KR950011799B1 - Process for the manufacture of carbon black - Google Patents

Abstract

No content.

Description

Carbon Black Manufacturing Method

The accompanying drawings are schematic cross-sectional views of one embodiment of a carbon black production reactor used in the present invention.

* Explanation of symbols for main parts of the drawings

1: Supply duct 2: Wind box

3: combustion burner 4: primary combustion chamber

5: 1st fuel oil nozzle 6: 2nd fuel oil nozzle

7: airway type combustion chamber 9: narrowing reaction chamber

10: raw material oil nozzle 12: cooler

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for producing carbon black having a large specific surface area and a small homogeneous aggregate structure, and more particularly to a method for producing carbon black effective for imparting high wear resistance required for large tires.

In recent years, in addition to improving the performance of automobiles, the performance of tires is also strictly required. In particular, there is a demand for supplying carbon black which can impart high wear resistance to timer rubbers for heavy-duty vehicles such as trucks and buses that require harsh driving regardless of the road surface.

Small particle carbon blacks, such as N-234 or N-110, which have a large specific surface area and high coloring power have been known to be effective for this purpose. It is common knowledge in the art that the production of this kind of carbon black requires high-speed swirling combustion gases, pyrolysis of raw hydrocarbons at high temperatures, and the improvement of the linear velocity of the gas flow at the injection position of the raw hydrocarbons. Suggestions for this purpose include:

U.S. Patent No. 2851337 discloses a carbon black production process comprising the use of a venturi tubular carbon black reactor equipped with a narrowing throat, which inserts a circular nozzle into the airway in the usual direction. And the linear velocity of the combustion gas at the insertion position is set to 150 ft / sec (46 m / sec), preferably 200 ft / sec (61 m / sec) to 4000 (ft / sec) (1219 m / sec). Flame temperature: 2000 to 3000 ° F. (1093 to 1649 ° C.) to improve contact with the raw materials of the combustion gas. The venturi tubular carbon black reactor has a forward convergence angle of 11 ° C or less, a rear enlargement angle of 4 ° or less, four raw material nozzles inserted into the throat at intervals of 90 °, and the raw material oil is atomized. It is atomized by the method. U.S. Patent No. 3490867 discloses an ISAF, SAF by allowing two systems of combustion chambers provided at the head of the reactor to be gathered at a point at the inlet of the wide reactor located before the solated airway, and by controlling the injection position of the reactor at the concentrated position. A venturi tubular carbon block reactor is disclosed that produces carbon black of particulates such as -HS or SAF-LM.

According to the description of the patent, in this case, the carbon black has a linear velocity of 300 to 1600 ft / sec (91 to 792 m / sec), preferably 450 to 1600 ft / sec (137 to 487 m / sec) at the narrowing throat portion. The combustion gas and the combustion gas at the outlet of the throat after the injection of the raw materials are produced under heat distribution conditions in a reactor at a temperature of 3500 to 2900 ° F. (1929 to 1593 ° C.) and 3200 to 2600 ° F. (1760 to 1427 ° C.).

US Pat. No. 3922335 discloses a method in which a liquid raw material is injected into the narrowing portion of a cylindrical reactor from its outer periphery in a plurality of forms of individual coherent flows, in fact, into the combustion gas flow. In this method, it is required that the combustion gas linear velocity at the raw material injection position is at least Mach 0.35, preferably 0.4 to 0.8.

The fuel penetrates into the combustion gas to a depth equivalent to 15 to 50% of the diameter of the narrowing portion for the purpose of achieving sufficient contact with the combustion gas and preventing contact with the reactor walls (preventing coke deposition).

US Pat. No. 39,520, in particular, discloses a method of introducing a raw material into a carbon black reactor which is partly narrowed inner cylinder airway type or venturi tube type in order to produce carbon black having a largely developed structure. According to the description of this patent, the introduction point of the auxiliary hydrocarbon is located in the zone of 2 to 60% of the distance from the first stage hydrocarbon introduction point to the cooling device, and the carbon content of the auxiliary hydrocarbon is about 2 to based on the total carbon content. 60% by weight, raw hydrocarbon is radially introduced into the combustion gas of the airway part from the surroundings of the reactor to penetrate into the combustion gas to such a depth that the hydrocarbons introduced through the target position do not collide with each other, and the raw hydrocarbon is injected. The gas flow velocity in the reactor is at least 150 ft / sec (46 m / sec), preferably 50 ft / sec (152 m / sec). Abrasion resistance superior to that of N-110 (SAF), which is commercially available, cannot be obtained by a simple increase in specific surface area and coloring power, and the aggregate structure of the particles constituting the carbon black is as small as possible. It is necessary to equalize its distribution. However, reduction in aggregate size and uniformity of aggregate distribution are not satisfactorily achieved with prior art devices, which mainly consist of turning the combustion gas at high speed and increasing the linear velocity of the narrowing airway portion. For this reason, it is difficult to obtain a significant improvement without provision of additional devices. Accordingly, a first object of the present invention is to provide a method for producing carbon black having a large specific surface area and a fine and uniform aggregate structure.

