Abstract:
A cyclone separator includes a body having a side entry fluid inlet, a first outlet and a second outlet both aligned substantially transverse to the fluid inlet, and has the first and second outlets opposing each other. A cyclone tube assembly is positioned within the body having at least a portion of the cyclone tube assembly positioned in a direct unobstructed alignment path with the fluid inlet. The cyclone tube assembly includes a plurality of cyclone tubes, each including a first tube section and a second tube section partially positioned within the first tube section. A ceramic material forms at least a portion of the second tube section of each cyclone tube. A first tube connection plate supports the first tube section of each of the cyclone tubes. A second tube connection plate supports the second tube section of each of the cyclone tubes. The first tube connection plate is angularly offset from the second tube connection plate.

Description:
FIELD OF THE INVENTION 
     The present invention relates in general to hydrogen generation by steam reforming of natural gas and more specifically to a device and method for separating solid materials from a solids/gaseous flow stream used in such a reforming process. 
     BACKGROUND OF THE INVENTION 
     The generation of hydrogen from natural gas via steam reforming is a well established commercial process. One drawback is that commercial units tend to be extremely large in volume and subject to significant amounts of methane slip, identified as methane feedstock which passes through the reformer un-reacted. 
     To reduce the size and increase conversion efficiency of the units, a process has been developed which uses calcium oxide to improve hydrogen yield by removing carbon dioxide generated in the reforming process. See U.S. patent application Ser. No. 10/271,406 entitled “HYDROGEN GENERATION APPARATUS AND METHOD”, filed Oct. 15, 2002, commonly assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. The calcium oxide reacts with the CO 2  in a separation reaction, producing a solid calcium carbonate (CaCO 3 ) and absorbing the CO 2 . 
     The calcium carbonate reuse process requires that the calcium, in either CaCO 3  or CaO (solid) be separated from the system gases, including the hydrogen gas product as well as carbon dioxide, un-reacted methane, excess oxygen and/or nitrogen, so the calcium carbonate particles can be either reformed to calcium oxide or transferred for reuse as calcium oxide. Cyclone separators are commercially known which can separate small particles from a fluid flow stream. At the 649° C. (1200° F.) to 983° C. (1800° F.) temperatures of the calcium carbonate reuse process, however, known commercial cyclone separators may not provide adequate resistance to thermal shock or a pressure drop meeting system requirements. 
     SUMMARY OF THE INVENTION 
     According to a preferred embodiment of the present invention, a cyclone separator includes a body having a side entry fluid inlet, a first outlet and a second outlet both aligned substantially transverse to the fluid inlet, and the first and second outlets opposing each other. A cyclone tube assembly is positionable within the body and having at least a portion of the cyclone tube assembly positioned in a direct unobstructed alignment path with the fluid inlet, the cyclone tube assembly including: a plurality of cyclone tubes, each including a first tube section and a second tube section partially positionable within the first tube section; a ceramic material operably forming at least a portion of the second tube section of each cyclone tube; a first tube connection plate connectably supporting the first tube section of each of the cyclone tubes; and a second tube connection plate connectably supporting the second tube section of each of the cyclone tubes. The first tube connection plate is angularly offset from the second tube connection plate. 
     According to another preferred embodiment of the present invention, a cyclone separator system includes a cyclone separator body having a body wall and opposed first and second ends. A first insulation layer is positioned within the separator body in contact with the outer wall. A cyclone tube assembly has a plurality of cyclone tubes, the cyclone tube assembly positioned in contact with the insulation layer. A substantially gas-tight seal is operably formed between the cyclone tube assembly and the insulation layer. A mixture inlet is connected to the body wall substantially transverse to the opposed first and second ends, the mixture inlet having an interior insulation layer. A plurality of arc-shaped flow directing members are disposed on each of the cyclone tubes. A mixture contacting the flow directing members is operably directed in a cyclonic flow path within each of the cyclone tubes. 
