IE47248B1 - Apparatus for the production of carbon black - Google Patents

Description

This invention relates to apparatus for the production of carbon black.

Such apparatus is known, and consists for example of a cylindrical or parallelepipedic reactor with a reaction chamber for carbon black formation, a cover for the chamber provided with a plurality of feed units for the metered supply of air from an air heating apparatus and of hydrocarbons from a preparation apparatus, reactor heat exchangers on the discharge side of the reactor for reducing the temperature of the waste or flue gases leaving the reactor and the carbon black produced, and a filter unit downstream of the heat exchanger in which the carbon black is separated from the waste or flue gases.

Various designs of carbon black production apparatus are known. In one known construction fuel gases are produced separately in a reactor and are mixed with hydrocarbons sprayed in at a different part of the reactor for Initiating the reaction processes. The decomposition of hydrocarbons and the formation of carbon black Btarts to a limited extent at temperatures of 700 to 800° C and reaches its optimum level at between approximately 1,100 and 1,h00° C, depending on the desired carbon black quality.

Variants of this known construction in which fuel gaeee are introduced into the reactor separately from the hydrocarbons are known and said variants particularly relate to the arrangement of the burner heads for pro4724» - 3 duoing the fuel gases and the nozzles for introducing the hydrocarbons for carbon black production. Furthermore, an additional carrier gas is added. In addition for temperature control purposes water is added in various ways, although thie reduces the efficiency of an apparatus.

In the above constructions of carbon black production apparatus it is relatively difficult and also costly to produce different carbon black grades. This is 10 mainly due to the fact that various operating parameters must be adapted to one another, because on the one hand the fuel and air quantities for producing the fuel gases and on the other the hydrocarbon quantities, as well as optionally the carrier gas and water quantities have to 15be regulated and matched to one another. If a carrier gas or watei· and/or water vapour are added, then additional reactions occur with the other components. Thus, with the known construction of a carbon black production apparatus few carbon black grades can be produced in an economic 2omonner. However, this Ib an important disadvantage, because it is desirable to be able to produce the particular carbon black grade which Ib in demand.

It Ib therefore obvious to reduce the number of operating parameters which have to be regulated. Thus, 25a further group of carbon black production plants is known, ln which the same hydrocarbons are used both for producing the heat of reaction and for producing the carbon black, which leads to a significant operational slm47 34$ plification (U.S. Patents 2 64j5 182 and. 2 144 971). However, this simplification does not lead to a rapid adaptation of the operation of the carhon black production apparatus to the production of different carbon black grades. As is known for producing different carbon black grades it is necessary to adhere to different operating conditions and in particular a specific hydrocarbon : air ratio. Carbon black is always produced in a reducing atmosphere, i.e. with a deficiency of air.

As for the production of increasingly fine carbon black it is necessary to use an increasingly large proportion of air, the thermal loading of the reactor rises in proportion to the production of finer carbon black grades and therefore limits the range of carbon black grades which can be produced in the same apparatus. However, in the case of inadequate mixing of the two components air and hydrocarbon the free oxygen introduced into the reactor is not completely combined. As a result the carbon black quality obtained differs from that required.

According to the present invention there is provided apparatus for the production of carbon black which apparatus comprises a cylindrical or parallelepipedic reactor comprising a reaction chamber for carbon black formation, a heat exchanger on the discharge side of the reactor for reducing the temperature of the reactor output gases and the carhon black produced therein, and 17248 - 5 a filter unit arranged downstream of the heat exchanger for separating the carbon black from the reactor output gases, the reactor, upstream of the reaction chamber, being provided with at least one mixing chamber the or each mixing chamber having at least one feed unit each for supplying air from an air supply apparatus and hydrocarbon material from a hydrocarbon supply apparatus to the or the associated mixing chamber, each feed unit comprising an air plenum chamber for connection- to the air supply, which chamber is connected to the feed unit outlet via a guide section, a hydrocarbon supply pipe extending through the air plenum chamber and guide section and having a spray nozzle mounted thereon for spraying hydrocarbon material into air passing through the guide section, a vortex member having flow openings mounted within the guide section and fixed to the hydrocarbon supply pipe extending therethrough, and an outlet restricting nozzle within the outlet of the feed unit and fixed to the hydrocarbon supply pipe adjacent the outlet, the hydrocarbon supply pipe, spray nozzle, vortex member and outlet restricting nozzle being removable as a unit from the air plenum chamber and guide section and being proportioned to feed reagent air and hydrocarbon for production of a particular grade of carbon black in the apparatus.

