KR930001209B1 - Method of and apparatus for production of carbon black - Google Patents

Abstract

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Description

Carbon black manufacturing apparatus and method

1 is a schematic cross-sectional view of an axial flow reactor according to a preferred embodiment of the present invention.

2 is an enlarged cross-sectional view showing the reaction chamber of the reactor of FIG.

3 is a sectional view taken along line 3-3 of FIG.

4 is a view similar to FIG. 2 showing a co-current embodiment of the invention.

5 is a cross-sectional view of an oil supply pipe covered with air according to the present invention.

FIG. 6 is a front view of the oil supply line in FIG. 5, partially cut away. FIG.

FIG. 7 is a cross sectional view taken along line 7-7 of FIG. 6, schematically illustrating the operation of the air covered tube.

* Explanation of symbols for main parts of the drawings

10 reactor 11: combustion chamber

17: neck 18: reaction chamber

22,22a: spray nozzle 23: oil supply pipe

27: inner wall 28,28a: spray oil

33: air pipe 34: air outlet name

37: air film

The present invention relates generally to a reactor for producing carbon black, and more particularly, to an axial flow reactor for controlling the particle size distribution of carbon black produced in the reactor.

Carbon black, typically oil, is produced by thermal decomposition of hydrocarbons in such a way that they are introduced into a stream of hot combustion gases. This pyrolysis reaction takes place in a refractory tubular structure known as a reactor.

Commercial production of carbon black usually takes place in two different reactors: tangential reactors and axial reactors. The name refers to the flow of combustion gases in the reactor. Both kinds of carbon black reactors are known to those skilled in the art. In general, axial flow reactors are preferred when producing carbon blacks intended for certain applications, especially those where the control of the particle size distribution of the carbon black product must be maintained within some relatively narrow range. For example, tire manufacturers, where tire traction is a major requirement, require carbon black with a very narrow particle size distribution to produce high performance tires for racing. Therefore, the carbon black used to make racing tires must have a relatively narrow particle size distribution (or also known as ″ tint ″, a coefficient that increases as the particle size distribution decreases).

Carbon blacks having a relatively narrow particle size distribution have been produced so far by axial reactors in which the flow of one or more crude oils is introduced radially into the hot combustion gas stream. This arrangement disperses the oil relatively quickly in the gas stream so that all raw oils are thermally cracked under substantially the same thermal conditions, ie, generally at the same location in the reactor. Radial introduction was a common way to achieve rapid mixing of oil and hot gases and the resulting short flame in the reactor neck, which is very narrow particle size distribution, ie higher tint, for the same surface area and structure of the carbon particles. To produce a carbon black having. Carbon blacks used in some other applications should have a lower tint, i.e. a wider particle size distribution. Such carbon blacks are made in reactors designed to increase the reaction time of the raw materials rather than minimize them, but using different reactors to make the two types of carbon blacks is expensive. Nevertheless, there is a need for carbon blacks with higher tints than would normally be obtained with conventional radial spray axial reactors. In addition, radially spraying the raw material oil into a conventional reactor having a circular cross section can cause grit and corrosion of the reactor inner wall if the injection pressure and the axial gas velocity are not properly balanced.

It is therefore an object of the present invention to provide an improved reactor for producing carbon black.

Another object of the present invention is to provide an improved axial flow reactor having improved flexibility to increase or decrease the particle size distribution by control.

Another object of the present invention is to provide an improved axial flow reactor for producing carbon black having a relatively narrow or relatively wide particle size distribution.

It is a further object of the present invention to provide a carbon black reactor which allows a more complete coverage of the cross section of the gas flow through the reactor neck.

It is another object of the present invention to provide an improved method for producing carbon black having a relatively narrow or relatively wide particle size distribution.