     According to still another preferred embodiment of the present invention, a method for separating a plurality of particles from a fluid using a cyclone separator, the cyclone separator including a separator body, a fluid inlet, a gas outlet, a particle outlet, and a cyclone separator tube assembly having a plurality of cyclone tubes, includes: continuously reducing a height of the cyclone tube assembly from an inlet to a distal end of the cyclone tube assembly; aligning at least a portion of the inlet of the cyclone separator tube assembly with the fluid inlet; directing a heated fluid containing at least a plurality of particles via the fluid inlet into the cyclone separator tube assembly; accelerating the heated fluid at a tube inlet of each of the cyclone tubes; separating the heated fluid within the cyclone tubes into the plurality of particles and a gas; and discharging the plurality of particles from the particle outlet. 
     The features, functions, and advantages can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  is a diagrammatic view showing a calcium oxide reuse system having a plurality of solids cyclone separators according to a preferred embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of a multi-clone separator according to a preferred embodiment of the present invention; 
         FIG. 3  is a perspective view of a cyclone-tube assembly according to a preferred embodiment of the present invention; 
         FIG. 4  is a partial cross-sectional view of an individual cyclone tube according to a preferred embodiment of the present invention; and 
         FIG. 5  is a cross-sectional view of another preferred embodiment of a cyclone separator of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     Referring generally to  FIG. 1 , according to a preferred embodiment of the present invention, a reformation system  10  includes a hydrogen generator  12  which receives reaction products from a calciner  14  via a generator feed line  16 . Discharge from the hydrogen generator  12  is provided via a generator discharge line  18  to a hydrogen cyclone separator  20  of the present invention. Hydrogen gas  22  is largely removed from hydrogen cyclone separator  20  via a hydrogen discharge line  24 . A plurality of calcium carbonate (CaCO 3 ) particles  25 , which are entrained in a flow that can contain hydrogen, steam and nitrogen gases from hydrogen generator  12 , are separated and collected for discharge at a discharge end  27  of hydrogen cyclone separator  20 . The calcium carbonate particles  25  are transferred via a hot rotary screw pump (hereinafter screw pump)  26  via a return line  28  back to calciner  14 . An exemplary screw pump is disclosed in United States patent application entitled “HOT ROTARY SCREW VALVE/PUMP”, concurrently filed herewith, commonly assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. 
     In return line  28  a flow splitter  30  can be disposed having at least one feed tube  32  discharging the calcium carbonate particles  25  into a calciner injector  34 . An exemplary calciner injector  34  is disclosed in United States patent application entitled “DRY, LOW NITROUS OXIDE CALCINER INJECTOR, concurrently filed herewith, commonly assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. Calciner injector  34  can be connected to a calciner inlet  36  of calciner  14 . A hot, vitiated air volume  38  can be introduced via a vitiated air generator  40  into calciner injector  34 . Details of vitiated air generator  40  are provided in U.S. patent application entitled “Non-Swirl Dry Low NOx (DLN) Combustor” filed Feb. 26, 2004, commonly assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. 
     Calciner inlet  36  can receive a mixture  42  including the calcium carbonate particles  25  and the hot vitiated air volume  38  discharged into calciner inlet  36  upstream of a cyclone separator  44  of the present invention within calciner  14 . Regeneration of the calcium carbonate particles  25  back to calcium oxide occurs primarily within calciner inlet  36 . As a result of the regeneration process, as well as the addition of steam and methane as noted below, a calcium oxide/nitrogen/carbon dioxide mixture  46  is created within cyclone separator  44 . A plurality of relatively heavier calcium oxide particles  48  are separated within cyclone separator  44  and fall into a hopper  50  within calciner  14 . A gas volume  52  containing primarily nitrogen and carbon dioxide gases, together with a small carryover volume of calcium oxide particles  48 , is discharged from cyclone separator  44  via a gas discharge line  54  to a cyclone separator  56  of the present invention. Gas volume  52  can be discharged from cyclone separator  56 , leaving the carryover volume of calcium oxide particles  48  to collect in a bottom hopper area  58  of cyclone separator  56 . A screw pump  60  can return the carryover volume of calcium oxide particles  48  via a calciner input line  62  to hopper  50  of calciner  14 . A steam supply  64  and a methane supply  66  can be connected to calciner  14  and a steam/methane mixture  68  together with the regenerated calcium oxide particles  48  can be transferred via a screw pump  70  to hydrogen generator  12  to repeat the process. 
