US3630850A - Cracking furnace with burners engaging mirror image coiled tubes - Google Patents
Cracking furnace with burners engaging mirror image coiled tubes Download PDFInfo
- Publication number
- US3630850A US3630850A US847285A US3630850DA US3630850A US 3630850 A US3630850 A US 3630850A US 847285 A US847285 A US 847285A US 3630850D A US3630850D A US 3630850DA US 3630850 A US3630850 A US 3630850A
- Authority
- US
- United States
- Prior art keywords
- furnace
- coils
- burners
- tubes
- burner
- 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
Links
- 238000005336 cracking Methods 0.000 title abstract description 7
- 239000000567 combustion gas Substances 0.000 claims abstract description 14
- 238000006243 chemical reaction Methods 0.000 abstract description 11
- 238000004891 communication Methods 0.000 abstract description 2
- 239000000446 fuel Substances 0.000 description 5
- 238000002485 combustion reaction Methods 0.000 description 4
- 230000004907 flux Effects 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 230000007423 decrease Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 230000000306 recurrent effect Effects 0.000 description 1
- 238000007665 sagging Methods 0.000 description 1
Images
Classifications
-
- 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
- B01J19/2425—Tubular reactors in parallel
-
- 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
-
- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
- B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
- B01J2219/00103—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor in a heat exchanger separate from the reactor
-
- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00157—Controlling the temperature by means of a burner
-
- 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
- B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
- B01J2219/00049—Controlling or regulating processes
- B01J2219/00051—Controlling the temperature
- B01J2219/00159—Controlling the temperature controlling multiple zones along the direction of flow, e.g. pre-heating and after-cooling
Definitions
- the coils include inlet and outlet openings, the inlet openings being on one side of the chamber and the outlet openings on the other. At least two coils are adjacent in such a manner that one is the mirror image of the other. Burner means operatively engages the inlet openings and a combustion gas outlet in the chamber is in communication with the outlet openings.
- FIG. 1 A first figure.
- the invention relates to a furnace with vertical tubes for supplying heat to a medium that can he passes through the tubes, suitable for carrying out chemical reactions such as pyrolysis.
- Furnaces of this type are employed for thecracking of hydrocarbons, for instance for the preparation of ethene from naphtha.
- the incoming hydrocarbon mixture should rapidly be brought to a very high temperature, for instance 850 C., and be kept at least at that temperature for a short time.
- a furnace with vertical tubes is very suitable for such high temperatures, because sagging of the tubes cannot then occur and expansion of tubes can more easily be accommodated constructionally.
- the vertical tubes are located in a chamber which in its simplest form is bounded by smooth, vertical walls, a floor and a roof which chamber also contains the burners.
- this chamber is provided with the required lines and ducts for the supply of feed, fuel and air and for the discharge of product and combustion gases.
- this chamber the transfer of heat to the tubes takes place mainly by radiation. It is common practice for the heat content of the combustion gases leaving the chamber to be utilized as far as possible by preheating the feed by these gases in a separate convection chamber. As a rule this convection chamber is located very close to the outlet for the discharge of the combustion gases.
- a furnace fired in this way has several disadvantages.
- the use of residual oil as fuel is not possible.
- gas is fired, which is comparatively expensive.
- the large number of burners results in a complicated system of fuel supply and control valves.
- the invention therefore relates to a furnace provided with vertical tubes-which are present in a chamber of which at least two walls are relatively smooth, vertical and parallel to each otherfor the supply of heat to a medium that can be passed through the tubes, suitable for carrying out chemical reactions such a-pyrolysis, in which furnace:
- an odd number of tubes is combined into a coil by joining adjacent tubes in such a way that connections at the bottom ends of the tubes alternate with connections at the top ends of the tubes,
- the inlet openings of all the coils are located on the same side of the furnaceat the bottom or at the top,
- the outlet openings of all the coils are likewise located on the same side of the furnaceat the top or at the bottom-opposite the inlet openings,
- At least two coils are placed next to each other, so that one of two adjacent coils is the mirror image of the other, the tubes being located in one plane, parallel to the aforementioned vertical walls of the chamber, in such a way that always two inlet openings are adjacent,
- one or more outlets for the discharge of combustion gases is (are) located on the side of the furnace where the outlet openings of the coils are located.