A second object of the present invention is to provide a method for producing carbon black, which can impart high wear resistance of large tires for large vehicles such as trucks and buses, in particular, to which tires are subjected to high loads.

The object of the present invention described above is a primary combustion process for burning primary fuel oil in a sight combustion chamber, a secondary combustion process for completing combustion by introducing a secondary fuel into a starter type combustion chamber having a narrow front end side, and completing combustion. The reaction process consists of a narrow reaction chamber which introduces raw material oil into a combustion gas flow, and the reaction completion process of quenching the gas which mixes carbon black produced | generated by the reaction process to the rear reaction chamber of a sight, The said secondary combustion process is an airway In the combustion chamber, the combustion gas flow generated in the primary combustion process is accelerated at a linear velocity of at least 100 m / sec, and the secondary fuel oil is introduced into the accelerated combustion gas flow at a right angle to the combustion gas shaft to complete the combustion. The reaction step comprises a plurality of raw material nozzles for atomizing the raw material oil made of heavy hydrocarbon oil with oxidizing gas. A narrow carbon reaction chamber is disposed on the main wall, and is sprayed toward a high velocity combustion gas flow in a direction orthogonal to the atomized raw material oil mill, and rapidly cooled in the light reaction chamber to complete the reaction. do.

Now, with reference to the accompanying drawings will be described a carbon black manufacturing method according to the present invention.

The carbon black production reactor used in the present invention is divided into lengths of a primary combustion step, a secondary combustion step, a reaction step, and a reaction completion step.

The primary combustion stage consists of a windbox 2 having a tangential combustion air supply duct 1 provided at the head of the reactor, and a primary combustion chamber provided with a combustion burner 3. The combustion burner 3 has, for example, a primary fuel oil nozzle 5 having an ejection hole at the inlet of the primary combustion chamber 4 as an outer cylinder and a secondary ejection stage extending as a secondary combustion step as an inner cylinder. A double cylindrical structure consisting of a secondary fuel oil nozzle 6 which is present is used, and in the primary combustion step, a primary combustion gas flow is formed by primary fuel oil ejected through the primary fuel oil nozzle 5.

The secondary combustion stage consists of a throat-shaped combustion chamber 7 extending at a small inclination angle from the outlet of the primary combustion stage described above.

In this step, the secondary fuel oil is ejected from the secondary fuel oil nozzle 6 to form a complete combustion gas flow.

By ejecting the secondary fuel oil, the secondary fuel oil is led into the reactor in the axial direction of the reactor from the end of the secondary fuel oil nozzle 6. Instead, it is also possible to eject the secondary fuel oil in a direction perpendicular to the axis of the reactor via one provided secondary fuel oil orifices 8 in a plurality of stages. The secondary fuel oil can be carried out on one side or on both sides of the reactor in the axial or perpendicular direction.

An important prerequisite for the secondary combustion stage is that the linear velocity of the primary combustion gas at the secondary fuel oil introduction must be at least 100 m / sec.

Satisfying these requirements reduces heat radiation outside the reactor system, so that a complete combustion gas with hot and even heat bubbling can be formed around the raw material feed zone in the furnace. However, when the linear velocity of the primary flue gas flow is 100 m / sec or less, the heat radiation is increased outside the reactor apparatus so that the temperature distribution of the complete flue gas is not uniform.

Hydrocarbons having a specific gravity (15.4 ° C.) of 1.0 or less and an initial flow point of 140 ° C. or less are suitable as fuel oils used in the first secondary combustion stage.

The feedstock used in the reaction stage is generally high boiling hydrocarbon oil, which is usually used for production on carbon black.

The reaction step consists of injecting the raw material into the complete combustion gas flow formed in the secondary combustion step, thereby forming a carbon black-containing gas flow formed by pyrolysis of the raw material.

