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VORTEX FINDERS (DIP TUBES, IMMERSION TUBES). Cyclone with no vortex finder - Steel alloy or ceramic Plan view Section of cyclone A cyclone is a device.

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Presentation on theme: "VORTEX FINDERS (DIP TUBES, IMMERSION TUBES). Cyclone with no vortex finder - Steel alloy or ceramic Plan view Section of cyclone A cyclone is a device."— Presentation transcript:

1 VORTEX FINDERS (DIP TUBES, IMMERSION TUBES)

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3 Cyclone with no vortex finder - Steel alloy or ceramic Plan view Section of cyclone A cyclone is a device to separate the dust from the air. It does this very effectively. However a small portion of the air/dust mix escapes into the exit pipe

4 VORTEX FINDERS (DIP TUBES, IMMERSION TUBES) THE NORMAL PROCESS IN A CEMENT CYCLONE (VERY SIMPLIFIED) Cyclone with no vortex finder - Steel or ceramic For the dust which escapes : CaO + CO 2 CaCO 3 + Q (heat) Energy lost + re-circulation and concentration of impurities. This leads to build-up. CaCO 3 + Q (heat) CaO + CO 2

5 VORTEX FINDERS (DIP TUBES, IMMERSION TUBES) Cyclone with vortex finder - Steel alloy or ceramic The portion of the air/dust mix which escapes into the exit pipe is reduced

6 Which type to choose : Upper cyclones (where the temperatures are below 700 o C) There are usually no problems here and you can easily use a low cost steel alloy tube : There are many suppliers Lower cyclones (where the temperatures are above 700 o C) Steel alloy or ceramic vortex finders –We need to evaluate the advantages and disadvantages

7 THE EFFECTS OF ALTERNATIVE FUELS Aggressive chemicals – Certain chemicals attack the steel alloy vortex finder (chlorine, sulphur, CO) – Other chemicals attack the ceramic vortex finder (alkalies). Fluctuating temperatures (due to non-homogenous fuels and variable water content) – If the normal temperature in the cyclone is o C and severe fluctuations occur then there is a big risk of overheating the steel alloy vortex finder. – Too many fluctuating temperatures can cause failure due to thermal shock of the ceramic vortex finder elements

8 THE EFFECTS OF ALTERNATIVE FUELS Aggressive chemicals – Certain chemicals can attack the steel alloy vortex finder (chlorine, sulphur, CO) – Other chemicals can attack the ceramic vortex finder (alkalies). Fluctuating temperatures (due to non-homogenous fuels and variable water content) – If the normal temperature in the cyclone is 850 o C and severe fluctuations occur then there is a risk of overheating the steel alloy vortex finder. – Too many fluctuating temperatures can cause failure due to thermal shock of the CVF Under these conditions it is very difficult to estimate the lifetime of the vortex finder (steel alloy or ceramic) The answer : Do a trial !!!

9 VORTEX FINDERS (DIP TUBES, IMMERSION TUBES)

10 THE STEEL ALLOY VORTEX FINDER If the customer is satisfied with the lifetime (2 years or more) and there are no other problems then he will probably continue with the steel vortex finder. If the plant engineers are dissatisfied there can be the following reasons : Lifetime: corrosion or heat can cause short lifetime Build-up: causes the pressure drop to increase Buckling: becomes so distorted the pressure drop increases- reduced efficiency Abrasion: In some cases abrasion makes holes in the steel plates Thickness: need to measure the steel thickness every shutdown Sometimes difficult and time-consuming to remove and install (sometimes 3 – 7 days) Often blocks the cyclone when pieces fall Fallen steel segments damage the kiln lining, the cooler or the crusher

11 VORTEX FINDERS (DIP TUBES, IMMERSION TUBES) XX Group cement plant in Switzerland Photo taken after 19 months. Damaged below roof level after 27 months. Re-installation to be January 2012

12 THE CERAMIC VORTEX FINDER If the customer is satisfied with the lifetime (2 years or more) and there are no other problems then he will probably continue with the ceramic vortex finder. If the plant engineers are dissatisfied there can be the following reasons : lifetime too short : due to thermal shock lifetime too short : due to chemical deterioration of the precast elements Occasionally blocks the cyclone when pieces fall

13 CERAMIC VORTEX FINDERS About 3 years ago we did a full analysis of the ceramic vortex finder elements. The analysis recommended that we stop using Silicon carbide (SiC) in the precast elements The analysis recommended that we stop using steel alloy fibres in the precast elements We did this and the lifetimes have definitely improved

14 CERAMIC VORTEX FINDERS The development continues …………………

15 CERAMIC VORTEX FINDERS INSTALLATIONS IN NEW INDUSTRIES : Power plants – CFB boilers Alumina industry – due to heavy abrasion


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