- the furnace according to the invention has no burners that are mounted in the sidewalls.
- the burners are located in the bottom or in the roof. near the inlet openings of the coils.
- the number of burners is small and each burner has a comparatively large capacity, the class of burners with such a capacity comprising burners suitable for firing residual oil.
- a coil consists of at least three tubes.
- the second and following tubes, counting from the tube with the inlet opening, are farther removed from the burners, as a result of which the heat supply is decreased. It may be desirable that the distances between adjacent tubes of one bank be unequal, that is, should increase along the route from the tube with the outlet opening to the tube with the inlet opening. Then the largest distance is between the first and the second tube, counting from the tube with the inlet opening, as a result of which that section of the second pipe which again comes near the burner is prevented from being heated to too high a temperature.
- the distances between the first and the second tube may, for instance, be three times the distance between the second and the third.
- the net heat flux is unevenly distributed over the coil, in order that a more uniform tube wall temperature is obtained. This causes the fuel consumption to decrease. Also, it will be possible for the length of each coil to be adapted more closely to the desired conversions, which results in optimum minimum dimensions of the radiant section of the furnace.
- a simple embodiment of a furnace according to the invention is that in which each coil consists of three tubes.
- the coils, of which there should be present two or more in an even number, may all be located in one level plane, which plane is located between and at equal distances from the aforementioned vertical walls of the chamber.
- the burners then may have the same capacity and be arranged in pairs, the two burners of one pair being arranged symmetrically relative to the set of adjacent inlet openings of two coils. This results in a flat, vertical furnace with a recurrent pattern of burners and coils comprising two burners and two coils.
- the burners then may be arranged in one or more groups of at least three, so that the burners of one group are located on a line that is perpendicular to the level planes of the coils located in one plane, in such a way that always one bumer is present between a vertical wall and the nearby inlet openings and one burner is present between two planes containing coils, the burners present between the planes containing coils having a larger capacity than the burners present near a vertical wall.
- the ratio between the capacities may be approximately 2: l.
- a furnace having this arrangement is less flat than the one described hereinbefore. With this arrangement, to obtain a given capacity, a smaller wall area of the chamber is required, which is favorable in view of the walls being very costly owing to the high requirements concerning heat resistance. A furnace of this type is particularly suitable for applications where large capacities are required.
- the burners should give only short, vertical flames, that is short relative to the length of a tube, the flame length being, for instance, at most one-third of the tube length. In this way it is ensured that the heat production does not take place over the entire length of the nearby tubes but remains limited to the neighborhood of the inlet openings.
- burners capable of producing a flame of low luminosity the requirement of an uneven distribution of the heat production over the length of the pipe is met even more fully.
- Particularly suited are burners of the multiple vortex type. With these burners the combustion takes place mainly in a combustion chamber which is integrated with the burner into a combustor. This combustion chamber communicates with the chamber of the furnace that contains the tubes. The burners produce a flow of combustion gas of a high temperature.
- burners can be fired with fuel of almost any type. It is preferred that the burners be present in the bottom part of the chamber.
- the stream of hot gas then enters the chamber in the vertical, upward direction. Along the vertical, in the upward direction, the temperature of the gas decreases.
- the discharge of combustion gases takes place in the upper part of the chamber via one or more openings.
- FIG. I is a vertical cross-sectional view of a furnace according to the invention.
- FIG. 2 is a cross-sectional view of the furnace of FIG. 1 taken along the lines [1-1] of FIG. 1.
- FIGS. 3 and 4 show cross-sectional views similar to the view of FIG. 2 of two embodiments of furnaces according to the invention.
- FIG. 1 the vertical sidewalls l and la of the chamber 2 of a furnace 2a are shown.
