivered from furnace pouring span, and packaged

according to the requirement of clients.

Overall dimension of storeroom: 18m72m=1296 ,the inventory is for 1 month.

Configured equipment: 1 set of 10t double beam crane

7.2 Maintenance shopmainly for maintenance, repair of furnace, manufacture of

electrode enclosure, maintenance of electrical equipment.

Overall dimension of plant: machine maintenance: 12m24m=288

electrical maintenance: 12m12=144

Configured equipment: 1 set of 5t single beam crane, plate shearing machine, rib

plate coiling machine, bench drill, electric welding machine, etc.

7.3 Control lab12m16m=192,mainly for chemical component analysis and

alloy products.

II. Technical specification and description of equipment

1. Main parameters of 21000kVA submerged arc furnace

Secondary voltage

Silicon manganese alloy usually use secondary voltage wave at 165/171V, and high

carbon ferromanganese at 156/162V, this technical proposal consider both smelting

conditions.

The secondary voltage of transformer is at 132~153~186V (grade difference is 3V,

total 19 grades), when star angle change, the lowest voltage is 76.2V, then the new

furnace can directly bake electrode, this will help electrode baking when new furnace

start or have accident.


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Diameter of electrode 1350mm

When at 165V ( silicon manganese alloy),the current density is 5.14A/cm, and when

at 156V(high carbon ferromanganese) , the density is 5.43 A/cm. This can apply for

both the requirement of silicon manganese and high carbon ferromanganese.

Diameter of electrode circle 3300

The power density of electrode circle is 1842kw/m,it is smaller for production of

silicon manganese, and bigger for high carbon ferromanganese.

Diameter and depth of furnace hearth

The diameter of furnace hearth is 8000mm, the depth is 3200mm. The area power

density is 357kw/m, the volume power density is 111 kw/m,it can basically meet the

production requirement of silicon manganese, and it is bigger for high carbon

ferromanganese, and it will increase number of iron tapping and water cooling

furnace shell to make up for this.

1.1 Technical parameters of furnace proper

No. Technical parameters 21000kVA

1 Diameter of furnace shellmm 10000

2 Height of furnace shellmm 5500

3 Diameter of furnace chambermm 8000

4 Depth of furnace chambermm 3200

5 Diameter of electrodemm 1350

6 Working stroke of electrodemm 1400

7 Diameter of electrode circlemm 3300100

8 Fluctuation speedm/min 0.5

9Number of iron output mouth/included

angleUnit2/150

10 Consumption of cooling water t/h 450

11 Days of annual production d/a 330

1.2 Technical parameters of transformer

1.2.1 Mono-phase transformer

ModelHKDSPZ-7000kVA/35kV 3 set

Rated capacityKVA21000permitted overload of 20%


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Cooling methodOFWFForced oil water cooling, the inlet water temperature is

not higher than 32,the outlet water temperature is not higher than 45.

Primary voltageKV35

Secondary voltage(V):132153186Vgrade difference is 3Vtotal 19

grades

Secondary rated voltage (V):153V

Short circuit impedance: when at 153V6%coil internal impedance5%

Voltage regulating mode: power-driven load voltage regulation

Cooling method: Forced oil circulating water cooling

Lateral outlet line terminal: 20 units

1.3 Busbars electrical data

Conductive copper tube current density:2.53A/mm2

Pickup current density between conductive elements and electrode:1.5

2.0A/cm2.

Water cooled cable current density :2.53A/mm2

Degree of unbalance for busbars:


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forged cooper tile, etc. The equipment composition of main part: furnace proper,

smoke hood and chimney, electrode part(include holder, elevation system, electrode

slipping device, pressure ring device),opener and mutegun system, hydraulic

pneumatic system; the composition of auxiliary equipment: raw material feeding

system, double beam bridge crane, iron tapping system, slag tapping system, casting

system, etc.