Such apparatus accordingly has interchangeable components in the feed units and thus enables the production of carbon black with no restrictions regarding the production of carbon black grades of different fineness.

Suitably the feed units of the apparatus according to the invention may be unjacketed.

Preferably the total cross-sectional area 10 presented by openings in the vortex member and the total cross-sectional area presented by openings in the output restricting nozzle are substantially of' equal magnitude for each of the feed units.

Preferably the apparatus contains, upstream of the 15 reaction chamber, a plurality of mixing chambers each opening into the reaction chamber and there is also provided a second heat exchanger extending across the reactor such that temperature control fluid can pass through the second heat exchanger substantially at right angles to the direction flow within uhe reactor and around the mixing chambers to control the temperature therein as described and claimed in our copending Application No. 35362/78 (Serial No. 47247 2003457) from which this application is divided. Thus during the use of such apparatus, temperature control fluid is passed through the second heat exchanger around the mixing chambers. Thus the operating conditions, in particular the temperature desired for - 7 the mixing of the component air and hydrocarbon, can be maintained in the mixing chambers. In particular, thermal overstressing of the reactor in the intake area of the two components, hydrocarbon and air, may be prevented.

The invention is illustrated, by way of Example, with reference to the accompanying drawings, wherein Figure 1 is a diagrammatic representation of a vertical section through a reactor of a carbon black production apparatus according to the present invention; Figure 2 is a diagrammatic representation of a vertical section through the cover portion of the reactor of Figure 1, but with a modified mixing chamber; Figure 3 is a diagrammatic representation of a plan view of the cover portion of a reactor according to Figure 1, with a symbolically indicated air supply; Figures 4 and 5 are in each case a diagrammatic vertical section of two feed units along the line IV-IV of Figure 3; Figure 6 is a diagrammatic representation of a vertical section through a feed unit, and Figure 7 is a diagrammatic representation of a cross-section through a reactor with a cooling duct incorporated into the reactor wall.

In Figure 1, a reactor 1 of a carbon black production apparatus is positioned vertically, but it could also be positioned horizontally. The carbon black production apparatus, whereof reactor 1 forms the essential part, - 8 comprises a plurality of further components, namely a preparation apparatus for the hydrocarbons, an air heating apparatus for preheating the reaction air, a cooling apparatus for cooling the resulting reaction product, a filter unit in which the carhon black is separated from the waste or flue gases, a carbon black collecting and packaging mechanism and a regulating device for regulating the operational parameters necessary for completely satisfactory operation. These components of the apparatus dre not described in detail, because they arc not essential for the present invention, Reference is made in this connection to known constructional embodiments, e.g. according to U.S. Patent Specification 3,369,870.

Reactor 1 has a reactor cover 2, a reaction chamber 3 and a heat exchanger U. Diagrammatically represented preheating burners 7 are incorporated into the wall of reaction chamber 3» which comprises an outer wall 5 and an inner lining 6. During the heating-up period of reactor 1 the preheating burners 7 are in operation, but they are switched off during the normal carbon black production process. A not shown opening, closed by a flap, but which can open if overpressures occur is provided in lining 6 and in outer wall 5.

The reactor cover 2, which is advantageously made from Bteel, e.g. stainless steel, is essentially a hollow structure with various built-in and built-on units. A plurality of feed units 12 are mounted on the top 8 of - 9 47248 cover 2. The feed unite 12 serve to supply hydrocarbons and the reaction air to reaction chamber 3· In the construction according to Figure 1 each feed unit 12 is provided with a connection 1 3, which extends up to a mixing chamber 22 and can e.g. be constructed ae a cone. Feed units 12 and connection 13 extend in the direction of the longitudinal axis of reactor 1. A conduit 1b, which is provided with an inlet connection 15 and an outlet connection 16, is arranged substantially at right angles to the longitudinal axis of reactor 1 in cover 2. Conduit 1U embraces the mixing chamber 22 and bounds it by wells 10, 11 (Figures 1 ani 2). Due to the fact that they are arranged outeide cover 2 and specifically on its top 8 the feed units 12 are not surrounded by conduit 1b. How15 ever, it ie alBO possible to permit connection 13 and/or feed units 12 to project into conduit 1b. In any case mixing chamber 22 and optionally connection 13 and/or further parts of feed units 12 are located in conduit 1b and can be either cooled or heated by a fluid flowing through conduit 1b, bo hb to maintain the appropriate - 10 temperature for operation throughout the complete operating period.

