Discussion on factors affecting solid yield of calcined coke
Calcined coke is an important bulk material in the production of carbon anodes for aluminum, accounting for more than half of the total cost, for there are matching carbon carbon enterprise or electrolytic aluminium enterprises, take effective measures to improve calcined recovery efficiency, the promotion enterprise's economic benefit is very obvious, this article will analyse the influencing factors of calcining recovery efficiency, provide the reference for the enterprise.
一．Influence of water content in petroleum coke
After calcination at high temperature, the water of petroleum coke is basically exhausted. Therefore, every 1% increase in the actual water content of petroleum coke means that the actual yield of calcination will decrease by 1%.At the same time, the water in petroleum coke is quickly vaporized into a large amount of superheated steam at high temperature, which will lead to material breakage and porosity increase.
二、Influence of volatile content of petroleum coke
As a kind of available high calorific value fuel, volatile matter is very necessary to improve the temperature of calcining zone and reduce the consumption of natural gas. In production, it is ideal to control the volatile matter content of petroleum coke in the range of 10% ~ 10.5%.If the volatile content of petroleum coke is relatively large, it will be basically discharged after high-temperature calcination, which means that the actual yield of calcined coke will decrease by 1% for every 1% increase in the volatile percentage content beyond the ideal range, affecting the actual yield of calcined coke.
三、Effect of petroleum coke size
The finer the particle size of petroleum coke is, the total surface area of combustion in contact with hot gas flow in the kiln will increase greatly, and the combustion loss will increase.Secondly, the finer the size of petroleum coke is, the lower the flame in the burning zone and the lower the calcining temperature is. In order to ensure the temperature and position of the calcining zone, it is necessary to increase the amount of air and natural gas as well as the negative pressure at the kiln head and the kiln tail, which results in the burning loss of carbonic materials and the increase of powder extraction, and the actual yield of calcining decreases greatly.The fineness of petroleum coke not only affects the actual yield of calcination, but also affects the balanced production of molding and the stability of ingredients, resulting in the increase of the rejection rate of roasting.
四、Effect of ingredients and sieving
Petroleum coke in front of the broken under the condition of without screening, 85% ~ 90% of petroleum coke don't need a broken petroleum coke will double toothed roll crusher the crushing process, due to the material and the roller, material and material between extrusion, part of the small particles of petroleum coke is broken into more broken again small particles and powder, influence calcination recovery efficiency, so the enterprise should pay attention to calcined before the screening process.
五、Influence of process operation
In the production process, the control of calcination belt is a very important link. If the temperature of calcination belt does not reach the standard or exceeds the standard, the quality of calcination belt will be affected.At the same time, the negative pressure in the kiln also needs to be paid attention to. When the negative pressure in the kiln is high, the flow rate of flue gas speeds up and the amount of powder removed increases, leading to the decrease of the actual yield.
六、Influence of sealing effect of equipment
After long-term operation, the sealing performance of the equipment decreases gradually. When the air entering the equipment comes into contact with the high-temperature coke after preheating, oxidation reaction occurs, which increases the carbon burning rate.However, due to the large number of connecting ports and poor sealing effect in the discharge system such as vibration conveyor, the powder flying and the loss of granule will ultimately affect the overall actual yield.
It is estimated that if the actual calcination yield increases by 1%, the cost of calcination can be saved by about 10 ~ 15 yuan per ton. For a carbon enterprise with an annual output of 100,000 tons, the annual cost can be saved by about 1 ~ 1.5 million yuan, with considerable economic benefits.