The above and other objects are satisfied according to the present invention. In general terms, the present invention includes a carbon black reactor in which a sprayed hydrocarbon feed is introduced into the reaction chamber, generally in a countercurrent or concurrent direction with respect to the hot gas flow through the reaction chamber. The backflow of the hydrocarbon raw oil increases the rate of dispersion of the atomized hydrocarbons in the gas flow, thereby narrowing the particle size distribution of the carbon black particles finally produced by the reactor. Cocurrent flow of raw hydrocarbons reduces the rate of dispersion, thus increasing the reaction time of the raw materials and increasing the particle size distribution.

In more detail, the carbon black reactor according to the present invention includes a spray nozzle spaced radially inward from the inner wall of the reaction chamber. The denominator nozzle directs the spray of oil along a path that is generally coaxial with the longitudinal axis of the reaction chamber. This spray oil is directed in the counter-flow direction, i.e. upstream to the hot gas flow approaching through the reaction chamber or in the opposite co-current or downstream direction, which spray oil is preferably symmetric about the longitudinal axis. The countercurrent spray thus spreads over the entire front region of the hot gas flow through the reaction chamber, thereby increasing the extent to which the front cross section of the gas flow is occupied by the spray oil. Therefore, the reaction time of the raw materials is reduced and the resulting tint of carbon black is increased. In comparison with countercurrent, cocurrent oil spraying generally spreads less than the entire front region of the hot gas flow, increasing the reaction time of the raw materials. The reactor according to the invention can thus have a circular cross section which is auxiliary to the spraying of oil in the reaction chamber, without the disadvantages associated with radially spraying oil into the circular cross section reactor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring first to Figure 1, an axial carbon black reactor is shown at approximately 10. This reactor 10 includes a combustion chamber 11 containing an appropriate combustion fuel source at the fuel inlet 12 and an air source at the inlet 13 that aids combustion in the combustion chamber. The resulting hot gases formed by fuel combustion in the combustion chamber 11 pass through a converging zone 16 which leads to a reaction chamber having a cylindrical neck 17. The outlet end of the neck portion 17 is connected to a reaction chamber 18 having a generally increased diameter as compared to the neck portion, where pyrolysis of feedstock oil occurs to produce a carbon black product.

A certain amount of raw oil is introduced into the reactor neck 17 by a spray nozzle 22 provided in the neck 17. The spray nozzles 22 are generally coaxial with the longitudinal centerline or longitudinal axis of the neck 17 and the entire reactor 10. Although not shown here, this spray nozzle 22 is connected to an oil supply line 23 which receives raw material oil from a suitable source known to those skilled in the art. The spray nozzles 22 are arranged to direct the spraying oil in the counterflow direction in the neck 17, ie upstream facing the hot gas flowing into the neck from the converging portion of the reactor.

The neck 17 of the reactor 10 is shown in great detail in FIG. 3. The neck 17 comprises a pair of concentric fire resistant linings 26 and has an inner wall 27 which is preferably generally circular in cross section as shown in FIG. The spray nozzles 22 are generally installed coaxially with the longitudinal center of the neck 17 and are spaced at equal intervals from the inner wall around the entire circumference of the inner wall 27.

In operation of the reactor 10, as is known to those skilled in the art, hot gases flow generally axially from the chlorine chamber 11 toward the neck 17. The raw oil is pulled into the pump through the feed pipe 23 and exits the nozzle in the counterflow direction with respect to the hot gas, creating a symmetric oil spray form 28 along the longitudinal axis of the neck 17. Therefore, this spray form 28 is generally over the entire cross section of the hot gas flow through the neck, increasing the rapid mixing of the spray oil with the hot gas flow. This rapid mixing provides the resulting short flame with very narrow particle size distributions for the same surface activity and structure of the carbon particles, ie producing carbon particles with higher tints. The symmetric spray form 28 can be adjusted to minimize or avoid contact with the inner wall 27 at all locations around the circumference of the neck, such that thermal shock of the spray material in contact with the relatively hot inner wall. This reduces or eliminates reactor grit that normally occurs.

A test axial flow reactor with an axial countercurrent oil sprayer according to the invention was constructed and operated. The results of this test reactor are shown in the following table, where the ″ normal ″ column is installed flat on the refractory inner wall and has a conventional axial flow reactor with radial oil atomizers that direct spray oil radially inward from the inner wall to the reactor axis. Indicates normal operation. The right column shows the data by the operation of the test reactor constructed in accordance with the present invention.

