JPH02232269A - Preparation of carbon black with high efficiency - Google Patents

Abstract

PURPOSE:To obtain with high efficiency and easily a carbon black having required characteristics to cope with various uses by using the same furnace by mixing a high- temp. burnt gas obtd. by burning a mixture of fuel and an O2-contg. gas with a raw material hydrocarbon under a specified condition and reacting the mixture. CONSTITUTION:In the method for preparing a carbon black by using a reaction furnace having the first reaction zone 3 where a gas mixture contg. a fuel and oxygen is burned, the second reaction zone 4 with a constriction where the obtd. high-temp. burning gas is mixed with a raw material hydrocarbon and the mixture is reacted, and the third reaction zone 5 equipped with a cooling water spray 7 for stopping the reaction, the high-temp. burning gas obtd. in the first reaction zone 3 is made into an axial flow flowing in the approximately same direction as the axial direction of the furnace and the axial flow is divided into two or more divided flows having different spouting flow rate and/or spouting gas temp. from each other by means of a plurality of outer burning nozzles 9 with an inlet 8 for the O2-contg. gas and a plurality of inner burning nozzles 11 with an inlet 10 for the O2-contg. gas and the divided flows are introduced into the second reaction zone 4, where the raw material hydrocarbon is introduced from a nozzle 6 in the direction transversing the axial flow of the high-temp. burning gas and they are reacted.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) OBJECTS OF THE INVENTION The present invention provides a furnace process polymer having desirable physical properties for use in applications such as filler materials, reinforcing materials, conductive materials, and colored pigments. This invention relates to a method for manufacturing black with high efficiency.

(Prior art) In the furnace method for producing carton black, oxygen-containing gas and fuel are generally introduced into a cylindrical carton black manufacturing furnace in the axial direction or tangential direction, and the gas is obtained by combustion. 9. While moving the high-temperature combustion gas to the downstream reaction zone, feedstock hydrocarbons are introduced into the high-temperature combustion gas stream to produce carden black, but due to the complexity of the pyrolysis reaction of the feedstock hydrocarbons, it is A car material with the physical and chemical properties of.

In particular, how to efficiently mix, contact, and react the high-temperature combustion gas flow formed in the first reaction zone with the raw material hydrocarbon introduced in the second reaction zone depends on the performance of the produced carden black and the It is considered to be an important requirement that affects efficiency. Conventionally, in order to mix and contact the high-temperature combustion gas and the raw material hydrocarbon in the second reaction zone, the high-temperature combustion gas is generally given a strong swirling motion to increase its kinetic energy, or Efforts have been made to improve the shape of the band diaphragm υ, but no fully satisfactory results have been obtained.

For example, in Japanese Patent Publication No. 55-27112, a hot gas flow is formed that is divided into outward and inward directions from the circumferential direction around the furnace axis, and feedstock hydrocarbons are axially oriented. A method for producing carden black to be supplied is described, but the external hot gas flow introduced in parts is for retention of the furnace wall, which causes a significant decrease in the yield of carbon black. , high turbulence cannot be obtained at the constriction part by dividing the introduction into one plane of the circle from the tangential direction of the furnace axis. In addition, since the raw material supply nozzle is held on the furnace axis, it is necessary to protect the nozzle with a cooling jacket when moving the nozzle to control the physicochemical properties of the produced Kagen black. This causes heat loss, and feeding the raw material from a nozzle installed on the furnace shaft takes time due to radial diffusion of the raw material, making it impossible to perform effective mixing at high speed. A decrease in black yield is unavoidable.

In addition, Japanese Patent Publication No. 55-45581 discloses that combustion air is preheated and heat is recovered by heat exchange with reaction products after quenching, and a part of the preheated air is used to protect the furnace wall. A method for manufacturing car & carbon black is described, which is supplied into the furnace as a split flow for the purpose of the furnace, but the fuel is introduced only at the center of the furnace shaft, and a high-temperature combustion gas flow is generated in the furnace wall flow. Therefore, the formation of a high-temperature turbulent region that can thermally decompose raw material hydrocarbons with high efficiency is insufficient. Moreover, since feedstock hydrocarbons are supplied from a feedstock introduction nozzle held in the high-temperature furnace in the direction of the furnace axis, a cooling jacket is required to protect the nozzle, resulting in extra heat loss and Since the raw materials are introduced from above, it takes time for the raw materials to spread in the radial direction, and effective mixing cannot be performed at high speed, resulting in a decrease in carpon crack yield.