2.1 Main equipment of furnace

Transformer of electric furnace

Model of mono-phase transformerHKDSPZ-7000kVA/35kV 3 set

Rated capacityKVA 7000permit overload of 20%

Cooling type OFWF3245

Primary voltageKV 35

Secondary voltage(V) 132153186V(Grade difference is 3V

total 19 grades

Secondary rated voltage (V): 153V

Short circuit impedance: when at 153V6%coil internal impedance5%

Interface type Iio

Pressure regulating method:power driven load voltage regulation

Insulation level BIL480Ac200

Cooling typeForced oil circulating water cooling

Lateral outlet line terminal: 20 units of outlet line copper tube 70/50 0-0.02length

220 mm

Three-phase cascade group /YY connection type for initial

shaping/Normal smelting

FrequencyHZ 50

Furnace shell

The furnace shell is rolled by steel plate 20,transverse and vertical rib plates 20,the

width is 250mm,the distance between is 1m. The baseplates is made of steel plate


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25, and supported by double T-steel in 45 radiation shape.2 furnace nozzles are

made of 25steel plate,and arranged in 150 shape.

The material of steel plate: Q235-A. There is installed with 3 thermicouples under the

furnace shell

for testing furnace lining temperature. The bottom of furnace shell should equip with

forced wind cooling device.

Diameter of furnace shell10000

Height of furnace shell: 5500

Furnace lining

The furnace wall is built by high aluminum bricks, and use clay bricks above slag line,

the furnace bottom is built by carbon bricks,lay foundation by high aluminum bricks

and clay bricks. It is necessary to leave thermal expansion joint150mm between

furnace lining and shell, and filled with refractory fibrofelt, asbestos board,etc.

Diameter of furnace hearth8000

Depth of furnace hearth: 3200

Furnace bottom Air cooling device at furnace bottom The air cooling function is supplied by draught fan, and lead to center of funace

bottom through pipeline (steel plate 5 ),then disperse along with radiation T-steel

after cold and hot exchange.

Air capacity: Q=82000m3/h

Total pressure:P=1800Pa

Power of electric motor:N=75kW380V

Diameter of pipeline: 1200

Water cooling smoke hood

The outline is dodecagon vault construction. Twelve water cooling columns support

one set of water cooling framework beam of turtle back shape,there is insulation

between framework beam and column, and insulation between column and furnace

shell, and filled with high aluminum ramming materials between framework

beams(there is stainless steel bar mesh12), there is two kinds of cover plates above,

the outer ring is carbon steel water cooling cover plate, the triangle center zone is

stainless steel water cooling cover plate. There is dodecagonal smoke hood walls


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between columns, and leave three doors, nine small doors. The side plate inside

hood, big and small doors, columns are welded with slag hanging nail, and with

80mm thick high aluminum ramming materials.

Smoke hood diameter10600

Height of smoke hood: 2200

Chimney

There are two water cooling smoke tubes on top of water cooling smoke hood

(steel plate10),and insulation between cover plates. And there is single wall smoke

tube (steel plate 6). Also insulation for chimney at every storey of building, there is

pneumatic butterfly bamper for closing chimney and preserved mouth of dust flue,

and equipped with raincap for single wall chimney top, and lighting rod on top of

raincap.

Diameter of chimney1700

Standard height of chimney: +40.000

Busbars

The electric furnace adopts three mono-phase transformer for power supply,and use

water cooling secondary tubular structure bus system for power supply between

transformer and electrode, secondary bus system include cast copper connector,

conductive copper tube, water cooling cable, insulated hoisting system, water cooling

copper tile, etc. Three mono-phase transformer and busbars form in 120 distribution,

each phase has 10 groups, total 20 bars.

Copper tube specification7010

Water cooling cable: 1800mm22.6m

Holder

The specification for circle diameter of three sets holders is3300100, the

diameter for each set of electrode is 1350, the elevation of electrode adopts 2 sets

of overhung type oil cylinder 250, the stroke is 2000mm. The electrode slipping

device adopts hydraulic mechanical brake control and slipping oil tank, the stroke is

2050mm. It can realize slipping with electricity, and the conduction adopts water

cooling copper tube and forged copper tile, water cooling jacket and lower holder tube

use stainless steel 1Cr18Ni9Ti.