Ab can he gathered from Figures 1,2, 3 and 4 , the feed units 12 can he interconnected by pipes 18, 19 and issue into mixing chamber 22 which, viewed in the flow direction of the reactor, is arranged in front of the reaction chamber 3. In Figure 2 the feed units 12 have no connection and issue directly into mixing chamber 22.

Reaction chamber 3 can have a random cross-section 1Θ and can e.g. be circular or rectangular. A rectangular cross-Bectional configuration of reaction chamber 3 with two roWB of feed units 12 is assumed for reactor 1 (Fig. 3). The cross-section of mixing chamber 22 approximately corresponds to the cross-section of reaction chamber 3· The mixing chamber 22 can optionally be subdivided by partial ducts 11* (Fig. 5) running in the direction ol' conduit 14. The feed unite 12 are arranged in :ows or concentrically on top 8 of cover 2. The subdivision of mixing chamber 22 by the partial ducts 11’ only takes place to the extent which is necessary for maintaining favourable conditions for mixing the components.

The heat exchanger 4 comprises individual, independent heat exchanger parts, which are not shown in detail or described. The heat exchanger 4 is positioned downstream of the reaction chamber and through the former flow the reaction products, i.e. the carbon black produced and the fuel gaaee, whereby the temperature thereof is reduced.

After flowing through heat exchanger 4 the reaction prod11 4 7 2 4 8 ucts pace Into a pipe 24 and from there to the not shown filter unit. A carbon black discharging valve 25 for discharging already separated carbon black is arranged at the lowest point of heat exchanger 2+.

Advantageously the inlet connection 15 of conduit 14 is connected via a pipe 26, which serves aa the fluid supply pipe, with heat exchanger 4. As a result the transverse flow conduit 14 can optionally be subject to the action of heated air and mixing chamber 22 can be kept at an approximately constant temperature, between approximately 500 and 700° C and preferably at approximately 600° C. A not ahown cold air connection is provided on pipe 26, bo that mixing chamber 22 can also be cooled.

Figure 3 shows the supply of feed units 12 with reaction air. The feed units 12 are arranged on cover 2 in tv/o rows parallel to conduit 14. Mixing chamber 22 is indicated by broken lines hb an elongated chamber with rounded corners, which is aurrounded by conduit 14 and can also be subdivided by partial duotB 11 The reaction air for feed units 12 is supplied by a symbolically represented feed device 28, which supplies the air, which it sucks in,via a pipe 29 and a not shown part of heat exchanger 4 to a distribution casing 30, located outBide reactor 1. By means of a measuring device 31 arranged in casing 30 it is possible to measure the pressure produced by the supply device 28.

Connecting lines 32 lead to the feed units 12 from distribution casing 30. Each connecting line 32 contains 7 2 4 8. - 12 a shutoff device 33» which can shut or constrict lines 32. Not Bhown throttle valves can he incorporated Into lines 32 so that feed units 12 are subject to a uniform action. As a result pipes 18 and/or 19 may he rendered superfluous, if it is simultaneously ensured that the second component, i.e. the hydrocarbon is precisely metered for each feed unit 12, e.g. hy metering pumps and/or metering units, connected to one another on a constrained motion basis and thus supply the same hydro10 carhon quantity to each feed unit 12.

Figures 4 and 5 show sections through cover 2 with two feed units 12. In Figure 4 a connection 13 is associated with each feed, unit‘12, whilst in Figure 5 the feed units 12 are arranged in mixing chamber 22 subdivided by the partial ducts 11’. The coyer 2 and/or the conduit 14 is sealed with respect to reaction chamber 3 by a base rj.