Furthermore, Japanese Patent Application Laid-Open No. 183364/1983 discloses a car engine in which a gas inlet is provided in the tangential direction of the combustion chamber K. A method for producing cargen black is described in which raw materials are introduced in a direction transverse to the gas flow into the throttling section of a combustion rack production furnace and thermally decomposed, but since the high-temperature combustion gas flow is a swirling flow, Since it is not possible to form a sufficient high-temperature turbulent region at the point where the raw material is introduced, carbon can be produced with high efficiency.
Unable to generate rack.

(Problems to be Solved by the Invention) The present invention aims to provide a method for producing carbon black with high efficiency, which can produce carbine black having desired physicochemical properties depending on the intended use. .

(b) Structure of the Invention (Means for Solving the Problems) The method for producing a car pump rack of the present invention is characterized in that the first reaction zone in which a mixture of fuel and oxygen-containing gas is combusted converts the obtained high-temperature combustion gas into a raw material hydrocarbon. In the method K of producing carden black using a reactor having a second reaction zone having a throttling section for mixing and reacting with the reactor, and a third reaction zone having a cooling water spray for stopping the reaction, The high-temperature combustion gas obtained in one reaction zone is made into a trickle flowing in substantially the same direction as the furnace axis, and the axial flow is trapped into two or more split streams having different jet flow velocities and/or jet gas temperatures. This method is characterized in that the raw material hydrocarbon is introduced into two reaction zones, and in the second reaction zone, the raw material hydrocarbon is introduced from a nozzle in a direction transverse to the axial flow of the high-temperature combustion gas.

According to the research conducted by the present inventors, the efficiency of the cargoon black production reaction and its product properties (quality) are determined by
(t
It was found that it strongly depends on three factors: K)m1n and its distribution, and (tK) the ratio of the raw material flow rate passing through the region where rnln exists (Q)tK/Q.

Here, the minimum vortex diameter t of the Koromoko 9 Lof. is avff. in fluid mechanics. It is one of the /IP parameters representing the turbulence characteristic scale derived from theory, and is known per se.

Below, we will explain the contents of the experimental analysis and considerations that led to this finding.

The present inventors conducted various experiments using a carbon black reactor for testing, and as a result, the physicochemical properties of carbon plaque, namely the reactor lower limit particle diameter, structure index, particle size dispersion, and aggregates, were determined. It was found that there is a qualitative relationship between the degree of distribution dispersion, the yield for the raw material, and the geometrical conditions of the reactor as shown below. In the following formula, de is the diameter of the constriction part of the reactor, and θ is the constriction angle]. Le is the distance from the raw material nozzle to the constriction section.

Reactor lower limit particle diameter oe (d6/θ) Coloring power oc (
1/Lc) Particle size distribution dispersion c-c (La) Aggregate distribution dispersion oc (Lc) Particle size distribution dispersion 《(1/yield) Physical interpretation of the phenomenal characteristics obtained here through flow experiments The result of doing this is as follows.

In other words, what about the high temperature combustion gas inside the reactor? Assuming that the degree U is expressed by the average velocity U and the fluctuating velocity U' as U=u+u', the diameter da of the throttle part is the average velocity U of the combustion gas, and the throttle angle θ is the ratio of the throttle part diameter da to the combustion gas average velocity U. For the contraction degree, t, b, the maximum velocity (u) in the cross-sectional velocity distribution, m&e,
Further, the distance Lc from the raw material nozzle to the throttling part has a direct influence on the average residence time τ of the raw material hydrocarbon in the reactor and its degree of dispersion, as shown in the following equations.

(da) ” 1/(u) (θ) −(u)m■ (Le) oc(τ.σ) An increase in the combustion gas average velocity U also causes an increase in the maximum velocity (u)rn■ of the cross-sectional velocity distribution. Because it will be accompanied at the same time, (#
/da) is considered to be related to ('')max. Here, considering that the basic physical properties of Cargen Black depend on the absolute value of the minute particle size, (.).,E will be considered in relation to the fine structure of the turbulent flow formed by the combustion gas flow.According to turbulence theory, the increase in velocity is proportional to the increase in the fluctuating velocity, so the following equation holds true.

