FIELD OF INVENTION
The present invention relates to a new arrangement and configuration used in cyclones for material separation in all Filtration and Separation industries and Material handling industries such as Cement and Steel plants and in Power Plants particularly based on Circulating Fluid Bed (CFB) boilers where solid separation is the key for process efficiency.
BACKGROUND OF THE INVENTION:
CFB boilers widely use a solid separator to collect coarse particles pneumatically transported upwards along with gas and send them back to the furnace to enhance the solid particle circulation and in turn the turbulence to achieve higher fuel burn-out efficiency and fuel flexibility. This way, the gas is stripped off the solid particles and in turn cleaned. This stripping or separation can be performed with the help of traditional cyclone separators or with unconventional mechanisms depending on the extent of collection efficiency required. The traditional cyclones can also either be of cooled or uncooled versions.
Cyclones are devices that employ a centrifugal force generated by spinning gas stream to separate particles from the carrier gas. Cyclone separators operate under the action of centrifugal forces. Fluid mixture, the particle laden gas, enters the cyclone tangentially at the top of the cylinder and makes a swirl motion spiralling downwards until the conical section is reached. In this part of the device, the centrifugal forces can be several times greater than gravity and forcing the dense phase of the mixture gaining a relative motion in the radial direction and is separated from the main flow. Then, the gas flow is deflected upwards and outflows from the exhaust duct, maintaining the swirling motion. Typically these cyclones would have a component called Vortex Tube (also known as centre pipe, dip tube, immersion tube or thimble) which locates this "central core" axially along the cylinder centreline, capturing the spinning gas that gradually migrates inward, and letting it out upwards.
The vortex tube in a cyclone is a very important component with its dimensions significantly affects the cyclone performance. Its size and configuration play a critical role in defining the flow field inside the cyclone, including the pattern of the outer and inner spiral flows. The vortex tube affects the collection efficiency of the cyclone and the pressure drop across the cyclone which has a bearing on the power consumption of the plant. Typically, the vortex tubes work under severe conditions such as high gas-solids temperature of 900 - 1000 degree C, thermal shocks with the sudden rise in temperature or cooling when circulation of material stops, chemical attack from the potassium, sulphur and chlorine found in the raw material and the fuel burnt, high possibility for abrasion with higher gas-solids velocity, etc and there is a requirement for high tensile strength of the material used to withstand these severity.
The size and configuration of the vortex tube varies with the size and configuration of the cyclone, and in turn has an impact on its support. The larger the cyclone diameter, the bigger the vortex tube and more complex is its support design. Generally, cyclones are employed in high temperature applications, be it in material handling industries, spray dryer or gasification reactors or in a CFB power plant. The support system of vortex tube gets complicated and becomes more difficult when the gas-solid mixture temperature is very high. When the temperature of the solids laden gas is around 900 - 1000 degree C, there is a limitation in the availability of suitable steel material and stress values of the steel at such temperatures are getting lower, and warranting a higher grade steel for the manufacture of

