JP2000297227A - Apparatus for producing carbon black and production of carbon black - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus by which operation especially at a higher temperature than 1,800 deg.C can be carried out and carbon black satisfying, e.g. both a higher blackness and better dispersibility than those of conventional carbon black can be produced, a raw material spraying burner and an apparatus for producing the carbon black capable of withstanding the production of the carbon black using a high-temperature gas. SOLUTION: This apparatus for producing carbon black comprises the inner wall surface of a choke part composed of a good heat conductive material having a coating made of a bad heat conductive material in the apparatus for producing the carbon black equipped with a first reactional zone for forming a combustion gas stream, a second reactional zone equipped with the choke part for mixing the resultant combustion gas stream with a raw material hydrocarbon and producing the carbon black and a third reactional zone located on the downstream side of the second reactional zone and capable of terminating the reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of carbon black suitably used for various uses such as a filling material, a reinforcing material, a conductive material, and a color pigment, and an effective production for controlling the physical properties thereof. The present invention relates to an apparatus and a manufacturing method.

[0002]

2. Description of the Related Art Carbon black is widely used as a pigment, a filler, a reinforcing pigment, a weather resistance improving agent, and the like, and its production method is generally such that a furnace shaft is provided in a first reaction zone of a cylindrical carbon black production furnace. While the oxygen-containing gas and the fuel are introduced in the tangential or tangential direction, the high-temperature combustion gas stream obtained by these combustions is successively moved to a second reaction zone provided in the furnace axis direction, while the gas stream is heated. A furnace-type production method is known in which a raw material hydrocarbon is introduced into a reactor to produce carbon black, the remaining hydrocarbon is carbonized in a third reaction zone, and then the reaction gas is rapidly cooled to stop the reaction.

In particular, carbon black used as a colorant in resin colorants, printing inks and paints is required to be excellent in blackness, dispersibility, gloss and coloring power, and is also used as a reinforcing agent for automobile tires. As the carbon black to be used, a material excellent in abrasion resistance and grip properties is mainly required. It is generally said that carbon black having a small primary particle diameter is suitable as carbon black having excellent blackness and coloring power (JP-A-50-68992). Also, such small particle size carbon black is
It is known to exhibit a high degree of wear resistance when used as a tire reinforcement. Further, the distribution of the primary particle diameter also has a significant effect on the rubber properties, particularly on the tire tread rubber composition which is required to have high abrasion resistance, and it is said that the narrower the primary particle diameter distribution is, the more preferable. In general, the smaller the average particle size, the narrower the distribution. However, patents for a method of narrowing the primary particle size distribution have also been disclosed.

[0004]

In order to obtain carbon black having a small particle diameter, it is effective to introduce a raw material hydrocarbon into a high-temperature combustion gas to produce carbon black under high temperature conditions. It is known that
4-14084).

[0005] As a refractory material that can withstand high temperatures as a furnace material in general, it has been proposed to use a refractory material containing chromia calcia and lanthanoid element oxide in high-purity alumina (Japanese Patent Publication No. 4-103670). Gazette).
However, when any of these conventionally proposed refractory materials is brought into contact with a high-velocity gas flow at a temperature of 1800 ° C. or more, the refractory material is significantly damaged and deformed by softening due to high temperature and collision with a high-velocity / high-turbulence gas. The present inventors have found that it is difficult to maintain a shape suitable for carbon black production.

In particular, since the conditions in the reaction zone where the raw material hydrocarbons are introduced to perform the carbon black formation reaction govern the physical properties of the obtained carbon black, it is necessary to maintain these sites at desired temperature conditions and shapes. Is considered important. This reaction zone is provided downstream of the combustion zone for generating the combustion gas flow, and a choke portion whose cross-sectional area is sharply reduced as compared with the combustion zone is performed. The flow increases, and the degree of the combustion gas flow directly hitting the inner wall and damaging the inner wall increases. Here, as the temperature control means of the raw material introduction region composed of a choke portion, the raw material introduction region is formed as a narrow-diameter throat portion (a so-called choke portion) constituted by a cooling cell having a metal double cylindrical structure having a heat exchange function. (See Japanese Patent Application Laid-Open No. 5-940).
No. 4) has been proposed.