(u)max"(")max The fluctuation speed has a relationship with Kolomogorov's minimum vortex diameter tk as shown in the following equation.

tkx 4 (t0 - u'/v) Here, t0 represents the length corresponding to the diameter of the reactor at that position.

Therefore, the maximum fluctuating velocity (u' moat.

(tk) mln-to (to ” (”) wax/ν
) h, that is, the parameter (θ/d e ) is presumed to indicate the tendency of vortices to become finer and that fine vortices are essential for the formation and development of aggregates ● Reactor lower limit particle size QC (Z k) m 1n Next, the distance La from the raw material nozzle to the drawing section will be considered. Since an increase in Lo increases the passage distance of the raw material in the reactor and the diffusion in the radial direction, it is thought that both the average residence time τ of the raw material in the reactor and its degree of dispersion σ increase. Therefore, as a result of conducting a model experiment, the following relationship was obtained.

(f) − (σ) Therefore, the particle size distribution dispersion is the average residence time of the raw material in the reactor τ
It can be seen that it is proportional to the degree of dispersion σ.

Since the quality of carbon black is better as the degree of dispersion σ is smaller, a decrease in σ can be realized by shortening Le and decreasing τ.

However, as can be seen from the fact that the pyrolysis reaction stop position is now a control target for quality adjustment, the improvement of σ is
It is considered that the process should originally be carried out under conditions where the residence time τ is constant.

A small dispersion degree σ of residence time means that the amount of raw material supplied at a certain time is large! If we consider that this means that the cargo has passed through the reactor through the same process, the quality of the cargoon black is determined by the minimum vortex diameter (tK) m1n that is formed along its path, and therefore the various dispersions are small. car?
A sample rack is generated.

Coloring power oe (1/σ)? Size distribution dispersity Cx-(σ) Aggregate distribution dispersity X(σ) Further, the relationship between particle size distribution dispersity oC1/(yield) indicates that the yield improves as the dispersion decreases. This is due to the reduction in variance within that path, which is smaller (
tK) ■Ratio of raw material flow rate passing through one region (Q)t, n
, , it can be estimated that n/Q increases. It is presumed that the following formula holds true.

(6) ” 1/((Q)t, /Q) Based on the above considerations, in order to improve the yield, the flow rate ratio (Q) of the raw material passing through the (tK)mln region in the reactor must be
It is important to increase tK min/Q.

Cargen Black Yield ” (Q)tx min/
Q: In order to verify the results of this study, we conducted an experiment in which only the flow rate of high-temperature combustion gas was varied while keeping all other conditions constant. This is because by increasing the flow rate of high-temperature combustion gas, changes in each of the following parameters are expected.

(tK) Increase in mln (σ) decrease? q) Increase in zi rn1n/Q And as a result of investigating the changes in the quality and yield of car pump racks with respect to the flow rate of high-temperature combustion gas, it was found that as the flow rate of combustion gas increased, high quality and efficiency increased at the same time. It has been confirmed that this can be achieved.

In other words, the conventional vague understanding of "increasing the mixing contact action in the reaction section" means that the specific K is ■ (tK)! ni ■ Minimize the o value ■ CZ.
t,,. Form locally on the central axis of the reactor away from the inner wall surface of the reactor■ (tC)mi■ So that the raw material flow rate (Q)t emlゎ/Q that passes through the region of existence is maximized. The purpose is to satisfy the condition of spraying and supplying the raw material.

The present invention has been made based on the above findings.
That is, in the present invention, first, an axial flow type turbulence generation method is adopted. In other words, in order to minimize the value of (tK)n1ln and to form (tIc) so that it is localized on the central axis of the reactor away from the inner wall surface of the reactor, a large disturbance is required in that area. become. Therefore, in the present invention, the high-temperature combustion gas flow is made into a trickle flowing in substantially the same direction as the furnace axis direction, and the trickle is divided into two or more divided streams having different jetting flow velocities and/or jetting temperatures. It was designed to be able to control the occurrence of extremely large disturbances in the area. Moreover, since the trickle has no swirling velocity component, its maximum axial velocity can be naturally localized on the furnace axis. In addition, the value of (tK)mln and the position of its existence region can be controlled by appropriately changing the jet velocity and jet angle of multiple high-temperature combustion gas jets, so that the generated carbon The physical properties of black can be easily controlled by K.

