Application of external circulation cement vertical grinding semi-final grinding systemDate: 2019-07-15 Views:
1. An overview of the
Cement industry is a large energy consumer, and the energy cost accounts for a high proportion in the total cost, including fuel cost and electricity cost.The grinding power consumption accounts for about 60~70% of the power cost. It is of great significance to improve the grinding technology level and reduce the grinding power consumption for the green and energy-saving development of cement industry
According to the development trend of cement grinding, the single tube mill grinding system has been basically eliminated due to its low grinding efficiency and high power consumption.The pulverizing system of material bed is widely used because of its high grinding efficiency.The so-called semi-final grinding refers to the pre-grinding stage of the grinding system, which selects a part of finished products with qualified fineness in advance and directly adds them to the finished products.Let the fineness of qualified products leave the grinding system in advance, no longer accept subsequent grinding, so as to improve the powder selection efficiency of the whole grinding system, reduce the phenomenon of over-grinding, reduce the waste of grinding energy, and improve the grinding efficiency of the system.At present, the roller press semi-final grinding system is widely used, but practice has proved that the standard consistency of the cement grinding system of roller press semi-final grinding system requires more water on the whole.Limited by the cement performance of roller press system, most completed production lines have abandoned the semi-final grinding production mode (generally, only PC32.5 cement is produced with the semi-final grinding system), and there are few successful cases in use.
2. Application of KVM external circulation cement vertical grinding semi-final grinding system
The main technological process is as follows: the materials from the mixing station are firstly fed to KVM external circular vertical mill. After the materials grinded by the vertical mill are sorted by the v-type powder separator, the fine powder is carried into the three-separation powder separator by wind for further sorting, and the coarse powder is returned to the vertical mill for circular grinding.Fine powder after separation by three separation separator is used as finished product. Medium and coarse powder can enter into vertical mill and tube mill respectively. Coarse powder can directly return to vertical mill for circular grinding.The tube mill adopts closed-circuit grinding form, and the abrasive materials from the tube mill pass through the upper spreader to the three-separation separator for sorting.The sorted finished products are collected together with the finished products directly sorted by the external circulation vertical grinding system through the bag dust collection and then stored in the warehouse.
The two grinders share a powder selecting system, which reduces the investment of equipment and civil engineering.At the same time, vertical grinding and tube grinding materials are entered into the three separation separator for sorting, which makes the two parts of materials fully mixed, avoiding the fluctuation of cement quality caused by the large performance difference of the two parts of products before and after the traditional semi-final grinding system and the uneven mixing in the later stage.
The operation of KVM external circulation cement vertical grinding semi-final grinding system shows that the power consumption of cement grinding is 26~27kWh/t, and the water demand of cement standard consistency is 25.6~26%. The successful operation of this system not only solves the performance problems of cement products faced by the semi-final grinding system, but also reaches the leading level in China.The system can be applied to new, modified and expanded production lines, providing a new solution for cement semi-final grinding system.