PROPOSAL OF 1x30MVA SILICON METAL FURNACE PROJECT

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PROPOSAL OF 1x30MVA SILICON METAL

FURNACE PROJECT 1 PRODUCTION CAPACITY

A 15000t/a SILICON METAL production project with assistances.

2 PRODUCTS Quality and specifications refer to Table 2-1

Si，% Fe，% Al，% Ca，% Purity

＞＜＜＜ SI METAL 98.6 0.2 0.32 0.04

3 PROJECT INTRODUCTIONS To set up a new production line with 15000t annual capacity SILICON METAL. The production line equipped with one SILICON METAL furnace and assistances. Scope of supply includes one SAF, three transformer, compensation, HV compensation, power system, oxygen system, water cooling system, furnace front door system, materials charging system, communication system, monitoring system, lab equipment and etc. 4 FURNACE DATA

Q— A/t 15000

Cosf 0.85（after compensation） d－working day（天） 330 W－power cost per ton 12000 kWh/t （average） k1— — efficiency change rate 0.99； k2— — efficiency utility rate 0.99 S－transformer rated capacity（KVA） Then, one 30MVA SAF with satisfied capacity of 15000t/a, production will be: Qh=2.08(t) Qd=2.08×24=49.92(t) Qa＝49.92×330＝16474 (t)

5 RAW MATERIALS

5.1 name of raw materials Quartz, carbon reducing agent, electrode and etc (1) quartz：quality of quartz required refer to Table 5-1


SiO2 Fe2O3 Al2O3 CaO+MgO LOI 99.65% 0.08% 0.07% 0.07% 0.18%

Size range 10～75mm, ＜15mm no more than 5%, ＞75mm no more than 5%. Physical properties of silica shall have thermal stability and anti explosion performance (=85%， 1200 hour). Fine material needed without any other ℃impurities.

(2) Pet coke: refer to Table 5-2 Fixed carbon Volatile Ash

82% 15.5% 2.2% Pet coke with low S content should be in 8~25mm, with moisture under 8%. (3) Electrode: carbon electrode with diameter of 1320mm, length of 2000mm~2400mm, and quality report show as Table 5-3, 5-4.5-5: Table 5-3. Physical & chemical index，%

Moisture Ash Volatile C =0.05 =2.00 =6.00 =92.00

Table 5-4. Ash of carbon electrode Name =SiO2 =Fe2O3 =Al2O3 =CaO =MgO

% 50.00 13.00 26.00 7.00 5.00 Table 5-5. Physical properties of carbon electrode

Name Unit Index Resistivity µO.m =38 Flexural strength MPa =5.0 Volume density g/cm3 1.56～1.61 Tensile strength MPa =2.5 Comprehensive strength MPa ＞22MPa

Max power density permitted =8.5A/cm2 (4) oxygen and compressed air: oxygen purity＞90%, air pressure 0.40Mpa. 5.2 raw materials consumption Refer to Table 5-6

No. Item Unit Qty Note 1. production

1.1 SI METAL T/A 16 474 1.2 DUST T/A 5 617 By-product

2. raw materials consumption 2.1 Quartz T/A 41 783 10~75mm 2.2 Pet coke T/A 21 945 8~25mm 2.3 Carbon electrode T/A 1 236 0.075t/t

3. power consumption 3.1 Smelting power consumption KWh/a 197 688 000 0.2 Billion 3.2 Dynamic power consumption KWh/a 14 826 600 15 Million


6 TECHNOLOGIES AND DESIGNING 6.1 Overview of smelting process

Qualified materials sizes are stacked in raw materials storage shed, and transfer into semi-underground ingredients plant. After weighing and mixing by proportion system, raw materials are transported to distributing platform silo by belt conveyer, and distributing to each bin in furnace top. Mixed materials are downward into furnace through tubes. There have valves in materials pipes to control materials charging. Stocking machines are used to arrange materials inside the furnace. Additional tubes are equipped for artificial supplementary feeding or adding material to the furnace. Gas produced during smelting will be cleaned by dedusting system and expelled into the air in the condition of national environment protection standard. After electrical reducing process inside the furnace, Silicon liquids accumulated and ready for tapping. During tapping, tapping machine used to open and close the furnace mouth. And oxygen blasting process will make impurities separated from the Silicon liquid. Static sediment and then cast liquids into mould. Then, after cooling, Silicon blocks transported to broken process. Packing and warehousing is the final process. Clothe bags dedusting are equipped to Silicon Metal furnace for gas cleaning. Powders collected by dedusting will compacted to Micro Silicon powder. 6.2 Raw materials system

6.2.1 Raw materia ls storage Materials stack shed, forklift, semi-underground, and materials bins are equipped. 6.2.2 Ingredients and charging (1) Ingredients One furnace has one ingredients system with 8 hour materials consumption

storage. Materials transfer flow： Materials ? load machine ? bin ? vibrating feeder ? weighing ? loading belt

conveyer ? mixing belt conveyer ? large dip angle charging belt conveyer (2) Charging Large dip angle charging belt conveyer ensures the stability of materials charging. (3) Materials distributing on the furnace top Equipped by reversible belt conveyer, distributing belt conveyer and so on, the

distributing system is easy maintained, high automated and reliable in materials distribution.