In addition, in order to maximize the raw material flow rate (Q)t, , , , /Q passing through the localized region of K'mln, it is necessary to flow the raw material rehydrated hydrogen along the furnace axis. It is necessary to introduce the raw materials in this manner, and the two methods of introducing raw materials to achieve this are, firstly, through a nozzle held on the furnace axis, and secondly, from the side perpendicular to the furnace axis. There are two methods, and the latter method is adopted in the present invention.The reason is as follows.

That is, in the former introduction method, the introduced raw material is (t,
)m, the material is diffused in the radial direction before reaching the region where yu exist, and as a result, not only does the raw material flow rate (Q)txm1n/Q that passes through the (tK)m region decrease, but also the high temperature A cooling jacket is required to protect the feed nozzle held within the furnace, resulting in additional heat loss.

On the other hand, in the latter Manpo K adopted in the present invention,
Radial diffusion of the feedstock is minimized by the orthogonal hot combustion gases at high flow rates, allowing high speed mixing in a narrow area without spatial spread. As a result, the ratio (Q) tKmin/Q of the retentate flow rate passing through the (td) ml4 region is increased, and no nozzle cooling jacket is required, and heat loss can be prevented accordingly.

In this way, by introducing the raw material from the side in a direction that crosses the axial flow of high-temperature combustion gas, the proportion of the raw material flow rate passing through the region where (t,)m, As a result, it is possible to dramatically improve the carburetor yield per furnace volume.

In short, in the present invention, (1) the swirling velocity component can be eliminated by making the high-temperature combustion gas flow a trickle;
By efficiently thermally decomposing raw material hydrocarbons to produce carden black with a high yield, it becomes possible to control the physical and chemical properties of the produced carbon plaque, such as coloring power and specific surface area. Using this method, various card/blacks having desired physical properties for various uses can be easily produced. Furthermore, since the raw material hydrocarbon is introduced in a direction transverse to the axial flow, the radial dispersion of the raw material can be minimized, resulting in a carton with a sharp particle size distribution and high coloring power. Black can be obtained in a high yield, and heat loss due to the jacket for cooling the raw material nozzle can be eliminated.

The high-temperature combustion gas in the present invention is obtained by combusting gaseous or liquid fuel mixed with air, oxygen or a mixture thereof in the first reaction zone. The fuels include gaseous fuels such as hydrogen, carbon monoxide, methane, natural gas, coal gas, and petroleum gas, petroleum liquid fuels such as kerosene, gasoline, and heavy oil, creosote oil, naphthalene oil, and Coal-based fuels such as acid oil are preferably used.

In addition, the raw material hydrocarbons in the present invention include aromatic hydrocarbons such as pe/zene, toluene, xylene, naphthalene, and a/thracene, coal-based hydrocarbons such as creonate oil and calgenic acid oil, ethylene heavy end oil, Petroleum heavy oil such as FCC oil, acetylenically unsaturated hydrocarbons,
Ethylene hydrocarbons, aliphatic hydrocarbons such as hexane, and the like are preferably used.

The attached FIG. 1 is a schematic vertical cross-sectional view of the main parts of an example of a two-carb manufacturing furnace used in carrying out the manufacturing method of the present invention, and 1 in FIG. 2 is a schematic sectional view taken along line AA in FIG. 2, 2 in FIG. 2 is a schematic sectional view taken along line BB in FIG. 1, and 3 in FIG. Moreover, 1 to 4 in FIG. 3 are cross-sectional schematic diagrams of the first reaction zone showing an example of a division mode of the high-temperature combustion gas axial flow. Furthermore, FIG. 4 is a schematic longitudinal sectional view of the second reaction zone for explaining the raw material nozzle, and FIG. 5 is an explanatory diagram of the direction in which the raw material hydrocarbon is introduced.

