US20060102327A1 - Cracking tube having helical fins - Google Patents

Cracking tube having helical fins Download PDF

Info

Publication number
US20060102327A1
US20060102327A1 US10/534,016 US53401605A US2006102327A1 US 20060102327 A1 US20060102327 A1 US 20060102327A1 US 53401605 A US53401605 A US 53401605A US 2006102327 A1 US2006102327 A1 US 2006102327A1
Authority
US
United States
Prior art keywords
tube
fins
helical
cracking
fin
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/534,016
Inventor
Masahiro Inui
Kaoru Hamada
Kenji Otsubo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kubota Corp
Original Assignee
Kubota Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kubota Corp filed Critical Kubota Corp
Assigned to KUBOTA CORPORATION reassignment KUBOTA CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HAMADA, KAORU, INUI, MASAHIRO, OTSUBO, KENJI
Publication of US20060102327A1 publication Critical patent/US20060102327A1/en
Priority to US12/379,845 priority Critical patent/US7799963B2/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • 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
    • F28F1/40—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only inside the tubular element
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
    • B01F25/4316—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor the baffles being flat pieces of material, e.g. intermeshing, fixed to the wall or fixed on a central rod
    • B01F25/43162—Assembled flat elements
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/431—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor
    • B01F25/43197—Straight mixing tubes with baffles or obstructions that do not cause substantial pressure drop; Baffles therefor characterised by the mounting of the baffles or obstructions
    • B01F25/431971—Mounted on the wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/0053—Details of the reactor
    • B01J19/006—Baffles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/24—Stationary reactors without moving elements inside
    • B01J19/2415—Tubular reactors
    • 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
    • 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
    • F28D2021/0022—Other heat exchangers for particular applications; Heat exchange systems not otherwise provided for for chemical reactors

