[go: up one dir, main page]

US3885530A - Shield tube supports - Google Patents

Shield tube supports Download PDF

Info

Publication number
US3885530A
US3885530A US485523A US48552374A US3885530A US 3885530 A US3885530 A US 3885530A US 485523 A US485523 A US 485523A US 48552374 A US48552374 A US 48552374A US 3885530 A US3885530 A US 3885530A
Authority
US
United States
Prior art keywords
support
furnace
tubes
supports
air
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.)
Expired - Lifetime
Application number
US485523A
Other languages
English (en)
Inventor
John A Kivlen
Jr James E Massey
Jr James H Martin
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.)
ExxonMobil Technology and Engineering Co
Original Assignee
Exxon Research and Engineering Co
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 Exxon Research and Engineering Co filed Critical Exxon Research and Engineering Co
Priority to US485523A priority Critical patent/US3885530A/en
Priority to SE7505030A priority patent/SE414827B/sv
Priority to CA225,791A priority patent/CA1017638A/en
Priority to AU80749/75A priority patent/AU494787B2/en
Priority to GB18455/75A priority patent/GB1510697A/en
Priority to FR7516243A priority patent/FR2277315A1/fr
Application granted granted Critical
Priority to JP50063420A priority patent/JPS5847634B2/ja
Publication of US3885530A publication Critical patent/US3885530A/en
Priority to BE156789A priority patent/BE829586A/xx
Priority to DE2524106A priority patent/DE2524106C2/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
    • F22B37/00—Component parts or details of steam boilers
    • F22B37/02—Component parts or details of steam boilers applicable to more than one kind or type of steam boiler
    • F22B37/10—Water tubes; Accessories therefor
    • F22B37/20—Supporting arrangements, e.g. for securing water-tube sets
    • F22B37/204—Supporting arrangements for individual tubes, e.g. for securing tubes to a refractory wall
    • 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