[0007] The structure described in Japanese Patent Application Laid-Open No. 5-9404 is considered to aim at forming a temperature distribution in the furnace cross-sectional direction in the combustion gas flow by forcibly cooling the choke portion. In the case of such a cooling structure, in a general double pipe structure, the temperature of the combustion gas at the material introduction site is set at 2 ° C.
When the temperature is around 000 ° C., it is difficult to cool the gas in the choke portion by flowing a gas such as air into the cooling cell as a cooling medium. This is because there is a limit in adopting a large heat transfer coefficient representing the cooling capacity because the density of the gas body is small when the gas body is used as the cooling medium. In a general double-pipe structure, there is such a restriction. In order to stably maintain a metal double-pipe structure, it is not necessary to operate the combustion gas at a temperature of 1000 ° C. or less at this portion. Not be. This is the same even when a high-temperature heat-resistant metal such as Inconel or Hastelloy is used. In fact,
Japanese Patent Application Laid-Open No. 9404 discloses a temperature distribution (temperature difference between the highest temperature and the lowest temperature) in the cross-sectional direction formed at the raw material introduction site. There is no disclosure that can judge whether there is damage due to overheating of the double-pipe structure, and whether or not stable operation is possible (it merely states that efficient production can always be performed with stable furnace operation).

[0008] Japanese Patent Application Laid-Open No. 5-9404 does not disclose a specific structure of the double tube portion, and does not cause local heating in the cell, so that the shape is as small as possible with no dead space. It is only to state the general desire that it is preferable to design. However, in order to cool the raw material introduction site, it is necessary to design the flow path of the cooling medium avoiding the raw material introduction nozzle and the like, and it is difficult to have no dead space at all. JP-A-5-940
No. 4, there is only a general description such as "the specification is appropriately designed in consideration of the flow velocity in a pipe such that a refrigerant such as air efficiently exchanges heat", and such a solution is difficult. There is no specific structure that satisfies the various conditions.However, it is not possible to solve the difficult problem that the refrigerant efficiently exchanges heat and obtains a desired flow rate that can keep the choke at a desired temperature. Unknown.
The temperature of the combustion gas in the choke is set to 2000
A cooling structure capable of sufficiently and uniformly cooling the choke member even at a high temperature of about ° C has not been found so far. In particular, when a gas is used as the cooling medium, since the heat transfer coefficient is limited in the general method as described above, when the combustion gas flow in the choke portion is at a high temperature, erosion due to insufficient cooling, If cracks or the like in the weld due to thermal stress occur in the choke, the stable operation is hindered, which is a serious problem.

As described above, all of the carbon black manufacturing furnaces according to the prior art efficiently produce carbon black exhibiting an excellent quality balance by stably operating at a high temperature of about 2000 ° C. That was not enough.

Further, when a choke portion having a double metal structure as described in JP-A-5-9404 is cooled, a temperature distribution is formed in the furnace cross-sectional direction, that is, the vicinity of the center of the cross-section is near the inner wall of the choke. That is, a temperature gradient is formed in which the temperature becomes higher than that near the circumference. Although this may be suitable for the purpose of producing a broad carbon black having an aggregate size distribution as intended in JP-A-5-9404, the blackness, dispersibility, gloss, coloring, The present inventors have found that the carbon black is not suitable for producing carbon black having excellent power. In other words, in order to maintain a high temperature of 1800 ° C. or more in the carbon black formation reaction region, it is necessary to use the method disclosed in
It has been found that a simple metal double tube structure as described in JP-A-9404 is insufficient.

As described above, it has been difficult for any of the conventional carbon black production furnaces to efficiently produce carbon black exhibiting an excellent quality balance in characteristics such as blackness and dispersibility. The solution was desired. The present invention particularly provides a method and an apparatus which can operate at a high temperature exceeding 1800 ° C. and can produce, for example, carbon black which satisfies both high blackness and good dispersibility as compared with the prior art.

[0012]

That is, the present invention comprises a first reaction zone for forming a combustion gas stream and a choke section for mixing a raw material hydrocarbon with the obtained combustion gas stream to produce carbon black. An apparatus for producing carbon black having two reaction zones and a third reaction zone downstream of the second reaction zone for stopping the reaction, wherein the inner wall surface of the choke portion has a coating made of a poor heat conductive material. Apparatus for producing carbon black composed of a material having good thermal conductivity, a first reaction zone for forming a combustion gas stream, and a choke section for mixing a raw material hydrocarbon with the obtained combustion gas stream to produce carbon black. A second reaction zone, a second
An apparatus for producing carbon black having a third reaction zone for stopping a reaction downstream of a reaction zone, wherein the inner wall surface of the choke portion is a non-good heat conductive material, and the heat conductive material is , A carbon black producing apparatus having an intermediate layer comprising a member having a coefficient of thermal expansion intermediate between that of the good thermal conductive material and the coating of the poor thermal conductive material, between the coating made of the poor thermal conductive material And a method for producing carbon black, wherein a carbon book producing reaction is performed using such a carbon black producing apparatus.

