Introduction

A company has two 5000t/d clinker production lines, rotary kiln with a diameter of 4.8m×74m, three air duct diameter with a diameter of 3200mm, the production operation has been relatively normal. The castables are often washed away, leading to the damage of the valve plate. Generally, the castables need to be repaired once a year, and the gate needs to be replaced three times in two or three years. Severe wear of the gate three times will affect the ventilation in the kiln, leading to the impact on the output and quality.

01 Improvement of tertiary air gate valve

Due to the mine limestone taste is poor, CaO content in about 46%~48%, clinker MgO content is higher (4.5%~4.9%), R₂O content in 0.8%~1.1%, adopt high saturation, high silicon rate of ingredients, KH is 0.91-0.93, SM is 3.0~3.2, due to the silicon rate is higher lead to kiln head fly sand material is more serious, into three air duct three times the air gate scour is more serious. In order to ensure the calcination of the clinker with high saturation and high silicon rate, the opening of the tertiary air gate is controlled at 30%~50%, and the large area of the gate into the tertiary air duct is also one of the reasons for scour damage.

To solve the problem of fast wear of the three-time air gate, the company carried out the transformation in January 2017:

(1) As the normal use ventilation area of the tertiary air duct of the company is about 30%~50%, the company decided to reduce the penetration area of the tertiary air gate to reduce the scour of the tertiary air gate. The wind retaining wall was constructed behind the tertiary air gate valve, and 60%~70% of the reserved ventilation area was reserved, and the remaining 20%~30% was adjusted by the gate valve. It is calculated that the fireproof brick wall is laid behind the sluice plate, with reserved ventilation of 1500mm×2800mm, and the area is about 4.2m², which is about 68% of the ventilated area.

(2) In view of the phenomenon of easy wear of castable material of the triple air gate, the company decided to use wear-resistant microcrystalline plate to inlaid on the surface of the gate on the windward side of the triple air gate to reduce the scour of the gate.

(3) for a long time to use three times the wind ram prone to ram adjustment difficulties or falls off phenomenon, the serious influence production and even cause downtime, to avoid the problem, in the original lifting gear flanked by adding a 3 t gourd (see figure 1), used as a standby adjustment, have the effect of double protection, to ensure that the three wind long-term effective operation of the gate.

02 Conclusions

After the transformation, the operation has been relatively normal. At present, the castable material has not been damaged for three and a half years. The air gate for the third time is in good condition, which ensures the normal operation of the rotary kiln. But after a long time of operation, it is necessary to do the corresponding maintenance work: one is the need to use waste firebrick to repair the wind retaining wall when it is seriously scoured, so as to ensure the normal ventilation area. Second, when the microcrystalline plate is worn seriously, it needs to be replaced in time to avoid damaging the castable.

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