Definitions

  • a hollow pipe serves as a beam support for the shield tubes, the support being extensively insulated to minimize radiant heat input and being cooled by air passing inside it as induced by natural draft available from the furnace. Air from outside the furnace is drawn into the hollow support, cools it and passes out into the furnace stack above the convection section. The support beam iscooled by air while the supports on which the shield tubes rest are cooled by conduction, either into the air cooled support or into the shield tubes. Contact of the supports with radiant energy is avoided.
  • the temperature of support beams for shield tubes in such furnaces may exceed 2000F. At such temperatures these beam supports are susceptible to creep failure.
  • the radiant section tubes are much hotter and so are usually supported from outside the furnace so their supports are not subjected to high temperatures.
  • the convection tube supports are not unduly hot, but the shield tube supports are. After a period of operation the beam may gradually sag to the point that a complete failure occurs, causing damage to the furnace and necessitating an expensive shutdown.
  • One approach to preventing such creep problems is to use materials which retain high strength at the high temperatures which are experienced. This is too costly to be a practical solution.
  • Another alternative is to shield the support beam from the radiation which causes them to sag and eventually fail.
  • the solid beam which is typical of the prior art shield tube supports is replaced in the present invention with a hollow structure, usually a piece of commercially available high strength pipe, which serves as a beam support.
  • a hollow structure usually a piece of commercially available high strength pipe, which serves as a beam support.
  • Such pipe would not be sufficiently strong to resist the high temperatures unless it is cooled.
  • Cooling is provided by opening one end of the hollow support beam to the atmosphere outside the furnace through which relatively cool air can enter.
  • the air is induced into the hollow support beam by the pressure differential which is available between the atmosphere and the furnace stack. Accordingly, the outlet end of the support beam is connected to piping which is passed upwardly and into the furnace stack above the convection section.
  • the furnace stack being at a negative pressure, creates a natural draft which induces sufficient air to cool the support beam so that it may resist the high temperatures which exist in the furnace.
  • a light weight insulation is placed completely about the support beam structure.
  • the shield tubes themselves are supported by T- shaped supports having the bottom of the T welded to the support beam and the cross bar of the T serving as the support for the tube. Insulation is placed around these T-shaped support pieces so that they receive a minimal amount of heat from radiation or from convection and they are cooled both by air passing through the support beam and by process fluid passing through the inside of theshield tubes. This combination of cooling and insulation prevents failures from high temperature creep.
  • the second row of shield tubes less exposed to radiant heat than the first row, are supported on Y- shaped supports which rest directly on the cross bar of the T-shaped supports for the first row of shielded tubes. These Y-shaped supports, being shielded by the air-cooled support, are less exposed to'radiant heat and mainly to convection heat. They are capable of supporting the second row of shield tubes without additional insulation.
  • the temperature of the structure is substantially below that which would otherwise occur were no cooling provided. This temperature is sufficiently low so that the furnace can operate for long periods without excessive creep and failure of the supports.
  • FIG. 1 is an elevation view of a typical vertical furnace to which the present invention has been applied.
  • FIG. 2 is an enlarged cross section taken substantially along line 22 of FIG. 1.
  • FIG. 3 is a sectional view taken substantially along line 33 of FIG. 2.
  • FIG. 4 is a cut-away prospective view.
  • FIG. 5 illustrates a non-cooled shielded support beam of the prior art.
  • FIG. 1 shows an elevation view of a vertical furnace 10 such as is often used in refineries or chemical plants and in particular, used for steam cracking of hydrocarbons to produce olefins.
  • Heat produced by burning of fuels occurs principally by large burners 12 at the floor of the furnace 10, although at times smaller burners spaced along the sidewalls may also be used.
  • the radiant section 14 which may be defined generally as the area of the furnace in which the tubes are within the line of sight of the flames produced by the burners.
  • the radiant section 14 is the hottest part of the furnace 10 and the tubes located there: receive the highest heat density. Also, the process temperatures are the highest in this area.
  • furnace tubes are positioned vertically in the radiant section and support from outside it, but not being particularly pertinent to the present invention, they are not shown in FIG. I.
  • Hot gases leaving the radiant section 14 pass upwardly into the convection section 16 of the furnace where heat is transferred to the convection section tubes 18 by convective heat transfer in much the same fashion as in a shell and tube heat exchanger. After giving up the optimum amount of heat to incoming feeds or to other extraneous streams, the furnace gas is passed upwardly past the damper 20 and out furnace stack 22 above, which is not shown in this illustration.
  • the radiant section and convection section are clearly separated from one another and there are no tubes in the convection section bank which see a portion of the radiant heat. In the furnace configuration of FIG. 1, this is not the case.
  • the first two rows of convection section tubes do see some radiant energy from the burners 12 in the radiant section 14.
  • These tubes are called shield tubes 22 since they shield the remainder of the convection section 16 from the radiant energy from the radiant section 14 of the furnace 10.
  • the lower two rows of tubes 22 receive substantially higher heat density than the remainder of the convection section 16 and, in a furnace which operates at very high temperatures, the shield tubes 22 and their supports will be subjected to very severe temperatures.
  • the process temperature of hydrocarbons leaving the shield tube section may be of the order of 1250F. If no heat is removed, temperatures in this region may reach about 2,200 to 2,250F. At these temperatures, most metallic materials have very little strength. As a result, support of the shield tubes becomes a major problem and a limiting factor in the life of the furnace. It should be understood that the support beam rests on the furnace structure and must carry a bending load different from that of radiant tube supports.
  • FIG. 5 a prior art configuration is illustrated which has been heretofore used with some success.
  • a typical shield tube 22 is supported by an I- shaped beam 24 which, if no heat were removed, could reach temperatures of 2,200F. and above, at which point the beam 24 would become exceedingly weak and its ability to support the shield tubes very limited even when high temperature metals are used, such as HK-40. Failures may occur in a very short time from creep under these high temperatures.
  • FIG. 2 a sectional view of the shield tube support is seen which, when combined with the views of FIGS. 3 and 4, illustrate the specific structure which has been found to give a substantial reduction of shield tube support temperature.
  • the two rows of shield tubes 22a and I lie in staggered fashion, one above the other, both resting upon the shield tube support beam.
  • a hollow tube typically a high strength HK-4O (25Cr/2ONi) steel may be used to support the shield tubes.
  • HK-4O 25Cr/2ONi
  • Five to seven number of intermediate supports will be required in order to support the shield tubes adequately. Air passing through the interior of the support significantly lowers its temperature and increases its strength.
  • the importance of cooling is illustrated by the following data for a typical I-IK-4O material.
  • the allowable stress is:
  • the hollow support beam 30 is completely encased in a light weight insulation 32, for example, a kaowool, which serves to reduce the temperature of the beam and to protect against creep failures. Performance of this insulation is critical to the success of the invention and, accordingly, in many applications, it will be desirable to provide a high temperature alarm to sense the temperature of the air leaving the support beam and warn of insulation failure.
  • the insulation 32 covers a major portion of the T-shaped support 34 which is welded to the support beam 30 and which accepts the weight of the lowest row of shield tubes 22a, and indirectly supports the upper row of shield tubes 22!) through a Y-shaped support 36 which can be more clearly seen in FIG. 3.
  • the Y-shaped support 36 is shown welded directly to the T-shaped member 34, which is in turn directly welded to the air cooled support beam 30. It will be noted that no insulation is provided for the Y- shaped support 36 and it might be thought that it would fail from overheating. In fact, however, it has been found that no insulation is required, since the heat removed from the Y-shaped support 36 through the T- shaped member 34 to the air-cooled beam 30 is very substantial. By way of illustration, it has been found by direct measurement that the temperature of the Y- shaped support may well be 300 lower than the 2200 which was typically experienced in this area without cooling. At this temperature the Y-shaped support without any further insulation is sufficiently strong to support the second row of shield tubes 22b. It will be appreciated that the supports lose heat in two ways,
  • T-shaped member with a wide extension is preferred embodiment, other shapes could also be used as were deemed to be mechanically suitable, as long as they followed the general teachings of the invention.
  • FIG. 4 in a perspective view illustrates the elements of the invention which have been previously described showing in a partially cut-away view the air-cooled support beam 30, its insulation 32, and the tube supports 34 and 36.
  • a method of supporting furnace tubes exposed to high temperatures at which metal support beams for said tubes are subject to creep failure comprising:
  • a supoort structure for furnace tubes exposed to high temperatures in a furnace having radiant and convection sections and where metal support beams for said tubes are subject to creep failure comprising:
  • an elongated air-cooled support beam having a passageway therethrough with one end of said passageway open to cool ambient air outside the furnace and the other end communicating with a location within the furnace having a negative pressure relative to the pressure of said ambient air;
  • said support beam of (a) comprises a hollow cylindrical tube fabricated of a metal having high temperature creep resistance.
  • furnace tubes are horizontal shield tubes disposed between said radiant and convection sections.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Engineering & Computer Science (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Supports For Pipes And Cables (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Physical Or Chemical Processes And Apparatus (AREA)
  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
  • Furnace Charging Or Discharging (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
US485523A 1974-07-03 1974-07-03 Shield tube supports Expired - Lifetime US3885530A (en)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US485523A US3885530A (en) 1974-07-03 1974-07-03 Shield tube supports
CA225,791A CA1017638A (en) 1974-07-03 1975-04-29 Shield tube supports
SE7505030A SE414827B (sv) 1974-07-03 1975-04-29 Sett och stodkonstruktion for att understodja ugnsvermevexlingsror
GB18455/75A GB1510697A (en) 1974-07-03 1975-05-02 Supports for heat exchange tubes in furnaces
AU80749/75A AU494787B2 (en) 1974-07-03 1975-05-02 Shield tube supports
FR7516243A FR2277315A1 (fr) 1974-07-03 1975-05-23 Procede et structure pour le support de tubes de fours exposes a des hautes temperatures
JP50063420A JPS5847634B2 (ja) 1974-07-03 1975-05-27 ロカンオシシヨウスルホウホウ オヨビ ソノタメノシジコウゾウタイ
BE156789A BE829586A (fr) 1974-07-03 1975-05-28 Procede et structure pour le support de tubes de fours exposes a de hautes temperatures
DE2524106A DE2524106C2 (de) 1974-07-03 1975-05-30 Vorrichtung zur Abstützung von Rohrleitungen innerhalb eines Industrieofens