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Circle diameter 3300100

Diameter of electrode 1350

Elevation speed 0.5m/min

Hoist cylinder: 250/2.0m

Slipping oil cylinder: 150/0.05m

Width of copper tile 380

Length of copper tile 1000

Thickness of copper tile 90

Water cooling system

Two sets of water dispensers are located at both sides of +7.000 platform, the water

source is supplied by water pump station, this system pump softened water (0.25Mpa)

to busbars,copper tile, pressure ring ,water cooling protection screen for cooling, and

pump ordinary water (0.25Mpa) to smoke hood, water cooling chimney, hydraulic

station for cooling. Another line of softened water (0.05Mpa) is pumped to forced oil

water cooling devide of transformer, there are air inflation and blow-down

device,which is used for fast-draining when blowing-out for maintennance. Every

water dispenser has sound and light alarm device for pressure and temperature.

Hydraulic system

The hydraulic system supply the function of regulation control for electrode elevation,

electrode slippong,material tube scallop valve,circular material distributor door

release structure.It is composed of hydraulic station, hydrailic pipline, 3 sets of

electrode and material tube scallop valve station, 3 sets of circular material distributor

valve station. The hydraulic station should meet the requirement for elevation of 2

sets of electrode system at the same time, pressure supply should meet the

requirement for working under 6Mpa.

Oil tank capacity2000L

Plunger pump: rate of flow 80L/min pressure 12Mpaelectrical motor 22kW,

one used, one backup

Hydraulic oilHM46


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Cleanliness degreeNAS7 degree

Charging system

13 sets of stock bin (6 m3) is ditributed in circular shape, furnace core (1 unit) and big

charge level(3 units) are separately feed by one stock bin and there are 4 stock bins

totally. Small charge level(9 units) are supplied by one stock bin. Every stock bin is

equipped with one enclosed hydraulix scallop valve,all the material tubes are

37712mm,furnace core,alternating area near by busbars use stainless steel

material tube 1Cr18Ni9Ti, other tubes use ordinary tubes Q235-A.

Stock bin capacity: 6m3

Diameter of material tube: 37712

2.2 Auxiliary equipment of furnace

Opener and mutegun system

2 set opener and mutegun systemTHJ1800-12 2 set of rails 43Kg/m-26m

1 set of gasholder6m3

Travelling system

No. Name Specification Qty Lifting height Workshop

1Electric double-beambridge crane QD-40/10-22.5-A6 1 13m Casting span

2Electric single beamcrane

QD-10-16.5-A5 1 10mFinishedproducts span

3Electric single beamsuspension crane

LX-2-10-A5 1 34mElectric furnacespan

4Electric single beammotor hoist

LX-2-10 1 6mElectrodecollection andinstallation

5Electric double beamgrab crane

10t K=13.5m 1 14.5mWater slagspan

2.3 Electrical part

The electrical equipment of 21000 KVA submerged arc furnace is composed of high

voltage power supply system, electric furnace transformer, busbars, lift control

system of electrode.

Transformer: adopt low wastage energy-saving transformer, lateral outlet line,

electric on-load voltage regulation, forced oil circulating water cooling, impedance

voltage is 4~6%,and it has advantages of small size, light weight, strong overload

ability, etc.High voltage power supply system


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Basic composition

35KV power supply line is built overhead, lead to factory area, then high pressure

through wall bushing, and from top to PT cabinet, PT cabinet is installed with high

voltage inlet wire disconnecting switch, voltage transformer, zinc oxide arrester, then

power supply is lead to high voltage power distribution main cabinet, this cabinet is

installed vacuum breaker, current transformer, etc.

Main parameters of high voltage switch cabinet

Rated voltage: 35kV 50HZ three-phase

Operational power supply: AC 220V

Outlet wire method: push-out

Protection degree: IP20

Disconnecting switch

Rated voltage: 35kV/50HZ

Rated current: 600A

Operation mode: manual

Disconnecting switch voltage transformer

Rated voltage35000V/3/100V/3/100V/3

Primary winding rated voltage: 35000/3V

Secondary winding rated voltage: 100/3V

Residual winding rated voltage: 100/3V

Capacity: lower than 150VA

3 sets of single phase three winding voltage transformer link group is

YO/YO/-12-11(the residual voltage winding group is connected in open-delta

shape.)

