Environmental Preheating Arc Furnace

Eco-friendly andenergy-saving vertical and continuous  

Charging scrap preheatingelectric arc furnace

    Thevertical arc furnace changes the tradition of rotating furnace lid to add scrapinto the inside furnace totally. It overcomes the shortages of traditional arcfurnace mentioned before and changes people’s traditional concept on arcfurnace. The way of adding scrap is using professional charge basket or beltconveyor to add scrap from top into the closed shaft. Preheating scrap is addedinto trough in the bottom shaft. The trough is moved by vibrating-type cart.Specialized four-axis type actuator is adopted to add scraps in the trough intothe inside furnace from the flank furnace body continuously. Thus,discontinuous charging is changed to continuous charging into the shaft. Thewhole molten pool operation of electric arc furnace is realized.

High temperature flue gas entersinto the feed throat from furnace side going through gas duct to shaft. Fluegas moves reversely with scrap steel. After preheating scrap, flue gas isdischarged into gas duct from the top shaft. Flue gas enters into dedusting systemthrough settling chamber. The vertical shaft electric arc furnace not onlyabsorbs part of good ideas of Consteel furnace and vertical furnace but alsoovercomes shortages. For example: It absorbs the idea of vibrating feed ofConsteel. But high temperature flue gas of Consteel can only pass from thesurface scrap, which is limited to preheat scrap steel. Besides, the conveyorbelt of scrap steel is so long (45-60m, generally) that takes up big area ofthe workshop. We adopted the idea of shaft preheating scrap. Meanwhile, we hada deeply discussion and research on the problems appearing during the operationof shaft furnace for a long time, such as scrap steel bonded, hanging, leakingwater, too much height of shaft, increasing the cost of workshop, etc. Wedeveloped and designed new furnace with proprietary intellectual propertyrights of our company.

Outstanding meritsof shaft electric arc furnace:

1) Scrap entered from top into shaft inbatches. High temperature flue gas and scrap flowed reversely. Effect of scrappreheating is obvious. Due to the reduction of the weight of each batch ofscrap steel and the reduction of scrap’s standing time on shaft finger. Thepossibility of bonded scrap steel is eliminated. Meanwhile, shock of scrapsteel on finger is reduced.

2) Lower fingers in the furnace can lift toavoid the damage caused by the falling of scrap steel.

3) The charging basket enters closed chamberfirstly before it enters into shaft. Scrap steel is added into shaft in fullysealed condition. So, when adding scrap, escape of fume and dust is avoided. Itis very helpful to environmental protection.

4) Vibrating continuous feed and 50% ofremaining steel capacity is adopted to ensure the condition of molten pool.Electric arc doesn’t contact with materials of steel. Electric arc is stable.Fluctuation and flicker of voltage is sharply reduced. Noise is very low.

5) Because there is no direct contact betweenelectric arc and scrap steel, volatile substance is reduced. The amount of dustis reduced because of filtration of scrap to flue gas. It lays the foundationof dedusting system.

6) Due to reduction of volatile substance andthe control of foaming slag, the iron recovery is increased 1.5-2.0%.

7) The rotary operation of furnace lid is notto reduce subsidiary operation time. Radiation heat of rotating furnace lid isavoided.

8) High impedance technology is adopted toimprove the secondary voltage and to reduce the secondary current. Consumptionof effective power is reduced 6-8%. Weight of short net system is effectivelyrelieved.

9) Device configuration is concise andreasonable. It overcomes the shortages such as taking up large area, too muchheight of shaft plant. Thus, the cost of investment is lowered.

Main technicalparameter:

Power consumption: <300Kwh/t (Above 40tons)

Time Shorten: 20min/furnace

Electrode Waste: 1.5-2KG/T

Scrap Steel Yield: 93.5-94%