US20170343301A1 - Furnace coil modified fins - Google Patents

Furnace coil modified fins Download PDF

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Publication number
US20170343301A1
US20170343301A1 US15/601,295 US201715601295A US2017343301A1 US 20170343301 A1 US20170343301 A1 US 20170343301A1 US 201715601295 A US201715601295 A US 201715601295A US 2017343301 A1 US2017343301 A1 US 2017343301A1
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United States
Prior art keywords
fin
weight
furnace tube
tube according
furnace
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Abandoned
Application number
US15/601,295
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English (en)
Inventor
Grazyna Petela
Leslie Wilfred Benum
Evan Geevouy Mah
Jeffrey Thomas Kluthe
Jeffrey Stephen Crowe
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Nova Chemicals International SA
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Nova Chemicals International SA
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Assigned to NOVA CHEMICALS (INTERNATIONAL) S.A. reassignment NOVA CHEMICALS (INTERNATIONAL) S.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BENUM, LESLIE WILFRED, MAH, EVAN GEEVOUY, PETELA, GRAZYNA, KLUTHE, JEFFREY THOMAS
Publication of US20170343301A1 publication Critical patent/US20170343301A1/en
Abandoned legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
    • C10G9/14—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
    • C10G9/18—Apparatus
    • C10G9/20—Tube furnaces
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C22C19/056—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 10% but less than 20%
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/058—Alloys based on nickel or cobalt based on nickel with chromium without Mo and W
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/07—Alloys based on nickel or cobalt based on cobalt
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C30/00—Alloys containing less than 50% by weight of each constituent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/02—Tubular elements of cross-section which is non-circular
    • F28F1/025—Tubular elements of cross-section which is non-circular with variable shape, e.g. with modified tube ends, with different geometrical features
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
    • F28D2021/0056—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for ovens or furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D2021/0019—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for
    • F28D2021/0075—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for syngas or cracked gas cooling systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/14—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending longitudinally
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/38—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and being staggered to form tortuous fluid passages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F2215/00—Fins
    • F28F2215/10—Secondary fins, e.g. projections or recesses on main fins