As a result it is possible for the conditions in mixing chamber 22 to be made Such that it serves virtually only for the production of a homogeneous mixture from the hydrocarbons and the reaction air. Thia is ensured by the fluid stream, e.g. air or liquid passed through conduit 14.

The arrangement of pipes 18 and 19 is best seen in Eigurfe 5, The two rows of feed units 12 arranged in cover 2 are staggered, which facilitates the arrangement of the pipes. The number of feed units 12 can be varied.

If only a few feed units 12 of corresponding size are used, their disassembly and maintenance are time consura47248 - 13 ing and costly, whilst a large number of small feed units la disadvantageous from the cost standpoint. Therefore the number of feed units chosen is based on economic aspects. If the mixing chamber 22 is kept free from combustion processes, a homogeneous mixture of the two components can be obtained with a relatively small number of feed units 12, which represents the prior requirement for the complete combining of the oxygen in reaction chamber J.

Each feed unit 12 (Figure 6) has an air container hO with a cylindrical cross-section, in whose longitudinal axis 39 ie arranged a feed pipe 1+1 for the liquid hydrocarbons. Λ spraying nozzle h2 is fitted at the end of pipe hi. Feed pipe hi is fixed to a cover h3 on the top of air container hO. The reaction nir 1b supplied by supply lines 32 (Figure 3) whose ende are connected to an air connection 1+U on the Bidewall of air container hO.

In addition to the air connection hh air container hO hae a cover connection U5 to which is fixed cover h3 with the aid of swivel pins h6 provided with butterfly nutB and which permit a rapid detachment of cover h3. Supply pipe hi is adjustably fixed to cover U3 by means of a clamping screw h-8. Clamping screw 1+8 is arranged in a boss 50 connected to cover 1+3 and in which is also pro25 vided a seal 51 for sealing the gap between supply pipe 1+1 and a bore 52 in boss 50» A. not shown sealing means is bIbo provided between cover connection i+5 and cover 1+3. - 14 On its bottom air container 1^0 has a conical connection 53 which passes into a cylindrical guide connection 5L having a smaller diameter than air container 40.

At the free end of guide connection 5A is provided an inwardly projecting shoulder 56, whilst on the outer periphery is arranged a mounting flange 57, with which feed unit 12 on cover 2, e.g. on its top S is fixed to a mounting flange 35 by means of screws and suitable scaling means.

If feed unit 12 with guide connection 5h is fitted into cover 2, mounting flanges 36, 37 can be provided for tills purpose at the transition between air container UO and conical connection 53· In thiB case the fluid stream in conduit 1h also flows round the lower part of feed unit 12 comprising connections 53, 5L.

A Pitot tube 60, which passes into an outlet connection 61 is supported on shoulder 56. The Pitot tube 60 has radially directed webB 62, carrying a boss 63, in whose bore 6h supply pipe U1 with spraying nozzle U2 is secured by means of a Betscrew 65. Above boss 63 supply pipe h-1 carries a further boss 68 provided with a setscrew 67 and to which is fixed a vortex body 70. The vortex body 70 can be constructed as a perforated plate (Figure 6) or bb a guide member with inclined webs.

‘ The important factor Ib that as a result of this arrangement supply pipe hi, together with the Pitot tube 60 and the vortex body 70 can easily be replaced by detaching cover 43· Depending on the desired grade of - 15 carbon black to be produced the corresponding spraying nozzle /+2 and Pitot tube Go, as well as vortex body 70 are fitted, after which the supply pipe hl is inserted in feed unit 12, cover hr is reattached and clamping screw U8 is tightened. An even faster replacement is obtained if complete fittings, comprising supply pipe hl, cover h3, vortex body 70 and ritot tube 60 are prepared. In this way it is possible to change very rapidly from producing one carbon black grade to another.

Feed unit 12 can advantageously be constructed from sheet steel, eo that the individual components together with pipeB 18 and 19 can be Interconnected by welding.

From the standpoint of the economic design of the carbon black production apparatus lt is advantageous if the heat of the waste gases produced in reaction chamber 3 can be used for heating the reaction air supplied to feed units 12 and the fluid used for flowing through conduit 1h and for this purpose heat exchanger h is provided, as shown in Figure 1. Heat exchanger h must also be able to cool the waete gases flowing out of reaction chamber 3 to such an extent that they can be introduced into the filter unit without damaging the latter.