In the manufacturing apparatus according to the present invention, since the specific site is coated with the specific material at the site where the carbon black generation reaction is performed, the inner wall surface of the choke portion, that is, the surface in contact with the combustion gas flow. Of the outer surface of the tube on the opposite side, that is, the tube constituting the choke portion (hereinafter referred to as “choke tube”) (if the choke portion has a jacket, the temperature on the jacket side) is lowered. It is possible to keep. For this reason, it is possible to perform a stable operation of the carbon black generation reaction while actually maintaining a high temperature range exceeding 1800 ° C. Furthermore, the amount of heat transferred from the combustion gas stream to the raw hydrocarbon can be reduced, and the temperature of the inner wall surface of the choke in contact with the combustion gas is kept high. Can be prevented. Furthermore, since the energy of the combustion gas stream can be used effectively,
Many raw materials can be supplied by spraying. In addition, when the cooling medium is circulated by providing the jacket, the temperature of the outer surface of the choke pipe, which is the surface that comes into contact with the cooling medium, can be kept low, so that the operation can be performed while keeping the temperature of the cooling medium low. .

When the choke portion is made of fire-resistant bricks as in the conventional manufacturing apparatus, the construction cost and material cost are large because of the multilayer structure of the bricks. The maintenance is heavy, and the mortar construction and the arched shape make it difficult to avoid impacts, so relocation and installation require time and cost. On the other hand, in the case of forming the manufacturing apparatus of the present invention, the coating treatment may be carried out by means such as solid welding of ceramics or the like melted to the metal surface subjected to the base treatment, thereby reducing the construction time and cost. it can. Further, by selecting the coating member and setting the thickness of the coating layer to a desired value, the coating can be prevented from peeling off and falling off. Further, if a crack (hair crack) not penetrating the layer is formed in a direction perpendicular to the coating surface, that is, in the thickness direction of the coating, thermal stress can be reduced, and more stable operation can be performed.

If there is an edge on the coating surface, the coating thickness at that portion is different from other portions,
It may cause peeling or the like. To prevent this,
By adopting a structure without such an edge portion or by chamfering the edge portion so as to have a desired angle or more, a stable operation without separation or the like can be performed.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, details of a manufacturing apparatus and a manufacturing method of the present invention will be described. The present invention relates to a so-called furnace method for obtaining carbon black by introducing a raw material hydrocarbon in a production furnace having a first reaction zone, a second reaction zone, and a third reaction zone. The configuration of the present invention will be described with reference to the drawings. FIG. 1 is a schematic longitudinal sectional view of a main part showing an example of the carbon black producing apparatus of the present invention.

(Overall Configuration of Production Furnace) The furnace has a first reaction zone 1 for forming a combustion gas flow in a longitudinal direction, and a choke for producing a carbon black by mixing a raw material hydrocarbon with the obtained combustion gas flow. A second reaction zone 2 having a portion and a third reaction-stopping downstream downstream of the second reaction zone.
The reaction zone is divided into three. The process itself in each reaction zone can basically adopt the same method as in the prior art. In the first reaction zone, fuel and oxygen-containing gas are generally introduced from the combustion nozzle 4 to generate a combustion gas flow. Air, oxygen, or a mixture thereof is used as the oxygen-containing gas, and hydrogen, carbon monoxide, natural gas, petroleum gas, petroleum liquid fuel such as heavy oil, and coal liquid fuel such as creosote oil are used as fuel. Is done.

The temperature of the combustion gas in the first reaction zone, also referred to as the combustion zone, is used to improve the amount and rate of vaporization of the raw material hydrocarbons in the second reaction zone to achieve uniform vaporization and thermal cracking. A sufficiently high temperature atmosphere is desirable, particularly preferably 1600 ° C. or higher, more preferably 1700 ° C.
２2400 ° C. By achieving such a high temperature, the temperature of the gas mixed with the raw material hydrocarbon is increased, and the production amount of carbon black is improved, and at the same time, the production of carbon black having a smaller particle diameter becomes possible.

In the second reaction zone, the raw hydrocarbon is sprayed and introduced into the chalk portion from the raw hydrocarbon introduction nozzle 5 provided in parallel or in the horizontal direction with the high-temperature gas flow obtained in the first reaction zone.
The raw hydrocarbon is pyrolyzed and converted into carbon black. As raw material hydrocarbons, aromatic hydrocarbons such as benzene, toluene, xylene, naphthalene, and anthracene;
Coal hydrocarbons such as creosote oil and carboxylic acid oil, heavy petroleum oils such as ethylene heavy-end oil and FCC oil, acetylene unsaturated hydrocarbons, ethylene hydrocarbons, and aliphatic saturated carbons such as pentane and hexane. Hydrogen or the like is preferably used. In FIG. 1, the second reaction zone indicated by reference numeral 2 comprises a choke portion and has a cooling jacket 6. In FIG. 1, reference numeral 8 denotes a refractory.