Definitions

  • the present disclosure relates to the field of cracking paraffins to olefins and more particularly to substantial fins on the external surface of the process coil(s) in the radiant section of a cracking furnace.
  • the fins may be transverse (horizontal) or longitudinal.
  • the fins have an array selected from upwardly or outwardly open grooves having a depth of less than a quarter of the maximum thickness of the fin; or protuberances having a base not exceeding 10% of the maximum thickness of the fin, and a height not exceeding 15% of the maximum thickness of the fin or both, in a regular or semi-regular pattern covering at least 10% of the surface area of at least one major surface of the fin.
  • the feed typically together with diluent steam is fed into a cracker comprising a series of pipes or tubes passing through several sections of a furnace.
  • a cracker comprising a series of pipes or tubes passing through several sections of a furnace.
  • the feed passes through the tubes in the convection section of the furnace where exhaust gasses flowing from the downstream radiant section of the furnace heat the external surfaces of the tubes.
  • the feed is heated to a temperature at or near the level at which cracking may begin.
  • the feed flows to the tubes in the radiant section of the furnace where the tubes are primarily heated by radiation from the refractory walls of the furnace and from combustion gases generated by burners typically mounted in the floor or walls of the radiant section.
  • Feed is heated in the furnace radiant section up to a temperature of about 800° C.-950° C. At these temperatures, the feed undergoes a number of reactions, including a free radical decomposition (cracking), reformation of a new unsaturated product and the coproduction of hydrogen. These reactions occur over a very short period of time that corresponds to the feed residence time in a coil.
  • the residence time is typically from about 0.01 to about 10 seconds, in some cases from 0.01 to 2 seconds in some cases from 0.01 to 1 second.
  • the reactants may be heated to temperatures from 750° C. to 950° C., in some cases from 800° C. to 900° C. at a pressure from 200 to 500 kPa in some cases from 250 kPa to 550 kPa.
  • the interior of the radiant section of the furnace is lined with heat absorbing/radiating refractory, and is heated typically by gas fired burners.
  • the cracked gas exits the radiant section of a furnace and then passes through a transfer line exchanger to a quencher to rapidly cool the product stream to a temperature at which the reaction stops.
  • the resulting product stream is then separated into various components such as ethylene, propylene etc.
  • One of the methods representing the second approach is the addition of internal fins to the inner walls of the furnace coil, to promote the “swirling” or enhanced mixing of the feed within the coil. This improves the convective heat transfer from the coil walls to the feed as the turbulence of the feed flow is increased and the heat transferring surface of the hot inner wall of the coil is increased as well.
  • U.S. Pat. No. 8,376,033 issued Feb. 19, 2013 to Robidou et al., assigned to GEA Batignolles Technologies Thermiques teaches a comparable fin in a convection heat exchanger except that the grooves are of diminishing depth from the base of the fin to the external edge.
  • the patent teaches that the fin may have a thickness at its inner edge (base) from about 0.4 to 1 mm and a thickness at its outer edge from 0.15 to 0.4 mm (Col. 5 lines 25-30).
  • the patent also teaches that the grooves may have a depth (thickness) between 0.4 and 1.5 mm.
  • the grooves seem to have a thickness of about half the thickness of the fin. Again these fins are for convective heating and not for radiant heating as in a cracking furnace.
  • the present disclosure seeks to provide thick or substantial fins for furnace tubes having on at least one major surface an array selected from: upwardly or outwardly open grooves having a depth of less than a quarter of the thickness of the fin; or protuberances having a base with the main dimension not exceeding 10% of the maximum thickness of the fin, and a height not exceeding 15% of the maximum thickness of the fin; or both, in a regular or semi-regular pattern covering at least 10% of the surface area of at least one major surface of said fin.
  • a furnace tube having on its external surface one or more thick fins having a thickness at its base from 1 ⁇ 4 to 3 ⁇ 4 of the of the radius of said furnace tube and having parallel sides or sides with an upward inward taper of less than 15° relative to the major axis of said fin, said fin having on at least one major surface an array selected from outwardly open grooves in a regular or semi-regular pattern covering at least 10% of the surface area of said grooves having a depth of less than a quarter of the maximum thickness of the fin; and protuberances having a base not exceeding 10% of the maximum thickness of the fin, and a height not exceeding 15% of the maximum thickness of the fin; or both in a regular or semi-regular pattern covering at least 10% of the surface area of at least one major surface of said fin.
  • a furnace tube wherein the grooves have a depth from a eighth to a tenth of the maximum thickness of the fin.
  • a furnace tube wherein the array of grooves covers not less than one quarter of at least one major surface of the fin.
  • a furnace tube wherein the grooves are in the form of an outwardly open V, a truncated outwardly open V, an outwardly open U, and an outwardly open parallel sided channel.