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US485523A US3885530A (en) 1974-07-03 1974-07-03 Shield tube supports

Publications (1)

Publication Number Publication Date
US3885530A true US3885530A (en) 1975-05-27

Family

ID=23928496

Family Applications (1)

Application Number Title Priority Date Filing Date
US485523A Expired - Lifetime US3885530A (en) 1974-07-03 1974-07-03 Shield tube supports

Country Status (8)

Country Link
US (1) US3885530A (sv)
JP (1) JPS5847634B2 (sv)
BE (1) BE829586A (sv)
CA (1) CA1017638A (sv)
DE (1) DE2524106C2 (sv)
FR (1) FR2277315A1 (sv)
GB (1) GB1510697A (sv)
SE (1) SE414827B (sv)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0065046A1 (en) * 1981-05-19 1982-11-24 Exxon Research And Engineering Company Supporting the weight of a structure in a hot environment
US4368695A (en) * 1981-05-28 1983-01-18 Exxon Research And Engineering Co. Supporting the weight of a structure in a hot environment
US5394837A (en) * 1994-02-25 1995-03-07 Tsai; Frank W. High-efficiency furnace
US20080036220A1 (en) * 2006-08-08 2008-02-14 Pempa Tashi Door locking system
WO2016202825A1 (en) * 2015-06-16 2016-12-22 Becton Dickinson France Transportation system for annealing glass containers
JP2018508739A (ja) * 2015-02-12 2018-03-29 安徽海螺川崎工程有限公司 余熱ボイラ
US10907822B2 (en) 2015-02-12 2021-02-02 Anhui Conch Kawasaki Engineering Company Limited Waste heat boiler
CN114234687A (zh) * 2021-12-23 2022-03-25 淮阴工学院 一种流化床换热管束吊架设备