     During operation of reformation system  10 , hydrogen generator  12  reacts steam from steam supply  64  and methane from methane supply  66  to generate hydrogen and carbon dioxide. The carbon dioxide is removed from hydrogen generator  12  by reaction with the calcium oxide particles  48  entrained with steam/methane mixture  68 . The hydrogen  22  is removed via hydrogen cyclone separator  20  as previously discussed. As the calcium oxide particles  48  absorb the carbon dioxide, calcium carbonate particles  25  are formed which are transferred by screw pump  26  in particulate form out of hydrogen cyclone separator  20 , as previously discussed, and into calciner injector  34 . Hot, vitiated air volume  38  impinges and reacts with the calcium carbonate particles  25  in calciner inlet  36  to reform calcium oxide particles  48  from mixture  42 , which subsequently enter cyclone separator  44  of calciner  14 . Within cyclone separator  44 , the calcium oxide particles  48  and calcium oxide/nitrogen/carbon dioxide mixture  46  are separated, with the calcium oxide particles  48  dropping down into hopper  50 . During operation of reformation system  10 , calcium carbonate particles  25  are continuously reformed to calcium oxide particles  48  and calcium oxide particles  48  are returned in particulate form with steam/methane mixture  68  using screw pump  70  to hydrogen generator  12 . 
     System conditions at the inlet to each of the cyclone separators  20 ,  44  and  56  are approximately as follows:
         a) Hydrogen cyclone separator  20  inlet: pressure approximately 0.793 MPa (115 psia), temperature approximately 649° C. (1200° F.);   b) Cyclone separator  44  inlet: pressure approximately 0.670 MPa (100 psia), temperature of calcium carbonate particles/steam/methane mixture approximately 982° C. (1800° F.); and   c) Cyclone separator  56  inlet: pressure approximately 0.655 MPa (95 psia), temperature of calcium oxide particles/steam/carbon dioxide/nitrogen mixture approximately 982° C. (1800° F.).       

     Referring generally to  FIG. 2 , an exemplary embodiment for hydrogen cyclone separator  20  includes a separator body  72  having a separator wall  74  and an inner wall layer  76 . In this embodiment, separator body  72  is provided from a metal material, including metal suitable for operating at temperatures at or about 1200° F. Materials for separator body  72  can include steel, stainless steel, or one of the super alloy materials. Inner wall  76  can be the metal material or super alloy material noted above and can also be coated with a high temperature ceramic material. Hydrogen cyclone separator  20  receives calcium carbonate particles and discharged gases from hydrogen generator  12  (shown in  FIG. 1 ), via generator discharge line  18  in the direction of flow arrow “A”, and are received in an inlet  78 . Exemplary system connections for inlet  78  include an inlet connector  80  shown in this embodiment as a flange connectible to a system connector  82  identified in this embodiment as a mating flange. It should be obvious to a practitioner in the art that inlet connector  80  and system connector  82  can be provided as a plurality of known connections including but not limited to welded connections, screwed connections, or coupling type connections. Hydrogen gas exits hydrogen cyclone separator  20  via a gas discharge end  84 . Gas discharge end  84  includes a discharge connector  86  connected to a system connector  88  which provides connectivity to hydrogen discharge line  24 . Hydrogen gas generally flows in the direction of flow arrow “B” to the gas discharge end  84 . 
     Upon entering hydrogen cyclone separator  20 , the fluid containing calcium carbonate particles  25  is flowing at a velocity ranging from approximately 3.05 m/sec (10 ft/sec) to approximately 15.24 m/sec (50 ft/sec). This flow can be directed along a direct, unobstructed flow path “W” into a cyclone tube assembly  90  which is shown and described in reference to  FIG. 3 . The gas flow can directly impinge a portion  91  of cyclone tube assembly  90  directly along flow path “W”. From cyclone tube assembly  90 , hydrogen can flow generally upward in the direction of flow arrow “B” and calcium carbonate particles  25  can drop in the general direction of flow arrow “C”. Calcium carbonate particles  25  can collect adjacent to discharge end  27  and can be directed to a particle discharge throat  92  via a conical portion  94 . Because the temperature of the fluid entering hydrogen cyclone separator  20  is approximately 649° C. (1200° F.), inlet  78  can also be coated with a layer of ceramic material (not shown) similar to inner wall  76 . A fluid tight seal  93  can be formed between cyclone tube assembly  90  and inner wall  76 . 