  • a furnace tube wherein the fin forms a transverse plate in the form of a circle, ellipse, or an N-sided polygon.
  • the base of the fins has a thickness from a third to one half of the radius of the furnace tube.
  • a furnace tube wherein the fin is a longitudinal fin having a cross section in the form of an outwardly extending parabola, parallelogram, or “E” shape (monolith with parallel longitudinal channels) or a blunted “V”.
  • a furnace tube wherein the array of grooves covers not less than one quarter of at least one major surface of the fin.
  • a furnace tube wherein the grooves have a depth from a eighth to a tenth of the maximum thickness of the fin.
  • a furnace tube wherein the grooves are in the form of an outwardly open V, a truncated outwardly open V, an outwardly open U, an outwardly open parallel sided channel.
  • a furnace tube having horizontal fins being spaced apart at least two times the external diameter of the furnace tube.
  • a furnace tube having longitudinal fins the base of said fins covering from one third to a half of the radius of the furnace tube.
  • furnace a tube wherein the array comprises protuberances having:
  • a furnace tube wherein the protuberance has a shape selected from:
  • furnace tube wherein the furnace tube and the fin comprise the same metal composition.
  • a furnace tube, and fin(s) comprising from about 55 to 65 weight % of Ni; from about 20 to 10 weight % of Cr; from about 20 to 10 weight % of Co; and from about 5 to 9 weight % of Fe and the balance one or more of the trace elements.
  • a furnace tube and fin(s) further comprising from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % the sum of the components adding up to 100 weight %.
  • a furnace tube, and fin(s) comprising from 40 to 65 weight % of Co; from 15 to 20 weight % of Cr; from 20 to 13 weight % of Ni; less than 4 weight % of Fe and the balance of one or more trace elements and up to 20 weight % of W the sum of the components adding up to 100 weight %.
  • a furnace tube and fin(s) further comprising from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight %.
  • a furnace tube, and fin(s) comprising from 20 to 38 weight % of chromium from 25 to 48, weight % of Ni.
  • a furnace tube and fin(s) further comprising from 0.2 up to 3 weight % of Mn, from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % and the balance substantially iron.
  • a cracking furnace comprising a radiant section having furnace tubes as above.
  • a method of cracking a paraffin comprising passing the paraffin in a gaseous state through the radiant section of a cracking furnace as above at a temperature from 600° C. to 950 ° C. for a time from 0.001 to 0.01 seconds, and separating the resulting olefins from the feed and co-products
  • FIG. 1 shows a furnace tube with longitudinal fins of the present disclosure modified with grooves on the surface.
  • FIG. 2 shows a fin of the present disclosure modified with protuberances of the present disclosure
  • FIG. 3 is a graph showing the per cent increase in the surface area of the fin modified with different protuberances of the present disclosure.
  • any numerical range recited herein is intended to include all sub-ranges subsumed therein.
  • a range of “1 to 10” is intended to include all sub-ranges between and including the recited minimum value of 1 and the recited maximum value of 10; that is, having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Because the disclosed numerical ranges are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations.
  • compositional ranges expressed herein are limited in total to and do not exceed 100 percent (volume percent or weight percent) in practice. Where multiple components can be present in a composition, the sum of the maximum amounts of each component can exceed 100 percent, with the understanding that, and as those skilled in the art readily understand, the amounts of the components actually used will conform to the maximum of 100 percent.
  • fin height refers to the distance the fin extends away from the external surface of the furnace tube.
  • the furnace tubes have fins which have high integrity, good stress resistance and are quite thick.
  • the fins will have a thickness at their base of not less than about 33% of the radius of the furnace tube, for example, about 40%, or for example not less than about 45%, in some embodiments up to 50% of the radius of the tube.
  • the fins are thick or stubby. They have a height to maximum width ratio of from about 0.5 to about 5, or from about 1 to about 3.
  • the sides (edges) of the fin may be parallel or be lightly tapered inward toward the external edge of the fin. The angle of taper should be no more than about 15 °, or about 10° or less inward relative to the center line of the fin.
  • the edge of the fin may be flat, pointed (at a 30° to 45° angle from each surface), or have a blunt rounded nose.
  • the fins may have a cross section shape in the form of an outwardly extending parabola, parallelogram, of a blunt “V” shape.
  • the fin cross section may be “E” shaped (monolith with parallel longitudinal extensions (having parallel grooves).
  • At least one major surface of the fin has an array of outwardly open grooves in a regular or semi-regular pattern covering at least 10% of the surface area of at least one major surface of the fin (e.g. top or bottom for horizontal fins or sides for longitudinal fins), said grooves having a depth of less than a quarter, in some instances from a eighth to a tenth of the maximum thickness of the fin.