- chamber 2 which represents the radiant section of the furnace 2a, are located, in the bottom thereof, burners 3, 4, 5 and 6 (FIG. 2).
- the combustion gases are discharged via an opening 7 (FIG. 1) near the roof lb of the chamber 2.
- the medium to be heated is passed through a line 8 to a heat exchanger 9.
- this heat exchanger 9 the medium is preheated by the combustion gases discharged via opening 7.
- the heat transfer takes place mainly by convection, for which purpose special constructions are known in the art.
- the heat exchanger 9 may be present on the roof lb of chamber 2, but may also be placed adjacent that chamber 2.
- Chamber 2 contains a number of vertical tubes which are combined into coils in such a way that each coil contains an odd number of tubes and that an even number of coils are present.
- four coils are present, indicated by reference numbers I0, 11, '12 and 13.
- Each coil here consists of three tubes.
- At the underside of the furnace 1a are present the connections to line 14 for the introduction of the medium; at the upper side are present the connections to line for the discharge of the product obtained by heating the medium.
- the coils 10 through 13 are preferably located in one plane and are so arranged that each coil is the mirror image of the adjacent one.
- the tubes 10a and lla are adjacent, and so are the tubes 12a and 130. It is through these tubes that the medium to be thermally treated enters.
- the burners 3, 4, 5 and 6 are located vertically and preferably produce nonluminous, short flames.
- the tubes 10a, lla, 12a and 13a receive-owing to the vertical, upward flows of hot combustion gas-more heat than the other tubes of each coil, which is favorable, since the medium should absorb the highest heat flux immediately after entrance.
- At least wall I and la are relatively smooth, vertical and parallel to each other.
- FIG. 2 clearly shows the symmetrical arrangement of the burners 3 through 6 relative to the tubes 10a through 13a with inlet openings.
- the tubes through which the medium flows in the upward direction are indicated by cross sections with a dot in the center, the tubes through which the medium flows in the downward direction by cross sections containing a cross.
- FIG. 3 A cross section of a furnace according to the invention where the coils are grouped in two planes is shown in FIG. 3.
- the coils again consist of three tubes each.
- the coils l6, l7, l8 and 19 are located in one level plane; the coils 20, 21, 22 and 23 in another level plane, parallel to the first.
- the coils are arranged in such a way that each coil is the mirror image of the adjacent one.
- the burners 24, 26 and 26 are in a line between the coils l6 and 17,20 and 21.
- the burners 27, 28 and 29 are arranged similarly relative to the coils l8 and 19, 22 and 23.
- the burners 25 and 28 have a larger capacity than the other burners, such as a ratio of approximately 2:l.
- a furnace according to FIG. 3 has a large capacity within a comparatively small wall area of the chamber.
- each coil holds that the distance between the first tube and the second, counted from the tube with the inlet opening, is larger than the distance between the second and the third tube.
- the burners 34 and 35 belong to the coils 30 and 31, the burners 36 and 37 to the coils 32 and 33.
- the inequality of the distances between the tubes of one coil makes it possible to obtain a certain uneveness of the net heat flux to those tubes, as a result of which the condition of a uniform tube wall temperature is approximated more closely.
- a closed chamber having a top wall, a bottom wall and a plurality of sidewalls, at least two of said sidewalls being relatively smooth, vertical and parallel to one another;
- each of said coils including inlet and outlet openings, all of said inlet openings being disposed on the same side of said chamber and all of said outlet openings being disposed on the side of said chamber opposite the inlet openings;
- At least two of said coils being disposed adjacent each other in such a manner that one of the coils is the mirror image of the other, all of said tubes therein being located in common plane in such a manner that the inlet openings of at least two adjacent coils are adjacent one another;
- burner means operatively engaging said inlet openings for providing flames to said inlet openings
- At least one combustion gas outlet disposed in said chamber on the side of said chamber communicating with the outlet openings of said coils.
- each coil consists of three tubes.