Definitions

  • the present invention relates to cracking tubes for use in thermal cracking reactors for producing ethylene or the like, and more particularly to a cracking tube which is provided on the inner surface thereof with fins for stirring the fluid therein and which is adapted to suppress pressure losses to the greatest possible extent while effectively promoting heat transfer to the fluid therein.
  • Olefins such as ethylene, propylene or the like are produced by thermally cracking material gases of hydrocarbons (naphtha, natural gas, ethane, etc.).
  • the thermal cracking reaction is conducted by introducing the hydrocarbon material gas and steam into a cracking coil disposed within a heating furnace supplied with heat from outside, and heating the mixture to a reaction temperature range while the mixture flows through the coil at a high velocity.
  • the cracking coil comprises a plurality of (straight) tubes which are connected into a zigzag assembly by bends.
  • FIGS. 12 to 14 show in development proposed examples of fins on cracking tubes (JP-A No. 1997-241781).
  • FIG. 12 shows fins 1 continuously extending helically at a constant angle of inclination with the tube axis.
  • FIG. 13 corresponds to the continuous helical fins of FIG. 12 as formed discretely. Fins 1 and nonfin portions 2 on helical loci are in a staggered arrangement wherein the fins are replaced by nonfin portions every turn of helix.
  • FIG. 14 shows fins 1 and nonfin portions 2 arranged alternately on a plurality of lines parallel to the tube axis.
  • the fins positioned in parallel to the tube axis fail to produce a sufficient effect to stir the fluid inside the tubes and to achieve the desired heat transfer performance.
  • an object of the present invention is to suppress pressure losses to the greatest possible extent while maintaining an effect to promote heat transfer to the fluid within the tube.
  • the present invention provides a cracking tube which has fins formed on an inner surface thereof and inclined with respect to an axis of the tube for stirring a fluid inside the tube, the fins being discretely arranged on one or a plurality of helical loci, the tube inner surface having regions wherein no fins are present over the entire axial length of the tube from one axial end of the tube to the other axial end thereof.
  • the tube of this construction is adapted to minimize the pressure loss of the fluid inside the tube while permitting the helical fins to transfer heat to the inside fluid with a high efficiency.
  • FIG. 1 is a development of the inner surface of a cracking tube of the invention for illustrating an embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 2 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 3 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 4 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 5 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 6 is a diagram for illustrating the arrangement of fins shown in FIG. 3 .
  • FIG. 7 is a view in cross section and showing the tube of the embodiment shown in FIG. 1 .
  • FIG. 8 is a diagram for illustrating an overlaying method of forming helical fins in the form of overlaid beads.
  • FIG. 9 is a graph showing heat transfer characteristics of test tubes determined by the experiment.
  • FIG. 10 is a graph showing pressure loss characteristics of the test tubes determined by the experiment.
  • FIG. 11 is a diagram for generally illustrating the configuration of a test coil.
  • FIG. 12 is a development of the inner surface of a conventional cracking tube for illustrating a pattern of fin formed on the tube inner surface.
  • FIG. 13 is a development of the inner surface of a conventional cracking tube for illustrating another arrangement pattern of fins formed on the tube inner surface.
  • FIG. 14 is a development of the inner surface of a conventional cracking tube for illustrating another arrangement pattern of fins formed on the tube inner surface.
  • FIG. 1 is a development of the inner surface of a tube showing an embodiment of arrangement of helical fins according to the present invention.
  • Fins 1 are formed discretely along a helical locus which is positioned at a predetermined angle of inclination ⁇ with respect to the axial direction x of the tube.
  • the helical locus is indicated by slanting dotted lines, and connections of the helix are indicated by vertical dotted lines.
  • Horizontal chain lines show regions Z A wherein fins are arranged in the axial direction, and regions Z B of nonfin portions 2 wherein no fins are present.
  • each fins are arranged along every turn of helix.
  • the corresponding fins 1 , as well as the corresponding nonfin portions 2 , on helical lines representing respective turns of helix are arranged in a direction parallel to the tube axis.
  • FIGS. 2 to 5 are developments of the inner surfaces of tubes showing other embodiments of arrangements of helical fins according to the invention.
  • FIG. 2 shows helical fins formed along continuous helical loci which are different in the angle of inclination ⁇ .
  • the angle of inclination ⁇ I of the helix in a region I of the tube channel is larger than the angle of inclination ⁇ II of the helix in a region II thereof.
  • the fins 1 and nonfin portions 2 are arranged within the respective regions Z A and Z B which are parallel to the tube axis.
  • FIG. 3 shows an embodiment wherein two helical loci are provided. Fins are formed discretely at the same angle of inclination ⁇ along respective helical loci S 1 and S 2 . Fins 11 and nonfin portions 21 are formed on the helical locus S 1 , fins 12 and nonfin portions 22 are formed on the helical locus S 2 , the fins 11 , 12 are arranged within regions Z A , and the nonfin portions 21 , 22 are arranged within regions Z B .
  • FIG. 4 shows an embodiment wherein helical fins are formed along two helical loci S 1 and S 2 , and fins along the locus S 1 are different from those along the locus S 2 in size.
  • the fins 11 along the helical locus S 1 are longer than the fins 12 along the helical locus S 2 .
  • the fins 11 , 12 are arranged within regions Z A , and all or some of nonfin portions 21 , 22 are arranged within regions Z B .
  • FIG. 5 shows an embodiment wherein helical fins are formed along four helical loci S 1 to S 4 , and fins 11 to 14 along the respective helical loci S 1 to S 4 are arranged at slightly varying intervals circumferentially of the tube.
  • the group of fins 11 to 14 on the respective four helical loci S 1 to S 4 are arranged within a region Z A
  • a group of nonfin portions 21 to 24 on these loci S 1 to S 4 are arranged within a region Z B .
  • These fins 11 to 14 within the region Z A are arranged along a wave (indicated in a chain line).
  • the tube inner surface has regions Z B wherein no fins are present over the entire axial length of the tube from one axial end of the tube to the other axial end thereof.
  • FIG. 6 is a diagram for illustrating the arrangement of fins shown in FIG. 3 .
  • Indicated at ⁇ is the angle of inclination of the helical fins, and at p is the fin pitch that is the center-to-center distance between corresponding fins on the adjacent helical lines in the direction of tube axis. These values are determined suitably according to the inside diameter D of the tube.
  • the angle of inclination ⁇ can be about 15 to about 85 degrees, and the pitch p, about 20 to 400 mm.
  • the height H (the height of projection from the tube inner surface) of the fins is, for example, about one-thirtieth to one-tenth of the inside diameter of the tube.
  • the length L of the fins is, for example, about 5 to 100 mm, and is determined, for example, according to the inside diameter D of the tube and the number of divided fins along every turn of helical locus.
  • FIG. 7 is a sectional view of helical fins in a plane orthogonal to the axis of the tube, and shows an embodiment wherein four fins are arranged on one turn of helical line.
  • the fin has a circular arc length (as projected on a plane) w and the number of fins on one turn of helical line is n.
  • the helical fins can be efficiently formed as beads by an overlaying method such as plasma powder welding (PTA welding).
  • PTA welding plasma powder welding
  • FIG. 8 shows an example of welding operation.
  • a tube 50 is horizontally supported by a rotary drive apparatus (not shown) and rotatable about its axis x.
  • a welding torch 51 is fixed to a support arm 52 , which is held parallel to the tube axis and is movable forward or rearward axially of the tube.
  • a powder (material for overlaying) is supplied by a pipe 53 to the welding torch 51 , which forms beads on the tube inner surface.
  • Plasma welding is performed intermittently by the rotation of the tube 50 and the horizontal movement (in the direction of the tube axis) of the welding torch 51 to form helical fins comprising beads formed by overlaying.
  • fins are formed along two helical loci.
  • the number of helixes of fins to be formed, the angle of inclination ⁇ , pitch p, the number and width (circular arc length of projected image in FIG. 6 ) of fin regions Z A , etc. are adjustable suitably by varying the speed of rotation of the tube 50 , the number of welding torches 51 installed, the speed of horizontal movement thereof, the cycle of intermittent application of the plasma arc, etc.
  • Helical fins are arranged over the entire length of tube channel from the inlet end of the tube to the outlet end thereof, or at suitable portion or portions of the channel, for example, in at least one of a region in the vicinity of inlet end of the channel, intermediate region thereof and a region in the vicinity of the outlet end.
  • the material for forming the helical fins is the same kind of heat-resistant alloy as the tube, such as 25Cr—Ni(SCH22), 25Cr-35Ni(SCH24) or Incoloy(Trademark) Also suitably usable are other heat-resistant alloys which are serviceable in the environment wherein the tube is to be used.
  • Test Tubes T 1 to T 5 were prepared and checked for film heat transfer coefficient h (W/m 2 /K) and pressure loss dP (Pa).
  • T 1 is according to the invention, and T 2 to T 5 are comparative examples. Table 1 shows the particulars about these test tubes.
  • Circular arc length ratio R (sum of circular arc lengths of fins along every turn of helix, as projected on a plane orthogonal to tube axis)/(circumferential length of tube inner surface) ** The circular arc length ratio for T4 was determined as (sum of thicknesses of fins)/(circumferential length of tube inner surface).
  • FIG. 9 film heat transfer coefficient h
  • FIG. 10 pressure loss dP
  • Each measurement is shown relative to the value of Test Tube T 5 at a Reynolds number of 20,000 which value is taken as 1.0 (reference value).
  • FIGS. 9 and 10 reveal that Test Tube T 1 of the invention is comparable to Test Tube T 2 having a continuous helical fin and Test Tube T 3 having discrete helical fins in heat transfer characteristics and is comparable to Test Tube T 4 in pressure loss.
  • Test Tubes T 2 and T 3 are greater than Test Tube 1 in pressure loss and result in a lower yield as will be described later.
  • Test Tube T 4 is inferior to Test Tube T 1 in heat transfer characteristics and therefore has the problem of permitting coking in addition to a lower yield.
  • Test Tube T 5 is a smooth-surfaced tube having no fins and accordingly superior to Test Tube T 1 of the invention with respect to pressure loss, but is inferior in heat transfer characteristics and involves the problem of yield and coking like Test Tube T 4 .
  • Test Tube T 1 of the invention is adapted to ensure a minimized pressure loss while maintaining the desired heat transfer characteristics.
  • the coil shown in FIG. 11 includes tubes (straight tubular portions) which are 63.5 mm in inside diameter, 6.4 mm in wall thickness and 9.6 m in length and which provide a first pass, second pass, third pass and fourth pass, respectively, as arranged in this order from the upstream side downstream.
  • Table 2 shows the construction of Test Tubes T 6 to T 9 .
  • Test Tube T 6 is according to the invention, and Test Tubes T 7 to T 9 are comparative examples. As to the arrangement of fins on the tube (straight tubular portion), Test Tube T 6 is the same as is shown in FIG. 1 , T 7 as is shown in FIG. 13 , and T 8 as is shown in FIG. 12 . T 9 is an example which has no fins. TABLE 2 Test Tubes Structure of T 6 T 7 T 8 T 9 passes (Invention) (Comp. ex.) (Comp. ex.) (Comp.
  • the analysis conditions are fluid pressure at the coil outlet of 1.98 kg/cm (absolute pressure), coil inlet temperature of 600° C. and coil outlet temperature of 830° C. Naphtha was caused to flow through one coil at a flow rate of 840 kg/h, and steam at a flow rate of 420 kg/h.
  • Table 3 shows the temperature of the first to fourth passes of the coil.
  • Table 4 shows the results of analysis, i.e. the pressure and temperature at the coil inlet and outlet, pressure loss and ethylene and propylene yields.
  • Table 3 reveals that T 6 is comparable to T 7 and T 8 in tube temperature and about 20 C lower than T 9 . This means that T 6 to T 8 are comparable in heat transfer efficiency and can be operated at a lower temperature.
  • Table 4 shows that T 6 is smaller than T 7 and T 8 in pressure loss and excellent in ethylene and propylene yields. Although small in pressure loss, T 9 is inferior in heat transfer efficiency and therefore lower in ethylene and propylene yields.
  • the arrangement of helical fins formed on the inner surface of the cracking tube of the invention enables the tube to minimize the pressure loss of the fluid inside the tube while permitting the tube to maintain high heat transfer characteristics due to the stirring action of fins. Accordingly the tube achieves improved ethylene and propylene yields, diminishes decoking work for the tube, has a prolonged life and is therefore useful as a cracking tube for thermal cracking furnaces for producing ethylene or the like.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Thermal Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Geometry (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Rigid Pipes And Flexible Pipes (AREA)