  • the array may cover not less than 25%, in some cases not less than 50%, for example greater than 75%, or for example greater than 85% up to 100% of the of the surface area of one or more the major surfaces of the fin.
  • the array could be in the form of parallel lines, straight or wavy, parallel to or at an angle from the major axis of the fin, crossed lines, wavy lines, squares, or rectangles.
  • the grooves may be in the form of an outwardly open V, a truncated outwardly open V, an outwardly open U, and an outwardly open parallel sided channel.
  • the fins may be transverse or parallel (e.g. longitudinal) to the major axis of the furnace tube.
  • the transverse fins could be at an angle from about 0° to 25° off perpendicular relative to the major axis of the furnace tube.
  • the transverse fins may have a shape selected from a circle, an ellipse, or an N sided polygon where N is a whole number greater than or equal to 3. In some embodiments N is from 4 to 12.
  • the major surface(s) for the transverse fins are the upper and bottom face of the fin. Transverse fins should be spaced apart at least two times in some instances from 3 to 5 times, the external diameter of the furnace tube.
  • the longitudinal fins may have a shape of a parallelogram, a part of an ellipse or circle and a length from about 50% of the length of the furnace tube (sometimes referred to pass) in the radiant section up to 100% of the length of the furnace tube in the radiant section and all ranges in between.
  • the base of the longitudinal fin may be not less than one quarter of the radius of the furnace tube, in some instances from 1 ⁇ 4 to 3 ⁇ 4, or from about 1 ⁇ 3 to 3 ⁇ 4 or in some instances 1 ⁇ 3 to 5 ⁇ 8 in other instances from 1 ⁇ 3 to 1 ⁇ 2 of the radius of the furnace tube.
  • the fins are thick or stubby. They have a ratio of height to maximum width of from about 0.5 to about 5, or from about 1 to about 3.
  • the sides (edges) of the fin may be parallel or be lightly tapered inward toward the tip of the fin. The angle of taper should be no more than about 15°, or about 10° or less inward relative to the center line of the fin.
  • the tip or leading edge of the fin may be flat, tapered (at a 30° to 45° angle from the top and bottom surfaces of the fin), or have a blunt rounded nose.
  • the leading edge of the longitudinal fin will typically be parallel to the central axis of the furnace tube. In cases where the fin extends less than 100% of the length of the furnace tube the leading edge of the fin will for the most part be parallel to the central axis of the furnace tube and then angle in to the furnace tube wall at an angle between about 60° and 30° , or for example 45° .
  • the fin may end in a flat surface perpendicular to the surface of the tube.
  • the furnace tube 1 comprises a central channel 2 and an annular wall 3 .
  • the fins 4 and 5 in this embodiment are straight sided and do not angle or taper inwardly to the tips 6 and 7 .
  • the fins bear on their surface a series of parallel grooves-channels 10 .
  • the fins may comprise an array of protuberances.
  • FIG. 2 shows a fin 20 having its surface 21 covered with one or more protuberances.
  • the protuberances may be in the shape of a square pyramid 23 , an equilateral cone 24 or a hemisphere 25 .
  • the protuberances may be applied by casting or machining the fin, or by using a knurl roll so that the surface 21 of the fin has a textured surface.
  • the array of protuberances can cover from 10% to 100% (and all ranges in between) of the external surface of the fin. In some embodiments, the protuberances may cover from 40 to 100%, or from 50% to 100%, or from 70% to 100% of the external surface of the fin radiant coil. If protuberances do not cover the entire surface of the fin, they can be located at the bottom, middle or top of the fin.
  • a protuberance base is in contact with the external coil surface.
  • a base of a protuberance has an area not larger than from 0.1%-10% of the maximum thickness of the fin.
  • the protuberance have geometrical shapes having a relatively large external surface that contains a relatively small volume, such as for example tetrahedrons, pyramids, cubes, cones, a section through a sphere (e.g. hemispherical or less), a section through an ellipsoid, a section through a deformed ellipsoid (e.g. a tear drop) etc.
  • Some useful shapes for a protuberance include:
  • a tetrahedron (pyramid with a triangular base and 3 faces that are equilateral triangles);
  • a pyramid with isosceles triangle sides e.g. if it is a four faced pyramid the base may not be a square it could be a rectangle or a parallelogram
  • a section of a sphere e.g. a hemi sphere or less
  • a section of an ellipsoid e.g. a section through the shape or volume formed when an ellipse is rotated through its major or minor axis
  • a section of a tear drop e.g. a section through the shape or volume formed when a non uniformly deformed ellipsoid is rotated along the axis of deformation
  • a section of a parabola e.g. section though the shape or volume formed when a parabola is rotated about its major axis—a deformed hemi- (or less) sphere
  • a section of a parabola e.g. section though the shape or volume formed when a parabola is rotated about its major axis—a deformed hemi- (or less) sphere
  • delta-wings e.g., different types of delta-wings.
  • the selection of the shape of the protuberance is largely based on the ease of manufacturing the fin.
  • One method for forming protuberances on the fin surface is by casting in a mold having the shape of the protuberance in the mold wall. This is effective for relative simple shapes.