Vacuum breaker

ModelZN12-35/1250-25

Operation method: electric operation

Operation power source voltage: AC220V

Current transformer

Rated voltage: 35kV

Ratio of transformation: 300A/5A

Current transformer grade group: 0.5/10P grade

Zinc oxide arrester


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Nominal voltage: 35kV

Arrester rated voltage: 42kV

Continuous running voltage: 23.4kV

Basic function

There is installed two sides of high pressure cabinet in high pressure chamber, one is

PT inlet line cabinet with built-in zinc oxide arrester, another is control cabinet with

high pressure vacuum breaker, it supply power for high pressure wingding of furnace

transformer. Zinc oxide arrester is for atmospheric over-voltage protection, and

operation over-voltage protection when vacuum breaker separate and close

transformer.

The vacuum breaker can operate on counter of high pressure cabinet, and switch on,

separate brake operation in master-control room, the disconnecting switch is

manually operated in high pressure chamber.

High pressure cabinet can display high pressure voltage and current, and installed

with electric power measurement and protection device.

Power house

The workshop operation room is installed with one side of operation platform, power

distribution cabinet, PLC cabinet. The dash board of operation platform is equipped

with 3 units of ampere meter, 3 units of primary side voltmeter, 3 units of secondary

side voltmeter and fault indicating light. The operation panel control the lifting of

three-phase electrode, automatic slipping, manual slipping and divide-shut brake of

high pressure cabinet. The workshop power distribution cabinet supply power for

hydraulic station, main transformer chamber, winch, bridge crane, vertical winch,

material distribution car, lighting distribution box of each storey of workshop, and

equipped with two sets of workshop backup power source, third floor hydraulic station

is installed with one side of control cabinet, two sets of hydraulic pump motor, two

sets of air compressor motor and direct current 24V power source, lifting system of

electrode and slipping system circuit.

21000KVA submerged arc furnace is installed with 13 sets of scallop valve operation

box in 13th floor.

The layout method of power pipeline is to use plastic power cable and lay along flat

iron hanging bracket.

Lighting


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The workshop lighting power source is lead from power distribution cabinet to lighting

distribution cabinet of each storey, the controlled centrally. The switch of lighting

lamps is installed nearby the lamps.

The equipped level of electrical control system

The design principle of electric system: 1. Choose international brand; 2.General

model of electric furnace industry; 3.Quality guarantee and stable performance;

4. Convenient for application and maintenance.

Based on the above principles, high pressure electric system adopts high pressure

breaker applicable for frequent on-off, this is specially designed and configure for

electric furnace.

The low voltage control system is composed of low voltage electrical system and

automatic control system, low pressure electric system elements adopt international

known brand Schneider, intermediate relay adopts Weidmuller or Omron. PLC

system adopts German Siemens S7-300 and S7-200 system. The upper computer

adopts high performance Siemens. The display monitor is Samsung color LCD model.

The printer is HP laser printer. UPS power source is Santak brand.

The switch and indicator light use the product of Suzhou Siemens. The knife switch

and breaker use Schneider or ABB brand.

The elements selection of electric system is internationally used, advanced products

with stable performance, that will guarantee the safety and stability of control system,

and convenient for user to maintain.

2.4 Auxiliary equipment

2.4.1 Batching and charging system

The proportional qualified manganese ore, rich manganese slag, silicon, flux, coke

are unloaded to corresponding stock bins (8 units).Every stock bin is equipped with

one set electric vibrating feeder and electric scale hopper. The burdening materials

are unloaded onto batching belt by pneumatic scallop valve unload under scale

hopper, deliver to charging belt conveyor and to 22m platform, then unload the

materials to charging bin. The whole system of batching and feeding adopt PLC

control.

One electric furnace is equipped with one set of batching, feeding system.2.4.2 Automatic charging system


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27m platform is equipped with 13 units charging bin and 13 tremie pipes, among

these pipes, there is one center tremie pipe; three bedding faces are equipped with

three charging pipes; three small faces are equipped with 9 charging pipes.

The volume of charging bin is 6m3, and there are 13 units fixed on 27m platform,

every stock bin is equipped with one full-sealed pneumatic scallop valve and one

weighted valve. The function of weighted valve is to seal up the rising high

temperature exhaust gas when not charge materials, and pneumatic scallop valve

cant solve the problem of blocking. The number of operation button of pneumatic

valve is suspended on furnace platform according to the serial No. of tremie pipes.

The charging worker is operated before furnace, and charge materials according to

in-furnace condition, and with convenient operation and reliable charging.

