US2780529A - Apparatus for producing carbon black - Google Patents

Description

Feb. 5, 1957 F. K. wRlGLEY APPARATUS RoR PRonUcING CARBON BLACK 2 Sheets-Sheet l Filed Feb. 8, 1954 Feb. 5, 1957 F. K. wRlGLEY APPARATUS F'OR PRODUCING CARBON BLACK 2 Sheets-Sheet 2 Filed Feb. 8, 1954 Y S RE MY ma m mm Xo Vw Mw mK A F M Y B FIG. 7

APPARATUS FR PRODUCING CARBON BLACK Frederic K. Wrigley, Idaho Falls, Idaho, assigner to Phillips Petroleum Company, a corporation of Delaware Application February 8, 1954, Serial No. 408,801

8 Claims. (Cl. 23-259.5)

This invention relates to the production of carbon black. In one aspect it relates to an improveed burner for use in connection with a carbon black furnace. In another aspect it relates to a method for preventing damage to said burner at high temperatures. In another aspect it relates to a method for obtaining unusually smooth combustion.

It is known in the art to produce carbon black by reacting a hydrocarbon thermally by virtue of heat imparted to said hydrocarbon from a hot combustion gas. Such a process is described in U. S. Patent 2,564,700, Krejci, 1951. Such a process utilizes a reactor comprising a combustion zone positioned coaxially and in open communication with a reaction zone of smaller diameter than said combustion zone. A fuel and an oxidant in combustible proportions are introduced at high velocity, tangentially, into said combustion zone and resulting combustion gas travels in a spiral path toward the axis of said zone. Combustion of the fuel is completed near the periphery of the combustion zone. The combustion gas travels, from the combustion zone, in a helical path into the reaction zone. A reactant capable of being converted to carbon black is introduced longitudinally into the combustion zone and is reacted in the reaction zone by virtue of heat directly imparted thereto by the combustion gas.

This invention provides an apparatus and a method whereby combustion of the tangential fuel gas is effected in an improved manner.

This invention, in one embodiment, provides a burner for the introduction of fuel and oxidant tangentially into a furnace of the type described above. The burner comprises an inner conduit longitudinally positioned within an outer conduit; orifice means adjacent the outlet end of said outer conduit; closure means at the corresponding end :of said inner conduit; a plurality of peripheral openings in said inner conduit adjacent said closure means; and at least one peripheral opening in at least one of said conduits and positioned upstream from the oriiice means.

In one modiiication the burner comprises the elements set forth above, and the inner conduit is provided with a group of peripheral openings positioned upstream from the openings adjacent the closed end. Said openings can be arranged in staggered relationship with the openings adjacent the closed end; thus, each of said openings can be longitudinally non-aligned with respect to each of the openings adjacent the closed end.

In another embodiment of the invention, the burner comprises the inner conduit and the outer conduit as set forth above, and the outer conduit is provided with a group of circumferentially spaced peripheral openings upstream from the openings in the inner conduit. The inner conduit can be provided with the additional openings upstream from the openings adjacent the end thereof, or such additional openings can be omitted.

According to another embodiment of the invention, a burner of the type above described, utilized in a carbon black apparatus of the type above described, is protected fnited States Patent .2,780,529 Patented eb. 5, 1957 from the eects of the high temperatures produced in said apparatus by withdrawing part of the air which is supplied through the outer conduit and passing the withdrawn air around the outside of said conduit, whereby a cooling effect is provided.

According to another embodiment of the invention, the

. fuel supplied tangentially to a carbon black process of the type described is mixed with the tangentially supplied oxidant in a plurality of stages, the iirst stage occurring upstream of a zone of turbulent mixing which zone exists adjacent the outlet ends of the conduits supplying the fuel and the oxidant.

In the drawings,

Figure 1 is an elevational iiow diagram, partly in section, of a process in connection with which the present invention is utilized.

Figure 2 is a sectional view taken along line 2 2 of Figure l.

Figure 3 is an enlarged sectional View .of the tangential burner diagrammatically shown in Figure 2.

Figure 4 is a sectional view taken along line 4-4 of Figure 3.

Figure 5 is a sectional elevation of a modified burner according to this invention.

Figure 6 is a sectional View taken along line 6 6 of Figure 5.

Figure 7 is a sectional elevation of another modied burner according to this invention.

Figure 8 is a sectional View taken along line S--S of Figure 7.

Figure 9 is a sectional view taken along line 9-9 of Figure 7.

Figure 1 illustrates an apparatus and process of the type described in Patent 2,564,700, previously cited, and illustrates the use of one embodiment of the present invention in connection with such a process. The process described in the cited patent is known as a tangential iiame process of the precombustion type.