In Figure 1 heat exchanger h follows directly onto reaction chamber 3, but heat exchanger h and its component parts could also be arranged in some other way. Advantageously the heat exchanger parts arc located in a vertical section of the apparatus to obviate blockages - 16 due to carbon black deposits in the plpo systems.

Figure 7 Bhows a variant of the construction of reaction chamber 3· Between outer wall 5 and inner wall 6 is provided a duct 8b with guide surfaces 93» which can be used for cooling and/or heating reaction chamber 3. The cooling air enters at a connection 87 and escapee at a connection 90. The cooling air supply can be regulated by means of thermocouples 91 arranged on inner wall of the reaction chamber.

The described apparatus functions ln the following manner: Aftei’ putting into operation the preheating burner the air heating apparatus and the hydrocarbon preparation apparatus are etarted up. After heating has taken place the prepared liquid hydrocarbons and the preheated reaction air are passed through feed units 12 into mixing chamber 22, where the hydrocarbons are intimately mixed and vaporized, but not burnt. The thus homogenised mixture passes into reaction chamber 3 in which part of the hydrocarbons are burnt for producing the heat of reaction and the other part is converted into carbon blade The resulting waste gases and the carbon black are passed through heat exchanger b and are introduced at a temperature of about 250° C into the filter unit in which the carbon black is separated, collected and packed.

By meanB of the above-described apparatus the temperature conditions in the range in which air and hydrocarbons arc mixed are perfectly controlled. This permitG - 17 an extension to the range of carbon black grades which can be produced, without operating faults occurring.

Tho extra expenditure involved, in the fora of conduit 14 in cover 2 is small compared with the advantages which can be obtained. Conduit 14 has an advantageous action on the service life of feed units 12, particularly their eenaitive part3, e.g. the epraying nozzles 42, Its UBe makes it possible to operate the apparatus on a permanent basis.

If the combustible waste gases leaving the filter unit are to be further treated, e.g. purified, equipment known in the furnaces art can be used.

Claims (5)

1. Apparatus for the production of carbon black which apparatus comprises a cylindrical or parallelepipedic reactor comprising a reaction chamber for carbon black formation, a heat exchanger on the discharge side of the reactor for reducing the temperature of the reactor output gases and the carbon black produced therein, and a filter unit arranged downstream of the heat exchanger for separating the carbon black from the reactor output gases, the reactor, upstream of the reaction chamber, being provided with at least one mixing chamber the or each mixing chamber having at least one feed unit each for supplying air from an air supply apparatus and hydrocarbon material from a hydrocarbon supply apparatus to the or the associated mixing chamber, each feed unit comprising an air plenum chamber for connection to the air supply, which chamber is connected to the feed unit outlet via a guide section, a hydrocarbon supply pipe extending through the air plenum chamber and guide section and having a spray nozzle mounted thereon for spraying hydrocarbon material into air passing through the guide section, a vortex member having flow openings mounted within the guide section and fixed to the hydrocarbon supply pipe extending therethrough, and - 19 an outlet restricting nozzle within the outlet of the feed unit and fixed to the hydrocarbon supply pipe adjacent the outlet, the hydrocarbon supply pipe, spray nozzle, vortex member and outlet restricting nozzle being removable as a unit from the air plenum chamber and guide section and being proportioned to feed reagent air and hydrocarbon for production of a particular grade of carbon black in the apparatus.

2. Apparatus according to claim Ί wherein the feed units are unjacketed.

3. Apparatus according to claim 2 or 3 wherein the total cross-sectional area presented by openings in the vortex member and the total cross-sectional area presented by openings in the output restricting nozzle are substantially of equal magnitude for each of the feed units.

4. Apparatus according to any one of the preceding claims which comprises, upstream of the reaction chamber, a plurality of mixing chambers, there being also provided a second heat exchanger extending across the reactor such that temperature control fluid can pass through the second heat exchanger substantially at right angles to the - 20 direction flow within the reactor and around the mixing chambers to control the temperature therein.

5. Apparatus according to claim 1 substantially as described with reference to or illustrated in any one of the accompanying drawings.