Abstract

A cracking tube (50) for use in thermal cracking furnaces for producing ethylene or the like has fins (1) formed on an inner surface thereof and inclined with respect to an axis of the tube for stirring a fluid inside the tube. The fins are arranged discretely on one or a plurality of helical loci, and the tube inner surface has regions (ZB) wherein no fins are present over the entire axial length of the tube from one axial end of the tube to the other axial end thereof.

Description

    TECHNICAL FIELD
  • The present invention relates to cracking tubes for use in thermal cracking reactors for producing ethylene or the like, and more particularly to a cracking tube which is provided on the inner surface thereof with fins for stirring the fluid therein and which is adapted to suppress pressure losses to the greatest possible extent while effectively promoting heat transfer to the fluid therein.
    • BACKGROUND ART
  • Olefins such as ethylene, propylene or the like are produced by thermally cracking material gases of hydrocarbons (naphtha, natural gas, ethane, etc.). The thermal cracking reaction is conducted by introducing the hydrocarbon material gas and steam into a cracking coil disposed within a heating furnace supplied with heat from outside, and heating the mixture to a reaction temperature range while the mixture flows through the coil at a high velocity.
  • Typically, the cracking coil comprises a plurality of (straight) tubes which are connected into a zigzag assembly by bends.
  • To conduct the thermal cracking reaction efficiently, it is important to heat the fluid flowing inside the coil at a high velocity to the reaction temperature range radially inward to the central portion of the tube channel within a short period of time and to avoid heating at a high temperature to the greatest possible extent. If the gas is heated at a high temperature over a prolonged period of time, lighter fractions of hydrocarbons (methane, free carbons, etc.) will be produced in excessive amounts or the product of cracking will undergo, for example, a polycondensation reaction to reduce the yield of the desired product. Promoted coking (deposition of free carbon on the tube inner wall) will also result to lower the coefficient of heat transfer, giving rise to a need to perform decoking frequently.
  • Accordingly it is practice to provide fins on the tube inner surface of the cracking coil as elements for stirring the fluid within the tubes. The fluid flowing at a high velocity produces turbulence by being stirred by the fins, and can be heated to a higher temperature rapidly. As a result, the reaction is completed within a shortened period of time, while production of lighter fractions due to excessive cracking is avoided. Furthermore, an improvement in the coefficient of heat transfer of the tubes makes it possible to lower the temperature of the tubes, producing an effect to improve the serviceable life of the tubes.
  • FIGS. 12 to 14 show in development proposed examples of fins on cracking tubes (JP-A No. 1997-241781).
  • FIG. 12 shows fins 1 continuously extending helically at a constant angle of inclination with the tube axis.
  • FIG. 13 corresponds to the continuous helical fins of FIG. 12 as formed discretely. Fins 1 and nonfin portions 2 on helical loci are in a staggered arrangement wherein the fins are replaced by nonfin portions every turn of helix.
  • These examples have a great effect to stir the fluid within the tubes and are highly efficient in heat transfer to the fluid within the tubes, whereas the internal pressure of the fluid inside the tubes builds up owing to a great pressure loss of the fluid, entailing the drawback that the cracking operation produces ethylene, propylene or the like in a lower yield.
  • FIG. 14 shows fins 1 and nonfin portions 2 arranged alternately on a plurality of lines parallel to the tube axis. However, the fins positioned in parallel to the tube axis fail to produce a sufficient effect to stir the fluid inside the tubes and to achieve the desired heat transfer performance.
  • In view of the above problems, an object of the present invention is to suppress pressure losses to the greatest possible extent while maintaining an effect to promote heat transfer to the fluid within the tube.
    • SUMMARY OF THE INVENTION
  • To fulfill the above object, the present invention provides a cracking tube which has fins formed on an inner surface thereof and inclined with respect to an axis of the tube for stirring a fluid inside the tube, the fins being discretely arranged on one or a plurality of helical loci, the tube inner surface having regions wherein no fins are present over the entire axial length of the tube from one axial end of the tube to the other axial end thereof.
  • The tube of this construction is adapted to minimize the pressure loss of the fluid inside the tube while permitting the helical fins to transfer heat to the inside fluid with a high efficiency.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a development of the inner surface of a cracking tube of the invention for illustrating an embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 2 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 3 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 4 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 5 is a development of the inner surface of a cracking tube of the invention for illustrating another embodiment of arrangement pattern of fins formed on the tube inner surface.
  • FIG. 6 is a diagram for illustrating the arrangement of fins shown in FIG. 3.
  • FIG. 7 is a view in cross section and showing the tube of the embodiment shown in FIG. 1.
  • FIG. 8 is a diagram for illustrating an overlaying method of forming helical fins in the form of overlaid beads.
  • FIG. 9 is a graph showing heat transfer characteristics of test tubes determined by the experiment.
  • FIG. 10 is a graph showing pressure loss characteristics of the test tubes determined by the experiment.
  • FIG. 11 is a diagram for generally illustrating the configuration of a test coil.
  • FIG. 12 is a development of the inner surface of a conventional cracking tube for illustrating a pattern of fin formed on the tube inner surface.
  • FIG. 13 is a development of the inner surface of a conventional cracking tube for illustrating another arrangement pattern of fins formed on the tube inner surface.
  • FIG. 14 is a development of the inner surface of a conventional cracking tube for illustrating another arrangement pattern of fins formed on the tube inner surface.
    • BEST MODE OF CARRYING OUT THE INVENTION
  • The cracking tube of the present invention will be described below in detail with reference to the illustrated embodiments.
  • FIG. 1 is a development of the inner surface of a tube showing an embodiment of arrangement of helical fins according to the present invention.
  • Fins 1 are formed discretely along a helical locus which is positioned at a predetermined angle of inclination θ with respect to the axial direction x of the tube. The helical locus is indicated by slanting dotted lines, and connections of the helix are indicated by vertical dotted lines. Horizontal chain lines show regions ZA wherein fins are arranged in the axial direction, and regions ZB of nonfin portions 2 wherein no fins are present.