In the narrow reaction chamber 9 having a diameter substantially the same as the diameter of the outlet of the throat-shaped combustion chamber 7, the complete combustion gas flow becomes the highest temperature and its temperature distribution becomes uniform.

The raw material is introduced into the reactor radially through a plurality of raw material nozzles 10 (although one nozzle is shown in the figure) provided in a plane perpendicular to the reactor axis in the vicinity of the complete combustion gas flow. A nozzle having an external mixing device is used as the raw material nozzle 10, and the raw oil is introduced into the reactor in the state sprayed by the oxidizing gas.

Oxidized gas is preferably air of oxygen concentration of 21 to 40%. The reason is that when the oxygen concentration is 21%, the high temperature and uniform temperature distribution in the target furnace cannot be achieved smoothly. On the other hand, when it exceeds 40%, the target furnace is well oxidized and burned in the furnace. Although high temperature and uniform temperature distributions can be achieved, the melting loss is remarkable, exceeding the fire resistance of the reactor material (usually high purity alumina refractory material).

In the reaction step, when a low boiling point hydrocarbon oil (hereinafter simply referred to as a raw material oil) having the same properties as the raw oil is injected into the reactor as an auxiliary raw material at the same plane as the raw oil injection position, the auxiliary raw material is a secondary combustion gas. It causes a selective combustion reaction with the oxygen components remaining in the furnace, causing the inside of the furnace to sound louder. The reaction completion step consists of sending a carbon black-containing gas flow to the sight rear reaction chamber 11 located at the end of the reactor, and cooling the gas flow by means of the cooler 12. The electric cooler 12 is a spray nozzle for a conventional cooler that sprays cooling water toward the flow direction of the reaction gas.

The carbon black-containing gas formed through the above-described continuous step is then subjected to gas-solid separation in a collecting device consisting of a bag filter (not shown) to provide output.

According to the present invention, the two stages of the first and second combustion stages and the injection of the raw materials into the reaction stage, which are carried out under specific conditions, provide a significantly high temperature and uniform temperature distribution in the furnace from the raw material introduction position to the thermal decomposition point. Enable state to have.

As a result, it is possible to produce carbon black having a large specific surface area and consisting of aggregates having a small mode diameter and uniform distribution.

Moreover, the high temperature and the uniform temperature distribution in the furnace of the narrow reaction chamber 9 are carbons that can give the raw materials high tire wear resistance even when a crude hydrocarbon oil containing a large amount of residue is used as the raw material. Allows conversion to black.

Now, embodiments of the present invention will be compared and described.

The properties of the carbon black produced according to the process of the present invention were measured by the following method.

(1) Oxo adsorption amount:

Calculated by the test method of JIS K 6221-82, carbon black for rubber, corresponding to ASTM D1510-81.

(2) Nitrogen adsorption specific surface area (N ₂ SA):

Calculated by the ASTM D3037-86 "Standard Test Methods of Carbon Black-Surface Area by Nitrogen Adsorption" B method. Nitrogen adsorption specific surface area (N ₂ SA) of IRS (Industry Reference Blacks) # 5 calculated by this method was 80.3 m ² / g.

(3) , ΔDst:

According to JIS K6221 (1975) 6.2.1 Clause A method, carbon black is dried, and a dry carbon black sample is mixed with 20% aqueous ethanol solution containing a small amount of surfactant to prepare 50 mg / l of carbon black spray solution. Then, it is sufficiently dispersed with ultrasonic waves to obtain a sample.

Next, a disk centrifuge device (British Joyes Loeb1 Corp.) was set at a rotational speed of 8000 rpm, 10-20 ml of spin liquid (2% aqueous glycerin solution) was added, and then 1 ml of buffer liquid (ethanol aqueous solution) was injected.

Finally 0.5-1.0 mL of sample is added to the syringe and centrifugation is initiated.

At the same time, the recorder is operated to create a distribution curve of the aggregate stokes diameter. The Stokes diameter of the highest frequency in the distribution curve thus obtained (nm), and the difference between two Stokes diameters at which a frequency of 50% of the maximum frequency is obtained is ΔDst (nm). Of ASTM D-24 Standard Reference Black C-3 (N234), measured by the method described above. And ΔDst were 80 nm and 60 nm, respectively.

