Internal modification measures of tube mill with roller press

Date: 2019-06-28 Views:

Tube mills are often the most important part of the combined grinding system. How to play the potential of the tube mill is the goal that every cement worker is striving for. The internal structure design of the original tube mill has far exceeded the requirements of the process parameters of the tube mill in the current combined grinding process system engineering. To this end, the internal technological transformation of the mill is imperative. This paper introduces the technical transformation of the key parts in the tube mill grinding machine with roller press, so that it can better adapt to the requirements of the combined grinding process system to improve production and reduce consumption.

1 Pre-adjustment situation

Although the system has a significant increase from the initial system output, from 110t/h to the highest 160t/h (P·C32.5R cement), the overall power consumption of the cement is reduced to 30kWh/t, but the system runs for 2 months. After that, the output dropped rapidly, and finally stabilized at around 140t/h, and the overall power consumption of cement also increased to 36kWh/t. The economic benefits are not good. The operating parameters of the system are 25~40mm, the working pressure of the roller press is 9~10MPa, the working size of the grinding material is 80μm, and the remaining 18%~23% of the sieve.

P·C32.5R cement material ratio: clinker 55%, limestone 12.5%, slag 6%, fly ash 21% and gypsum 5.5%, 25% slag powder (not counting production); P·O42. 5 Cement material ratio: clinker 74.5%, limestone 10%, slag 9.5% and gypsum 6%, 25% slag powder (not counting production). The mixed material with fine particles is directly ground, and the mixed material and clinker with poor grindability and large particles are put into the roller press.

2 Analysis of existing problems

In July 2014, the system was diagnosed by experts from China Cement Technology Network. It is believed that the original configuration of the grinding system is basically reasonable, and the roller press +V type separator system works normally. The main problem is that some equipment in the mill can not adapt to the characteristics of the raw materials of the factory. In addition, the adjustment of the grading of the grinding body does not take into account the specific conditions of the raw materials, so that the system does not play its due ability, resulting in low output and unreasonable product gradation. The specific issues are as follows:

1) The configuration of a warehouse liner is unreasonable. After the roller press +V type separator system, the particle size of the milled material has been reduced, and the 80μm sieve sieve is ≤23%. The main function of the silo is grinding, no need to be broken. The original lining of the warehouse is a step lining. The main function of the step lining is to raise the grinding body to have a certain potential energy, so as to form impact crushing on the material. This configuration results in a small unit of the length of the grinding body doing less work, and the material entering the second bin is thick.

2) The design of the compartment board is unreasonable. The compartment board adopts the products developed in the early stage and is equipped with a blind board. This type of compartment board is easy to cause blockage, affecting ventilation and normal material flow.

3) The design of the grinding tail slab is unreasonable. The grinding tail plate is severely blocked, which affects the discharge and ventilation.

4) The grading of the abrasive body is unreasonable. When adjusting the grading of the grinding body, the factors such as the grindability of various materials, material size and material moisture should be considered comprehensively, but the original grading scheme cannot be considered comprehensively.

3 renovation measures

In response to the above problems, combined with the actual situation of the factory, we have formulated the following technical changes and adjustment measures.

3.1 Reconstruction of the feeding device

The double-layer feeding air inlet device transformed into the upper layer feeding, the lower layer and the side inlet air increases the cross-sectional area of ​​the inlet duct.

The specific measures are: the feeding pipe enters the air inlet pipe, and no leakage is allowed. The straight pipe enters the mill and the warehouse is closed. The position of the material feeding port should be blocked at the front, open up and down, left and right, and the opening area of ​​each face should be The cutting section of the cutting pipe is equal, and the front blocking plate should be in a warehouse, and the steel ball can not be hit. Such a blanking device alleviates the impact force of the material to be unloaded, and the material cannot be rushed to the tail of a warehouse at a time, and the blind spot of the silo is also eliminated.

