- Time:Dec 26, 2022
Although co-disposal increases the work load of refractory materials and affects the service life of refractory materials, the service life of refractory materials can still meet the production needs by strengthening the production management level, analyzing the causes of damage and making up for the shortcomings. Taken together, the following measures are the main ones.
1、Optimization of kiln system operation
The stable operation of the kiln system is a fundamental guarantee of the performance of the refractory material. Any measure to promote the stable operation of the rotary kiln system directly or indirectly optimizes the service life of the refractory material. From the production point of view, this means controlling the degree of circulation of harmful volatile components such as alkali, chlorine and sulfur in the kiln and reducing the equilibrium concentration of harmful components. In addition to the daily optimization measures, the following measures should be focused on.
(1) Strictly control the quality of each raw combustion material, and especially strictly control the content of volatile components of co-disposal materials to meet the quality control requirements.
(2) The co-disposal materials should be evenly spoken to avoid too much fluctuation of harmful components at the time of entering the kiln, resulting in the aggravation of crusting; if the chlorine content in the co-disposal materials is high, it is suggested to increase the bypass venting facilities in the kiln tail flue chamber.
(3) Do a good job of various homogenization measures to stabilize the chemical composition of raw materials into the kiln, and control the standard deviation of raw materials C3S not more than 1.5%.
(4) Reasonable control of the fineness of raw material into the kiln, to 80μm sieve sieve 12%~14%, 200μm sieve sieve sieve not more than 1.5% is good.
(5) Stabilize the flow fluctuation of raw materials and fuel into the kiln, with short-term standard deviation of not more than 2%.
(6) Control the sulfur to alkali ratio of clinker, preferably around 0.8~1.2, to create conditions for harmful components to be taken away through the clinker.
(7) If a high thrust burner is used at the head of the kiln, the inner and outer winds are reasonably set to form a thin and short flame to reasonably distribute the hot work area in the kiln.
(8) stabilize the operation of the cooler, the second and third air temperature fluctuations are controlled to fluctuate within 25℃ every 20min.
(9) Reasonable use of wind in operation, control of kiln tail oxygen content generally 3% to 5% (low value is used when NO is high), CO content not more than 1000ppm, and control of kiln sulfur content of the cycle not more than 65%.
(10) Stabilize the decomposition rate of the hot raw material entering the kiln and control the decomposer outlet temperature to fluctuate within 10℃ every 20min.
(11) Preheater reasonable arrangement of crust cleaning devices, such as air cannons, etc.
2、The management optimization of kiln machinery
refractory brick due to bear alkali, chlorine, sulfur and other harmful components of the erosion, the formation of densification area in the brick reduces the mechanical flexibility of the brick itself, and therefore withstand the mechanical stress generated by the deformation of the kiln body is greatly reduced. To avoid damage to the refractory bricks, it is imperative to strengthen the condition of the kiln barrel monitoring, mainly.
(1) Regularly/online measure the slip amount of each wheel belt, 12~15㎜/turn is good in normal operation, and turn on and stop the cooling fan in time when deviation is found. If it is above 25㎜/turn for a long time, you must plan to add extra pads.
(2) Regularly monitor the deviation of the centerline of rotary kiln, and generally control the deviation of left and right not more than ±5㎜ and vertical deviation not more than ±3㎜ in the cold state.
(3) Regularly monitor the thickness of the key parts of the equipment shell, such as rotary kiln shell, kiln door cover, decomposer shell, found serious corrosion timely plan to replace, to avoid the thickness is too thin resulting in mechanical stress large impact on the service life of refractory materials.
(4) In areas with frequent heavy/stormy rainfall, it is best to add a rain shelter above the shell to avoid thermal shock.
3、Refractory material selection and construction
(1) The refractory material gives priority to the product that has its own characteristics of preventing the passage of harmful gases, and it is generally desired to choose the applicable product with a porosity of less than 15%.
(2) refractory construction for the erosion of harmful gases pay attention to the work surface gaps are filled with fireclay, reasonable set expansion joints, reasonable choice of expansion joints filling materials to prevent gas short-circuiting into the lining interior.
(3) insulation layer to choose a small shrinkage rate of the product, shrinkage rate of the insulation layer is not recommended single-layer arrangement. Insulation layer installation should be set up according to no 2~3 ㎡ one to isolation layer to prevent problems with insulation layer to form through seams.
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