2.4.3 Iron tapping and slag tapping system

The iron tapping system is composed of opener, mutegun, baffle for tapping mouth,

molten iron ladle, slag ladle, ladle transportation truck, rails, winch. The opener will

open iron notch, the slag iron flow into ladle through this notch, the alloy sink into the

bottom of molten ladle, and the slag float on the surface of ladle, after filling in the

ladle, the slag flow from long nozzle to cast steel slag ladle, the slag overflow into

tank for water quenching after filling in slag tank, which could realize the goal for

water slag tapping. At the same time it also could flow into several cast steel slag

ladles, and realize the goal for dry slag tapping. After molten iron tapping, adopt

winch to pull ladle transportation truck and slag ladle to casting workshop. The

residual slag will be cooled and crushed after skimming, and delivered to mixing

workshop, and return to smelting furnace. The furnace slag is washed into slag tank

after water quenching, The water slag is bailed out and delivered away by 10t grab

travelling crane, if there is dry slag, lift off the slag ladle and deliver away.

No. Name Specification Qty Remarks

1 Molten iron ladle 3.5m3 2 4 units backup

2 Cast steel slag ladle 2m3 12 6 units backup

3Molten iron ladle

truck

2


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4 Slag ladle truck 12

5 Winch 20t 2Rope speed

10m/min

6 Winch 8t 2Rope speed

17m/min

7 Gantry hook 40t 1Test lifting weight

80t

8 Ingot mould 0.2m3 15 10 units backup

2.4.4 Casting systemThe winch pull out from slag ladle to casting workshop, the slag ladle on the truck is

hoisted with 40/10t bridge crane, and pour into ingot mould of pig casting machine,

then put in storage after solidification, cooling and demould.

III. Dust collector

The dust collector equipment include dust removal system of furnace proper and

tapping notch, dust removal for furnace-top charging and material distribution

equipment, dust removal for material batching system.

3. Design basis, principle and index

3.1 Design basis

(1) Air Pollution Prevention and Control Law of the People's Republic of China

(2) Environmental Protection Law of the People's Republic of China

(3) Sanitary design of industrial enterprise TJ36---79

(4) Blowback bag type dust collector JB/T8534----1997

(5)Emission standard of pollutants of industrial furnaceGB9078-1996

Technical parameters

No. Name Unit Parameter Remarks

1 Furnace type 1 unitSemi-closed low

smoke hood2 Volume KVA 21000


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3

Flue gas at furnace mouth m3/h 280000

Positivepressure big bagtype dustcollector

Flue gas temperature atfurnace mouth

250-350

Resistance force of dustcollector Pa 4800

Dust concentration g/Nm3 3

4

Flue gas volume at furnacetop and distribution part

m3/h 50000

Negativepressure pulsebag type dustcollector

Flue gas temperature atfurnace top and distributionpart


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removal methods are mature technologies. The positive pressure big bag dust

collector belong to unorganized emission, which reach the requirement of

environmental protection, it is lower than 5mg/m3, negative pressure pulse dust

collector belong to organized emission, which reach the requirement of

environmental protection, it is lower than 30mg/m3

3.3 Design index

3.3.1 Flue gas capture ratio 99.5%

3.3.2 Service life of Glass fiber filter bag and polyester bag 1

3.3.3 Outlet dust emission concentration after cleaning of dust removal

system30mg/m3 (organized emission); 5mg/m3( unorganized emission)

3.4 Work theory, parameters and model selection of dust collector

3.4.1 Dust removal system of electric furnace and furnace mouth

3.4.1.1 Work theory

The dusty high temperature flue gas of electric furnace flow into main flue pipeline

through chimney, and the flue gas at iron tapping notch of furnace too, then enter into

high efficient cyclone, it will forcibly remove big particles and part of harmful impurities,the processed dusty gas enter into dust collector through intake tubes besides ash

hopper through main draught fan, part of dust deposit naturally in dust hopper, and

fine dust enter into filter bag following with air flow, and the dust is intercepted inside

filter bag, and gas is discharged through filter bag. The inner wall of filter bag thicken

gradually, which will increase the resistance force of filter bag, when the pressure

difference of dust collector reach the stipulated upper limit( usually 2000pa),

pneumatic switching valve start, and dust collector chambers stop filtering and clean

ash in turn. Due to sudden change of air flow direction, the filter bag change from

positive pressure condition to negative pressure, and at this time the filter bag change

shape and become sunken, the dust accumulated on inner wall of filter fall off into

dust hopper, when back-suction ash cleaning stop, filter bag change from negative

pressure to static condition, and at this time dust fall into dust hopper. This process is

called three conditions of ash cleaning. And this process repeat for 2-3 times, when

pressure difference of inlet and outlet of dust collector reach the lower limit value, the

procedure of ash cleaning automatically stop, and repeat the whole filtering process.


