Cyclone separator

Cyclone separator presentation completely defines you about the mechanism of cyclone phenomenon.

1. Cyclone Separators Jehangir Akram Muhammad Ali Muhammad Nafees Nabeel Naeem 1

2. Cyclonic separation is a method of removing particulates from an air, gas or liquid stream, without the use of filters, through vortex separation. When removing particulate matter from liquids, a hydrocyclone is used; while from gas, a gas cyclone is used. Rotational effects and gravity are used to separate mixtures of solids and fluids. The method can also be used to separate fine droplets of liquid from a gaseous stream. Cyclonic separation 2

3. It consists of a cylindrical vessel with the conical base. In the upper part of the vessel is fitted with a tangential inlet and a fluid outlet and at the base it is fitted with the solid outlet. CONSTRUCTION 3

4. Cyclone separators operate by incorporating centrifugal, gravitational, and inertial forces to remove fine particles suspended in air or gas. These types of separators use cyclonic action to separate particulates from a gas stream. Typically, particulate matter enters the cyclone separator at an angle and is then spun rapidly. A centrifugal force is created by the circular airflow that throws the particulate towards the wall of the cyclone. Once the particulate matter hits the wall, it falls into a hopper below. “Clean” exhaust is then either blown through or recirculated to be filtered again. Operation 4

5. Operation 5

6. Based on the construction and orientation of the inlet and outlet cyclones can be classified as: Reverse flow Cyclones Uniflow Cyclones Based on types based on the body size cyclones can be classified as: High efficiency  designs High rate  designs   Types of cyclones 6

7. 1. In  reverse flow  (seen in Figure 1 above), the gas enters through a tangential inlet at the top of the cyclone body, shaped to create a confined vortex gas flow. The clean gas exits through a central pipe also at the top of the body. 2. In  uniflow  or “straight through” cyclones, the gas enters at one end of the body and leaves at the other end; this type is less frequently used in industry because it is a much less practical design in most cases. Types of cyclones based on the construction and orientation 7

8. Uniflow Cyclone Sample 8

9. Reverse Flow Cyclones Sample 9

10. High efficiency  designs are characterized by long bodies in addition to small openings. This construction allows for high recovery rates at higher pressure drops. High rate  designs are characterized by shorter bodies in addition to larger openings, which allow for a larger volume with lower capture rates or pressure drops. Type of cyclones based on types based on the body size cyclones 10

11. Process conditions are the characteristics surrounding a cyclone’s operation. These include the air conditions and the particulate/dust conditions that are essential to finding or designing an appropriate cyclone for a given system. When having a cyclone custom built, these conditions are requested from the cyclone manufacturer.   Process Conditions 11

12. Air conditions  include the pressure, temperature, and moisture content at the inlet of the cyclone. Solids collection becomes more difficult as humidity rises because the moisture tends to cause PM to adhere to the cyclone walls. Air-Conditions 12

13. Dust conditions  at the inlet of the cyclone can include material type, specific gravity, bulk density, dust load ,and particle size distribution. Sizing, densities, and loads are needed to determine the required capacity and design specifications for sufficient capture. It is also important to specify any unique characteristics of the particulate matter that may lead to corrosion or degradation of certain construction materials. Dust-Conditions 13

14. Large scale cyclones are used in sawmills to remove sawdust from extracted air. Cyclones are also used in oil refineries to separate oils and gases, and in the cement industry as components of kiln preheaters. Cyclones are increasingly used in the household, as the core technology in bagless types of portable vacuum cleaners and central vacuum cleaners. Cyclones are also used in industrial and professional kitchen ventilation for separating the grease from the exhaust air in extraction hoods.  Applications 14

15. Smaller cyclones are used to separate airborne particles for analysis. Some are small enough to be worn clipped to clothing, and are used to separate respirable particles for later analysis. Similar separators are used in the oil refining industry to achieve fast separation of the catalyst particles from the reacting gases and vapors. Analogous devices for separating particles or solids from liquids are called hydrocyclones or hydroclones. These may be used to separate solid waste from water in wastewater and sewage treatment. Continue… 15