the vortex tube. Also, the thermal expansion of the steel at such high temperature is a lot different from the main cyclone cylinder steel which is normally lined with refractory for protection. These limitations with respect to the steel ultimately result in a complex support design with huge size pins, more pins, expensive material grades etc. Notwithstanding all these, if in an operating power plant if the vortex plate undergoes deformation and falls it affects the availability of the plant and ends up with huge monetary losses. A deformed vortex obviously impacts the cyclone's collection efficiency, even if does not fall and remain in its place.
The current designs for vortex tubes use a circular configuration with a longer length. Usually these are of high grade materials and may warrant heat treatment on the joints if welded. These are uncooled and not lined with refractory considering the expansion potential of the steel at high temperatures of 900 - 1000 degree C. The vortex is supported with gussets welded circumferentially on their body and hanging from the top roof of the cyclone or through high grade steel pins piercing the vortex. The support design is almost the same irrespective of whether the cyclone is of cooled or uncooled design.
Some designs have retainer rings along the length of the vortex tube to keep the deformation of the vortex within certain limits. Some suppliers provide a segmented design with an overlapping arrangement. Some prefer to avoid steel and make the entire vortex tube by ceramic materials. However, all designs widely involve a high degree of complexity, and higher grade materials. By the way it is supported any form or type of vortex tube in the current designs needs to be supported considering a multi axis movement. The vortex tube is literally hanging from the top and during expansion it can move into any axial direction, depending on the material of construction and the gas-solids mixture temperature. The "floating" nature of the vortex tube with respect to the support mechanism is a great challenge for designing the support system.
The existing system is also not leak proof in the sense that a certain amount of the hot gas would flow outside the vortex tube and leave the system. If not designed, manufactured and constructed properly, this leakage could be more than anticipated and could result in some unwarranted erosion of the support pins and weaken the support system. This may also impact the performance of the expansion joint provided in certain systems just above the cyclone.
Moreover, the location where this vortex tube is installed is such that it is not easy to access in case of a failure and requirement of repair. The warping and the subsequent deformation of the steel material starting from the bottom to the top of the vortex tube are unavoidable in the current designs and this determines and limits the life of the vortex tube.
Following are a few examples on existing systems. U.S. Pat. No. 5,441,081 to Maury discloses a new immersion tube for a cyclone which is suitable for differently sized cyclones and in which individual components can be easily replaced.
U.S. Pat. No. 6,837,913 to Schilling et al. discloses a cyclone separator, in particular, hot gas cyclone with a segmented dip tube whose dip-tube segments are securely fastened.
Hasle's ceramic vortex finders are installed in preheater cyclones to improve the separation between the raw meal and the hot gas, for increasing the efficiency of the cyclones. Ceramic dip tube of Zhejiang Ruitai Shengao Refractory Co. Ltd. has excellent resistance to chemical attack, dimensional stability at elevated temperatures as like Hasle's ceramic vortex finders.

Magotteaux's dipping tubes are made of hooking of individual segments (called as rings) for desired length. ATEC has products namely Cyclone dip tube and "Hurrivane®" for improving separation of particles.
A case study of Haywood et al. on the topic titled "Enhanced problem solving; the integration of CFD and other Engineering applications" presented in Seventh International Conference held in December 2009, at Melbourne, Australia, describes on the re-designing of vortex finder in an alumina gas suspension cyclone.
KRK process solutions offers a 'Side Entry Multi-Cyclone' for liquid or solids separation in which each cyclone element starts with an outer tube with one or more integral swept inlet nozzles to initiate the spin. FL Smidth Krebs T-Series Classifying Cyclones has exceptional abrasion resistance which is achieved by using high purity alumina ceramic in the lower cones and silicon carbide ceramic in the upper sections. Alternately, the entire cyclone may be provided with urethane or ceramic liners. Process Group's Cyclonixx® (Desander Cyclones / Hydrocyclones) is a static cyclone separator which uses pressure as the energy for separation of sand and solids from produced water, condensate and/or gas streams.
The system of the present invention overcomes the above disadvantages by completely changing the way the vortex tube is supported and thus preventing its "floating" in multi-axis directions and offers a less expensive design.
The present invention is for use in any system having an application of separating high temperature solid particles, especially systems like a circulating fluidized bed boiler with integrated or external cyclone attached with its furnace and also in other industries such as Filtration and Separation industries, material handling industries like cement plants and steel plants etc.
SUMMARY OF THE INVENTION:
The present invention relates to a new arrangement called NofloatX useful in any system having an application of separating high temperature solid particles. This system is mainly applied to boilers such as circulating fluidized bed type provided with a cyclone either integral or external to its furnace.
The purpose of this invention is to provide a simple support system for the vortex tube in a cyclone separator which is less expensive and provides higher availability to the plant.
The NofloatX is basically made out of steam cooled tubes; however, this can also be made out of water cooled tubes. In a CFB boiler, the gas flue over the cyclone is typically steam cooled and is called the cyclone outlet chamber (COC) or Cross Over Duct (COD). In some designs the COC is also made uncooled with steel ducts lined with refractory. The NofloatX uses the steam cooled floor tubes of the COC or COD to form either a circular or polygonal enclosure in the required configuration of the vortex tube, creating the necessary diameter and length. The steam cooled tubes will have studs welded both on to their inside and outside which act like reinforcing pins for the refractory lined over the tubes. Thus, the NofloatX is a cooled and refractory lined vortex tube eliminating the need for high grade material and the inevitable deformations of the uncooled vortex tube. The NofloatX vortex can still be studded tube arrangement without refractory and the studs will minimize the erosion of the tubes to a higher extent.