  • In the embodiment of FIG. 1, four fins are arranged along every turn of helix. The corresponding fins 1, as well as the corresponding nonfin portions 2, on helical lines representing respective turns of helix are arranged in a direction parallel to the tube axis.
  • FIGS. 2 to 5 are developments of the inner surfaces of tubes showing other embodiments of arrangements of helical fins according to the invention.
  • FIG. 2 shows helical fins formed along continuous helical loci which are different in the angle of inclination θ. The angle of inclination θ I of the helix in a region I of the tube channel is larger than the angle of inclination θ II of the helix in a region II thereof. The fins 1 and nonfin portions 2 are arranged within the respective regions ZA and ZB which are parallel to the tube axis.
  • FIG. 3 shows an embodiment wherein two helical loci are provided. Fins are formed discretely at the same angle of inclination θ along respective helical loci S1 and S2. Fins 11 and nonfin portions 21 are formed on the helical locus S1, fins 12 and nonfin portions 22 are formed on the helical locus S2, the fins 11, 12 are arranged within regions ZA, and the nonfin portions 21, 22 are arranged within regions ZB.
  • FIG. 4 shows an embodiment wherein helical fins are formed along two helical loci S1 and S2, and fins along the locus S1 are different from those along the locus S2 in size. The fins 11 along the helical locus S1 are longer than the fins 12 along the helical locus S2. The fins 11, 12 are arranged within regions ZA, and all or some of nonfin portions 21, 22 are arranged within regions ZB.
  • FIG. 5 shows an embodiment wherein helical fins are formed along four helical loci S1 to S4, and fins 11 to 14 along the respective helical loci S1 to S4 are arranged at slightly varying intervals circumferentially of the tube. The group of fins 11 to 14 on the respective four helical loci S1 to S4 are arranged within a region ZA, and a group of nonfin portions 21 to 24 on these loci S1 to S4 are arranged within a region ZB. These fins 11 to 14 within the region ZA are arranged along a wave (indicated in a chain line).
  • Thus, according to all the embodiments of FIGS. 2 to 5, the tube inner surface has regions ZB wherein no fins are present over the entire axial length of the tube from one axial end of the tube to the other axial end thereof.
  • FIG. 6 is a diagram for illustrating the arrangement of fins shown in FIG. 3. Indicated at θ is the angle of inclination of the helical fins, and at p is the fin pitch that is the center-to-center distance between corresponding fins on the adjacent helical lines in the direction of tube axis. These values are determined suitably according to the inside diameter D of the tube.
  • In the case of a tube having an inside diameter D of about 30 to 150 mm, for example, the angle of inclination θ can be about 15 to about 85 degrees, and the pitch p, about 20 to 400 mm. The pitch p is increased or decreased for adjustment depending on the angle of inclination θ of the helix and the number N of helixes (p=E/N wherein E is helix lead).
  • The height H (the height of projection from the tube inner surface) of the fins is, for example, about one-thirtieth to one-tenth of the inside diameter of the tube. The length L of the fins is, for example, about 5 to 100 mm, and is determined, for example, according to the inside diameter D of the tube and the number of divided fins along every turn of helical locus.
  • FIG. 7 is a sectional view of helical fins in a plane orthogonal to the axis of the tube, and shows an embodiment wherein four fins are arranged on one turn of helical line. Suppose the fin has a circular arc length (as projected on a plane) w and the number of fins on one turn of helical line is n. The total circular arc length TW of the fins is then TW=w×n.
  • Incidentally, the proportion of the total circular arc length TW of the fins to the circumferential length C(C=πD) of the tube inner surface, namely, R(R=TW/C), is preferably about 0.3 to 0.8 in order to ensure a minimized pressure loss while permitting the helical fins to promote heat transfer to the fluid inside the tube. If this value is too small, the effect to promote heat transfer will be lower, whereas if the value is excessively great, an excessive pressure loss will result.
  • The helical fins can be efficiently formed as beads by an overlaying method such as plasma powder welding (PTA welding). FIG. 8 shows an example of welding operation.
  • A tube 50 is horizontally supported by a rotary drive apparatus (not shown) and rotatable about its axis x. A welding torch 51 is fixed to a support arm 52, which is held parallel to the tube axis and is movable forward or rearward axially of the tube.
  • A powder (material for overlaying) is supplied by a pipe 53 to the welding torch 51, which forms beads on the tube inner surface. Plasma welding is performed intermittently by the rotation of the tube 50 and the horizontal movement (in the direction of the tube axis) of the welding torch 51 to form helical fins comprising beads formed by overlaying.
  • In the case where two welding torches 51 are installed as illustrated, fins are formed along two helical loci.
  • The number of helixes of fins to be formed, the angle of inclination θ, pitch p, the number and width (circular arc length of projected image in FIG. 6) of fin regions ZA, etc. are adjustable suitably by varying the speed of rotation of the tube 50, the number of welding torches 51 installed, the speed of horizontal movement thereof, the cycle of intermittent application of the plasma arc, etc.
  • Helical fins are arranged over the entire length of tube channel from the inlet end of the tube to the outlet end thereof, or at suitable portion or portions of the channel, for example, in at least one of a region in the vicinity of inlet end of the channel, intermediate region thereof and a region in the vicinity of the outlet end.
  • The material for forming the helical fins is the same kind of heat-resistant alloy as the tube, such as 25Cr—Ni(SCH22), 25Cr-35Ni(SCH24) or Incoloy(Trademark) Also suitably usable are other heat-resistant alloys which are serviceable in the environment wherein the tube is to be used.
  • The present invention will be further described with reference to specific examples.
    • EXAMPLE 1
  • Test Tubes T1 to T5 were prepared and checked for film heat transfer coefficient h (W/m2/K) and pressure loss dP (Pa).
  • T1 is according to the invention, and T2 to T5 are comparative examples. Table 1 shows the particulars about these test tubes.
    TABLE 1
    Test Tubes Fin Specifications
    Circum- Circular Number
    ferential arc Number of rows Angle
    length length Number per in circum- of Length
    of inner Draw- Thick- as pro- of turn of ferential incli- ratio
    No. I.D. surface ing Shape Height ness jected helixes helix direction nation Pitch R * Note
    T1 42 mm 132 mm FIG. Dis- 2.2 mm 8 mm 16.5 mm 1 4 — 60 deg 76 mm 0.5 Inven-
    1 crete, tion
    helical
    T2 42 mm 132 mm FIG. Con- 2.2 mm 8 mm 18.9 mm 1 — — 60 deg 76 mm 1.0 Comp.
    12 tinuous, ex.
    helical
    T3 42 mm 132 mm FIG. Dis- 2.2 mm 8 mm 18.9 mm 1 4 and 3 — 60 deg 76 mm 1.0 Comp.
    13 crete, alter- ex.
    helical nating
    (stag-
    gered)
    T4 42 mm 132 mm FIG. Paral- 2.2 mm 8 mm 18.9 mm — — 8 — — 0.5 Comp.
    14 lel to ** ex.
    tube
    axis
    T5 42 mm 132 mm None No fin — — — — — — — — — Comp.
    ex.