(Structure of Choke Part) In the present invention,
A specific one is used as the choke portion in the second reaction zone. That is, it is assumed that the inner wall surface is coated with a poor heat conductive material.
The material of the choke portion is made of a good heat conductive material. Here, the material having good thermal conductivity means that heat exchange sufficient to maintain the temperature of the choke portion in a desired range under the desired carbon black generation reaction conditions is possible between the medium and the medium flowing through the jacket. The thermal conductivity is specifically 10 kcal / mhr ° C or more, preferably 140 kcal / mhr ° C or more, more preferably 300 kcal / mhr ° C or more, and further preferably 3 kcal / mhr ° C or more.
30 kcal / mhr ° C or higher.

When a gas is used as the cooling medium,
In order to withstand high temperatures, if a high-temperature refractory metal such as Hastelloy or Inconel is used as a material for forming the choke tube, it can withstand temperatures around 800 to 1000 ° C. Since ceramics can generally be used at a temperature of 1200 ° C. or lower, it is possible to apply ceramic coating to a high-temperature refractory metal and to operate with the temperature of the inner wall surface of the choke part raised as much as possible. Therefore, by increasing the temperature of the inner wall surface of the choke that comes into contact with the high-temperature combustion gas by using a structure that cools the metal member to the design temperature, the amount of heat transferred from the inside of the choke portion to the outside can be reduced, and efficient operation becomes possible. .

More specifically, examples of the material include copper and aluminum, which are metals having high thermal conductivity, and alloys containing them. Particularly preferred is, for example, high-purity copper such as phosphorus-deoxidized copper. Materials other than metals include, for example, SiC, diamond, aluminum nitride, silicon nitride, and the like. Materials other than these metals have the drawback that they cannot be thinned and are liable to be broken, so that a molding method, a cooling structure, and the like need to be devised in order to use them as a choke in the present invention. By using such a material having good thermal conductivity, it is possible to carry out the carbon black generation reaction at a high temperature and to maintain the inside of the furnace at a high temperature in order to obtain desired physical properties, and further to produce the carbon black at such a high temperature. For a long period of time without changing the state of the inner wall of the furnace. Therefore, 200
It maintains durability even at a high temperature of 0 ° C. or more, does not leak or blow out contents such as a high-temperature gas flow in the chalk, and maintains a desirable degree of shape and smoothness as an inner surface of the chalk. This makes it possible to produce high-quality carbon black.

(Coating) In the present invention, the inner wall surface of the choke portion is coated with a poor heat conductive material. The non-good heat conductive material refers to a material other than the above-described good heat conductive material, and is not particularly limited as long as it is such a material. However, since there is a relationship between the thermal conductivity and the required thickness of the coating as described later, the thermal conductivity is generally preferably 8 kcal / mhr ° C or less, particularly preferably 1 kcal / mhr ° C or less, more preferably 0.5 kcal or less. / Mhr ° C or lower.

The greater the thermal conductivity of the coating material, the smaller the temperature difference between the inner and outer walls of the choke portion, and the smaller the thermal stress, the more the design becomes possible. A ceramic material such as alumina, silica, or zirconia may be used as the non-good heat conductive material, and a non-good heat conductive material that can be uniformly coated is more preferable. Here, the coating is not limited to a forming method as long as it forms a layer having a desired thickness and covers the surface, and is typically formed by coating and fusing, but also by vapor deposition and chemical plating. No.

The thickness of the coating is not limited,
mm or less is preferable. More preferably, it is 3 mm or less. As the thickness of the coating layer increases, the coating effect increases, but on the other hand, problems such as peeling tend to occur. In particular, as the thickness of the coating layer increases, the surface on the high-temperature side (side in contact with the combustion gas flow) of the coating wall (coating surface) and the surface on the low-temperature side (side in contact with the material forming the choke pipe) (low-temperature side) ) Increases. Therefore, since thermal stress or the like is generated between both surfaces, when coated with a material having a low thermal conductivity, the temperature gradient becomes large, and problems such as peeling and falling off are likely to occur.
Therefore, in general, the thickness is desirably 3 mm or less, preferably 0.3 mm or less. Members with different thermal conductivity,
The temperature of the inner wall surface of the choke can be controlled by adjusting the thickness, or by providing a jacket on the choke to allow the cooling medium to flow and adjust the flow rate of the cooling medium. Although the coating method is not limited, there are typically two types: a coating method and a thermal spraying method in which a coating base material is melted and welded. The thermal spraying method is preferred because it has better adhesion. There are the following three types of thermal spraying methods depending on the type of spray gun and the method of supplying the base material. Plasma powder spray method, locide rod spray method,
There is no problem as long as the desired performance can be obtained by any of the thermospray methods. Preferably a variety of base material types,
The plasma powder spray method is preferable from the viewpoint of thermal spraying cost and the like. Both methods require a base treatment to increase adhesion by increasing the surface area by sandblasting the surface of the material to be coated. Next, it is desirable to coat a member having a coefficient of thermal expansion between the material to be coated and the coating material on the surface of the material to be coated, and then coat a desired coating material thereon. This intermediate layer can provide a corrosion prevention effect and is effective in preventing cracks due to thermal stress. As the intermediate layer having an excellent corrosion prevention effect, a layer made of Ni, Cr-based alloy or the like is preferable. The thickness of the intermediate layer is preferably 200 μm or less,
More preferably, it is 100 μm or less. A typical method of forming the intermediate layer is spray coating. The surface finish of the coating can be processed to a desired roughness by polishing.

When a method such as refractory brick lining is adopted for the chalk portion, if the thickness of the brick is one layer, the temperature gradient between the inside and outside of the brick becomes large, and cracks and falling off occur due to thermal stress and the like. Therefore, when cooling a refractory brick, it is necessary to make the temperature difference with the brick thickness of each layer, that is, a temperature gradient suitable for the refractory material used. When the brick layers are multi-layered, the construction is complicated and the cost may be high. On the other hand, by applying the ultra-thin coating as described above according to the present invention, the combustion gas in the choke portion is not rapidly cooled even when the chalk portion made of a good heat conductive material such as metal is used. This achieves the operating condition, which has not been achieved before, of maintaining the temperature of the stream stably at a high temperature exceeding 1800 ° C., and its industrial significance is great.

[0027] If there is a difference in the thickness of the coating, a temperature difference occurs partially, and peeling and falling off of the coating member easily occur as described above. Therefore, it is desirable to form a substantially uniform coating layer. That is, the coating surface should be smooth. The degree of smoothness is preferably R _max = 100S or less, and more preferably R _max = 25S or less. The value of R _max is JI
This is a measured value according to SB0601. Further, it is preferable to form cracks (hair cracks) that do not penetrate the layer in the thickness direction, that is, the direction perpendicular to the inner wall, on the coating surface. By doing so, thermal stress is reduced, and peeling can be prevented, so that more stable operation is possible. The coated area is 90
こ と が It is preferable not to have the following edges. For example, it is necessary to process the edge of the chalk entrance to ensure uniformity of the coating. If this is not done, peeling and chipping may be caused, and stable operation may not be performed. Processing of this part is C1 or R1
It is preferable to perform the above chamfering. JIS B
As in 0001 and the like, R1 and C1 each mean that an edge portion forms an arc having a radius of 1 mm or more, and each of two adjacent sides is chamfered by cutting 1 mm or more at 45 °.

When a gas is used as the cooling medium, the temperature of the surface of the coating is preferably 500 to 1600.
It is preferable to adjust the coating thickness and / or the thermal conductivity of the coating material so that the temperature is in the range of 800C to 1600C. When using a liquid as a coolant, preferably, the temperature of the surface of the coating is 300 to
It is preferable to adjust the coating thickness and / or the thermal conductivity of the coating material to be 800 ° C., more preferably 500 to 800 ° C. This is because, when a liquid such as water is used as described above, it is preferable that the outer surface of the choke tube, that is, the wall surface on the cooling side does not reach a temperature exceeding the boiling point of the liquid as the cooling medium. is there.

(Construction of Jacket) It is desirable to provide a jacket at the choke portion. It is desirable to keep the choke at a desired temperature by flowing a cooling medium through the jacket. The material of the jacket is not particularly limited as long as the durability of the structure as the jacket can be maintained. That is, in order to allow a cooling medium such as cooling water to flow therethrough so that heat can be exchanged between the cooling medium and the choke portion, for example, when the cooling medium is water, the characteristics required for the jacket withstand water pressure. , Insolubility in water, installation, etc. The cooling medium used for cooling is not particularly limited, and various gases such as air and nitrogen, and liquids such as water may be appropriately selected and used. The temperature of the refrigerant flowing through the jacket is not particularly limited, but when a liquid is used as the refrigerant, the temperature may be generally 20 to 50 ° C, more preferably 30 to 40 ° C. When a gas is used as the refrigerant, the temperature is not particularly limited, and may be selected in consideration of the flow rate and the target temperature. However, it is simplest to use the air as it is.

It is also desirable to apply a coating to the hot side surface of the flange constituting the jacket. The flanges are located on the upstream side of the combustion gas flow path, that is, on the first reaction zone side, and on the downstream side, that is, on the third reaction zone side. Since the upstream side has a higher temperature, it is particularly desirable to apply a coating to this surface. When the operation is performed under the high temperature as described above, the temperature is considerably high even on the downstream side, so it is desirable to apply the coating on this side as well.
The above-described jacket can be appropriately designed by dividing it in the length direction as necessary, that is, by employing a jacket structure having a plurality of layers as shown in FIG. 2 described later.

Here, a specific example of the structure of the chalk is shown in FIG.
This will be described below with reference to the schematic diagram shown in FIG. FIG.
FIG. 2A is a cross-sectional view of the choke portion, and FIG. 2B is a view of the choke portion illustrated in FIG. Reference numeral 9 denotes a flange which forms a chalk jacket. Since the temperature of the flange, especially in the vicinity of the central axis of the furnace, becomes higher, it is desirable that the high temperature portion is made of a good heat conducting member. Specifically, a portion having a temperature of 600 ° C. or higher, more preferably a portion having a temperature of 400 ° C. or higher, and still more preferably a portion having a temperature of 250 ° C. or higher may be formed of a good heat conductive member. In the figure, the flange has a structure in which a gasket is attached to the outer periphery and can be fixed with a bolt and nut.
9a is a high-temperature side surface of the flange. That is, in the flange on the upstream side of the combustion gas flow path, the upstream side of the combustion gas flow path out of the two surfaces of the flange, and on the flange on the downstream side of the combustion gas flow path, the downstream side of the combustion gas flow path out of the two surfaces of the flange has a higher temperature. Surface.

Reference numeral 10 denotes a choke tube. 10a is a chalk inner wall surface. 10b is the outer surface of the choke tube. Numerals 11 and 12 are coating layers of a poor heat conductive material. Reference numeral 11 denotes a coating layer applied to the inner wall surface of the choke portion, and reference numeral 12 denotes a coating layer applied to the high-temperature side surface of the flange. 11a and 12a are the coating surfaces, and 11b is the cold side of the coating.

Reference numeral 13 (13a, 13b, 13c) denotes a flow path for the cooling medium. 13a is a layer closest to the combustion gas flow side in the flow path of the cooling medium (hereinafter, referred to as a flow path first layer), 1
Reference numeral 3b denotes a layer second closest to the combustion gas flow side (hereinafter, referred to as a flow path second layer), and reference numeral 13c denotes a layer furthest from the combustion gas flow (hereinafter, referred to as a flow path third layer). The cooling medium introduced into the flow path first layer, after passing through the flow path first layer in the AC direction with the combustion gas flow in the choke portion while cooling the choke pipe,
The liquid passes through the second layer of the flow path and the third layer of the flow path sequentially and is discharged. The flange portion is mainly cooled by the cooling medium flowing through the flow path second layer and the flow path third layer. A desired flow rate can be obtained for each layer by forming a channel having a cross section adjusted by further providing a partition. 14 (14a, 14b) is a partition tube. 14a separates the flow path first layer and the flow path second layer, 14b separates the flow path second layer and the flow path third layer, and is installed concentrically with the choke tube and the jacket outer cylinder. . Reference numeral 15 denotes a jacket outer cylinder.

(Description of Cooling Method in the Present Invention) A cooling medium is circulated through the jacket described above.
The refrigerant may be a liquid or a gas, and may be any. However, if the material of the choke tube to be coated is a non-good heat conductive material, the temperature of the outer surface of the choke tube, which is the wall on the cooling side, becomes higher than the boiling point of water, causing local heating, etc. Stable operation is difficult because it leads to melting and damage. When cooled with a liquid such as cooling water, it is difficult to reuse the transferred heat. When a liquid such as water is used as the cooling medium, the temperature on the side of the reaction zone wall that contacts the high-temperature combustion gas flow is maintained at a desired temperature or higher, and the temperature on the side of the wall that contacts the outer cooling water is maintained. There is a limit in setting each material, thickness, and heat transfer coefficient on the cooling side so that the temperature is lower than the boiling point of water. A decrease in the temperature of the wall in contact with the combustion gas flow results in an increase in the amount of heat exchange between the combustion gas flow and the wall of the reaction zone. As a result, the reaction at a desired high temperature cannot be sustained, so that carbon black of a desired quality cannot be obtained.

If gas is used as the cooling medium,
Problems can be solved. The conditions for flowing the cooling medium are as described above.
Cooling medium flowing directly outside the choke tube
Film coefficient is 200kcal / m^TwoFlow over hr ° C
Pass. Among these, particularly desirable distribution conditions are that the cooling medium is
The gas and liquid cases are as follows, respectively. By gas
Cooling, the film coefficient is 200 kcal / m^Twohr ℃ or less
Above, preferably 300kcal / m^Twohr ℃ or more, more preferable
Is 500kcal / m^Twohr ℃ or more. Film coefficient is 200kca
l / m^TwoBelow hr ° C, it is difficult to prevent the chalk from overheating
It is. When a liquid is used as the cooling medium,
The pipe wall temperature must be higher than the boiling point of the liquid.
Is undesirable, the film coefficient is 2000 kcal / m
^Twohr ° C or higher, particularly preferably 7000 kcal / m^Twohr ℃ or more,
More preferably 10,000 kcal / m^Twohr ℃ or more
It is suitable.

The film coefficient can be calculated by the following calculation. h = 0.023 × Re ^0.8 × Pr ^0.4 × (λ / D _e ) (I) (where Re is Reynolds number, Pr is Prandtl number, Re = ρvD _e / η, Pr = C _p η) / lambda, [rho is the density of the fluid, v is the flow velocity of the fluid, D _e is the relative size of the cross section of the flow channel, eta
Is the viscosity of the fluid, C _p is the specific heat of the fluid, λ is the thermal conductivity of the fluid) The film coefficient h is a function of the flow velocity of the cooling medium and the equivalent diameter of the cross section of the flow path as expressed by the above equation. These may be selected to obtain a predetermined film coefficient.

The flow velocity of the cooling medium has a great influence on the film coefficient on the cooling medium side. The preferred flow rate varies depending on the fluid density of the cooling medium, viscosity, thermal conductivity, specific heat and the cross-sectional shape through which the fluid flows, but if the cooling medium is a liquid such as water, the average flow velocity in the cross section is 0.5 m / flow rate. sec or more, 3m / sec or more,
8 m / sec or more is preferable. The upper limit of the flow velocity is not particularly limited, but as the flow velocity is increased, the pressure loss sharply increases, and the energy for flowing the fluid increases.
The flow velocity may be determined in consideration of this energy and the obtained film coefficient. Excessive cooling of the choke tube increases the amount of heat deprived of the combustion gas flow, which leads to a loss of energy used for the carbon black generation reaction. When the cooling medium is a gas such as air, the density of the cooling medium is smaller than that of the liquid, so that the cooling medium flows at a higher flow rate than that of the liquid. Specifically, the flow velocity is 15 m / sec or more, 40 m / sec or more, 100 m / sec.
More than sec is appropriate. When the flow velocity is less than 15 m / sec, it is necessary to extremely divide the flow path to reduce the cross-sectional area in order to maintain the film coefficient required in the present invention within a predetermined range, which is practically applicable. It is very difficult to design the device.

The equivalent diameter of the cross section of the flow path is 0.000075-
1.25 m, more preferably 0.002 to 0.01 m,
More preferably, it is 0.0025 to 0.0038 m. If it is less than 0.00075 m, the pressure loss increases in order to secure a flow rate for obtaining necessary cooling conditions. 1.
If it exceeds 25 m, the apparatus becomes very large and there is no special advantage that is not economically feasible. The equivalent diameter of the flow path cross section is represented by a value obtained by dividing the cross sectional area by the perimeter of the cross section. For example, in the case of a rectangle, the lengths of two sides are a and b, and the cross sectional area is S.
Then, the equivalent diameter can be expressed by S / (a + b).

(Production of carbon black in the present invention) In the method for producing carbon black of the present invention, the carbon black producing reaction may be carried out using the production apparatus of the present invention described above. The temperature at the position is preferably 1600 to 2400 ° C., more preferably 1700 to 2400 ° C., and further preferably 180 ° C.
0 to 2400 ° C is good. The present inventors have found that, particularly in this range, the raw material hydrocarbon is uniformly vaporized and thermally decomposed, and carbon black having a small particle size and a sharp particle size distribution can be obtained. The faster the gas flow rate in the choke is, the better. After introduction of the raw material hydrocarbons, they are atomized by the motion and thermal energy of the combustion gas. The speed of the combustion gas at that time is preferably as high as possible, preferably 250 m / s or more, and more preferably 300 to 500 m / s.