     Referring generally to  FIG. 3 , cyclone tube assembly  90  can include a plurality of cyclone tubes  96  which can be connectably supported by a tube upper connection plate  98  and a tube lower connection plate  100 , respectively. Fluid flow in the direction of flow arrow “A” enters cyclone tube assembly  90  from the left as viewed in  FIG. 3 . This fluid containing calcium carbonate particles  25  contacts each of the plurality of cyclone tubes  96 . An inlet end  97  having an entrance height “D” of cyclone tube assembly  90  is greater than a height “E” of a distal end  99  to maintain a substantially equivalent pressure drop across each of the plurality of cyclone tubes  96  in cyclone tube assembly  90 . Each of cyclone tubes  96  can be connected to either tube upper connection plate  98  or tube lower connection plate  100  by a fluid tight connection, for example by a welded joint. Other connection designs can also be used as known in the art providing that a fluid tight connection can be maintained at each of the intersections of a cyclone tube  96  and either tube upper connection plate  98  or tube lower connection plate  100 , respectively. 
     As previously noted in reference to  FIG. 2 , hydrogen discharge flow exits cyclone tube assembly  90  in the direction of flow direction arrow “B” and calcium carbonate particles  25  are separated from the fluid portion and discharged from cyclone tube assembly  90  in the directional flow arrow “C”. In the embodiment shown in  FIG. 3 , a length of each portion of cyclone tubes  96  either above tube upper connection plate  98  or below tube lower connection plate  100  can vary. Material for cyclone tubes  96  is preferably provided of a ceramic or a ceramic matrix composite material as previously discussed herein. Materials for tube upper connection plate  98  or tube lower connection plate  100  can be provided of a steel, a super alloy steel or a ceramic material. Each of the cyclone tubes  96  can be provided with a first tube section  102  which directly interface with tube lower connection plate  100 . Material for first tube section  102  is preferably a steel or a super alloy material permitting a junction between each first tube section  102  and tube lower connection plate  100  to be formed as a welded joint. 
     As best seen in  FIG. 4 , each cyclone tube  96  includes first tube section  102  having a second tube section  104  connected thereto, for example by welding or brazing. Second tube section  104  can be a steel or super alloy material previously discussed herein having a ceramic or a CMC ceramic coating applied thereto or section tube section  104  can be entirely formed of a ceramic or CMC material. The ceramic or CMC ceramic material can provide resistance to the thermal shock each cyclone tube  96  is exposed to when fluid entering cyclone tube assembly  90  varies from a cold condition through and including the normal operating condition of approximately 635° C. (1200° F.). Each first tube section  102  can include a tube connection plate  106  externally connected to first tube section  102 . Tube connection plate  106  can be joined to tube lower connection plate  100  of cyclone tube assembly  90  by a weld or braze joint  107 . Each second tube section  104  can be connected to tube upper connection plate  98  using an attachment joint  108 . Attachment joint  108  can be also a welded or brazed joint. 
     Flow in the direction of flow arrow “A” entering cyclone tube assembly  90  contacts an outer surface “X” of each second tube section  104 . A portion “F” the overall flow entering cyclone tube assembly  90  can be directed by a plurality of flow directing members  110  into an upper open end  111  of first tube section  102 . This fluid is directed into a cyclonic flow path  112  by the orientation of flow directing members  110 . Flow directing members  110  direct the flow of fluid into an interstitial area  114  between a tube inner wall  116  of each of first tube section  102  and the outer surface “X” of second tube section  104 . As fluid flow enters in the direction of flow portion “F” it is accelerated from the inward flow velocity (ranging from approximately 3.05 m/sec to approximately 15.24 m/sec) up to approximately 30.48 m/sec (100 ft/sec). This velocity increase is sufficient to separate the calcium carbonate particles  25  from the entrained gas flow. As the fluid flows in the cyclonic flow path  112 , calcium carbonate particles  25  strike tube inner wall  116  slowing the heavier particles causing the calcium carbonate particles  25  to drop along tube inner wall  116  toward a discharge end  118  of first tube section  102 . Calcium carbonate particles  25  subsequently can be discharged from first tube section  102  via a discharge opening  120 . The remaining gas from the fluid flow entering first tube section  102 , which can include hydrogen, unreacted methane, and/or steam, rises in the direction of flow arrows “B” and enters a second tube inlet  122  of second tube section  104 . This gas volume continues to flow in the direction of flow arrows “B” within second tube section  104  and can be discharged from a tube discharge end  123  above tube upper connection plate  98 . 