    (Note)

    * Circular arc length ratio R = (sum of circular arc lengths of fins along every turn of helix, as projected on a plane orthogonal to tube axis)/(circumferential length of tube inner surface)

    ** The circular arc length ratio for T4 was determined as (sum of thicknesses of fins)/(circumferential length of tube inner surface).
  • Experimental conditions are as follows.
  • Test fluid: air
  • Fluid temperature (inlet end): room temperature
  • Reynolds number: 20,000-60,000
  • Pressure loss measuring section: 1000 mm
  • The results of measurement are shown in FIG. 9 (film heat transfer coefficient h) and FIG. 10 (pressure loss dP). Each measurement is shown relative to the value of Test Tube T5 at a Reynolds number of 20,000 which value is taken as 1.0 (reference value).
  • FIGS. 9 and 10 reveal that Test Tube T1 of the invention is comparable to Test Tube T2 having a continuous helical fin and Test Tube T3 having discrete helical fins in heat transfer characteristics and is comparable to Test Tube T4 in pressure loss.
  • However, Test Tubes T2 and T3 are greater than Test Tube 1 in pressure loss and result in a lower yield as will be described later.
  • On the other hand, Test Tube T4 is inferior to Test Tube T1 in heat transfer characteristics and therefore has the problem of permitting coking in addition to a lower yield.
  • Test Tube T5 is a smooth-surfaced tube having no fins and accordingly superior to Test Tube T1 of the invention with respect to pressure loss, but is inferior in heat transfer characteristics and involves the problem of yield and coking like Test Tube T4.
  • In contrast, Test Tube T1 of the invention is adapted to ensure a minimized pressure loss while maintaining the desired heat transfer characteristics.
    • EXAMPLE 2
  • Next, a thermal fluid analysis was conducted using a W-shaped coil shown in FIG. 11 and simulating the conditions under which reactors are used for producing ethylene to determine pressure loss of the fluid inside the coil and yields of ethylene and propylene.
  • The coil shown in FIG. 11 includes tubes (straight tubular portions) which are 63.5 mm in inside diameter, 6.4 mm in wall thickness and 9.6 m in length and which provide a first pass, second pass, third pass and fourth pass, respectively, as arranged in this order from the upstream side downstream. Table 2 shows the construction of Test Tubes T6 to T9.
  • Test Tube T6 is according to the invention, and Test Tubes T7 to T9 are comparative examples. As to the arrangement of fins on the tube (straight tubular portion), Test Tube T6 is the same as is shown in FIG. 1, T7 as is shown in FIG. 13, and T8 as is shown in FIG. 12. T9 is an example which has no fins.
    TABLE 2
    Test Tubes
    Structure of T 6 T 7 T 8 T 9
    passes (Invention) (Comp. ex.) (Comp. ex.) (Comp. ex.)
    First pass No fin No fin No fin No fin
    Second pass No fin No fin No fin No fin
    Third pass Fin A* Fin B** Fin C*** No fin
    Fourth pass Fin A* Fin B** Fin C*** No fin

    (Note)

    *Fins A: Discrete helical fins (4 fins/turn of helix) in the arrangement of FIG. 1, 60 deg in angle of inclination, 3.5 mm in the height of fins, 115.2 mm in pitch.

    **Fins B: Discrete helical fins in the arrangement of FIG. 13, 60 deg in angle of inclination, 3.5 mm in the height of fins, 115.2 mm in pitch.

    ***Fin C: Continuous helical fin extending as shown in FIG. 12, 60 deg in angle of inclination, 3.5 mm in the height of fin, 115.2 mm in pitch.
  • The analysis conditions are fluid pressure at the coil outlet of 1.98 kg/cm (absolute pressure), coil inlet temperature of 600° C. and coil outlet temperature of 830° C. Naphtha was caused to flow through one coil at a flow rate of 840 kg/h, and steam at a flow rate of 420 kg/h.
  • Table 3 shows the temperature of the first to fourth passes of the coil.
  • Table 4 shows the results of analysis, i.e. the pressure and temperature at the coil inlet and outlet, pressure loss and ethylene and propylene yields.
    TABLE 3
    Temperature
    at each Test tubes
    pass of T 6 T 7 T 8 T 9
    test tubes (Invention) (Comp. ex.) (Comp. ex.) (Comp. ex.)
    First pass 849 847 846 860
    (° C.)
    Second pass 870 868 867 881
    (° C.)
    Third pass 880 879 877 906
    (° C.)
    Fourth pass 915 914 913 936
    (° C.)
  • TABLE 4
    Test tubes
    T 6 T 7 T 8 T 9
    (Invention) (Comp. ex.) (Comp. ex.) (Comp. ex.)
    Coil inlet pressure (kg/cm2)* 3.68 3.84 3.98 3.25
    Coil outlet pressure (kg/cm2)* 1.98 1.98 1.98 1.98
    Pressure loss of fluid (kg/cm2)* 1.70 1.86 2.00 1.27
    Coil inlet temperature (° C.) 600 600 600 600
    Coil outlet temperature (° C.) 830 830 830 830
    Ethylene yield (wt %) 26.8 26.5 26.3 26.1
    Propylene yield (wt %) 16.5 16.2 16.1 15.9

