Carbon material production technical problems & answers 1 -- calcination

I. What are the classifications of petroleum coke?

According to different coking processes, petroleum coke can be divided into delayed petroleum coke and kettle petroleum coke. At present, the delayed coke produced by delayed coking method is the most widely used. Graphite electrode for steelmaking, a conductive raw material with high temperature oxidation resistance, and its preparation technology has reached the world advanced level. 

II. Why should petroleum coke be broken before calcination?

If the petroleum coke block is too large, not only the calcined coke quality uniformity cannot be guaranteed during calcination process, but also it is limited by the calcination equipment, which makes it difficult to feed and discharge materials, and also affects the efficiency of the medium crushing equipment. Therefore, before calcination, the carbon raw materials should be crushed to a medium particle size of about 40mm to ensure that both large and small pieces can be calcined at a uniform temperature. However, carbon raw materials cannot be finely crushed, otherwise it will lead to excessive powder and increase burning loss.

III. What is calcination?

The process of high temperature (1200 ~ 1350 º C) heat treatment of carbon raw materials under air isolation is called calcination. Calcination is the first heat treatment process of carbon production, which makes a series of changes in the structure, physical and chemical properties of various carbon containing raw materials.

IV. What is the purpose of petroleum coke raw material calcination? What are the quality indicators of calcination?

The purposes are:

1. Remove water and volatile matter from petroleum coke;

2. Improve the density and mechanical strength of petroleum coke;

3. Improve the conductivity of petroleum coke;

4. Improve the anti-positive performance of petroleum coke.

The calcination quality of petroleum coke is generally controlled by two indicators: powder specific resistance and true density. The higher the calcination degree of petroleum coke, the lower the specific resistance of calcined powder and the higher the true density pressure.

V. What should be paid attention to in the production and operation of tank calciner?

1. Temperature control;

2. Feeding and discharging;

3. Sealing of calciner and cooling of calcined materials;

4. Mixing ratio and particle size requirements.

Ⅵ. What are the main factors affecting the calciner temperature?

1. Influence of volatile matter;

2. Influence of air volume;

3. Influence of Negative pressure.

VII. How to ensure the normal calcination operation of calciner?

According to the different properties of raw materials, they are stored in the feed tank respectively. In order to prevent equipment maintenance, a certain amount of pre-crushed raw materials need to be stored. The particle size of the pre-crushed raw material shall not be greater than 40mm to meet the calcination requirements. The calcined coke should be mixed evenly and proportioned accurately in the raw material warehouse. The pre-crushed raw materials are weighed by the weighing scale, and then transported to the feeding funnel. The raw materials in the feeding funnel are intermittently or continuously sent to the calcining tank for calcination. The feeding should be carried out regularly and evenly, consistent with the discharge volume.

In terms of calcination operation, it is mainly to control the temperature of each layer of fire path and exhaust gas. Flue temperature can be controlled by adjusting fuel consumption, flue negative pressure, air preheating temperature and rational use of volatile matter. The calcined materials are cooled by the cooling water jacket and then discharged by the discharging device. The discharged materials shall not have red materials, and then the discharged materials shall be sent to the next process. Consult us to learn more about the graphite electrode market trend.