The entire load of the NofloatX is on the COC floor tubes and the COC is supported from the top outside the gas path. Thus, the NofloatX is still hanging as in a conventional design, but it is no longer floating. It expands in a pre-determined direction and its expansion is more dependent on the steam temperature inside the tubes rather than the temperature of the gas-solids mixture it experiences outside. The NofloatX system has refractory lining making the whole vortex tube a rigid body, essentially arresting any possibility for a deformation. Thus, it guarantees consistent cyclone efficiency for the cyclone.
The main features of the invention include (1) the use of steam cooled tubes arrangement (2) the use of refractory lining (3) hanging but not floating support system (4) elimination of headers (5) avoidance of exposure of other parts of cyclone, pressurized, to high temperature gas-solids path (6) perfect zero leakage sealing by not allowing any gas to flow outside the vortex tube (7) easy to install and remove (8) remote possibility of the vortex tube to buckle (9) elimination of corrosion of the vortex tube steel or other chemical attacks (10) reduced material build up on the surface of the vortex tube for the solids does not stick to the refractory (11) nil dependence on higher grade steel material with high tensile strength etc (12) the arrangement of the system is less complex and ensures safe and clean environment by providing required sealing from the finer, hot solids that puffs out of the separation system. The system avoids the need for any expansion joints and higher grade material. It results in zero deformation and hence assures anticipated cyclone performance. Compared to the conventional design, NofloatX system would result in higher plant availability considering the low possibility for failures and lesser down time even if a failure occurs. The non-necessity of any higher grade materials also is an advantage in terms of sourcing the spare components etc.
The system also includes a provision of having headers for both the COC floor tubes and the vortex enclosure tubes, circular or polygonal enclosure, finned membrane or unfinned tube construction.
The further aspect of the invention is that the NofloatX system can be utilized in any system where hot solids particles are to be separated either from a gas or air stream.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 shows the location of the vortex tube in a cyclone body.
Fig. 2 illustrates the front view of the NofloatX arrangement along with COC or COD and the cyclone body.
Fig. 3 illustrates the three dimensional view of the NofloatX arrangement.
Fig. 4 illustrates an alternate arrangement of NofloatX With circular collecting header.
Fig. 5 illustrates an alternate arrangement of NofloatX with polygonal form of the cooled tubes.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a new arrangement termed NofloatX for a vortex tube utilized in any cyclone system employed for particle separation in Filtration and Separation industries and in Spray dryers and other components in material handling industries such as