The results showed that the tint, a measure of particle size distribution, was increased by five units. This reflects that the particle size distribution is narrowed by calculating the tint residuals by methods known to those skilled in the art. The tint residual is 0 for normal reactors and +4 for test reactors. The larger the number, the narrower the particle size distribution.

CTAB (measurement of particle size) values and particle structure (expressed as DBP absorption) remained essentially constant.

Carbon black particles produced by the two reactors were measured by electron microscopy. As shown in the heterogeneity index (HI), the particles produced by the normal reactor have a larger surface area, but the particles produced by the test reactor have a narrower particle size distribution. As the heterogeneity index approaches 1, the distribution narrows.

The oil supply pipe 23 may require special equipment to prevent oil deposits in the pipe. This is accomplished by using an air covered tube with spray oil and a series of small holes in a row to form an air film around the tube, as shown in FIGS. The air membrane allows the droplets to deviate around the tube, preventing oil deposits that might otherwise cause coking in the reactor. The oil supply pipe 23 includes an oil supply pipe 32 arranged concentrically on the inside of the air pipe 33. The oil supply pipe 32 accommodates an appropriate amount of raw oil as described above and supplies this oil to the spray nozzle 22. The outer air line 33 is connected to a suitable air source under pressure. Many outlet holes 34 are formed in the side 35 of the air tube 33 that encounters the hot gas flow moving past the reactor neck 17. Air entering the sealed air duct 3 3 near the atomizer nozzle 22 exits through the outlet holes 34. This exhaust air encounters a hot gas approaching the reactor neck and is deflected around the outside of the air line, returning to form an air film 37 flowing around the air line near the spray oil 28 exiting the nozzle 22. . This air membrane 37 allows oil droplets to escape around the oil tube 23 and prevents oil from hitting the tube, thereby reducing or eliminating oil deposits that may otherwise result in coking in the reactor. The outlet holes 34 in the air pipe 35 are shown as small round holes in FIG. 6, but it is also possible for the outlets or the elongated slots to be arranged in place of such outlet holes.

4 shows another embodiment of the present invention for a raw material flowing in a direction corresponding to the hot gas flow direction through the neck 17 of the reaction chamber. Here, the spray nozzle corrected by reference numeral 22a is rotated by 180 ° in the neck 17, to generate spray oil 28a downstream from the neck coaxially to the longitudinal axis of the neck.

流) 가스 흐름의 결과 분무오일(28a)의 분산이 감소되며, 그리하여 그 분무오일은 가스 흐름의 전체 앞쪽지역 보다는 대체로 덜 퍼진다. 결과적으로, 원료오일이 가스유동과 혼합하며 제1도 내지 제3도에 도시된 역류의 실시예에서 보다는 더 느린 반응이 수행되어서, 비교적 큰 입자 크기 분포를 가지는 카본블랙 입자들을 생성시킨다. 제1도 내지 제3도의 실시예와 제4도의 실시예와 제4도의 실시예는 단지 원료 분무 노즐(22 및 22a)의 방향에 있어서 구조적으로 다르며, 그 방향은 단일 반응기내에서 쉽게 바뀔 수 있다.Cocurrent in the neck

As a result of the gas flow, the dispersion of the spray oil 28a is reduced, so that the spray oil generally spreads less than the entire front region of the gas stream. As a result, the raw oil is mixed with the gas flow and a slower reaction is carried out than in the countercurrent examples shown in FIGS. 1 to 3, producing carbon black particles having a relatively large particle size distribution. The embodiment of FIGS. 1 to 3 and the embodiment of FIG. 4 and the embodiment of FIG. 4 are only structurally different in the direction of the raw material spray nozzles 22 and 22a, and the direction can be easily changed in a single reactor. .