- said burner means includes a burner associated with each inlet opening, each burner having the same capacity and being arranged in pairs, the two burners of one pair being arranged symmetrically relative to the set of adjacent inlet openings of two adjacent coils.
- said burner means includes a burner associated with each inlet opening, each burner being arranged in at least one group of at least three burners so that the burners of on group are located on a line that is perpendicular to the level planes of the coils and that runs symmetrically between the adjacent inlet openings of two coils located in one plane, in such a way that one burner is al- 5 jacent a vertical sidewall.
- burner means is located in relation to at least two of said coils so that the second and following tubes of each coil, counting from the tube with the inlet opening, are farther removed from said burner means.
- the apparatus of claim 1 including preheater means adapted to preheat the medium with combustion gas from the furnace chamber.
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- General Chemical & Material Sciences (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL6817224A NL6817224A (pt) | 1968-12-02 | 1968-12-02 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3630850A true US3630850A (en) | 1971-12-28 |
Family
ID=19805303
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US847285A Expired - Lifetime US3630850A (en) | 1968-12-02 | 1969-08-04 | Cracking furnace with burners engaging mirror image coiled tubes |
Country Status (2)
Country | Link |
---|---|
US (1) | US3630850A (pt) |
NL (1) | NL6817224A (pt) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4014749A (en) * | 1973-04-25 | 1977-03-29 | Linde Aktiengesellschaft | Tube furnace for the cracking of organic feed stock |
US4160701A (en) * | 1973-04-25 | 1979-07-10 | Linde Aktiengesellschaft | Tube furnace for the cracking of organic feed stock |
US4997525A (en) * | 1986-06-25 | 1991-03-05 | Naphtachimie S.A. | Hydrocarbon cracking apparatus |
US5124003A (en) * | 1986-06-25 | 1992-06-23 | Naphtachimie S.A. | Apparatus for the steam cracking of hydrocarbons for the preparation of olefins an diolefins |
EP0519230A1 (en) * | 1991-06-17 | 1992-12-23 | Abb Lummus Crest Inc. | Pyrolysis heater |
EP0523762A1 (en) * | 1991-07-16 | 1993-01-20 | Stone & Webster Engineering Corporation | Thermal cracking furnace and process |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3215502A (en) * | 1962-07-30 | 1965-11-02 | Chemical Construction Corp | Reformer furnace |
US3407789A (en) * | 1966-06-13 | 1968-10-29 | Stone & Webster Eng Corp | Heating apparatus and process |
-
1968
- 1968-12-02 NL NL6817224A patent/NL6817224A/xx unknown
-
1969
- 1969-08-04 US US847285A patent/US3630850A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3215502A (en) * | 1962-07-30 | 1965-11-02 | Chemical Construction Corp | Reformer furnace |
US3407789A (en) * | 1966-06-13 | 1968-10-29 | Stone & Webster Eng Corp | Heating apparatus and process |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4014749A (en) * | 1973-04-25 | 1977-03-29 | Linde Aktiengesellschaft | Tube furnace for the cracking of organic feed stock |
US4160701A (en) * | 1973-04-25 | 1979-07-10 | Linde Aktiengesellschaft | Tube furnace for the cracking of organic feed stock |
US4997525A (en) * | 1986-06-25 | 1991-03-05 | Naphtachimie S.A. | Hydrocarbon cracking apparatus |
US5124003A (en) * | 1986-06-25 | 1992-06-23 | Naphtachimie S.A. | Apparatus for the steam cracking of hydrocarbons for the preparation of olefins an diolefins |
EP0519230A1 (en) * | 1991-06-17 | 1992-12-23 | Abb Lummus Crest Inc. | Pyrolysis heater |
EP0523762A1 (en) * | 1991-07-16 | 1993-01-20 | Stone & Webster Engineering Corporation | Thermal cracking furnace and process |
Also Published As
Publication number | Publication date |
---|---|
NL6817224A (pt) | 1969-11-25 |
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