    (Note)

    *Absolute pressure
  • Table 3 reveals that T6 is comparable to T7 and T8 in tube temperature and about 20 C lower than T9. This means that T6 to T8 are comparable in heat transfer efficiency and can be operated at a lower temperature.
  • Table 4 shows that T6 is smaller than T7 and T8 in pressure loss and excellent in ethylene and propylene yields. Although small in pressure loss, T9 is inferior in heat transfer efficiency and therefore lower in ethylene and propylene yields.
    • INDUSTRIAL APPLICABILITY
  • The arrangement of helical fins formed on the inner surface of the cracking tube of the invention enables the tube to minimize the pressure loss of the fluid inside the tube while permitting the tube to maintain high heat transfer characteristics due to the stirring action of fins. Accordingly the tube achieves improved ethylene and propylene yields, diminishes decoking work for the tube, has a prolonged life and is therefore useful as a cracking tube for thermal cracking furnaces for producing ethylene or the like.

Claims (5)

1. A cracking tube having fins formed on an inner surface thereof and inclined with respect to an axis of the tube for stirring a fluid inside the tube,
the cracking tube being characterized in that the fins are arranged discretely on one or a plurality of helical loci, the tube inner surface having regions wherein no fins are present over the entire axial length of the tube from one axial end of the tube to the other axial end thereof.
2. The cracking tube according to claim 1 wherein the fins have an angle of inclination of 15 to 85 degrees.
3. The cracking tube according to claim 1 wherein assuming that the sum of the circular arc length of fins is TW (TW=w×n wherein w is the circular arc length of the fin as projected on a plane orthogonal to an axis of the tube, and n is the number of fins on one turn of the helical locus), and that the circumferential length of the tube inner surface is C(C=πD wherein D is the inside diameter of the tube), the ratio TW/C is 0.3 to 0.8.
4. The cracking tube according to claim 1 wherein the fins are weld beads formed by overlaying.
5. The cracking tube according to claim 2 wherein assuming that the sum of the circular arc length of fins is TW (TW=w×n wherein w is the circular arc length of the fin as projected on a plane orthogonal to an axis of the tube, and n is the number of fins on one turn of the helical locus), and that the circumferential length of the tube inner surface is C(C=πD wherein D is the inside diameter of the tube), the ratio TW/C is 0.3 to 0.8.
US10/534,016 2002-11-15 2003-11-12 Cracking tube having helical fins Abandoned US20060102327A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/379,845 US7799963B2 (en) 2002-11-15 2009-03-03 Cracking tube having helical fins

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2002332257 2002-11-15
JP2002-332257 2002-11-15
PCT/JP2003/014403 WO2004046277A1 (en) 2002-11-15 2003-11-12 Cracking tube with spiral fin

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2003/014403 Continuation WO2004046277A1 (en) 2002-11-15 2003-11-12 Cracking tube with spiral fin

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US12/379,845 Division US7799963B2 (en) 2002-11-15 2009-03-03 Cracking tube having helical fins

Publications (1)

Publication Number Publication Date
US20060102327A1 true US20060102327A1 (en) 2006-05-18

Family

ID=32321658

Family Applications (2)

Application Number Title Priority Date Filing Date
US10/534,016 Abandoned US20060102327A1 (en) 2002-11-15 2003-11-12 Cracking tube having helical fins
US12/379,845 Expired - Lifetime US7799963B2 (en) 2002-11-15 2009-03-03 Cracking tube having helical fins

Family Applications After (1)

Application Number Title Priority Date Filing Date
US12/379,845 Expired - Lifetime US7799963B2 (en) 2002-11-15 2009-03-03 Cracking tube having helical fins

Country Status (11)

Country Link
US (2) US20060102327A1 (en)
EP (1) EP1561795B1 (en)
JP (1) JP4290123B2 (en)
KR (2) KR101028052B1 (en)
CN (1) CN100342199C (en)
AU (1) AU2003280759A1 (en)
CA (1) CA2505518C (en)
HK (1) HK1085760A1 (en)
SA (1) SA03240437B1 (en)
TW (1) TWI270574B (en)
WO (1) WO2004046277A1 (en)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070028984A1 (en) * 2003-03-18 2007-02-08 Imperial College Innovations Limited Helical piping
US20080014342A1 (en) * 2004-08-12 2008-01-17 Schmidt + Clemens Gmbh + Co., Kg Composite tube, method of producing for a composite tube, and use of a composite tube
US20080017550A1 (en) * 2004-09-21 2008-01-24 Caro Colin G Piping
US20080257436A1 (en) * 2004-09-21 2008-10-23 Caro Colin G Piping
US20090095594A1 (en) * 2004-09-21 2009-04-16 Heliswirl Technologies Limited Cracking furnace
US20100133146A1 (en) * 2008-12-02 2010-06-03 Van Egmond Cor Franciscus Coil for pyrolysis heater and method of cracking
US20100143206A1 (en) * 2007-03-30 2010-06-10 Kubota Corporation Thermal cracking tube
US20120060727A1 (en) * 2009-03-17 2012-03-15 ToTAL PETROCHECMICALS RESEARCH FELUY Process for quenching the effluent gas of a furnace
US8354084B2 (en) 2008-09-19 2013-01-15 Technip France S.A.S. Cracking furnace
WO2016023776A1 (en) * 2014-08-13 2016-02-18 Basf Se Method for producing a cracked gas containing ethylene, and a cracking tube for use in said method
WO2018204060A1 (en) * 2017-05-05 2018-11-08 Exxonmobil Chemical Patents Inc. Heat transfer tube for hydrocarbon processing
WO2019133215A1 (en) * 2017-12-29 2019-07-04 Exxonmobil Chemical Patents Inc. Coke mitigation in hydrocarbon pyrolysis
WO2019233680A1 (en) 2018-06-04 2019-12-12 Universiteit Gent Devices and methods for hydrocarbon cracking
US20200326141A1 (en) * 2017-10-27 2020-10-15 China Petroleum & Chemical Corporation Heat transfer enhancement pipe as well as cracking furnace and atmospheric and vacuum heating furnace including the same
WO2023218435A1 (en) * 2023-05-18 2023-11-16 Saldorgar Mohammadjavad A set of water-cooled panels for electric arc furnaces