Claims (11)

Hot gas source; A reaction chamber having an inlet for receiving a flow of the hot gas and an outlet through which the hot gas flows to leave the reaction chamber; In the carbon black manufacturing apparatus comprising a spray hydrocarbon introduced into the reaction chamber in a counterflow direction generally parallel to the hot gas flow, thereby increasing the dispersion rate of the spray hydrocarbon in the gas flow, the result Means for narrowing the particle size distribution of carbon black particles; Carbon black manufacturing apparatus characterized in that it further comprises. 2. A spray according to claim 1, characterized in that the spray introduction means generates a symmetric spray form coaxial with the longitudinal axis of the reaction chamber, thereby spreading the spray over a generally full cross section of the hot gas flowing past the reaction chamber. Carbon black manufacturing apparatus. The method of claim 1, wherein the reaction chamber is formed by an inner wall and the spray introduction means comprises a spray nozzle generally radially inwardly away from the surface of the reaction chamber, and adapted to receive any amount of oil and to be connected to the spray nozzle. Carbon black manufacturing apparatus characterized in that it further comprises a tube extending inwardly beyond the inner wall. 4. The reaction chamber of claim 3, wherein the inner wall forming the reaction chamber has a circular cross section such that the hot gas flowing through the reaction chamber has a generally circular cross section and the spray nozzle is operated to produce a symmetric spray form and the reaction chamber. Arranged to direct the symmetric countercurrent spray of the oil along a path coaxial with the longitudinal axis of the spray so that the spray generally spreads over the entire cross section of the hot gas flow through the reaction chamber and thereby the gas flow area by the spray oil. Carbon black manufacturing apparatus, characterized in that to increase the occupancy range of the. 4. The apparatus of claim 3, further comprising means associated with the conduit, the means for providing an air jacket around the conduit to prevent oil from depositing in the conduit. . A method of producing carbon black, comprising providing a flow of hot gas through a reaction chamber; Hydrocarbon spray is introduced into the gas flow generally in the counter flow direction with respect to the gas flow, thereby increasing the dispersion rate of the hydrocarbon water spray in the gas flow and narrowing the particle size distribution of the finally produced carbon black particles. step ; Carbon black production method characterized in that it further comprises. 7. The method of claim 6, further comprising: generating a spray form symmetrically coaxially with the longitudinal axis of the hot gas flow, thereby spreading the hydrocarbon spray generally over the entire cross section through the hot gas flowing through the reaction chamber; Carbon black production method characterized in that it further comprises. A combustion chamber operative to generate hot gas flow; A reaction chamber through which the hot gas flows due to an inlet and an outlet receiving the flow of the hot gas; An apparatus for producing a carbon black, comprising: a tube connected to receive a certain amount of raw hydrocarbon and radially extending into the reaction chamber; Means for controlling the particle size distribution of the carbon black particles produced by said hydrocarbon chamber connected to said tube in said reaction chamber and operative to introduce said hydrocarbon feedstock into said reaction chamber in an axial direction generally parallel to said hot gas flow. Carbon black manufacturing apparatus characterized in that it further comprises. The method according to claim 8, wherein the introduction means introduces the hydrocarbon raw material in a generally counterflow direction to the flow of the hot gas passing through the reaction chamber, so that the introduced raw material is spread throughout the entire front region of the hot gas flow, Thereby increasing the dispersion rate of the hydrocarbon in the gas flow and consequently narrowing the particle size distribution of the carbon black. The method according to claim 8, wherein the introduction means introduces the hydrocarbon raw material in a cocurrent direction to the flow of the hot gas passing through the reaction chamber so that the introduced raw material spreads smaller than the entire front region of the hot gas flow, Thereby reducing the dispersion rate of spraying with the carbonized water in the gas flow and increasing the resulting particle size distribution of carbon black. The method of claim 8, wherein the reaction chamber is formed by an inner wall, extending radially beyond the inner wall from the outside of the reactor of the tube, the introduction means is connected to the tube and installed coaxially with the longitudinal axis of the reaction chamber Carbon black manufacturing apparatus comprising a spray nozzle.

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