A practical embodiment of the present invention will be explained in which casen black is produced using the production furnace shown in FIG. 1 and the like. 1 in FIGS. 1 and 2, the combustion nozzle is provided with four combustion nozzles 9 having an oxygen-containing gas inlet 8 as an outer nozzle on the outside, and these four outer nozzles f'! ．． It is possible to operate all four at once. Further, K4 inner combustion nozzles 11 each having an oxygen-containing gas inlet 10 are provided as inner combustion nozzles, and these four inner nozzles can be operated all at once. These combustion nozzles 9 and 11 can be moved forward and backward into the furnace. The high-temperature combustion gas combusted using these inner and outer combustion nozzles becomes a gas flow in which the ejection flow velocity and/or ejection gas temperature differs between the inner and outer sides, that is, as shown in 1 in Fig. 3. The inner high temperature gas flow (0) and the outer high temperature gas flow (b) are divided into two streams, which become an axial flow flowing in almost the same direction as the furnace axis and are introduced from the first reaction zone to the second reaction zone. be done.

Note that 2 in FIG. 3, 3 in FIG. 3, and 4 in FIG. 3 show other examples of how the divided flow is divided. These various embodiments vary depending on the type of recycled hydrogen and the physicochemical properties of the carbon black to be produced (i.e., the desired type and use of carbon black).
K is selected as appropriate, and the ejection flow velocity and ejection gas temperature of the divided flow are also selected accordingly.

In the axial flow of high-temperature combustion gas introduced into the second reaction zone, cumulative hydrocarbons are introduced through the raw material supply nozzle 6, and the direction of introduction thereof is in a direction that crosses the flow of high-temperature combustion gas as a trickle. However, the introduction direction does not necessarily have to be perpendicular to the axial flow, and as shown in FIG.
In contrast, an appropriate angle within the range of 20'' to 150° can be selected.

Further, the medical supply nozzle 6 may be provided symmetrically, as shown at 2 in FIG. 2, or may be provided only on one side, as shown at 3 in FIG. M2. , and the nozzles 6 are provided at different positions of the second reaction zone 4 as shown in FIG. , 61 alone, 6, alone, 68 alone, 61 and 6, together, 6, and 6. or 6, and 6. It can be used in various ways in combination with. Generally, it is desirable to install three or more sets of raw material supply nozzles 6 at different positions within the second reaction zone, and it is desirable that the number of raw material supply nozzles 6 in one set is plural. The raw material nozzle 6 can be moved forward and backward into the furnace.

The carbon plaque-containing thermal suspension stream generated in the M2 reaction zone 4 was then introduced into the third reaction zone 5, where it was rapidly cooled by water spouted from a water sugley 7 for stopping the reaction at an arbitrary position to stop the reaction. after. Car after passing through collection devices such as cyclones and bag filters? black is collected.

(Examples, etc.) The following is a more detailed explanation of Examples and Comparative Examples.

The carton black produced in these Examples and Comparative Examples was tested according to Method K below.

(2) Coloring power The temperature-dried sample and zinc white are accurately weighed at 20 Da and 2 I, respectively, and kneaded with 2.7 d of mineral oil using an evaporator and an automatic foamer to prepare a sample yeast.

This paste is visually compared with a standard paste prepared in a similar manner and judged.

■ Particle size sample Kagen black was poured into chloroform and 20
After irradiation with 0 kHz ultrasonic waves for 20 minutes and dispersion, the dispersed sample is fixed on a support membrane, observed and photographed with an electron microscope, and the particle diameter is calculated by area average and expressed in mμ.

■ Nitrogen adsorption specific surface area Low-temperature nitrogen adsorption device (Quan manufactured by Quantachrome, USA
tasorb Surface Area Analysis
The amount of nitrogen adsorbed and adsorbed by Cargen Black was measured using a low-temperature nitrogen adsorption method, and the value was calculated using the BET l-point method and expressed in m/I.

(2) Zoptylphthalate oil absorption measured in accordance with JIS K6221-1982. Hereinafter, referred to as "rDBP oil absorption" 56 ■ Compressed dibutyl 7 tallate oil absorption A specified amount of constant temperature dry sample was weighed, 1 6 8 7 kg/c
Hold at m2 for 5 seconds to compress the sample. The sample is then completely passed through a 16 Messier sieve.

After repeating this operation 4 times, JIS K6'22L
- Measure the zoptylphthalate oil absorption (hereinafter referred to as rDBP a oil amount) in accordance with 1982.

■Iodine adsorption amount Measured in accordance with JXB K6221-1982.