cement plants and steel plants or in power plants with CFB boilers or fluid bed gasifiers etc. Usually in these industries the solid particles will be at high temperatures. The vortex tube is supported in such a way that its static load, expansion in multiple axes with respect to the material used, stability to withstand external forces from the solids, vibration of the vortex tube as a whole, thermal shock, abrasion and chemical attack it undergoes etc are carefully considered.
The present invention is directed more towards the use of the system for a stable support system completely avoiding the possibilities of failure with respect to its "floating" due to multiple axes expansion, heat treatment of higher grade materials, use of higher grade materials, vibration of the vortex tube, corrosion due to chemical attack, abrasion and thermal shock due to high velocity and sudden reversals in solids temperature etc and to result in a less expensive solution providing a higher availability to the operating plant.
The NofloatX system is developed eliminating the multiple axis expansion movements that make the vortex tube to "float" during the plant operation which makes its support system more complex and difficult warranting a comprehensive and careful analysis. With this system, the expansion of the vortex tube is limited and more predictable. It is still made to hang from the top as shown in Fig. 2, but supporting is no longer complex. The entire load of the vortex is transferred to the cyclone outlet chamber (COC) which is supported from the top through hanger rods.
Figure 3 illustrates the NofloatX arrangement showing the steam cooled tubes configured to form the desired shape of the vortex tube, either circular or polygonal as shown in Fig. 5.
The system uses the floor tubes 1 of the COC or COD in such a way that a required enclosure can be formed in the desired configuration resulting in the requisite diameter and length for the vortex tube 2. Studs 3 will be welded on the tubes on both inside and outside so that they act as reinforcing pins for the refractory material 4 to be lined on the tubes. Steam from the COC floor tubes will flow through these vortex tubes also and keeps them all the time cooled, resulting in a much more uniform expansion. The cooled vortex is still hanging, but made to not floating. Hence, the expansion is not any longer in multiple axes. The vortex tubes 2 are only commercially available carbon steel or alloy steel tubes and not of any high grade steel. The refractory 4 makes the vortex rigid arresting any possible deformation, at the same time protecting the vortex tubes from erosion.
The vortex enclosure can alternately be made as shown in Fig. 5 by a membrane panel construction with fins 5 welded between the tubes. This would provide more stability to the vortex tube along with the refractory lining.
It is also possible to have a circular ring header 6 collecting the COC floor tubes at the floor level and connecting the top header 8 of the COC with links 9 to the roof (10) as illustrated in Fig. 4. With this arrangement, vortex steam tubes will be straight vertical tubes forming the circular enclosure and will be connected to another circular collecting ring header 7 at the bottom. This arrangement felicitates a higher degree of flexibility for fixing and removal of the vortex tube as a whole.
During plant operation, particularly a CFB boiler operation, large amount of solid fuel is burnt to produce energy and the process will usually take place at high temperature and above atmospheric pressure. In a fluidized bed boiler, fluidized bed is conventionally located in the bottom of the boiler furnace and the heat generated by burning fuel is transferred to the

water being heated by the boiler by different modes of heat transfer such as radiation, convection and conduction. After combustion, the solid particles (ash) leave the furnace to a cyclone system.
The solid particles are comprised of both the coarser and finer particles and the purpose of the cyclone is to collect the coarser particles and send them back to the furnace, while allowing the clean gas with some amount of fine particles to flow out through the vortex tube. These solids and gas mixture will usually be at a high temperature (900 - 1000 degree C) and quantum wise will be a huge amount. The forces exerted by the solids on the vortex, the temperature the vortex tube experiences, the fluctuations in the gas pressure, the vibration the vortex tube undergoes, all these factors contribute a lot and influence to a great degree the type of support system for the vortex tube over and above the static load of the vortex itself.
In most of the existing designs the vortex tube is hung from the top and made to float in all directions since it is of an uncooled design irrespective of the cyclone body which can be either cooled or uncooled. With an uncooled version, a large number of support pins or rods at several locations with high grade materials are employed to support the vortex. This makes the whole support system complex. It also results in deformation of the vortex tube, leakage of gases around the vortex tube etc impacting the cyclone performance. In case of any failure, accessing the vortex is also difficult and so its removal. But, with the new cooled tube arrangement of the present invention, all these possibilities can be avoided and expansion can be for very small movements in the predictable directions.
The advantage of this invention is that the vortex is part of the cooled circuit and expands along with the system, and not independently. Whereas in the existing systems, the steel made vortex expands completely different from the other circuits of the system. Some industries use a vortex entirely made of ceramic material. This also results in complex support design and not relatively easy to handle for installation or removal in case of any requirement of change of the vortex.
The invention further explains the flexibility of having the vortex tube configuration in several ways such as a circular tube or polygonal tube that facilitates ease of fabrication and manufacturing. This design has more provisions to have the steam cooled tubes finned or unfinned so that the vortex tube can be made still more rigid and composite. The design offers the provision of application of refractory on both sides of the cooled vortex tubes to prevent them from erosion and at the same time making the whole tube rigid avoiding any possibility for deformation, and in turn any change in the performance of the cyclone as a whole.
In the present invention, the cooled arrangement considered for the vortex tube is a unique feature. This arrangement offers a wide range of benefits starting from design of the support system, selection of materials, manufacturing the component, installing and removing depending on the requirement etc, apart from eliminating any dissimilar welding and associated heat treatment methods. This feature offers excellent benefits from the points of view of the high temperatures, thermal shocks, chemical attacks, abrasion, and material build up on the surface of the vortex tube material, dimensional variations etc the vortex tube undergoes during the operation of the plant.
The NofloatX system avoids the expansion joints and higher grade material and so complexities are nil or avoided. The system also makes the whole vortex tube rigid with the