As shown in Figure l, there is provided a carbon black reactor designated generally as 7 and comprising an outer metal shell 8, insulation 9, and refractory liner i0. The reactor contains combustion zone 11 and reaction zone 12. These zones are coaxially positioned in open communication with each other, and are generally cylindrical. Combustion zone 11 is of greater diameter than reaction zone 12 and preferably has a shorter length than zone 12 and a length shorter than its own diameter.

A reactant, which is ordinarily a liquid hydrocarbon and preferably an aromatic gas oil, but which may be either liquid or gaseous, enters the system through inlet 2 and is preheated, and preferably vaporized, in heater 3. The heated oil passes to axially positioned inlet 4 and is axially injected into the furnace 7. A small amount of air enters through inlet :"5 into annular inlet 6, which surrounds the oil inlet 4. Only suiiicient air is added at this point to prevent deposition of carbon around the outlet of oil injector 4.

Simultaneously, as shown in Figure 2, air is tangentially injected through inlets 20 and 23 and a fuel, such as natural gas, is injected through inlet 22. As shown in Figure 2, combustion zone 1l is provided with tangential inlets or tunnels 13. Positioned within each of said tunnels is a burner according to this invention. The burner comprises air inlet 20 and gas inlet 2l which is preferably positioned coaxially within conduit 20. Air and fuel gas enter combustion zone 11 at a very high velocity. Combustion is ordinarily completed within tunnels 13 but may continue to some extent beyond said tunnels. The combustion of the fuel gas at high linear velocity produces a combustion gas which moves spirally inward toward the axis of chamber ll. The hot combustion gas then proceeds in a helical path into reaction zone 12,

thus heating reaction zone 12 to a carbon blacksforming temperature. The axially introduced oil is thermally reacted in chamber 12 to form high-quality carbon black in high yields. A resulting mixture of carbon black and resulting gas passes from reaction zone 12 into pipe 14. The reaction mixture is preferably initially cooled to a temperature below 1250 F. by means of water directly injected through quench inlet 15. The resulting mixture proceeds through pipe 14 and can be further cooled therein by exposing an uninsulated section of pipe 14 to the atmosphere or by the use of a water jacket or additional quench inlets, not shown. The cooled mixture of carbon black and combustion gas passes to gas-solids separation zone 18, which can be one or more cyclone separators, Cottrell precipitators, bag filters, or any combination of these, or other known equipment for the separation of solids from gases. Combustion gas is withdrawn through outlet 16 and product carbon black is withdrawn through outlet 17.

Figure 3 shows structural details of one modiiication of a burner according to this invention, said burner being positioned in tunnel 13 of the carbon black reactor, as indicated. in Figure 2. An air tube or blast tube 20 is provided with an annular oriiice plate 25, which can be secured to tube 2t) by any suitable means such as welding. VFlange 36 is provided for connection to an air pipe 23, as shown in Figure 2. Fuel gas tube 21 is positioned .'ithin blast tube 20 and is preferably coaxial with tube 20 at the outlet ends. Tube 21 extends through the wall of blast tube 20 and can be secured thereto by welding, as indicated at 32. Gas tube 21 is suitably threaded as indicated at 3i, for connection to a gas line. A support or saddle 29 is provided within tube 20, and tube 21 rests on said support. At the outlet end of gas tube 21 is a closure means 26 which completely closes the end of tube 21. Adjacent closure means 26 are circumferentially spaced peripheral outlets 27, which can be formed, for example, by drilling. Upstream from openings 27 and orifice 25 is a second set of openings 23 which are peripherally nonaligned longitudinally with openings 27.

Figure 4, which is a section view of the burner, shows an end view of support or saddle 29 with tube 21 resting thereon.

'l he modification of the burner shown in Figures 3 and 4 affects a partial premixing of part of the fuel gas which passes out of pipe 21 through openings 28 and mixes with the air in blast tube 2l. The outlet end of tube 21 is positioned adjacent orice plate 2S, so that a zone of turbulent mixing of gas and air occurs adjacent said orifice.

Combustion occurs downstream from said orifice plate in tunnel i3. The end of tube 21 can be positioned as shown in the drawing or can be slightly retracted within blast tube 2i? or can be flush with orice plate 25. The partial premixing therefore occurs upstream from the zone of turbulent mixing. ln any event, it is preferred that openings 27 be near the zone of turbulence adjacent orifice plate 25.

Another modification of the burner, according to this invention, is shown in Figures and 6. In this modification, the additional gas openings 28 (Fig. 3) are omitted. Openings 4t) are provided, in blast tube 20, upstream from opening 27. These openings iti cause part of the air to llow out of blast tube 2d and along its outer surface providing a cooling effect and thus protecting the burner i rom the high temperatures to which it is subjected.

