Compared with seven typical cement grinding systems, the final grinding system of vertical grinding is the first choice!Date: 2019-07-12 Views:
The cement grinding system is gradually developed from the earlier simple ball mill system to the ball mill roll press system and roll grinding system. According to the technological process, the cement grinding system is divided into two systems: open flow and coil flow. Among them, the combined grinding system composed of ball mill and roller press, the grinding system composed of ball mill and vertical mill, and the final grinding system of vertical grinding are widely used at present. In this paper, seven representative typical processes are introduced, and their advantages and disadvantages are compared, which can be used as a reference for everyone to choose a reasonable cement grinding system.
1. Open flow system composed of roller press and ball mill
The system is mainly composed of a V-shaped powder separator, a roller press, a cyclone dust collector and a ball mill. The ball mill system is an open-flow system, and a set of dust collection system is shared between the air discharge of the roller press system and the ventilation of the ball mill.
The system is characterized by simple process, less investment in equipment and civil construction, but more fine powder in cement particle gradation, high power consumption per unit product, especially high cement temperature and dehydration of some gypsum.
2. Semiopen flow system composed of roller press and ball mill
The composition of this system is basically similar to that of figure 1 system, but a 0-Sepa powder separator is added to select part of the qualified fine powder in the roller press system as finished product. Due to the addition of powder separator, the ventilation of the mill can be increased.
The characteristics of this system are basically similar to those of figure 1 system, but the output of the system is slightly increased, the cement temperature is slightly decreased, but it is still high, and the installed power consumption of the product (only considering the power of the main engine) is also higher.
3. Combined grinding system consisting of roller press and ball mill(with combined powder separator).
This system is mainly composed of V type powder separator, roller press, cyclone dust collector, ball mill and combined powder separator, and the ball mill system is a closed circuit system.
Among them, the roller press system is equipped with a separate air release system, and the ball mill is ventilated separately and the combined powder separator shares a set of dust collection system.
This system features:
The main results are as follows:
1) the process is complex, the investment of equipment and civil construction is high, especially the shape volume of the combined powder separator is large, and the area of the factory building is more.
2) the powder selection efficiency is not high;
3) the number of fans is large, which increases the power consumption of the system;
4) the open flow ratio of finished cement particles is reasonable, the output is also higher than that of open flow system, especially the cement temperature is lower, and the cement quality is obviously better than that of open flow system.
5) because there are still some overgrinding phenomena in the long ball milling system of roller press, the system changes fine and long ball milling to short and coarse ball milling.
4. Combined grinding system composed of roller press and ball mill (with 0-sepa separator)
The composition and process of the system are basically the same, the main difference is that the combined powder separator in figure 3 is replaced by the 0-sepa powder separator with better performance (small shape and high powder separation efficiency). The advantages and disadvantages of the system are basically the same as those of the system.
5. Combined grinding system composed of roller press and ball mill (with vortex separator)
The system is mainly composed of V-type separator, roller press, ball mill and vortex separator. The ball mill system is a closed circuit system.
6. Combined grinding system composed of vertical mill and ball mill
This system is mainly composed of vertical mill, combined powder separator, ball mill and 0-Sepa separator. The ball mill system is a closed circuit system. The neutral mill is used as pre-grinding equipment, and the system is equipped with a separate air release system. The gas extracted from the ball mill is the primary air, the secondary air and the third air are the ambient air of the 0-Sepa powder separator.
This system is characterized by:
The main results are as follows: 1) the process is relatively complex, the equipment investment is the same as the fourth system, but the civil construction cost is relatively small, because the vertical mill can be arranged in the open air;
2) the maintenance of vertical mill is less than that of roller press, so the running rate is higher.
7. Final grinding system of vertical grinding
The system is mainly composed of vertical mill, high concentration bag dust collector and fan.
This system features:
1) the process is simple and the power consumption of the system is low;
2) the factory building covers a small area and the vertical mill can be arranged in the open air, so the civil construction cost is relatively small;
3) the maintenance quantity of vertical mill is less than that of roller press, so the running rate is higher than that of roller press system.
From the above comparison, it can be seen that:
1. The final grinding system of vertical mill has the advantages of simple flow, low energy consumption and less metal consumption, so it should be the first choice of cement grinding scheme. However, at present, the vertical grinding cement has not been popularized on a large scale in China, the main reasons are:
1) The cement vertical mill needs to be imported from abroad, and some technologies of domestic vertical mill also need to be further improved;
2) the cement products produced by the ball mill system for a long time have to be adapted to the vertical grinding cement for a certain period of time.
2. The combined grinding system composed of roller press and ball mill (with swirl separator), and the combined grinding system composed of vertical mill and ball mill have similar flow chart, each has advantages, disadvantages and energy consumption, which is higher than that of vertical mill.
These two systems can be used as the best scheme of cement grinding system.
3. There are many shortcomings in the open and semi-open flow system composed of roller press and ball mill. In addition to the poor quality of cement, the energy consumption is also higher, so avoid the choice as far as possible.