     Referring still to  FIG. 4 , the incoming flow of the fluid containing calcium carbonate particles  25  indicated as flow portion “Y” is reduced by the amount of the fluid which enters each cyclone tube  96  (indicated by flow portion “F”) which results in a net reduction of overall fluid flow indicated as the flow relationship “Y” minus “F” (Y−F) viewed to the right of second tube section  104  in  FIG. 4 . To maintain a generally constant pressure drop across cyclone tube assembly  90 , tube lower connection plate  100  is angled upwardly as viewed in  FIG. 4  from left to right such that a continuously decreasing volumetric flow of fluid containing calcium carbonate particles  25  is directed to subsequent ones of the cyclone tubes  96 . It is desirable that within each first tube section  102  cyclonic flow path  112  be provided with sufficient distance to achieve at least 5 rotational turns within first tube section  102  to maximize removal of calcium carbonate particles  25 . 
     Referring generally to  FIG. 5 , a cyclone separator  124  according to another preferred embodiment of the present invention is adaptable to receive fluid flow from reformation system  10  where fluid temperatures reach approximately 983° C. (1800° F.). Because of the increased thermal load from fluid temperatures at approximately 983° C. (1800° F.) cyclone separator  124  can be provided with additional insulation materials. Cyclone separator  124  can include a separator wall  126  which is provided with an insulation layer  128  having an insulation thickness “H”. An inlet connector  130  can be similarly provided with an inlet insulation layer  132 . Materials for insulation layer  128  and inlet insulation layer  132  can be a ceramic material or a ceramic matrix composite material as previously discussed herein. This insulation material can be provided as a coating, as a plurality of individual blocks of insulation material, or by other processes generally known in the art. Cyclone separator  124  can further include a conical portion  134  similar to conical portion  94  of hydrogen cyclone separator  20 . A reduced insulation area  136  can be provided adjacent to conical portion  134  to maintain a substantially constant flow area “Z” through a particle discharge throat  138 . Reduced insulation area  136  can include insulation material similar to insulation layer  128  and inlet insulation layer  132 . 
     Cyclone separator  124  differs from hydrogen cyclone separator  20  most significantly by the addition of the various insulation layers. Cyclone tube assembly  90  can be the same assembly as provided with hydrogen cyclone separator  20  or can be either increased or decreased in size relative to hydrogen cyclone separator  20 . If cyclone tube assembly  90  is approximately the same size, an outer diameter “G” of cyclone separator  124  can be increased relative to hydrogen cyclone separator  20  to accommodate for insulation thickness “H”. Similarly, a diameter “J” of inlet connector  130  can also be increased to accommodate a thickness of inlet insulation layer  132 . A length of inlet connector layer  130  is also adjustable to accommodate insulation thickness “H”. Gases discharged from cyclone separator  124  can exit via a gas discharge end  140  which can be partially formed through a reduced insulation area  142  adjacent to a discharge connector  144 . Reduced insulation area  142  can be provided as similar insulation to insulation layer  128 . Outer diameter “G” is provided if cyclone tube assembly  90  is formed as a generally circular assembly. Cyclone tube assembly  90  and cyclone separator  20  can be formed in a circular, an oval, a rectangular (similar to that shown in  FIG. 3 ) or other geometric shape depending upon the design parameters and required total volumetric flow for either hydrogen cyclone separator  20  or cyclone separator  124 . 