Figures 7, S and 9 illustrate a modilication of the invention wherein both air outlet openings 4) and premix gas openings 2S are provided in the same burner, openings 40 preferably being upstream from openings 28. Figures 8 and 9 show the relative arrangement of openings 27 and 28. As shown in these figures, openings 27 and 28 are 45 out of alignment with each other.

Although in each of the above cases a group of 4 openings has been shown, any desired number of openings within one set of openings can be used. Also, the different groups can contain different numbers of openings from each of the other groups. Also, the openings need not be of circular cross-section, indicated in the drawings. They can be eliptical, elongated either transversely or longitudinally, or a group of slots can be used instead of a plurality of drilled holes.

It will also be evident to those skilled in the art that any desired preheating of the air or gas supplied to the burner can be utilized. Although two tangential inlets in combustion zone 11 have been shown in Figure 2, any desired number can be used, including a single inlet.

Burners of the type shown in Figures 3, 5 and 7 have been utilized in connection with the commercial production of carbon black according to the method described in the cited patent. Thus, in one plant, burners of the type illustrated in Figure 3, each having a blast tube 71/2 inches in internal diameter and a gas tube l inch in outside diameter was utilized at a volume ratio of air to natural gas of 15:1. The carbon black reactor had a reaction section l5 inches in diameter and 12.5 feet long y and a combustion section 33 inches in diameter and 1 foot long. The combustion section was provided with two tangential tunnels lOl/2 inches in diameter and 16 inches long. The tunnels were spaced apart. The blast tube of each burner extended 11/2 inches into the tunnel. Air was supplied through the blast tube at a rate of 105,000 cubic feet per hour, and a pressure of 4 p. s. i. The gas was supplied at a pressure of 30 p. s. i. Extremely smooth combustion is obtained in this apparatus.

Although certain process steps, structures and examples have been described for purposes of illustration, the invention is clearly not limited thereto. The essence of the invention is that there has been provided a process and a burner which effect partial premixing of fuel and oxidizing gas, and a burner which is protected, from high temperatures, by flow of air from within an air conduit along the outside thereof. Variation and modification are possible within the scope of the disclosure and the claims of the invention. Thus, the oxidizing gas can be pure oxygen or oxygen-enriched air and the fuel gas can be ethane, propane, butane, etc., natural gas or residue gas.

I claim:

l. In a carbon black production reactor comprising a reaction chamber coaxial with and adjacent a combustion chamber having a larger diameter than said reaction chamber, an axial inlet to said combustion chamber, and at least one tangential inlet to said combustion chamber, a burner positioned within said tangential inlet and comprising, in combination: a fuel conduit coaxially positioned within and air conduit, each of said conduits having and inlet end and outlet end, the outlet ends of said conduits being adjacent each other; and annular orifice plate peripherally attached to the outlet end of said air conduit and out of contact with said fuel conduit, thus forming an annular passageway adjacent said fuel conduit; closure means at the outlet end of said fuel con duit; a group of circumferentially spaced peripheral openings in said fuel conduit adjacent said closure means; an additional group of circumferentially spaced peripheral openings in said fuel conduit at a locus upstream from the first-mentioned group and intermediate the inlet and the outlet end of said fuel conduit, each of the openings of said additional group being longitudinally nonaligned with all of the first-mentioned openings.

2. A burner according to claim 1 wherein said air conduit is provided with a group of circumferentially spaced openings upstream from said additional group of openings in said fuel conduit and intermediate the inlet and the outlet end of said air conduit.

3. In a carbon black production reactor comprising a reaction chamber coaxial with and adjacent a combustion chamber having a larger diameter than said re- 5 action chamber, an axial inlet to said combustion chamber, and at least one tangential inlet to said combustion chamber, a burner positioned within said tangential inlet and comprising, in combination: ya fuel conduit coaxially positioned within an air conduit, each of said conduits having an inlet end and an outlet end, the outlet ends of said conduits being adjacent each other; an orifice plate peripherally attached to the outlet end of said air conduit, said plate being unattached to said fuel conduit, thus forming an annular passageway adjacent said fuel conduit; closure means -at the outlet end of said fuel conduit; a group of circumferentially spaced peripheral openings in said fuel conduit adjacent said closure means; and a group of circumferentially spaced peripheral openings in said air conduit upstream from said openings in said fuel conduit and intermediate the inlet and the outlet end of said air conduit.

