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Comparison of energy consumption

Release time:2019-12-18 From: Zhengnai Industry in China

Single chamber furnace in graphite electrode production

A single chamber furnace consists of a fuel combustion chamber, a roasting chamber, a volatile combustion chamber, a chimney, and the like.

Comparison of energy consumption

The energy consumption of the single-chamber furnace is slightly higher than that of the external-fired secondary roasting tunnel kiln, but lower than that of the under-floor roaster.

3 kinds of roasting equipment are heated differently

The product charged in the ring furnace is in a relatively static state, and the product is fired by moving the baking temperature field. In contrast, the tunnel kiln is in a relatively fixed state, and the products installed on the kiln car pass through the temperature zones at a prescribed speed. The bottom type of Shanghai is a single furnace operation. After the product is placed in the furnace, it is also in a static state. The furnace temperature is low to high according to the specified heating curve, and the roasting process is completed.

4 stages in one roasting cycle of graphite electrode

The product is fired in a ring furnace, and for each individual furnace chamber, the following stages are experienced in one firing cycle:
  • 1. Preheating the low temperature chamber with the flame gas of the high temperature furnace chamber
  • 2. After heating in the gas,
  • 3. Cooling process uses cold air to cool the furnace chamber and products
  • 4. After the product is released, the furnace chamber is naturally cooled to about room temperature from about 300 °C.

Flue gas sensible heat comparison

In order to ensure the heat required for the ring furnace to roast the product, it is necessary to increase the amount of combustion to compensate for the heat storage loss of the furnace body, and the increase of the combustion intensity leads to a corresponding increase in the amount of smoke exhausted.

Utilization of latent heat of smoke

From the utilization effect of the volatiles escaping from the green body during the roasting process, although the ring furnace has a large amount of volatiles discharged in the pre-tropical zone, the combustion temperature of the volatiles is not reached because the temperature in the furnace is not reached.

Heat loss of the car bottom furnace

The heat loss of the under-floor furnace includes the heat storage loss of the furnace and the product, and the steam well generated by the water spray cannot be utilized.

Specifications of graphite electrode

Item Unit RP
Electric resistivity Electrode μΩm 7.8-8.8
Nipple 5.0-6.5
Flexural strength Electrode Mpa 7.0-12.0
Nipple 15.0-20.0
Elastic modulus Electrode Gpa 7.1-9.3
Nipple 12.0-14.0
Bulk density Electrode ≥g/cm3 1.53-1.56
Nipple 1.70-1.74
CTE(100-600℃) Electrode x10-6/℃ 2.2-2.6
Nipple 2.0-2.5
Ash   0.5

How to use the volatiles discharged from the green body

The volatiles discharged from the green body during the roasting process are only partially used in the furnace, and a considerable part of the volatiles are discharged into the incinerator to be sprayed with human fuel for combustion.
The emitted flue gas is brought to environmental standards. The heat generated by the incinerator is most available.