Families Citing this family (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
PL2037202T3 (en) * 2006-07-05 2019-03-29 Nippon Steel & Sumitomo Metal Corporation Metal tube for thermal cracking reaction
KR101422879B1 (en) * 2007-03-28 2014-07-23 베이징 리서치 인스티튜트 오브 케미컬 인더스트리, 차이나 페트로리움 앤드 케미컬 코포레이션 A tube type cracking furnace
JP5289811B2 (en) * 2008-03-31 2013-09-11 株式会社クボタ Reaction tube
JP5224877B2 (en) * 2008-04-01 2013-07-03 株式会社クボタ Pyrolysis tube
CN101723784B (en) * 2008-10-16 2012-12-26 中国石油化工股份有限公司 Ethylene cracking furnace
EP2248581A1 (en) 2009-05-08 2010-11-10 Total Petrochemicals Research Feluy Process for quenching the effluent gas of a furnace
CN101824333B (en) * 2010-05-07 2013-01-09 华东理工大学 Field synergy effect-based cracking furnace tube
CN102679791B (en) * 2011-03-10 2015-09-23 卢瓦塔埃斯波公司 For the heat-transfer pipe of heat exchanger
CN103673603A (en) * 2012-09-26 2014-03-26 中国石油大学(北京) Heating furnace radiation furnace tube with lining arranged in staggered mode
US20150211115A1 (en) * 2014-01-28 2015-07-30 Hzo, Inc. Multi-channel pyrolysis tubes, material deposition equipment including the same and associated methods
WO2016099738A1 (en) 2014-12-16 2016-06-23 Exxonmobil Research And Engineering Company Alumina forming refinery process tubes with mixing element
CA2971073C (en) 2014-12-16 2019-04-09 Exxonmobil Chemical Patents Inc. Pyrolysis furnace tubes
CN105180702A (en) * 2015-09-28 2015-12-23 湖北雷迪特冷却系统股份有限公司 Heat radiating turbulence tube
CN106016306B (en) * 2016-05-24 2018-06-12 浙江普林派特涂镀科技有限公司 Organic solvent prepainted waste gas incinerator system and its application method
CA3075483C (en) 2017-09-12 2022-07-05 Exxonmobil Chemical Patents Inc. Aluminum oxide forming heat transfer tube for thermal cracking
CN109724447B (en) * 2017-10-27 2021-02-05 中国石油化工股份有限公司 Reinforced heat transfer pipe
CN109724448B (en) * 2017-10-27 2021-04-13 中国石油化工股份有限公司 Enhanced heat transfer tube, cracking furnace and atmospheric and vacuum heating furnace
CN109724444B (en) * 2017-10-27 2020-12-18 中国石油化工股份有限公司 Heat transfer pipe and cracking furnace
SG11202004978QA (en) * 2017-12-06 2020-06-29 Mitsubishi Electric Corp Heat exchanger, refrigeration cycle apparatus and method of manufacturing heat exchanger
US20190346216A1 (en) * 2018-05-08 2019-11-14 United Technologies Corporation Swirling feed tube for heat exchanger
FR3096766B1 (en) 2019-05-31 2021-08-06 Manoir Pitres tube comprising at least one twisted segment with elliptical or lobed section for a steam cracking furnace
GB2590363B (en) 2019-12-09 2023-06-28 Paralloy Ltd Internally profiled tubes
JP7510868B2 (en) 2019-12-27 2024-07-04 株式会社クボタ Pyrolysis tube with fluid stirring element
EP4083563A4 (en) * 2019-12-27 2024-02-07 Kubota Corporation Pyrolysis tube provided with fluid stirring element
WO2022250366A1 (en) * 2021-05-24 2022-12-01 주식회사 다원시스 Apparatus and method for pyrolyzing organic compound raw material
CN114100539A (en) * 2021-11-02 2022-03-01 中国石化工程建设有限公司 Intraductal enhanced heat transfer plug-in components and pyrolysis furnace
FR3129935B1 (en) * 2021-12-03 2023-12-01 E T I A Evaluation Tech Ingenierie Et Applications Device for producing hydrogen by gas pyrolysis
EP4379080A1 (en) * 2022-07-05 2024-06-05 LG Chem, Ltd. Alloy material having high-resistivity characteristics, preparation method therefor, and joule-heating tube including same

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5950718A (en) * 1994-07-11 1999-09-14 Kubota Corporation Heat exchange tubes

Family Cites Families (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59119192A (en) * 1982-12-27 1984-07-10 Hitachi Ltd Heat transfer pipe
JPH06100432B2 (en) * 1984-06-20 1994-12-12 株式会社日立製作所 Heat transfer tube
JPH0670556B2 (en) * 1985-06-14 1994-09-07 株式会社日立製作所 Heat transfer tube and manufacturing method thereof
JPH0696708B2 (en) 1986-06-06 1994-11-30 出光石油化学株式会社 Hydrocarbon pyrolysis method
JP3027658B2 (en) * 1992-09-25 2000-04-04 株式会社クボタ Method of forming inner projection of metal tube
JPH0734949B2 (en) * 1992-11-06 1995-04-19 株式会社日立製作所 Heat transfer tube manufacturing method
JP2722984B2 (en) * 1993-02-19 1998-03-09 凸版印刷株式会社 Diffraction grating detector
JP3323682B2 (en) 1994-12-28 2002-09-09 株式会社日立製作所 Heat transfer tube with internal cross groove for mixed refrigerant
JPH08303905A (en) * 1995-05-12 1996-11-22 Hitachi Ltd Heat transfer tube for mixed medium and its manufacture
JPH09243283A (en) * 1996-03-04 1997-09-19 Kubota Corp Heat exchanging metallic tube equipped with inner surface projection
JP3284330B2 (en) * 1996-03-12 2002-05-20 株式会社クボタ Pyrolysis reaction tube for ethylene production with inner protrusion
JPH1024337A (en) * 1996-05-09 1998-01-27 Nakamura Jikou:Kk Heat exchanger tube, its manufacturing method and device
JP2000274983A (en) * 1999-03-18 2000-10-06 Kobe Steel Ltd Inner surface grooved pipe
JP2001208495A (en) * 2000-01-25 2001-08-03 Hitachi Cable Ltd Internally grooved heat exchanger tube
JP4632487B2 (en) * 2000-06-22 2011-02-16 住友軽金属工業株式会社 Internal grooved heat transfer tube and manufacturing method thereof
JP2002107081A (en) * 2000-09-29 2002-04-10 Hitachi Cable Ltd Heat transfer pipe for condensing water outside of pipe
KR100419065B1 (en) * 2001-03-07 2004-02-19 주식회사 엘지화학 Pyrolysis Tube and Pyrolysis Method for using the same

