Currently, there are two main types of negative pressure back suction large cloth bagsin use in China: negative pressure back suction and negative pressure back blowing. Due tothe issue of the service life of cloth bags, several newly built units in China have adoptednegative pressure back blowing forms. The selected air volume for the main fan of the dustcollector is basically between 600000-650000 m³/h, and the air pressure is basically between9000-11000Pa.
There are basically two forms of desulfurization and denitrification schemes used do.mestically. One is to arrange desulfurization in front of the negative pressure large bag, andthe other is to arrange it behind the negative pressure large bag, adding a secondary bag forcollecting desulfurizer; Both forms have their own advantages and disadvantages. The entireprocess route of desulfurization in the front end is short, with low system resistance, but itaffects the quality of micro silicon powder. The entire process route is long and the systemresistance is high when placed in the backend, and the quality of micro silicon powder is notaffected.
Gas flow rate at the outlet of the submerged arc furnace: standard condition 220000Nm3/h (operating condition: 650000 m³/h), temperature 450-600℃. The high-temperatureflue gas first enters the waste heat recovery system for waste heat recovery and utilization,and then enters the negative pressure large bag dust removal system after passing throughthe cyclone dust removal system, The micro silicon powder collected by the dust removalsystem is recycled and utilized; And set up an air cooler bypass system when the waste heatboiler malfunctions. The flue gas from the negative pressure large bag filter enters the desul-furization and denitrification system, and the net flue gas from the denitrification reactor issent to the chimney for discharge by the induced draft fan. The purified gas has a dust con-centration of less than 10mg/m³, sulfur dioxide of 35mg/m³, and nitrogen oxides of50mg/m³.
Processing air volume: 650000 m³/h
Filter area:21120m2(24*96*0.292*3.14*10)
The maximum working temperature tolerance of the cloth bag shall not be lower than 260°C
Number of bags per room: 96
Number of rooms: 24 rooms
Single room filtration area: 880m2,
Filter bag specification: ￥292 x 10000
Filter bag material: acid resistant and alkali free expanded yarn with glass fiber coating Dust collector resistance: < 2500Pa,
Leakage rate: < 1%
Filtering wind speed: 0.51m/min
Two ore heat furmaces share one set of air cooler, with a heat dissipation area of 5000m2. The diameter of thecooling pipe is $ 850mm, and the material of the cooling pipe is Q235B
with a wall thickness of > 4mm. EachU-shaped air cooling pipe is equipped with an anti blocking valve (diameter > DN200mm) at the bottom.and the air cooler elbow and square rounding are made of 4mm steel plate.
Four shut-off valves are installedat the front and rear ends of the air cooler.
Using double rotating air ducts to handle an air volume of 650000m3/h; Install 4500 x 500 explosion-proofvalves at the top of each cylinder; The auxiliary cyclone ash discharge adopts an electric ash dischargevalve, and the outlet flange of the ash discharge valve is 3 meters above the ground.
it is transported by asmall flatbed truck for manual ash discharge.
Function of explosion relief valve: Due to the special nature of industrial silicon electric furnace smelting. there may be explosions of carbon monoxide or dust in the flue gas. Therefore, an explosion relief valve isinstalled at the top ofthe cyclone.
Each dust collector is equipped with one encryption system and two 195m3 encryption silos are set up:Seamless steel pipe DN150 for encrypted pipelines Equipped with a flow meter, level gauge, thermometer, pressure transmitter, and electronic electric regulating release valve, the encryption ability is required: the encryption density can be adjusted;2 pulse bag filters on the top of the warehouse.
The ash unloading system needs to have automatic weighing andpackaging functions: small bag packaging (15-25kg), large bag pack-aging (500-1200kg),and tank truck conveying capacity, and canswitch between each other.Weighing accuracy requirements: weighing error of small bags is 士0.3kg, and weighing error of large bags is ± 3kg.
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