     To maintain the pressure drop across an individual cyclone separator below approximately 1 psid generally requires the gas velocity not to be accelerated within each cyclone assembly inlet above approximately 100 feet/second. Hence, the number of parallel operating cyclones, N c , required for gas/solids separation is given by the following equation: 
                     N   c     =         Q   .     t         v     g   ,   in       ⁢     A   in                 Eq   .           ⁢   1               
where the variable Q T  is the total volumetric flow rate of the particle laden gas stream, the variable v g,in  is the cyclone separator&#39;s inlet gas velocity, and the variable A in  is the cyclone separator&#39;s inlet cross-sectional flow area. For standard cyclone designs (as provided in Perry&#39;s, Chemical Engineers&#39; Handbook, 5 th  Ed., McGraw-Hill, 1973), the inlet cross-sectional flow area, A in , is a function of the smallest particle diameter to be removed from the gas, D p ; the gas dynamic viscosity, μ; the gas inlet velocity, v g,in ; and the particle/gas density difference, ρ p −ρ g , according to the following relation:
 
                     A   in     ≈       0.1   ⁡     [           V     g   ,   in       ⁡     (       ρ   p     -     ρ   g       )       ⁢     D   p   2       μ     ]       2             Eq   .           ⁢   2               
Hence, Equations 1 and 2 can provide the total number of cyclones, N c , required for efficient separation within the assembly.
 
     The cyclone tube assembly  90  includes a tapered cross-section, as shown in  FIG. 3 , so that the gas approach velocity to the most downstream cyclone tube  96  is maintained above the calcium carbonate particle  25  horizontal settling velocity. The tapered assembly is also designed so that the gas approach velocity is approximately the same to each cyclone tube, generally about 3.05 to 15.24 m/sec (10 to 50 ft/sec). Uniform flow distribution among all N c  cyclone tubes will be maintained as the gas velocity is accelerated to approximately 30.48 m/sec (100 ft/sec) at each cyclone tube&#39;s inlet. 
     For reformation system  10 , there are at least 2 high temperature 649° C. to 983° C. (1200° F. to 1800° F.) cyclones: hydrogen cyclone separator  20  operating within a reducing gas environment (downstream of hydrogen generator  12 ), and cyclone separator  44  operating within an oxidizing environment (downstream of the entrained flow calciner injector  34 ). In the case of the high temperature reducing gas cyclone, the individual cyclones are preferably manufactured from ceramic matrix composite (CMC) material which is not degraded by high temperature hydrogen rich gases. This can include a carbon fiber, silicon carbide matrix structure as described in U.S. Pat. No. 6,418,973 issued to Cox et al., commonly assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. 
     For the high temperature oxidizing gas cyclone separator  44 , a nickel based super alloy metal may be used. Other metals can be used such as aluminum metal containing alloys such as Fecralloy™ and Haynes 214™. The aluminum in these alloys has been shown to produce excellent protective alumina barrier coatings which help to prevent further substrate metal oxidation from the oxygen rich calciner gas. In addition to these iron or nickel based (aluminum containing) metals, CMCs made from alumina fibers with alumina matrix can also be used. In one embodiment, CMCs are made from SiC/SiC fiber/matrix structures. The SiC matrix on the CMC surface will oxidize to protective silica in an oxidizing environment and remain SiC in a reducing environment. 
     Cyclone separator  56 , if required in reformation system  10 , operates at similar temperatures as cyclone separator  44 . Cyclone separator  56  is therefore preferably constructed from the same materials as cyclone separator  44 . 
     A solids cyclone separator of the present invention offers several advantages. Because of the high operating temperatures (approximately 649° C. to approximately 983° C.) for the fluids of reformation system  10 , high temperature materials having insulation (including ceramic and CMCs) can effectively perform the gas/solids separations at temperature and in compact devices without having to first cool and subsequently reheat the solid particle flow streams. CMC construction can allow these separators to maintain high structural strength at high temperatures while also providing adequate thermal shock protection. Particle sizes down to approximately 10 microns can be separated from the fluid flow using individual cyclone tubes according to the present invention. Calcium carbonate particle sizes ranging from approximately 30 to approximately 50 microns can therefore be separated by the cyclone tubes of the present invention. A total volumetric flow of the gas and calcium carbonate particles of approximately 60 million standard cubic feet/day can be separated using a multi-clone separator of the present invention. By configuring the plurality of the cyclone tubes into a tapering assembly a flow velocity ranging from approximately 3.05 to 15.24 m/sec (10 to 50 ft/sec) can be maintained throughout a cyclone tube assembly of the present invention while permitting the total pressure drop across the cyclone tube assembly to be maintained at or below approximately 0.0138 MPad (2 psid) differential. 
     While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.