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5950718A (en) * 1994-07-11 1999-09-14 Kubota Corporation Heat exchange tubes

Cited By (30)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090218037A1 (en) * 2003-03-18 2009-09-03 Caro Colin G Piping
US20070028984A1 (en) * 2003-03-18 2007-02-08 Imperial College Innovations Limited Helical piping
US20080014342A1 (en) * 2004-08-12 2008-01-17 Schmidt + Clemens Gmbh + Co., Kg Composite tube, method of producing for a composite tube, and use of a composite tube
US20090235850A1 (en) * 2004-09-21 2009-09-24 Heliswirl Technologies Limited Piping
US20090095594A1 (en) * 2004-09-21 2009-04-16 Heliswirl Technologies Limited Cracking furnace
US20080257436A1 (en) * 2004-09-21 2008-10-23 Caro Colin G Piping
US20080017550A1 (en) * 2004-09-21 2008-01-24 Caro Colin G Piping
US7749462B2 (en) 2004-09-21 2010-07-06 Technip France S.A.S. Piping
USRE43650E1 (en) 2004-09-21 2012-09-11 Technip France S.A.S. Piping
US8029749B2 (en) 2004-09-21 2011-10-04 Technip France S.A.S. Cracking furnace
US8088345B2 (en) 2004-09-21 2012-01-03 Technip France S.A.S. Olefin production furnace having a furnace coil
US20100143206A1 (en) * 2007-03-30 2010-06-10 Kubota Corporation Thermal cracking tube
US8231837B2 (en) 2007-03-30 2012-07-31 Kubota Corporation Thermal cracking tube
US8354084B2 (en) 2008-09-19 2013-01-15 Technip France S.A.S. Cracking furnace
US8163170B2 (en) 2008-12-02 2012-04-24 Lummus Technology Inc. Coil for pyrolysis heater and method of cracking
WO2010065302A3 (en) * 2008-12-02 2010-08-26 Lummus Technology Inc. Coil for pyrolysis heater and method of cracking
US20100133146A1 (en) * 2008-12-02 2010-06-03 Van Egmond Cor Franciscus Coil for pyrolysis heater and method of cracking
US20120060727A1 (en) * 2009-03-17 2012-03-15 ToTAL PETROCHECMICALS RESEARCH FELUY Process for quenching the effluent gas of a furnace
WO2016023776A1 (en) * 2014-08-13 2016-02-18 Basf Se Method for producing a cracked gas containing ethylene, and a cracking tube for use in said method
US11053445B2 (en) * 2017-05-05 2021-07-06 Exxonmobil Chemical Patents Inc. Heat transfer tube for hydrocarbon processing
KR20200014741A (en) * 2017-05-05 2020-02-11 엑손모빌 케미칼 패턴츠 인코포레이티드 Heat Transfer Tubes for Hydrocarbon Treatment
WO2018204060A1 (en) * 2017-05-05 2018-11-08 Exxonmobil Chemical Patents Inc. Heat transfer tube for hydrocarbon processing
KR102379113B1 (en) 2017-05-05 2022-03-25 엑손모빌 케미칼 패턴츠 인코포레이티드 Heat Transfer Tubes for Hydrocarbon Treatment
US20200326141A1 (en) * 2017-10-27 2020-10-15 China Petroleum & Chemical Corporation Heat transfer enhancement pipe as well as cracking furnace and atmospheric and vacuum heating furnace including the same
US11976891B2 (en) * 2017-10-27 2024-05-07 China Petroleum & Chemical Corporation Heat transfer enhancement pipe as well as cracking furnace and atmospheric and vacuum heating furnace including the same
US12123661B2 (en) 2017-10-27 2024-10-22 China Petroleum & Chemical Corporation Heat transfer enhancement pipe as well as cracking furnace and atmospheric and vacuum heating furnace including the same
WO2019133215A1 (en) * 2017-12-29 2019-07-04 Exxonmobil Chemical Patents Inc. Coke mitigation in hydrocarbon pyrolysis
US11254877B2 (en) 2017-12-29 2022-02-22 Exxonmobil Chemical Patents Inc. Coke mitigation in hydrocarbon pyrolysis
WO2019233680A1 (en) 2018-06-04 2019-12-12 Universiteit Gent Devices and methods for hydrocarbon cracking
WO2023218435A1 (en) * 2023-05-18 2023-11-16 Saldorgar Mohammadjavad A set of water-cooled panels for electric arc furnaces

Also Published As

Publication number Publication date
EP1561795A4 (en) 2011-08-17
JPWO2004046277A1 (en) 2006-03-16
KR20110022710A (en) 2011-03-07
CN1711340A (en) 2005-12-21
AU2003280759A1 (en) 2004-06-15
TWI270574B (en) 2007-01-11
WO2004046277A1 (en) 2004-06-03
CA2505518A1 (en) 2004-06-03
KR101075999B1 (en) 2011-10-21
HK1085760A1 (en) 2006-09-01
CA2505518C (en) 2009-09-22
JP4290123B2 (en) 2009-07-01
SA03240437B1 (en) 2007-10-29
KR20050084873A (en) 2005-08-29
TW200418975A (en) 2004-10-01
US20090177022A1 (en) 2009-07-09
KR101028052B1 (en) 2011-04-08
EP1561795B1 (en) 2014-04-02
CN100342199C (en) 2007-10-10
EP1561795A1 (en) 2005-08-10
US7799963B2 (en) 2010-09-21

Similar Documents

Publication Publication Date Title
US7799963B2 (en) Cracking tube having helical fins
EP0692693B1 (en) Method for producing ethylene
US8231837B2 (en) Thermal cracking tube
JP6046836B2 (en) Pyrolysis furnace pipe fittings
KR19980070125A (en) Water Pipe Boiler
JP5289811B2 (en) Reaction tube
JP2000234887A (en) Heat exchanging bent tube having inner face protrusion
JP5619174B2 (en) HEAT EXCHANGE DEVICE AND ITS MANUFACTURING METHOD
US20230019344A1 (en) Internally profiled tubes
JP7538028B2 (en) Pyrolysis tube with fluid stirring element
JP2021107762A (en) Thermal decomposition pipe including fluid stirring element
JPH09264683A (en) Thermal decomposition reaction tube having fin for petrochemical

Legal Events

Date Code Title Description
AS Assignment

Owner name: KUBOTA CORPORATION, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:INUI, MASAHIRO;HAMADA, KAORU;OTSUBO, KENJI;REEL/FRAME:017390/0594

Effective date: 20050330

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION