JP2000355662A - Production of carbon black - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing carbon black by the oil furnace method giving high production yield and productivity and excellent operational stability. SOLUTION: In the process for producing carbon black which uses a cylindrical reaction furnace having a combustion zone in the furnace nose, a feedstock introduction zone, a reaction zone, and a reaction termination zone which are coaxially arranged and comprises a combustion step of burning a fuel in the combustion zone to form a high temperature combustion gas; a feedstock introduction step of introducing a feedstock of hydrocarbons from the direction at a right angle to a high temperature combustion stream into the feedstock introduction zone; a reaction step of converting the feedstock of the hydrocarbons into carbon black by thermal decomposition reaction in the consecutive reaction zone; and a reaction termination step of quenching the reaction product gas stream to complete the reaction in the reaction termination zone, the feedstock of the hydrocarbons to be introduced in the feedstock introduction step is introduced in an atomized state with oxygen at the position of 20-600 mm on this side of the outlet of the feedstock introduction zone and further, the furnace has a structure in which the inner diameter of the reaction zone is smaller than that of the feedstock introduction zone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an industrially advantageous production method for efficiently producing carbon black with excellent operation stability by an oil furnace method, high production yield and high productivity.

[0002] The basic manufacturing technology of furnace black is to use a reaction furnace in which a cylindrical combustion zone, a reaction zone and a reaction stop zone lined with refractory bricks are coaxially connected, and burn fuel in the combustion zone. A high-temperature combustion gas is generated, the combustion gas stream is guided to a subsequent reaction zone, and the raw hydrocarbon is introduced into the combustion gas stream. The hydrocarbon is converted into carbon black by incomplete combustion and thermal decomposition of the raw hydrocarbon. Then, the reaction is terminated by rapidly cooling the carbon black-containing gas stream in the reaction stop zone, and finally collecting the carbon black in a collecting step.

[0003] In the above process, the process of converting the raw hydrocarbon to carbon black is extremely complicated and has not yet been elucidated in detail. However, in general, a large amount of the raw hydrocarbon is introduced into the high-temperature combustion gas stream. Condensed into fine droplets via a ring-aromatic hydrocarbon or acetylene, and these droplets repeatedly collide and coalesce while dehydrogenating to form nuclei, and then gradually grow to form particle aggregates It is believed that. Therefore, if the temperature of the combustion gas stream is increased, the vaporization and pyrolysis reaction of the raw material hydrocarbons are promoted, and the productivity can be expected to be improved by increasing the amount of introduced raw materials, and the nucleation speed is increased. Is brought. In addition, the greater the degree of disturbance of the gas flow when the raw material hydrocarbon is converted into carbon black, the more the vaporization is promoted, which is advantageous for improving the productivity of carbon black.

For example, when the inner diameter of the reactor is reduced, the surface area inside the furnace for dissipating heat to the outside is also reduced, so that the amount of heat dissipated is reduced. Further, the degree of disturbance of the gas flow is increased, and the vaporization of the raw material is promoted. As a result, the conversion ratio of the raw material hydrocarbon to carbon black, that is, the production yield and the production efficiency can be improved.

However, when the inner diameter of the reactor is reduced, the probability that the mist of the raw material hydrocarbons collide with the inner wall of the furnace before the raw material hydrocarbons are sufficiently vaporized increases, and so-called coke grit is formed to reduce the quality of carbon black. Will be greatly impaired. Further, the coke attached to the inner wall of the furnace gradually grows and accumulates in the furnace, which hinders stable operability and lowers productivity.

[0006] Generally, during the pyrolysis process of the raw material hydrocarbon,
If the concentration of hydrocarbons in the reaction zone is reduced, the production of coke grit can be prevented, but the introduction amount of the raw material hydrocarbons is reduced, so that there is a problem that the productivity is reduced. Therefore, as a method of reducing coke generation while maintaining the productivity of carbon black, for example, Japanese Patent Application Laid-Open No. 1-188412 discloses a method of reducing coke generation by providing an uneven portion on the inner wall of a reaction chamber region of a carbon black reactor. A method is disclosed. This method aims to reduce coke generation while maintaining the quality of carbon black without changing the amount of hydrocarbon feed oil or air introduced, and is not intended to improve productivity or production yield. Absent.

[0007]

Therefore, in order to reduce the coke generation and increase the production amount,
It is advantageous to increase the inner diameter of the reactor, while it is preferable to reduce the inner diameter of the furnace in order to improve the production yield. As described above, increasing the productivity and improving the production yield are contradictory factors in producing carbon black.

In order to solve the above-mentioned problems, the present inventor studied the method of introducing the raw material hydrocarbon into the carbon black reactor and the furnace structure during the pyrolysis reaction. We have developed a production technology that can suppress the generation of coke even if the amount of introduction is increased and that can produce carbon black with a high production yield.

That is, the present invention is based on the above-mentioned results, and an object of the present invention is to provide a method for producing carbon black by an oil furnace method which has a high production yield and a high productivity and is excellent in operation stability. .

[0010]

According to the present invention, there is provided a method for producing carbon black, comprising: a combustion zone on a furnace head, a raw material introduction zone, a reaction zone, and a reaction stop zone coaxially connected. A combustion process in which fuel is burned in a combustion zone using a cylindrical reactor provided to generate high-temperature combustion gas, and a raw material introduction process in which a raw hydrocarbon is introduced from a direction perpendicular to the high-temperature combustion gas flow in a raw material introduction zone. A reaction step of converting the starting hydrocarbon into carbon black by a thermal decomposition reaction in a subsequent reaction zone, and a reaction stop step of quenching the reaction product gas stream in a reaction stop zone to terminate the reaction. In the raw material introduction step, the introduction of the raw material hydrocarbon is performed by atomization with oxygen from a position 20 to 600 mm before the exit of the raw material introduction region, and the inner diameter of the reaction region is smaller than the inner diameter of the raw material introduction region. It characterized in construction that it is a small furnace structure.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic sectional view illustrating a reaction furnace for producing carbon black used in the present invention. The reactor is divided into a combustion zone 1 at the furnace head and a raw material introduction zone 2, a reaction zone 3 and a reaction stop zone 4 downstream thereof, and is coaxially connected therewith. Each part is lined with refractory bricks and cylindrical. Built in structure.

In the combustion zone 1, a combustion chamber is formed as a wide-diameter section in which an oxidant introduction duct 5 such as air and a combustion burner 6 are mounted in a tangential direction and a combustion burner 6 in an axial direction. The raw material introduction area 2 is provided continuously by the parts. A plurality of raw material introduction nozzles 7 having an outer tube for supplying oxygen are provided in the cylindrical raw material introduction region 2 in a direction perpendicular to the furnace axis, that is, in a direction in which the raw material is introduced from a direction perpendicular to the flowing combustion gas flow. Is installed. A cylindrical reaction zone 3 is connected to the downstream outlet end of the raw material introduction zone 2, and the downstream outlet end of the reaction zone 3 is connected to a reaction stop zone 4 whose diameter gradually increases. A quenching water introduction nozzle 8 is mounted in the reaction stop zone 4, and the reaction is terminated by spraying cooling water into a reaction gas stream in which carbon black has been generated. The downstream side of the reaction stop zone 4 is connected to a collection system (not shown).

The production of carbon black includes a combustion process in which fuel is burned in a combustion zone 1 to generate a high-temperature combustion gas, and a feedstock in which a raw hydrocarbon is spray-injected from a direction perpendicular to a high-temperature combustion gas flow flowing down in a feedstock introduction zone 2. The reaction is performed in a continuous process including an introduction step, a reaction step of converting a raw material hydrocarbon into carbon black by a thermal decomposition reaction in a reaction zone 3, and a reaction stop step of quenching a gas stream in a reaction stop zone 4 to terminate the reaction. .

In the combustion step, fuel supplied from a combustion burner 6 mounted in the combustion zone 1 is burned by an oxidant such as air supplied from an oxidant introduction duct 5 to generate a high-temperature combustion gas flow. . As the fuel, methane, natural gas, petroleum-based, or coal-based gaseous or liquid fuel is used.

In the raw material introduction step, the raw material hydrocarbon is introduced into the high-temperature combustion gas flow flowing down the raw material introduction area 2 from a direction perpendicular to the direction. As the raw material hydrocarbon, a coal-based or petroleum-based raw material oil such as creosote oil or ethylene bottom oil, which is commonly used as a raw material for producing carbon black, is applied.

The first feature of the method for producing carbon black of the present invention resides in that the feed hydrocarbon is introduced into the feed zone 2 from a position 20 to 600 mm before the exit of the feed zone 2. That is, the material is introduced from a position where the distance L from the material introduction nozzle 7 shown in FIG. 1 to the downstream exit end of the material introduction area 2 is 20 to 600 mm.

The position L for introducing the starting hydrocarbon is set at 20 to 6
The reason for setting the range to 00 mm is that if L is within 20 mm, the raw material hydrocarbons easily flow into the reaction zone 3 with insufficient gasification. As described later, in the present invention, the inner diameter of the reaction zone 3 is designed to be smaller than the inner diameter of the raw material introduction zone 2. This is because the frequency of generation of coke grit due to collision increases. On the other hand, even if L is introduced from a position exceeding 600 mm, the effect of improving the gasification of the raw material hydrocarbon is small, but rather, the heat loss due to heat dissipation increases, leading to a decrease in production yield and productivity. .

A second feature of the method for producing carbon black of the present invention is that, when the raw material hydrocarbon is introduced into the raw material introduction region 2, it is atomized and introduced with oxygen. Atomization by oxygen partially burns the raw material hydrocarbons rapidly and locally to form a high temperature part, and gasification of the raw material hydrocarbons proceeds rapidly. Can be suppressed from directly colliding with the inner wall of the furnace. The atomization by oxygen includes not only atomization by pure oxygen but also atomization by oxygen-enriched air.

Further, a third feature of the method for producing carbon black of the present invention is that a furnace structure is designed in which the inner diameter of the reaction zone 3 is designed to be smaller than the inner diameter of the raw material introduction zone 2. As described above, the raw hydrocarbon introduced into the raw material introduction zone 2 is rapidly vaporized and flows into the reaction zone 3 in a gasified state, so that the inner diameter of the reaction zone 3 is smaller than the inner diameter of the raw material introduction zone 2. Even if it is designed, the frequency of the mist droplets of the raw material hydrocarbon directly colliding with the inner wall of the reaction zone 3 is extremely low, and the generation of coke grit and the deposition of coke in the furnace are effectively suppressed. By reducing the inner diameter of the reaction furnace, the amount of heat dissipated to the outside in the reaction zone 3 is reduced, and the degree of disturbance of the gas flow is increased. As a result, the conversion of the raw material hydrocarbon into carbon black is improved. Is achieved. The degree of reduction from the inner diameter of the raw material introduction region 2 to the inner diameter of the reaction region 3 depends on the inner diameter D1 of the raw material introduction region 2 and the inner diameter D of the reaction region 3.
It is preferable to design the diameter reduction ratio such that the value of D2 / D1 is about 0.3 to 0.85.

As described above, according to the method for producing carbon black of the present invention, the raw material hydrocarbon is atomized with oxygen and spray-injected from a specific position in the raw material introduction region 2, and the inner diameter of the reaction region 3 is changed to the raw material introduction region. By having a furnace structure designed to be smaller than the inner diameter of No. 2, they function synergistically to increase the amount of raw material hydrocarbons introduced and increase the conversion to carbon black while suppressing the generation of grit coke. Becomes possible.

[0021]

EXAMPLES Examples of the present invention will be described in detail below in comparison with comparative examples.

EXAMPLE A combustion zone 1 having an inner diameter of 600 mm and a length of 1200 mm, an inner diameter of 220 mm
The reactor structure illustrated in FIG. 1 is formed by coaxially connecting a raw material introduction region 2 having a length of 1000 mm and a length of 1000 mm, a reaction region 3 having an inner diameter of 170 mm and a length of 350 mm, and a reaction stop region 4 having a tapered diameter. A reactor was installed. In addition, a raw material introduction nozzle 7 having an outer tube for supplying oxygen is provided in the raw material introduction region 2.
The distance L to the downstream exit end was set at a position of 350 mm. The specific gravity of the fuel (15/4 ° C) 0.90
3 petroleum hydrocarbon oil to feed hydrocarbons (15/4
℃) 1.103 creosote oil was used, and the creosote oil was atomized and introduced with oxygen to produce carbon black.

Comparative Example 1 Carbon black was produced under the same conditions as in the example except that creosote oil was atomized without using oxygen.

Comparative Example 2 Carbon black was produced under the same conditions as in the example except that the installation position L of the raw material introduction nozzle 7 was 10 mm.

Comparative Example 3 Carbon black was produced under the same conditions as in the example except that the installation position L of the material introduction nozzle 7 was 900 mm.

Comparative Example 4 Carbon black was produced under the same conditions as in the example except that the inner diameter of the raw material introduction zone 2 was 170 mm, which was the same as the inner diameter of the reaction zone 3.

Comparative Example 5 Carbon black was produced under the same conditions as in the example except that the inner diameter of the reaction zone 3 was 220 mm which was the same as the inner diameter of the raw material introduction zone 2.

Thus, a soft carbon black having an iodine adsorption amount of 31 to 34 mg / g was produced within a range in which stable production and quality maintenance were possible. The sieve residue, production yield, production amount and the like of the obtained carbon black were measured and shown in Table 1 in comparison with the production conditions.

[0029]

[Table 1]

From the results shown in Table 1, in Comparative Example 1 in which oxygen was not used for atomizing introduction of creosote oil, the amount of creosote oil introduced had to be reduced in order to maintain the quality of carbon black. The production volume was lower than that. The distance L from the material introduction nozzle 7 to the downstream exit end of the material introduction area 2
In Comparative Example 2, which was as short as 10 mm, coke adhered to the inner wall of the reaction zone 3, so that the introduction amount of creosote oil had to be greatly reduced, and the production amount was significantly reduced. On the other hand, L is 900
In Comparative Example 3 having a length of mm, there is sufficient space for gasification of creosote oil, so that creosote oil equivalent to that of the example can be introduced. The amount has also decreased.

In Comparative Example 4 in which the inner diameter of the raw material introduction zone 2 is 170 mm, which is the same as the inner diameter of the reaction zone 3, the reaction zone 3 is the same as in Comparative Example 2.
The amount of coke adhering to the inner wall of the car became remarkable, and the amount of creosote oil introduced was greatly reduced, resulting in a large decrease in production.
On the other hand, the inner diameter of the reaction
In Comparative Example 5 designed to be 0 mm, as in Comparative Example 3, there is sufficient space for gasification of creosote oil, so that the same creosote oil as in the example can be introduced. The production yield was lower and the production amount was lower than in the examples.

[0032]

As described above, according to the method for producing carbon black of the present invention, a raw material hydrocarbon is atomized with oxygen and spray-injected from a specific position in the raw material introduction region 2;
By having a furnace structure in which the inner diameter of the reaction zone 3 is designed to be smaller than the inner diameter of the raw material introduction zone 2, they function synergistically to suppress the generation of grit coke while increasing the amount of raw material hydrocarbon introduced and increasing the carbon black. It is possible to improve the conversion rate to Therefore, while maintaining the quality of carbon black, with high production yield and productivity,
Provided is a method for producing carbon black by an oil furnace method having excellent operation stability.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a reactor applied to a method for producing carbon black of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion area 2 Raw material introduction area 3 Reaction area 4 Reaction stop area 5 Oxidant introduction duct 6 Burner for combustion 7 Material introduction nozzle 8 Water introduction nozzle for quenching

Claims (1)

[Claims] A high-temperature combustion gas is produced by burning a fuel in a combustion zone using a cylindrical reactor in which a combustion zone at a furnace head, a raw material introduction zone, a reaction zone, and a reaction stop zone are coaxially connected. A raw material introduction step in which the raw material hydrocarbon is introduced from a direction perpendicular to the high-temperature combustion gas flow in the raw material introduction area, and a reaction step of converting the raw material hydrocarbon into carbon black by a thermal decomposition reaction in a subsequent reaction area. A reaction stopping step of terminating the reaction by rapidly cooling the reaction product gas stream in the reaction stopping area, wherein the introduction of the raw material hydrocarbon in the raw material introducing step is performed in a range of 20 to 600 mm before the exit of the raw material introducing area. Atomized by oxygen from the position,
A method for producing carbon black, characterized in that the furnace has a furnace structure in which the inner diameter of the reaction zone is smaller than the inner diameter of the raw material introduction zone.