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When the flue gas is higher than 280the mixer selector valve of dust removal

system automatically start, if the temperature is still higher than 280, the main

draught fan will automatically stop running and start discharge valve.

3.4.1.2

21000KVA electric furnace semi-closed low smoke hood

300-350

Chimney Main flue gas pipeline system

Iron tapping mouth flue gas 200-250

Adjustable centrifugal high efficient cyclone

Mixer selector valve 250

Main induced draught fan Positive pressure back-suctionbag-type dustcollector

Dust

Vehicle

3.4.1.3 Model selection and parameters

Pipeline

From two chimneys of furnace lead out two flues, and the pipelines use15005,the

wind speed is about 22m/s. The pipeline is strengthened with fixed ring every 2

meters and expansion joint every 30 meters to prevent elongation and twist of

pipeline.8 meters for pipeline support. Try to make sure pipeline camber R1.5

2D.There is installed with mixed wind valve before high efficient cyclone, and

thermocouple at the outlet end of draught fan to realize automatic temperature control,

when the temperature is higher than 280,the draught fan automatically start, and

automatically turn off when lower than 250.

Adjustable centrifugal high-efficient cyclone

Choose 2 sets adjustable centrifugal high-efficient cyclone, one set for one flue, and

one set can process 140000m3/h wind volume.

Main air blower

Two chimneys of electric furnace separately connect with one set of dust removal flue,

each flue is equipped with one induced draught fan, total 2 sets of draught fan.

Technical parameters of draught fan:


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Model Y6-5115.2D

Flow capacity140000m /

hTotalhead

5200Pa Rotation rate 1480

Electric motor Y355L-4 Voltage 380V Power 315KW

Technical parameters of dust collector

Air flow 2140000m3/h Inlet temperature


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pipeline through branch pipeline which equipped with manual regulating valve, then

enter into negative pressure pulse dust collector, and drawn out by main draught fan

and enter into exhaust funnel.

Part of dust sink in dust hopper of pulse dust collector, and the fine dust deposit on

surface of filter bag under effect of air current, the dust on outer surface of filter bag

gradually thicken, that will increase the resistance of filter bag. When the pressure

difference of inlet and outlet of dust collector reach the upper limit value(usually at

2000Pa),pneumatic switching valve automatically turn off, the branch chamber of

dust collector will proceed with pulse dust removal in turn. The deposited dust on

surface of filter bag will crack off and fall into dust hopper, this procedure will repeat

for 2-3 times, when pressure difference of dust collector reach the lower limit value,

the process of cleaning dust will automatically stop, at the same time store the whole

filter procedure, and continuously work like this repeatedly. The dust in hopper is

unloaded into truck by screw feeder, electric ash unloading valve through pipeline.

3.4.2.2 Technical flow diagram

Circular material distribution seal cover

Charging belt conveyor gas hood

Material distribution belt conveyor gas hood

Negative pressure pulse dust collector Draught fan and exhaust funnelDust

Vehicle

3.4.2.3 Model selection and parameters

Pipeline

The seal cover of circular material distribution machine is installed with one smoke

discharge pipe, and the pipeline use size of 7504, the wind speed is about18.9m/s.

The seal cover for head of charging belt conveyor is installed with one smoke

discharge pipe, the pipeline use size of 3254, the wind speed is 20m/s. The seal

cover for head of material distribution belt conveyor is installed with one smoke

discharge pipe, the pipeline use size of 3254, the wind speed is 20m/s. The above

branch pipelines separately enter into one main pipeline, the pipeline use size

of9504, the wind speed is about 19.6m/s. Each branch pipeline is equipped withone manual regulating valve, 5 meters for pipeline support. Try to guarantee the


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camber of pipeline R1.5~2D.

