Reduce cyclone operating costs
Writer： admin Time：2020-08-06 14:03 Browse：℃
The slurry processed by the cyclone is driven by the pump to rotate into the cyclone along the tangential direction of the working cylinder at a certain pressure and flow rate, and then the slurry will rotate along the cylinder wall at a very fast speed and produce Centripetal force, so that under the action of centrifugal sedimentation, the separation of the slurry can be completed. Environmental protection valves: In the domestic environmental protection system, the water supply system mainly needs centerline butterfly valves, soft-sealed gate valves, ball valves, and exhaust valves (used to remove air in the pipeline). The hydrocyclone is a device that can realize separation and classification. It can effectively complete liquid clarification, degassing, sand removal, solid phase particle washing, and classification. During the application of cyclones, how to reduce operating costs has always been the focus of attention. So what is the most effective way to reduce operating costs and improve efficiency? That is to minimize the total energy consumption.
The factors affecting the total energy consumption of the cyclone mainly include three parts: inlet loss, outlet loss and internal flow loss. The inlet loss and outlet loss account for a small proportion of the total energy loss of the cyclone. The inlet loss is mostly caused by jet resistance and friction caused by the sudden expansion of the cross section when the slurry enters the cyclone; the outlet loss is mostly caused by the kinetic energy and pressure discharged by the slurry, and has little impact on energy consumption.
The internal loss is the largest in the total energy loss of the cyclone. Most of the energy loss is caused by inner wall friction, fluid viscous internal friction, turbulent dissipation and various local losses. If you want to improve these issues, you can look at the following aspects Get started.
One. Improve the structure of the overflow pipe of the cyclone
The overflow pipe structure design of the cyclone is unreasonable, and there will be a short-circuit flow phenomenon, resulting in the overflow of the cyclone and the mixing of coarse and fine particles in the separated product, which will directly affect the flow of the cyclone.
Solution:
1. Adding some ring teeth on the outer wall of the overflow pipe can greatly reduce or even eliminate the short-circuit flow. When the outer wall of the overflow pipe is added with ring teeth, the steep drop index can be increased from 0.176 to 0.332, and finally the cyclone is separated The accuracy index is 1.8 times higher than that of ordinary cyclones.
2. Open an annular gap between the top cover of the cyclone and the overflow pipe to draw out the short-circuit flow and return the short-circuit flow to the sealed gathering chamber. This design can effectively reduce the mixing of coarse particles in the overflow product. Compared with conventional classification efficiency, it is 8% higher.
3. Adding a reverse spiral on the outer wall of the overflow pipe of the cyclone that is opposite to the direction of rotation of the short-circuit flow can effectively solve the problem that the conventional cyclone accounts for 10%-20% of the short-circuit flow of the treated liquid, which not only improves the separation efficiency, but also The cone vortex, back vortex, and short-circuit vortex are integrated into one vortex, which saves energy.
4. Increasing the thickness of the overflow pipe wall of the cyclone can lengthen the path of the short-circuit flow and reduce the flow of the short-circuit flow. Therefore, it can effectively improve the separation efficiency of the cyclone and reduce its internal loss.
5. The overflow pipe is changed from a straight round pipe to a diverging pipe. The design idea is derived from the principle of reducing speed and pressure of the diverging pipe, which can make the slurry at the inlet of the overflow pipe smoothly drain under lower pressure. Outside of the hydrocyclone, energy consumption is reduced by 27% compared to straight round pipes. Moreover, the outlet slurry velocity of the overflow and the underflow can be effectively utilized without waste and reducing operating costs.
Two. Improve the wall structure of the cyclone
After long-term use of cyclone, the wall will form a wall boundary layer, which will shield fine materials and affect the classification efficiency of the cyclone.
Solution:
1. Change the smooth wall of the cyclone to a stepped wall, which can destroy the shielding of fine particles by the side wall boundary layer through the loop on the wall.