  • the protuberances may also be produced by machining the external surface of a cast fin such as by the use of knurling device for example a knurl roll.
  • a protuberance may have a height (L z ) above the surface of the fin from 3% to 15% of the maximum thickness of the fin, and all the ranges in between, for example from 3% to 10% of the maximum thickness of the fin.
  • the concentration of the protuberances is uniform and essentially covers the external surface of the fin.
  • the concentration may also be selected based on the radiation heat flux at the location of the coil pass (e.g. some locations may have a higher heat flux than others—corners).
  • protuberances care must be taken so that they adsorb more radiant energy than they may radiate. This may be restated as the transfer of heat through the base of the protuberance into the fin surface must exceed that transferred to the equivalent surface on a bare smooth fin at the same operational conditions. If the concentrations of the protuberances become excessive and if their geometry is not selected properly, they may start to reduce heat transfer, due to thermal effects of excessive conductive resistance, which is undesirable.
  • the properly designed and manufactured protuberances will increase net radiative and convective heat transferred to a fin, and subsequently to a coil from surrounding flowing combustion gasses, flame and furnace refractory.
  • protuberances on radiative heat transfer is not only because more heat can be absorbed through the increased fin external surface so the contact area between combustion gases and fin is increased, but also because the relative heat loss through the radiating fin surface is reduced, as the fin surface is not smooth any more. Accordingly, as a protuberance radiates energy to its surroundings, part of this energy is delivered to and captured by other protuberances, thus it is re-directed back to the fin surface.
  • the protuberances will also increase the convective heat transfer to a fin, due to increase in fin external surface that is in contact with flowing combustion gas, and also by increasing turbulence along the fin surface, thus reducing the thickness of a gaseous boundary layer adjacent to the fin surface.
  • FIG. 3 is a plot of the percent increase in the area of the surface 21 of the fin 20 when the protuberances are an equilateral pyramid 26 , a square pyramid 23 , an equilateral cone 24 and a hemisphere 25 , having a main dimension ‘a’ (side length of a pyramid or diameter for a cone or hemisphere) in mm.
  • the size of the protuberance must be carefully selected. In some embodiments the smaller the size, the higher is the surface to volume ratio of a protuberance, but it may be more difficult to cast or machine such a texture. In addition, in the case of excessively small protuberances, the benefit of their presence may become gradually reduced with time due to settlement of different impurities on the fin surface.
  • the protuberances need not be ideally symmetrical. For example an elliptical base could be deformed to a tear drop shape, and if so shaped, in some embodiments, the “tail” may point down, in line with the overall direction of flue gas flow, when the coil is positioned in the furnace.
  • the fins and the furnace tube may comprise the same material.
  • the fins are easiest to cast as part of the furnace tube.
  • the fins may be cast separately and welded in place.
  • the tube and the fin(s) may comprise from about 55 to 65 weight % of Ni; from about 20 to 10 weight % of Cr; from about 20 to 10 weight % of Co; and from about 5 to 9 weight % of Fe and the balance one or more of the trace elements.
  • the alloy from which the tube and fins are made may further comprising from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % the sum of the components adding up to 100 weight %.
  • the furnace tube and fins may comprise from 40 to 65 weight % of Co; from 15 to 20 weight % of Cr; from 20 to 13 weight % of Ni; less than 4 weight % of Fe and the balance of one or more trace elements and up to 20 weight % of W the sum of the components adding up to 100 weight %.
  • the alloy from which the furnace tube and fins are made may further comprise from 0.2 up to 3 weight % of Mn; from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % the sum of the components adding up to 100 weight %.
  • the furnace tube and fins may comprise from 20 to 38 weight % of chromium from 25 to 48, weight % of Ni.
  • the alloy from which the furnace tube and fins may be made may further comprise from 0.2 up to 3 weight % of Mn, from 0.3 to 2 weight % of Si; less than 5 weight % of titanium, niobium and all other trace metals; and carbon in an amount of less than 0.75 weight % and the balance substantially iron (for example at least 85%, or in other embodiments at least 95% iron), the sum of the components adding up to 100 weight %.
  • the grooves or protuberances could be machined on the surface of the cast fin.
  • the grooves or protuberances could be in a geometric pattern such as longitudinal or transverse parallel lines, diagonal lines, a cross hatch pattern, squares, rectangles, circles, ellipses, etc.
  • the pattern could be regular or semi-regular.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Geometry (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
  • Furnace Details (AREA)
US15/601,295 2016-05-25 2017-05-22 Furnace coil modified fins Abandoned US20170343301A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA2930827A CA2930827A1 (fr) 2016-05-25 2016-05-25 Ailettes modifiees destinees a des serpentins de chaudiere
CA2930827 2016-05-25