usage of refractory linings. The system takes care of the expansion and provides the required sealing during operation of the unit at various circumstances.
The NofloatX system includes provision of introducing ring headers for the COC floor tubes and the vortex tubes. It also includes the provision of having a finned tube configuration for the vortex tube enclosure, making the whole tube more stable and rigid.
The NofloatX system can be applied to any cyclone system such as the one provided in Circulating Fluid Bed (CFB) boilers but not limited only to it and can be applied to any similar cyclone system in Filtration and Separation industries, material handling industries such as Cement and Steel plants or in gasifiers and so on.

WE CLAIM:
1. The new NofloatX system is developed for use in any system having an application of separation of solid particles, at either low or high temperature in a cyclone and the system primarily comprising of: (a) the use of a cooled tubes arrangement (b) hanging, but not a floating arrangement (c) the use of refractory lining (d) elimination of external supporting arrangement using high grade pins, rods, tubes etc.
2. The system according to claim 1, is utilized to support the vortex tube considering different factors such as the static load of the vortex tube, its expansion movements, high temperature of solids entering the cyclone, the huge amount of solids entering the cyclone and the force it exerts on the vortex tube, the fluctuations in the gas -solids pressure at the inlet of the vortex tube, vibration of the vortex tube, thermal shocks due to sudden reversals of gas-solids temperatures, chemical attack on the material due to alkalis and chlorine present in the material, fuel burnt, material build up on the surface due to sticking of solids on the material surface etc.
3. The system according to claim 1, can handle solid particles that can be typical ash or molten slag or any chemical powder other refuse materials to be discharged safely.
4. The system according to claim 2, can be utilized in any system where solids particles are to be separated from either a gas or air stream, be it in cement plants or steel plants or gasifiers and filtration and separation industries etc.
5. The system according to claim 1, can be made either water or steam cooled and thus all complexities in the support design can be avoided.
6. The system according to claim 1, is made with cooled tubes in such a way that they create the enclosure of the vortex tube either in circular form or any polygonal form.
7. The system according to claim 6, wherein the said cooled tubes can be left as loose tubes or be made as a finned membrane construction.
8. The system according to claim 1, can be lined with a thin layer of refractory either inside or outside or both sides depending on the severity of application and the potential for erosion of the tubes; wherein the application of refractory can be further reinforced either by studs welded on to the tubes or the anchors attached to the fins between the tubes.
9. The NofloatX system according to claim 1,, offers a zero leakage arrangement around the vortex tube and protects any expansion joints or other such components installed outside the vortex tube, and provide a safe and clean environment.

10. The system according to claim 1, can be made with circular collecting headers at the bottom of the vortex tube so that vertical tubes can be used for fabrication.
11. The system according to claim 10, is arranged in such a way that the entire vortex tube can be easily installed or removed as a single piece.

12. The system according to claim 1, is less complex and can be applicable to any systems having an application of separation of solid particles in industries like Filtration and Separation, Gasifiers, Material handling industries etc.
13. The NofloatX system is developed for use in the boilers like fluidized bed boilers with cyclones for separation of solid particles at high temperature and fluctuating pressures, the system comprising of: (a) the use of a cooled tubes arrangement (b) hanging, but not a floating arrangement (c) the use of refractory lining (d) elimination of external supporting arrangement using high grade pins, rods, tubes etc. (e) circular or any polygonal shape (f) finned membrane or unfinned tube construction (g) circular collection header (h) studs welded on to tubes or anchors welded on to fins etc.
14. The system according to claim 13, is simple and easy to support without the need for any expansion joint, higher grade material, complex dissimilar metal welding or associated heat treatment and stress relieving.
15. The system according to claim 13, does not directly expose any pressurized part to high temperature solids.
16. This NofloatX system, according to claim 1, can be applied to any system that is installed vertically or horizontally or at an angle.