16. Particle Size When Particle Size Increases, efficiency increases. Particle density When Particle Density Increases, efficiency increases. Dust loading When Dust Loading increases, efficiency increases. Inlet gas velocity When Inlet gas velocity increases, efficiency increases. Factors Affecting Efficiency of Cyclone 16

17. Cyclone body diameter Increasing body diameter decreases efficiency. Ratio of cyclone body length to diameter Increasing length to diameter ratio, increases efficiency Smoothness of cyclone inner wall Increasing smoothness of cyclone’s inner wall increases efficiency. Gas viscosity Increasing gas viscosity, decreases efficiency. Continue… 17

18. Gas density Increasing gas density, decreases efficiency. Gas inlet duct area Increasing inlet gas duct area , decreases efficiency. Gas exit pipe diameter Increasing diameter of gas exit pipe, decreases efficiency. Continue… 18

19. A  hydrocyclone  is a device to classify, separate or sort particles in a liquid suspension based on the ratio of their centripetal force to fluid resistance. This ratio is high for dense and coarse particles, and low for light and fine particles. Also used in the separation of liquids of different densities. Hydrocyclones 19

20. A hydrocyclone is a classifier that has two exits on the axis: one on the bottom ( underflow  or  reject ) and one at the top ( overflow  or  accept ). The underflow is generally the denser or coarser fraction, while the overflow is the lighter or finer fraction. Design of hydrocyclones 20

21. Hydrocyclone 21

22. For a Bradley hydrocyclone, the dimensions of each part are always in the same proportions. The pressure drop should be between 20 psi and 60 psi. Di is the inlet diameter Do is the overflow diameter Du is the underflow diameter Dc is the chamber diameter L is the height of the hydrocyclone l is the height of the cylinder part of hydrocyclone ℓ is the height of the vortex tube of hydrocyclone Le is the length of the outlet tube Theta is the angle at the base of the hydrocyclone Di/Dc = 1/7 Do/Dc = 1/5 Du/Dc = - L/Dc = - l/Dc = 1/2 ℓ/Dc = 1/3 Theta = 9 degrees Design equations 22

23. Forward hydrocyclones remove particles that are denser than the surrounding fluid, Reverse hydrocyclones remove particles that are less dense than the surrounding fluid. In a reverse hydrocyclone the overflow is at the apex and the underflow at the base. There are also parallel-flow hydrocyclones where both the  accept  and  reject  are removed at the apex. Parallel-flow hydrocyclones remove particles that are lighter than the surrounding fluid. Various Hydrocyclones 23

24. Hydrocyclones can be made of metal , ceramic or plastic. Metal or ceramic hydrocyclones are used for situations requiring more strength, or durability in terms of heat or pressure. When there is an occurrence of much abrasion polyurethane performs better than metals or ceramics. Metal lined with polyurethane is used in cases of combined abrasion and high pressure. Material of Hydrocyclones 24

25. In the potato, cassava, wheat and corn starch industry for both concentration and washing of the crude starch milk. Hydrocyclone replace separators as a more price efficient separation technique. In pulp and paper mills to remove sand, staples, plastic particles and other contaminants. In the drilling industry to separate sand from the expensive clay that is used for lubrication during the drilling. In oil industry to separate oil from water or vice versa. Uses of Hydrocyclones 25

26. In metal working to separate metal particles from cooling liquid. In French fries and potato chips plants for in-line starch recovery from cutting water and from waste water. In mineral processing, hydrocyclones are used extensively both to classify particles for recirculation in grinding circuits and to differentiate between the economic mineral and gangue. To remove sand and silt particles from irrigation water for drip irrigation purposes. Continue… 26

27. Low capital cost. Ability to operate at high temperatures. Can handle liquid mists or dry materials. Low maintenance requirements (no moving parts). Small footprint - requires relatively small space. Advantages Of Cyclones 27

28. High operating costs (due to pressure drop). Low efficiencies (particularly for small particles). Unable to process "sticky" materials . Disadvantages of Cyclones 28

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