2. Inflate into the cyclone through the wall of the porous material, so that the content of fine particles in the underflow is relatively reduced by 30% to 50%.
3. Setting tooth-like grooves on the surface of the cyclone cone can effectively destroy the boundary layer of the wall and promote the formation of a certain strength of the vortex of the slurry, which is more conducive to the fine particles leaving the boundary layer and entering the overflow area, improving the separation accuracy.
three. Eliminate the air column in the cyclone
There is no separation process inside the air column in the cyclone, which is a waste of energy consumption, not only does not contribute, but also occupies the flow area of ??the overflow. At the same time, the fluctuation of the size and position of the air column aggravates the flow field. Instability, to a certain extent, destroys the regular distribution of separated particles in the cyclone, thereby reducing the separation efficiency of the cyclone.
Solution:
1. Use an appropriate amount of solid rods to occupy the original air column position in the cyclone. When the solid rods are full of the original air column position, the internal loss can be reduced by about 51%, and the separation performance is also improved.
2. Change the gas flow pattern in the cyclone, use the large vortex to forcefully break into small vortices, effectively reduce the turbulent energy consumption at the center, the velocity gradient of the fluid at the center of gravity, and the fluid velocity at the overflow port, avoiding the energy consumption of the air column The adverse effects on separation caused by sloshing not only increase the separation efficiency by 15%, but also reduce the operating energy consumption by about 40%.
A certain pressure is required at the inlet of the cyclone. These measures of moving the pump as close as possible to the cyclone are to minimize the static pressure and friction loss head of the pump, which can save power. The cyclone is at design time. Different radial cone ratios and pyramid ratios are used, which can maximize the tangential velocity of the cyclone, reduce energy loss, and achieve the best classification results.
According to different working conditions and requirements for working results, the length of the cylindrical body of the cyclone can be adjusted at will to ensure that the cyclone reaches the best working state. When pumping to a cyclone or a group of cyclones, the size and model of the pump must be carefully designed in detail to meet the requirements of the operation. And also have to design the pumping pipe diameter and pipeline length.
In order to improve the classification accuracy of the cyclone, the following method can be used: a rectangular tapered feed tube is used to gradually increase the flow speed of the slurry, so that the flocculation state gradually becomes a laminar flow state. The wear damage of the pump is roughly proportional to the cube of the speed. Therefore, the design of the cyclone should be as close to the pump as possible. The reason for this is to reduce the pump speed and the maintenance of the pump as much as possible. Quantity.
When installing the cyclone, a filter screen should be provided for each cyclone, the purpose of which is to reduce the clogging of the cyclone caused by impurities. The pore size of the filter screen in the cyclone is one third of the diameter of the cyclone. When installing the cyclone, it is also recommended to configure a pressure gauge to monitor the local pressure when the cyclone is running to ensure that the hydrocyclone runs more stable. If the operating pressure of the cyclone is too high, it will cause abnormal underflow concentration and increase the wear of the components in the cyclone.
If the cyclone adopts a distributor and a multi-cyclone substructure, in order to reduce unnecessary turbulence, a straight pipe section should be provided for the inlet pipe of the distributor, the length of which cannot be less than 9 times the pipe diameter. The inlet pipe setting of the cyclone distributor can be completed by referring to the design drawing of the feed pipe of the cyclone distributor provided by the manufacturer. The cyclone group is also often used in the mining field. The development of minerals often has adverse effects on the surrounding environment, and there are still many problems with the treatment of tailings. The use of cyclone separation technology can recycle coal slime, etc., effectively avoiding environmental pollution. my country is a country with severe water shortages. The use of cyclones can solve this problem to a certain extent, increase the utilization rate of water resources, and reduce the discharge of toxic wastewater.
The above content only analyzes the problems caused by the internal energy loss of the cyclone, such as the structure of the cyclone wall, the overflow tube and the air column, and proposes corresponding solutions. Faced with the various problems of the cyclone, it is necessary to A targeted solution is an effective way to reduce its operating costs and improve production efficiency.