Function flow：large dip angle belt conveyer ? reversible belt conveyer ? distributing belt conveyer ? furnace

6.3 Main equipments 6.3.1Furnace parameters A 30MVA SILICON METAL furnace body mainly included the following

technical parameters, refer to 6-1: No. Name Unit Qty Note


1 Furnace shell diameter mm 9500 2 Furnace shell highness mm 5150 3 Electrode diameter mm 1320 4 Tapping mouth pcs 5 5 Electrode strike mm 1200 6 Electrode speed m/mi 0.5 7 Electrode pressing mm 20 8 Pressure ring Pressure bellow 9 Contact shoe pcs 10 10 for each suit 10 Gas hood height mm 3150

6.3.2 Transformer parameters The furnace use 33KV, 3×10000KVA single phase transformers, parameters show

in Table 6-2. No. Name Unit Qty Note 1 Rated capacity kVA 10000×3 2 Primary voltage kV 33 3 Regulation mode Load regulation 4 Phase 3 5 Power frequency Hz 50

6.3.3 Furnace body structure and equipment Furnace body mainly includes: Rotating system, furnace body, electrode holding

system, electrode lifting system, electrode pressing system, gas hood and gas pipes, water cooling system, hydraulic system, hydraulic system, gas sealing system, inter-electrode wood panels, tap hole baffle, arc burner and etc.

Details are shown as following: (1) rotating system

To improve stability, rotating design in furnace bottom chooses as a advanced technology.

(2) furnace body Furnace shell (wall and bottom), tapping mouth (five) and lining are included in

this part. (3) electrode holding system

Here we use pressure ring as electrode holding, which consisted of electrode volume, pressure ring, contact shoe, copper tube, cooling shield and protection ring.

(4) electrode lifting system Hydraulic pressure cylinder used in electrode lifting.

(5) electrode pressing system It consists of up brake, down brake, oil cylinder and so on.

(6) Conductor Conductor is power conducting system from transformer to electrodes. It water

cooling, triangular distributed, which consists of copper pipes, cable and etc. (7) Longitudinal compensation

Longitudinal compensation with natural Cosf as 0.60~0.70, and will be up to 0.85 after compensation.


(8) gas pipes Two main gas pipes in 120°angle beside gas hood.

(9) gas hood In Hexagon shape with max cleaning height of 3150mm and door height ＞

1700mm. Totally 6 doors, which is convenient for stocking, charging and etc, in hydraulic control and all open at the same time.

(10) Materials distribution in Furnace top Triangle belt conveyor adopted in this part, with dedusting hood and etc.

(11) Materials charging system Totally 11 charging pipes with hydraulic valves and water cooling method

adopted. (12) water cooling system

Water cooling system supply “cool” working condition for furnace cover, furnace body, electrode system, bus-bar, arc burner, gas pipe, valves, hydraulics and so on. It includes water distributing, valves, water tank, pipes, hoses and etc. water flow-in pressure is 0.3~0.4MPa and temperature difference between flow-in and flow-out water should under 10 .℃

(13) hydraulic system Hydraulic pump, accumulator, the oil pipeline, the insulating joint, high pressure

hose, hydraulic valves mainly included here. Oil pressure range would be 0~10MPa. (14) Tapping mouth gas extraction (15) Arc burner

Two water cooling arc burners equipped for one furnace, which are mobile, with 100mm diameter carbon rods.

(16) Smelting operation safety control Tap-hole baffle are used for safety purpose. And wooden inter-electrode panel

also keep operators in safe from electrode power. 6.3.4 Furnace auxiliary equipment Stocking machine, tapping device, casting equipment and refining methods. (1) One stocking machine (2) Taping methods Ladle, cart and hoist Ladle capacity 4m3, eight ladles totally. 5T hoist (3) Refining Oxygen, pressed air are used. 6.3.5 Casting Bay Cast mould, deslagging, ladle and ladle repair. 6.3.6 Refining Bay Silicon metal blocks piled in this part together with broken equipment, lifting,

transferring and weighing devices. Working flow: Refining disk ? blanking bin ? jaw crusher ? belt conveyor

with corrugated baffle ? heavy vibration sieve ? landing / alloy disc ? car ? load meter ? finished product storage


6.3.7 Storage facilities One storage facilities and 1 integrated library, and one seat of silica

fume warehouse 7 WATER SUPPLY AND DRAINAGE FACILITIES

7.1 furnace water cooling system Inlet water pressure ＞0.35MPa with temperature of =35℃ 7.2 transformer cooling system 7.3 water for daily use 7.4 water for other uses

8 DEDUSTING SYSTEM

Include tapping mouth gas extraction, furnace gas dedusting, ingredients plant dedusting, refining part dedusting and etc. 9 HV POWER SUPPLY

Primary voltage is 33KV 10 POWER SUPPLY AND DISTRIBUTION FACILITIES

There are totally three power substations in furnace workshop, circulating water pump station and dedusting part. 11 AUTOMATION FACILITIES

11.1 PLC control 12 HYDRAULIC SYSTEM

Hydraulic pump, oil tank, a pressure regulating valve group 13 COMPRESSED AIR OXYGEN STATION For oxygen and compressed air supply purpose 14 LABORATORIES 15 MACHINARY SHOP For electrode volume machining and furnace spare parts 16 COMMUNICATION FACILITIES

16.1 communication system Telephone call

16.2 industrial TV Monitoring important aspects of furnace, are mainly distributed in: tapping, furnace cover and conductor, hydraulic pressing platform, belt conveyer, hydraulic station, ingredients station, furnace top materials bin and etc

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PROPOSAL OF 1x30MVA SILICON METAL FURNACE PROJECT