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Advantages of the car bottom roaster

Release time:2019-12-17 From: Zhengnai Industry in China

7 advantages of the car bottom roaster in graphite electrode

  • 1. During the roasting process, the flue gas in the furnace is always in the circulating convection state by the high temperature fan at the top of the furnace. Therefore, the temperature distribution throughout the furnace is always relatively uniform, the roasting yield is high, and the product quality is uniform.
  • 2. After the calcination heating phase is over, the forced cooling by the water spray method not only ensures the calcination cycle, but also helps to alleviate the internal stress of the roasted product and reduce the amount of waste due to improper cooling.
  • 3. Adopt advanced fuel nozzles and automatic temperature control measures
  • 4. Loading and unloading products are carried out at a dedicated loading and unloading station, which can design and manufacture special loading and unloading equipment, which improves the mechanization of loading and unloading products.
  • 5. Due to the good sealing performance of the furnace body and the automatic adjustment of the amount of air required for combustion
  • 6. The same furnace body is used for primary roasting or secondary roasting, and the product is placed in the iron frame during the second roasting.
  • No need for filler protection), the time required for the temperature rise of the secondary baking can be greatly shortened.
  • 7. According to the different needs of loading products

3 disadvantages of the car-type roaster

  • 1. The investment in the construction of the under-floor roaster is high.
  • 2. Temperature control technology is also more complicated.
  • 3. The unit energy consumption is higher than that of the tunnel kiln, because the volatile matter discharged from the green body cannot be directly used as fuel.

Advantages and disadvantages of rotary bed roaster

Since the heat generated by the combustion of volatiles decomposed by bitumen can be fully utilized, and the combustion process is controlled by a computer, the energy consumption is low, but the investment in such a roasting equipment is high.

Filler definition of graphite electrode

The filler is a loose-grained material used for greening the spinach and filling the gap to prevent oxidation and deformation of the green body during firing.

There are 4 aspects to the function of the filler.

  • 1. The heating flame cannot be in direct contact with the green body to prevent the green body from oxidizing.
  • 2. Fix the shape of the green body,
  • 3. Conducting heat, the high temperature generated by the combustion of the fuel during roasting is conducted to the green body through the filler.
  • 4. Retain the discharge channel of volatile matter

7 requirements for fillers

  • 1. Does not melt at the highest temperature of calcination nor chemically react with the green body.
  • 2. The volume occupied by the filler should not change greatly during the roasting process. The bulk density is better.
  • 3. Has good thermal conductivity.
  • 4. Adsorption is as small as possible.
  • 5. The granularity is moderate,
  • 6. The moisture content is as small as possible.
  • 7. The material is easy to get, and the price is relatively cheap.

Filling material is the use of fine grain river sand

The best filler is fine-grained river sand, which has high thermal conductivity and low adsorption, and does not require prior processing, but the river sand has high fluidity and does not agglomerate. When used in a ring-type baking furnace, It is easy to flow into the bottom flue through the crack of the guard body, causing partial blockage of the flue in severe cases.

Size of graphite electrode

Item Unit HP
300-500mm 550-700mm
Electric resistivity Electrode μΩm 5.5-6.8 5.5-7.0
Nipple 4.0-5.5
Bending strength Electrode Mpa ≥10.0 ≥8.5
Nipple ≥18.0
Elastic modulus Electrode Gpa ≤13.0
Nipple ≤15.0
Bulk density Electrode g/cm3 1.62-1.70
Nipple 1.72-1.80
CTE(100-600℃) Electrode 10-6/℃ 1.80-2.20
Nipple 1.50-1.80
Ash % ≤0.3