Negative pressure pulse dust collector

Technical parameters:

Processed airvolume

50000m3/h Inlet temperature


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Compressed airconsumption

4m3/min

Work pressure ofcompressed air

0.30.4Mpa

Volume of gasstorage tank

3m3

Design pressure ofgas storage tank

0.8Mpa

Electrical apparatus control system

This control system adopts high performance Siemens S200 programmable system,

it is designed and formulated according to the technical performance of TFC series

dust collector running. This control system can real-time monitor the running

condition, and detect, process data, adjust running state of equipment, it will keep

the best working state for dust collector.

3.4.3 Dust removal system of batching system

3.4.3.1 Work theory

The electric vibrating feeder under batching bin adopts sealed feeding type, and it is

equipped with gas hood for material falling point of discharging belt conveyor under

electric weighing hopper (8 units), gas hood for mixed materials belt conveyor

material falling point(1 unit).The dusty flue gas flow into main flue pipeline through

branch pipeline, then enter into negative pressure pulse dust collector, and exhaustedby main draught fan and discharge into exhaust funnel. Part of dust deposit in dust

hopper of negative pressure pulse dust collector, and fine dust enter into filter bag

following with air flow, and the dust is intercepted inside filter bag.

The inner wall of filter bag thicken gradually, which will increase the resistance force

of filter bag, when the pressure difference of dust collector reach the stipulated upper

limit( usually 2000pa), pneumatic switching valve start, and dust collector chambers

stop filtering and clean ash in turn. Due to sudden change of air flow direction, thefilter bag change from positive pressure condition to negative pressure, and at this

time the filter bag change shape and become sunken, the dust accumulated on inner

wall of filter fall off into dust hopper, when back-suction ash cleaning stop, filter bag

change from negative pressure to static condition, and at this time dust fall into dust

hopper. This process is called three conditions of ash cleaning. And this process

repeat for 2-3 times, when pressure difference of inlet and outlet of dust collector

reach the lower limit value, the procedure of ash cleaning automatically stop, and

repeat the whole filtering process. The dust in hopper will unload into car through


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screw feeder and electric ash discharge valve.

3.4.3.2 Technical flow diagram

Discharging belt conveyor gas hood

Mixed materials belt conveyor gas hood

Negative pressure pulse dust collector Draught fan and exhaust funnel

Dust

Vehicle

3.4.3.3 Equipment model selection

Pipeline

The head seal cover (8 units) for discharging belt conveyor under batching bin of

electric furnace is separately equipped with one exhaust pipe, the pipeline use size of

3254, the wind speed is about 20m/s. The head seal cover for mixed materials belt

conveyor is equipped with one exhaust pipe, the pipeline adopts size of 3254, the

wind speed is about 20m/s. The branch pipes separately enter into one main pipeline,

it adopts size of 10004, the wind speed is about 20m/s. Every branch pipeline isequipped with one manual regulating valve, 5 meters of pipeline as support, try to

keep the camber of pipelineR1.52D.

Negative pressure pulse dust collector


Processed air capacity 57000m3/h Inlet temperature


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Model Y4-73 11D

Flow rate 57000m3/h Total pressure 3800Pa Rotation rate 1450

Electric motor Y315S-4 Voltage 380V Power 90KW

Exhaust funnel

The outlet dynamic pressure of exhaust funnel is comparatively high, and the strong

airflow will cause loud noises, in order to reduce loss of dynamic pressure, the outlet

flow rate is designed at 6.2m/s, it adopts18004 pipeline, due to large diameter and

low flow rate, it will largely reduce exhaust noises

Pneumatic system

As auxiliary equipment for running of negative pressure pulse dust collector,

pneumatic system adopts air compressor and gas storage tank as power source of

cylinder working, and use steel pipe as main gas circuit, connect every valves and

cylinders with rubber tubes.

Technical parameters of pneumatic system:

Compressed air consumption 4Nm3/min

Work pressure ofcompressed air

0.30.4Mpa

Gas storage tank volume 3m

3

Design pressure of

gas storage tank 0.8Mpa

5th

, September,2014

21000kVA SUBMERGED ARC FURNACE TECHNICAL PROPOSAL.pdf

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