Currently the most commonly used is the cement rotary dryer, its structure and properties of yield and quality, thermal efficiency is very prominent influence, let’s focus on the interview from rotary dryer cylinder aspect ratio, speed, and lifting plate tripartite On some of the issues related to the structural performance rotary dryer.
First, the rotary dryer cylinder aspect ratio
At present, the commonly used rotary dryer simplified aspect ratio is generally between 5 to 8. Rotary dryer drying aspect ratio on the yield portable jaw crusher plant and quality of materials, thermal efficiency has a great influence. When a certain tilt angle of the rotary dryer, speed, flow rate, lifting plate structure, residence time in the rotary dryer cylinder body depends mainly on the English aspect ratio.
First Water and its properties
Material dried to the desired final moisture required length of stay and the material such as plastic, particle size is too small and so on. Beginning of the rainy season in the south higher moisture material, especially for some of the larger plastic clay, using the rotary dryer, the residence time is shorter. Or that material deviation from the final moisture; or have to reduce production and increase the flue gas temperature, flue gas to reduce the moisture content to ensure quality. This is not just the problem of declining production, but also led to a reduction in thermal efficiency. Because the material is too small, the average fill rate is too low material rotary dryer, rotary dryer will inevitably lead to the thermal efficiency decreases.
appropriate to increase the aspect ratio of the rotary dryer to extend the material in the rotary dryer residence time for drying moisture, plasticity and larger particle size material is advantageous. Practice has proved that this method helps to improve yield and quality, while coal consumption decreased, the thermal efficiency also improved.
Second, the speed
rotary dryer speed is generally 3 to 5 rev / min, the current domestic widespread use of a single speed rotary dryer, from the actual production situation, its ability to adapt is not strong enough.
Initial moisture difference
different periods of the same type of material is quite large, 14 and the different nature of different types of materials require different residence times during drying. For a rotary dryer, its aspect ratio, angle of inclination, lifting plate structure is fixed, if the speed becomes adjustable, it can adjust the residence time within a certain range. Materials such as spring water large, especially drying clay, due slow speed and extend the material stays in the rotary dryer to ask, will help to ensure production quality. From another perspective, the different types of materials require different speed in order to achieve better lifting height and adequate residence time, and the speed of rotation bake thousands of machines are doing so can be adjusted to provide favorable conditions.
Third, the lifting plate
lifting plate raised material, flue gas heat contact with the material more fully, in order to achieve better drying purposes. The lifting plate size, shape and arrangement of the yield and quality of rotary dryer thermal efficiency have a greater impact.
rotary dryer lifting plate is arranged copied plate, cell feeder Yang et al., The former is more commonly used, copied plate lifting plate there are common straight plate, curved bevel plate, right angle plate several. In general, a rotary dryer uses only one form of lifting plate. Various forms of lifting plate has its own characteristics. Ease thrown straight plate material, suitable for high water, more viscous material; bevel right angle bending and bending due to the curved portion is used for low moisture, looser material.
We believe rotary dryer lifting plate structure and layout to make some improvements, the effect will be better.
First, in the preheating zone near the feed end of the rotary dryer, the material moisture is higher, the larger viscosity, straight plate lifting plate is more appropriate, easy to dump material. Later, material moisture decreases, also decreases the viscosity, using a plate or bevel right angle bend the plate more appropriate, particularly in the constant drying section, strengthen the contact material with the hot flue gas to enhance heat transfer gas-solid phase mASS. This mtw molino trapezoidal compared to using the same form of more favorable lifting plate, better strengths.
In addition, the lifting plate arrangement should not be forced back and forth the entire agreement rotary dryer. The material in the rotary dryer rhyme warm-up phase and constant drying stage, lifting should be strengthened, increasing the contact area with the material of the flue gas, which can increase the drying rate. Lifting plate arrangement is advantageous to appropriate more dense. In the rotary dryer section after that falling rate drying stage, the drying rate of the material depends on the rate of migration of moisture in the material to the Department, the material has a lower moisture at this stage, looser, will inevitably produce a strong lifting large group dust, adding to the burden of collecting equipment, falling rate drying stage behind the war, especially in the vicinity of the discharge end, lifting plate may be appropriate to arrange the evacuation of some.