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6175869A (ja) * 1984-09-14 1986-04-18 山梨県 絣染金属加工糸の製造方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3026858A (en) * 1959-09-23 1962-03-27 Selas Corp Of America Tube support
US3259112A (en) * 1964-09-02 1966-07-05 Foster Wheeler Corp Removable tube support
US3378064A (en) * 1966-05-12 1968-04-16 Selas Corp Of America Tube support

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2355800A (en) * 1942-04-20 1944-08-15 Universal Oil Prod Co Heating of fluids

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3026858A (en) * 1959-09-23 1962-03-27 Selas Corp Of America Tube support
US3259112A (en) * 1964-09-02 1966-07-05 Foster Wheeler Corp Removable tube support
US3378064A (en) * 1966-05-12 1968-04-16 Selas Corp Of America Tube support

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0065046A1 (en) * 1981-05-19 1982-11-24 Exxon Research And Engineering Company Supporting the weight of a structure in a hot environment
US4368695A (en) * 1981-05-28 1983-01-18 Exxon Research And Engineering Co. Supporting the weight of a structure in a hot environment
US5394837A (en) * 1994-02-25 1995-03-07 Tsai; Frank W. High-efficiency furnace
US20080036220A1 (en) * 2006-08-08 2008-02-14 Pempa Tashi Door locking system
JP2018508739A (ja) * 2015-02-12 2018-03-29 安徽海螺川崎工程有限公司 余熱ボイラ
EP3258168A4 (en) * 2015-02-12 2019-02-20 Anhui Conch Kawasaki Engineering Company Limited WASTE HEAT BOILER
US10907822B2 (en) 2015-02-12 2021-02-02 Anhui Conch Kawasaki Engineering Company Limited Waste heat boiler
WO2016202825A1 (en) * 2015-06-16 2016-12-22 Becton Dickinson France Transportation system for annealing glass containers
US10640414B2 (en) 2015-06-16 2020-05-05 Becton Dickinson France Transportation system for annealing glass containers
CN114234687A (zh) * 2021-12-23 2022-03-25 淮阴工学院 一种流化床换热管束吊架设备

Also Published As

Publication number Publication date
JPS519075A (sv) 1976-01-24
SE7505030L (sv) 1976-01-05
DE2524106C2 (de) 1983-07-28
JPS5847634B2 (ja) 1983-10-24
CA1017638A (en) 1977-09-20
FR2277315A1 (fr) 1976-01-30
SE414827B (sv) 1980-08-18
FR2277315B1 (sv) 1980-11-21
BE829586A (fr) 1975-11-28
DE2524106A1 (de) 1976-01-22
AU8074975A (en) 1976-11-04
GB1510697A (en) 1978-05-10

Similar Documents

Publication Publication Date Title
US3885530A (en) Shield tube supports
US4100889A (en) Band type tube support
CA1259537A (en) Combustion of halogenated hydrocarbons with heat recovery
US2276527A (en) Apparatus for heating fluids
GB1587498A (en) Heat exchange apparatus
MX2010006119A (es) Termopermutador del tubo de humos.
US3554168A (en) Furnace apparatus
US4405565A (en) Tubular reaction furnace for indirect heating of crackable fluids
US4168737A (en) Heat exchange recuperator
US6364658B1 (en) Partially studded radiant tubes
US2617405A (en) Tubular gas heater, in particular for solid fuels
EP0401172B1 (en) A heating mantle with a porous radiation wall
US3164137A (en) Shielding of tube support for furnace tube panels
CS221976B2 (en) Water cooled slipper
CS270243B2 (en) Heat exchanger for hot streaming gases
US4368695A (en) Supporting the weight of a structure in a hot environment
US3302621A (en) Method of supporting horizontal heater tubes fired from both sides
US2332534A (en) Steam generator
US3947326A (en) Vertical tube type cracking furnace
KR850001538B1 (ko) 히이터
US2013985A (en) Fluid heater
EP0065046B1 (en) Supporting the weight of a structure in a hot environment
SU920338A1 (ru) Трубчата печь
US3127876A (en) Heavy duty fluid heater
JPS632432Y2 (sv)