What are the types of preheating furnaces with impregnated graphite electrodes?
(1) Preheating furnace of simple graphite electrode.
The structure of this kind of preheating furnace is relatively simple, divided into above-ground preheating furnace and underground preheating furnace, and the heat medium is the flue gas generated after gas combustion. This kind of preheating furnace with impregnated graphite electrode has the disadvantages of uneven heating temperature and high energy consumption, and the temperature difference in the preheating furnace is sometimes as high as 120 ~ 180℃, some carbon billets are overheated and oxidized, and some carbon billets are not preheated to the specified temperature, which affects the impregnation quality.
(2) direct heat type graphite electrode preheating furnace.
The high temperature flame gas is generated directly on the preheating furnace by an adjustable high speed gas nozzle, which is installed in the middle of the distance between the vault and the upper part of the carbon billet basket. The high temperature flame gas emitted by the nozzle has a large kinetic energy, which produces a strong enrolling and stirring effect on the air flow in the furnace. The flame gas forms a good circulation around the carbon billet basket, so as to achieve the purpose of balancing the temperature in the furnace, and the temperature difference in the furnace is reduced to less than 30℃. The preheating furnace has a micro-positive pressure operation, and can also add a secondary circulation system of flame gas, which is completed by a high temperature fan, so that the exhaust gas discharged from the preheating furnace is used as a secondary circulation air.
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3) Hot air preheating furnace.
The roasted carbon billet with graphite electrode is preheated by hot air in a large-sized single-door can-type preheating furnace. The hot air of the preheated carbon billet with graphite electrode is generated by burning gas in the combustion chamber by a gas burner located on the upper shelf of the preheating furnace. The hot air generated in the combustion chamber is driven into the top of the preheating furnace with impregnated graphite electrode under control. Implement hot air circulation preheating of carbon billet. The other type of hot air preheating furnace is tunnel type, and the carbon billet with graphite electrode is heated by the hot air generated by burning gas in the hot air producer furnace. The hot air is dispersed into several hot air blowing entrances on both sides of the furnace, so that the carbon billet in the furnace can be evenly heated.