Publications (1)

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US20170343301A1 true US20170343301A1 (en) 2017-11-30

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US15/601,295 Abandoned US20170343301A1 (en) 2016-05-25 2017-05-22 Furnace coil modified fins

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US (1) US20170343301A1 (fr)
EP (1) EP3465054B1 (fr)
JP (1) JP2019516942A (fr)
KR (1) KR20190010580A (fr)
BR (1) BR112018074206A2 (fr)
CA (1) CA2930827A1 (fr)
ES (1) ES2969775T3 (fr)
MX (1) MX2018013866A (fr)
TW (1) TW201743027A (fr)
WO (1) WO2017203388A2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112797834A (zh) * 2020-12-30 2021-05-14 西安交通大学 一种带有波纹的换热管翅片
US11391523B2 (en) * 2018-03-23 2022-07-19 Raytheon Technologies Corporation Asymmetric application of cooling features for a cast plate heat exchanger

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US2667337A (en) * 1947-08-06 1954-01-26 Chapman Everett Finned element for thermal or heat transfer purposes
US2731245A (en) * 1951-09-14 1956-01-17 Kaiser Aluminium Chem Corp Finned conduit and method of attaching fins to conduit
US3260652A (en) * 1955-10-25 1966-07-12 Parsons C A & Co Ltd Tubular heat exchange element
US3519070A (en) * 1968-06-14 1970-07-07 Coolenheat Inc Heat exchange unit
US4296539A (en) * 1978-01-27 1981-10-27 Kobe Steel, Limited Heat transfer tubing for natural gas evaporator
US4227572A (en) * 1978-03-27 1980-10-14 Seton-Scherr, Inc. Finned tubing
US4538677A (en) * 1982-04-06 1985-09-03 Energiagazdalkodasi Intezet Helicoidally finned tubes
US4648441A (en) * 1984-10-30 1987-03-10 U.S. Philips Corporation Heat exchanger comprising a finned pipe
US4753833A (en) * 1986-09-26 1988-06-28 Fishgal Semyon I Hollow article with zigzag projections
US5240070A (en) * 1992-08-10 1993-08-31 Fintube Limited Partnership Enhanced serrated fin for finned tube
US5377746A (en) * 1993-04-26 1995-01-03 Fintube Limited Partnership Texturized fin
US7093650B2 (en) * 2003-09-01 2006-08-22 Usui Kokusai Sangyo Kaisha, Ltd. Heat conduction pipe externally covered with fin member
US7418848B2 (en) * 2004-06-04 2008-09-02 Fin Tube Technology Co., Ltd. High-performance and high-efficiency rolled fin tube and forming disk therefor
US20120251407A1 (en) * 2011-03-31 2012-10-04 Nova Chemicals (International) S.A. Furnace coil fins

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11391523B2 (en) * 2018-03-23 2022-07-19 Raytheon Technologies Corporation Asymmetric application of cooling features for a cast plate heat exchanger
CN112797834A (zh) * 2020-12-30 2021-05-14 西安交通大学 一种带有波纹的换热管翅片

Also Published As

Publication number Publication date
EP3465054C0 (fr) 2023-11-29
TW201743027A (zh) 2017-12-16
WO2017203388A3 (fr) 2018-05-24
CA2930827A1 (fr) 2017-11-25
KR20190010580A (ko) 2019-01-30
ES2969775T3 (es) 2024-05-22
BR112018074206A2 (pt) 2019-03-06
JP2019516942A (ja) 2019-06-20
MX2018013866A (es) 2019-03-21
EP3465054A2 (fr) 2019-04-10
WO2017203388A2 (fr) 2017-11-30
EP3465054B1 (fr) 2023-11-29

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