4. In a carbon black production reactor comprising a reaction chamber coaxial with and adjacent a combustion chamber having a larger diameter than said reaction chamber, an axial inlet in said combustion chamber, and at least one tangential inlet in said combustion chamber, a burner positioned in said tangential inlet and comprising, in combination: a fuel conduit coaxially positioned within an air conduit, each of said conduits having an inlet and an outlet end, the outlet ends of said conduits being adjacent each other; an orifice peripherally attached to the outlet end of said air conduit and out of contact with said fuel conduit, thereby forming an annular passageway immediately adjacent said fuel cond-uit; closure means at the outlet end of said fuel conduit; a group of circumferentially spaced peripheral openings in said fuel conduit adjacent said closure means; and a plurality of circumferentially spaced peripheral openings at a longitudinally intermediate position in at least one of said conduits, intermediate the inlet and the outlet end thereof and positioned upstream from said group of openings, each of said circumferentially spaced peripheral openings, when positioned in said fuel conduit, being longitudinally non-aligned with respect to all of said first-mentioned openings.

5. In the reactor according to claim 4, a source of fuel under superatmospheric pressure connected to said fuel conduit and a source of air under superatmospheric pressure connected to said air conduit.

6. In a carbon black production reactor comprising a generally cylindrical chamber having axially positioned inlet means and outlet means and at least one tangentially positioned inlet means, the improvement which comprises a. burner positioned within said tangentially positioned inlet means and comprising, in combination: au inner conduit longitudinally positioned within an outer conduit each of said conduits having an inlet end and an outlet end the outlet ends being adjacent each other; orifice means peripherally attached adjacent the outlet end yof said outer conduit and out of contact with said inner conduit; closure means at the corresponding end of said inner cond-uit; a plurality of peripheral openings in said inner conduit adjacent said closure means; and at least one additional peripheral opening at a position in at least one of said conduits intermediate the inlet and the outlet end thereof and positioned upstream from the orifice means, each said additional opening, when positioned in said inner conduit, being nonaligned with respect to all of said first-mentioned openings.

7. A burner comprising, in combination: an inner conduit longitudinally positioned within an outer conduit, each of said conduits having an inlet end and an outlet end, the outlet ends being adjacent each other; orifice means peripherally attached to the outlet end of said outer conduit out of contact with said inner conduit; closure means at the outlet end of said inner conduit; a plurality of peripheral openings in said inner conduit adjacent said closure means; and at least one additional peripheral opening positioned intermediate the inlet and the outlet end of at least one of said conduits and upstream from said orifice means, each said additional opening, when positioned in said inner conduit, being longitudinally nonaligned with respect to all of said first-mentioned openings.

8. A burner comprising, in combination: an inner conduit longitudinally positioned within an outer conduit, each of said conduits having an inlet end and an outlet end, the outlet ends being adjacent each other; orifice means peripherally attached to the outlet end of said outer conduit out of contact with said inner conf duit; closure means at the outlet end of said inner con- References Cited in the file of this patent UNITED STATES PATENTS 864,589 Zimmerman Aug. 27, 1907 2,155,339 Stoll Apr. 18, 1939 2,564,700 Krejci Aug. 2l, 1951 2,641,534 Krejci June 9, 1953

Claims (1)

1. 6. IN A CARBON BLACK PRODUCTION REACTOR COMPRISING A GENERALLY CYLINDRICAL CHAMBER HAVING AXIALLY POSITIONED INLET MEANS AND OUTLET MEANS AND AT LEAST ONE TANGENTIALLY POSITIONED INLET MEANS, THE IMPROVEMENT WHICH COMPRISES A BURNER POSITIONED WITHIN SAID TANGENTIALLY POSITIONED INLET MEANS AND COMPRISING, IN COMBINATION: AN INNER CONDUIT LONGITUDINALLY POSITIONED WITHIN AN OUTER CONDUIT EACH OF SAID CONDUITS HAVING AN INLET END AND AN OUTLET END THE OUTLETS ENDS BEING ADJACENT EACH OTHER; ORIFICE MEANS PERIPHERALLY ATTACHED ADJACENT THE OUTLET END OF SAID OUTER CONDUIT AND OUT OF CONTACT WITH SAID INNER CONDUIT; CLOSURE MEANS AT THE CORRESPONDING END OF SAID INNER CONDUIT; A PLURALITY OF PERIPHERAL OPENINGS IN SAID INNER CONDUIT ADJACENT SAID CLOSURE MEANS; AND AT LEAST ONE ADDITIONAL PERIPHERAL OPENING AT A POSITION IN AT LEAST ONE OF SAID CONDUITS INTERMEDIATE THE INLET AND THE OUTLET END THEREOF AND POSITIONED UPSTREAM FROM THE ORIFICE MEANS, EACH SAID ADDITIONAL OPENING, WHEN POSITIONED IN SAID INNER CONDUIT, BEING NONALIGNED WITH RESPECT TO ALL OF SAID FIRST-MENTIONED OPENINGS.

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