cement vertical roller mill

For the cement industry were 30,25,20,10,8.8 tons of annual production and other industries use to meet the users of different materials with different yield and grinding requirements. At the same time I also have fine vertical grinding mill, the State Development Center has fine vertical cement mill as the "Eighth Five-Year" period focused on promoting the application of high efficiency, new energy-saving products.

The working principle of vertical roller mill

1, the main structure and function

Roller is the main material for rolling mill parts. Mill built with two pairs of roller, each pair of rollers mounted on the same shaft, rotating at different speeds.

Disc fixed to the reducer output shaft, the upper part of the disc material bed, the bed material a circular groove.

PRM-type separator mainly composed of vertical roller mill ,roller, disc, compression device, reducer, motor, housing and other components.

Fineness of separation is an important component of the decision, which consists of adjustable speed drives, rotor, guide blades, housing, meals, fighting off the cone material, composed of the outlet, and the separator works similar.

Pressure device is called the grinding pressure of the components provided by the high pressure oil station, hydraulic cylinder, rod, storage and other components, able to exert enough pressure roller grinding of materials.

2, the working principle of vertical roller mill

The material flow through the separator, in the role of guide vanes and the rotor, the coarse material to the disc from the hopper cone, the fine powder with a mill with air, dust collection device in the system to collect, is the product, the material in the contact process with the gas being dried to the required product water, by adjusting the angle and the wind guide vane separator rotor speed can be different fineness of the product.

Motor through reducer drive the disc rotation, the current hot air from the air inlet into the mill, the material from the feed opening falls on the central disc; the centrifugal force, material to the disc edge and moved across the ring groove on the disc by the grinding roll rolling and grinding, to the edge of the disc, moving through the air with the wind at the starting of large particles falling back to disc on the direct re-grinding.

Compared with the ball mill, vertical roller mill with the following features;

Compared with the cement vertical mill to mill the advantage is obvious, in order to establish a more intuitive description of the characteristics of MPS vertical mill, following the annual output of 10 tons of cement and production of raw material preparation system, for example, compared with the two HRM vertical mill and ball mill kinds of program indicators.

Grinding efficiency; drying large capacity; into the grinding material Liaodu large, medium and large vertical mill can save two broken; products, chemical stability; stars are homogeneous gradation, product Liaoduo uniformity is conducive to burning ; process is simple; low noise, less dust, the operating environment clean; metal loss, high utilization; use of the economy.

Assuming an annual output of 10 million tons of cement in order to meet production needs, may use the following two options:

Programme 1: HRM1300 vertical mill grinding system

Programme 2: @ 2.2 × 6.5 米 closed-circuit grinding system

Table II installed capacity of the two programs, technical and economic indicators in Table III.

As can be seen from the above comparison, the choice of vertical roller mill to reduce annual operating costs only 380,200 yuan, and the level of technology and products to improve yield, save energy, improve the operating environment, reducing noise and pollution, and enhance ability to adapt to other aspects of the play is not assess the long-term benefits.

Vertical roller mill grinding cement technology

International Progress:

• In the past 10 years, the vertical roller mill for cement and slag grinding technology has made an important breakthrough.

• the world's largest cement producer Ruishi Hao Rui Group in 1998 and Loesche companies, Hon Chong Cement Plant in Vietnam into the first vertical mill for cement grinding. Since then, more and more vertical roller mill for cement and slag in the final grinding.

•vertical roller mill for cement producers traditional grinding system compared with the practical and the quality of the cement to produce the same concerns have been eliminated. Vertical mill grinding cement has many advantages, not only has the economic advantage, while versatile, represents the future direction of development of cement industry.

Since the first vertical mill grinding cement in use since the cement grinding process, especially a large cement grinding power consumption and reduce power consumption is also a great potential. Cement and slag grinding, the vertical mill grinding energy is about 50% of the traditional ball.

• vertical mill is an air swept mill, so the fan's energy consumption must be included in the grinding system. Generally speaking, the vertical roller mill grinding plant ball mill power consumption is about 70%, which is new on the market to other comparable grinding technology.

Vertical roller mill raw material recycling technology

5000t / d production line of raw material preparation using RMR57/28/555 vertical roller mill. In the trial production period, there are often caused by improper operation of bucket elevator loop current is too high, resulting in crushing bucket elevator, mill jump stop the phenomenon, not only to field a larger increase in the workload of staff, also affected production. Through the operator and the constant review and practice, the current form of a set of effective control measures to effectively prevent the occurrence of such phenomena.

Problems outside the circle bucket elevator model: NSE300 × 33350, transmission capacity of 450t / h, motor power 75kW, rated current of 140A, the alarm value of 150A. In actual production, often due to sudden changes in raw materials, incoming instability and other reasons, the status changed to wear, resulting in material outside the circle, resulting in high current hoist. Early in the production, operation of commonly used method is a rapid reduction of the volume of feed at the same time increase the grinding pressure, appropriate to reduce the speed of the powder, so that as many as possible with the gas from the powder mill, mill to reduce the volume within the material, thereby reducing the external of recyclable materials. However, in practice found that such methods of operation to adjust for too long, large number of materials from outside the mill, will eventually cycle crushing bucket elevator. As the hoist is a chain of relations with the vertical roller mill, skip hoist will stop after the mill shut down.

Improvements through exploration and discovery, when the cycle of bucket elevator reach the threshold current 140A, even to the alarm value of 150A, to take the following measures, which can effectively avoid the cycle of bucket elevator of death.

① trip into the grinding belt, prohibited materials into the vertical roller mill. ② to quickly lower the ground pressure, so that in the disc of material formed on a temporary thick layers, so that the cycle bucket elevator plummeted materials. ③ appropriate separator to reduce speed, so that in fine grinding as soon as possible from outside the mill (separator speed should not be too low to prevent the raw material through the rough.) ④ When the cycle of current bucket elevator downward trend and dropped to 140A, can reduce the feeding amount to 200 ~ 300t / h, open the feed into the grinding belt, adjust the grind to a steady state condition, then normal operation.

Practice has proved that such methods of operation is simple, rapid decrease in a relatively short period of time outside the volume of recyclable materials to effectively prevent the large amount of recyclable materials caused by circulating outside the bucket elevator crushing, grinding stop jumping phenomenon long-term operation of the mill has played a crucial role, thus ensuring the normal kiln feed, but also greatly reduces the power consumption of raw material grinding system