3.2 Renovation of the liner of the mill

Replace the original warehouse step liner with the HX-C Forced Abrasive Surface Liner. The advantage of this lining is that after the grinding body is raised to a suitable height, it does not cause a drop, but a reverse sliding, thereby increasing the grinding ability. According to the manufacturer's experience, this alone can increase system throughput by approximately 10% in a roller press combined with a grinding system. The HX-C forced grinding surface lining is shown in Figure 2.

3.3 Renovation of the compartment board

Replace the original compartment board with HX-G compartment board to improve the ventilation and material flow inside the mill. In addition to the structure of the bracket and the center hole of the partition board, the existing double-layer compartment board is completely changed, and the front sill board, the rear blind board and the middle screen board are all changed. The front sill plate and the rear blind plate are all made into a new quilting device with good cross-sectional ventilation effect. The middle sieve plate is replaced with 6mm thick 304 stainless steel, and the sieve joint specification is changed from 3mm to 6mm. The modified double-layer compartment board has good cross-sectional area ventilation effect, strong material passing capacity, self-cleaning ability of the screen joint, and the front and rear sill quilting and sieve screen joints will not be blocked. At the same time, this compartment board also has the effect of eliminating the blind zone of the first and second bins. The HX-G compartment board is shown in Figure 3.

3.4 Reconstruction of the grinding tail plate

The former cast-type shovel slab was transformed into a shovel in the form of a sifter combination. The slab structure is opened in the original purlin area, and the maximum cross-sectional area is the ideal value. The sieve screen slat is used as the final structure of the squeezing quilting, which satisfies the need of over-winding and over-cutting area. This sieve-type combined fascia can solve the problems of high temperature, electrostatic paste and over-grinding in the tail chamber. To this end, the original grinding tail slab is replaced with a HX-B anti-blocking raft to improve the internal ventilation and material flow rate. The HX-B anti-blocking jaw is shown in Figure 4.

3.5 Reconstruction of the activation ring

The effective height of the heightening activation ring is above 1 000 mm, and the activation ring is provided with a height of 300 mm of the lower blind plate. The original 650mm activation ring structure was removed.

3.6 Adjusting the grinding body grading

The grinding body grading is adjusted according to the new process conditions. The grading of the grinding body should be calculated according to the grindability of various materials such as clinker and mixed materials. For different grinding systems, the corresponding grading scheme should be adopted. In the trial production, it must also be based on the production data (such as Surface area, screen residue, operating current, etc. are adjusted in real time to find the best gradation.

3.7 Other adjustments

Pre-employment training for operators. The new production process requires a new operating concept. To this end, it is necessary to change the traditional operating mode to meet the requirements of the operator's quality under the new process conditions.

4 adjusted situation

After the above transformation and adjustment, the operation of the combined grinding system has been greatly improved. Table 2 shows the actual operational data after the transformation and adjustment. It can be seen from Table 2 that the system output of P·C32.5R cement is 195-200t/h, the comprehensive power consumption of cement can be reduced to 25kWh/t, and the production of P·O42.5 cement is stable at 180~190t/ h, the product specific surface area and sieve residue meet the control requirements, and the power consumption per unit of cement production is greatly reduced. High-yield, low-consumption green production has been realized, and the economic benefits of enterprises have been greatly improved.

5 Conclusion

In addition to the system configuration, the factors that determine the quality of the mill have a lot to do with the operating concept and the grading of the grinding body. The technical transformation of the structure of the mill mill grinding machine only provides a prerequisite for product production, quality assurance and consumption reduction. The grinding machine has a poor ventilation effect, and even the fine grinding body gradation does not work. Reasonable internal grinding can improve the working condition of the grinding machine, thereby greatly increasing the system output and reducing the grinding power consumption. HX-C curved lining, HXB grinding raft, HX-G compartment series and other grinding equipment design is reasonable, which plays a decisive role in improving the internal ventilation and controlling the material flow rate. The capacity of the tube mill has gone up, and the combined grinding system has solved most of the problems. Then the roller press system transformation and commissioning work is done so that it does not affect the energy of the tube mill. If it is a double closed circuit system, it must be modified. And to debug the powder selection efficiency of the grinding and finishing machine, so that the quality of the combined grinding system can be optimized.

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