Examples 1 to 4 A carbon black manufacturing furnace having the structure shown in Fig. 1, 1 in Fig. 2, and 2 in Fig. 2 was used. The reaction was carried out using the following manufacturing conditions, the reaction was stopped by spraying cooling water, and the carbon black was recovered using a cyclone and a bag filter. The physical properties of each carbon plaque obtained were as shown in Table 1.

The outline of the carnon black production furnace used, the fuel used, and the raw material hydrocarbons were as follows.

■ Length of car pump rack production furnace first reaction zone 3: 0.65 ml Inner diameter: 0.45 m Number of outer combustion nozzles 9: 4 Number of inner combustion nozzles 11: 4 Length of second reaction zone 4
1.15m Inner diameter of aperture part 0
．． 07m Number of raw material supply nozzles Total 2 members Takashi Rokkura■ Fuel type Coal gas composition (capacity) CO■ 2.0 020.5 Cn% 3. O Co 6. 6H254.
O CM428.7 N25. 2 ■ Type of raw material Specific gravity Carbon content (weight i%) Hydrogen content (weight%) Viscosity (50°C) Comparative Examples 1 to 2 High-temperature combustion gas is introduced into the first reaction zone from 20,000 directions in a tangential flow, and the raw material hydrocarbon Carbon plaque was produced under the conditions shown in Section 1 using a known Kagenblack production furnace in which carbon was introduced from all directions along the furnace axis through a burner equipped with a cooling jacket. The results were as shown in Table 1.

Comparative Example 3 Creonut oil 1.100 90.5 6.3 1 0 cps The air amount and fuel consumption for the outer and inner combustion nozzles in Example 1 were changed as shown in Table 1, and the outer combustion gas Car/black was manufactured in the same manner as in Example 1, except that the jet flow velocity and the inner combustion jet flow velocity were made to be substantially the same, and the outer and inner combustion gas jet flows were jetted in parallel. did. The results were as shown in Table 1.

Notes to Table 1 *1: Expressed as the ratio of (air amount and fuel consumption of the inner combustion nozzle) / (air consumption and fuel consumption of the outer combustion nozzle).

The jet flow velocity was determined by calculating the average flow in front of the jet nozzle.

As is clear from the results in Table 1, when the embodiments of the present invention are used, carbon blacks having various characteristics can be produced using the same production furnace, and *yield per feedstock oil can be produced using the same production furnace. It was possible to obtain Kagen black with a high particle size and a small particle size.

(c) Effects of the Invention According to the production method of the present invention, it is possible to produce with high efficiency an excellent furnace black that has desired physical properties depending on the intended use.

[Brief explanation of the drawing]

Figure 1 is a schematic longitudinal sectional view of the main part of the car black cracking furnace used in the production method of the present invention. is $
1 is a schematic view of the B-BIFr plane, and 3 of FIG. 2 is a schematic cross-sectional view of C-C in FIG. 1. 1 to 4 in FIG. 3 are cross-sectional views of the first reaction zone showing an example of the divided flow of the axial flow, FIG. The figure is an explanatory diagram of the raw material introduction direction. Each symbol in the figure indicates the following. 1... Furnace body 2... Throttle section of second reaction zone 3... First reaction zone 4... Second reaction zone 5... Third reaction zone 6... Raw material hydrocarbon supply nozzle 7... Water spray nozzle for reaction termination 8... Oxygen-containing gas inlet for outer combustion nozzle 9...
・Outer combustion nozzle 10...Oxygen-containing gas inlet 11 for inner combustion nozzle
...Inner combustion nozzle ~2...High-temperature combustion gas split flow Figure 3-1 Figure 3-2

Claims (1)

[Claims] (1) A first reaction zone in which a fuel and oxygen-containing gas mixture is combusted, a second reaction zone having a constriction part in which the obtained high-temperature combustion gas is mixed with raw material hydrocarbons and reacted, and a cooling water spray for reaction termination. In a method for producing carbon black using a reactor having a third reaction zone,
The high-temperature combustion gas obtained in the first reaction zone is made into an axial flow that flows in substantially the same direction as the furnace axis, and the axial flow is divided into two or more divided flows having different jetting flow velocities and/or jetting gas temperatures. and introducing the raw material hydrocarbon into a second reaction zone through a nozzle in a direction transverse to the axial flow of the high-temperature combustion gas.