(4) DBP oil absorption:

JIN K6221 (1975) "Test Method for Rubber Carbon Black" Measured by Section 6.1.2 Oil Absorption A Method.

(5) 24 MDBP:

According to ASTM M 3493-85a "Standard Test Method for Carbon Black-Dibutyl Phtalate Absorption Number of compressed sampl".

[Examples 1-4] and [Comparatively 1-4]

Carbon black was manufactured using the reactor shown in the accompanying drawings.

In the reactor, the primary combustion chamber 4 is 600 mm in diameter and 600 mm in length. The throat-shaped combustion chamber 7 has an inlet diameter of 250 mm, an outlet diameter of 150 mm and a length of 800 mm. Narrow reaction chamber 9 is 150 mm in diameter and 300 mm in length. The diameter of the inlet of the rear reaction chamber 11 is 150 mm, the diameter of the outlet is 400 mm, and the length of the reverse taper portion gradually expanded toward the downstream side of the reactor is 600 mm. The cooler 12 is provided in the rear part by the rear reaction chamber.

The six spray raw material nozzles 10 are equidistantly provided through the reactor walls so that they are coplanar with each other at right angles to the axis of the reactor. In addition, two nozzles of auxiliary material injection face each other and are provided through the reactor wall in the same plane as the raw material nozzle.

In addition, the blowing hole of the primary fuel oil nozzle was provided in the inlet of the primary combustion chamber 4, while the blowing hole of the tip of the secondary fuel oil nozzle 6 was provided in the center of the throat-shaped combustion chamber 7. As shown in FIG.

Eight kinds of carbon black were produced under the conditions listed in Table 2 using the fuel oil and raw materials of Table 1. It was a low boiling oil such as auxiliary fuel oil injected in the same plane position as the raw material injection position.

The composition of the resulting carbon black is shown in Table 2 in comparison with the production conditions.

TABLE 1

Note: Raw material (B) is a preparation containing high residual carbon.

TABLE 2

(Note) (1): Maximum temperature of gas flow immediately before injection of crude oil. (2): The difference between the highest temperature and the lowest temperature in the common phase.

In Table 2, the carbon blacks of Examples 1 to 4 of the present invention satisfying the requirements have a large specific surface area and an aggregate mode diameter per maintenance surface area. It is evident that this comparative example is smaller than that and its distribution width ΔDst has such a highly balanced characteristic. Furthermore, improved observation of the primary structure 24M 4DBP is obtained. In particular, it is noteworthy that excellent properties were achieved in the embodiment 3 in which the crude raw material was used. In contrast, in the comparative example where no secondary fuel oil was used, Increased and its distribution ΔDst widened.

As will be apparent from the above description, the production process of carbon black according to the present invention enables the production of carbon black having a small mode diameter and a uniform mode diameter distribution while maintaining a large specific surface area. Moreover, a high residual carbon-containing crude raw material can be used to produce a product of the above-described characteristics without any interference in the reactor, which makes the present invention very useful from an industrial standpoint.

Therefore, the present invention is useful for the use of tire tread production, such as truck buses, which need to impart high wear resistance to the compounded rubber.

Claims (3)

Primary combustion process to burn primary fuel oil in sight combustion chamber, secondary combustion process to complete combustion by introducing secondary fuel into airway type combustion chamber with narrow longitudinal axis, and raw material oil to complete combustion gas flow. The reaction process consists of a narrow reaction chamber to be introduced, and the reaction completion process of quenching the gas containing carbon black generated in the rear reaction chamber reaction process of the sight, the secondary combustion process is produced in the primary combustion process in the airway type combustion chamber Accelerating one combustion gas stream at a linear velocity of at least 100 m / sec, introducing secondary fuel oil into the accelerated combustion gas stream in a direction perpendicular to the stockpile or the stockpile, thereby completing combustion. A plurality of raw oil nozzles for atomizing the raw material oil made of heavy hydrocarbon oil with an oxidizing gas is disposed on the circumferential wall of the narrow reaction chamber, Sprayed toward a high-speed combustion gas flow in the hwahan raw oil in a direction perpendicular to the nochuk method of producing a carbon black made as to complete the reaction quenched by the photo-reaction chamber. The method of claim 1 wherein the oxidizing gas is 21 to 40% oxygen enriched air. The method for producing carbon black according to claim 1, wherein a low boiling hydrocarbon having the same properties as fuel oil is injected as an auxiliary raw material at the same plane position as the raw material injection position.