In order to uniformly disperse the starting hydrocarbons in the furnace, the starting hydrocarbons are preferably introduced into the furnace from two or more nozzles. By keeping the gas in the chalk at high speed, the kinetic energy and heat energy of the combustion gas can be used for the refinement of the raw material hydrocarbons, resulting in a carbon black with a small particle size and the turbulence in the chalk. By mixing, the atmosphere in which the carbon black generation reaction occurs becomes uniform, and carbon black having a small particle size distribution width can be obtained. In addition, since the thermal energy of the combustion gas can be efficiently used for the carbon black generation reaction, the reaction speed is increased and the reaction field is uniform, so that carbon black having a small aggregate diameter can be easily obtained. It is thought that it contributes to.

In the third reaction zone, the high-temperature reaction gas is
Water or the like is sprayed from the reaction stop fluid introduction nozzle 7 in order to cool it to 800 ° C. or less. The cooled carbon black is subjected to a known general process such as separation and recovery from gas with a collecting bag filter or the like.

[0042]

The present invention will be described below with reference to examples of the present invention.
The present invention is not limited to this.

(Example 1) [Overall structure of furnace] A first reaction zone having an inner diameter of 500 mm and a length of 1400 mm provided with an air introduction duct and a combustion burner,
A second reaction zone consisting of a choke portion having an inner diameter of 50 mm and a length of 800 mm penetrating a plurality of raw material nozzles from the periphery, a third reaction zone having an inner diameter of 200 mm equipped with a quench device and a length of 6000 mm, and an inner valve diameter as a throttle mechanism A carbon black manufacturing furnace having a structure in which control valves of 80 mm were sequentially connected was installed. As shown in FIG. 2, the choke section has a cooling structure and a coating, and is formed of a 15 mm-thick cylindrical tube made of phosphor-deoxidized copper as a material. The coating is a nickel-chromium base coating (composition: Ni 80 wt%, Cr
(20 wt%) was applied to 100 μm to form an intermediate layer, and an alumina-based ceramic (composition: Al ₂ O ₃ 1
A coating having a thickness of 300 μm and a coating rate of 00%, thermal conductivity: 0.4 kcal / mhr · ° C.) is applied.

[Temperature measurement] Thermocouples are embedded at two points A and B in the furnace wall of the first reaction zone (point A is 75 mm inside the furnace inner wall surface, and point B is 220 mm inside the furnace inner wall surface). The analysis of gas flow and heat transfer was performed using a computer, and the relationship between the gas temperature in the furnace, the furnace wall temperature, and the temperature at the measurement points (points A and B) was clarified. Created. The furnace wall of the first reaction zone is composed of magnesia brick, magnesia chrome brick, high alumina brick, heat insulating brick, heat insulating board, iron shell, etc., and accurately models the dimensions of the parts where these materials are used. The temperature dependence of the thermal conductivity of the material was investigated, and a simulation program was created by inputting the physical properties of each material. Using this simulation program, the temperature (1780) that can be measured with a thermocouple
° C) was introduced into the choke section and the simulation results were compared with the measured values by the thermocouple embedded in the choke inlet. The simulation results showed no difference from the measured values, demonstrating the effectiveness of the simulation program. Verified.

[Formation of carbon black] In the first reaction zone, butane 21.9 Nm ³ / hr, combustion air oxygen concentration 2
A high-temperature combustion gas stream was formed by introducing 4.9 vol% and an air amount of 450 Nm ³ . The combustion gas stream formed in the first reaction zone is introduced into the choke section at a flow rate of 452 m / sec, and creosote oil is sprayed into the combustion gas stream as a raw material hydrocarbon from a raw material spray nozzle to perform a carbon black generation reaction. went. During operation of the furnace, a cooling medium was flowed through the jacket to cool the chalk. The equivalent diameter of the cross section of the portion of the cooling medium passage that cools the choke portion is 0.0
17 m, and the flow rate of the refrigerant is 9.6 m / sec. The film coefficient on the cooling water side is 25600 kcal / m ² hr ° C. The temperature of the combustion gas flow in the choke portion was 1857 ° C. as determined by the above simulation program. The combustion gas flow velocity in the choke section is a value obtained from the temperature obtained by the simulation program. The combustion gas oxygen concentration at the position where the raw material hydrocarbon was introduced was 0.5 vol%.

When a thermocouple was installed at a position 10.5 mm downstream from the chalk inlet and 8 mm inside the wall of the choke pipe, the measured value of the temperature at this location during the above operation was 99.1 ° C. . This is the allowable temperature range of the phosphorous deoxidized copper constituting the choke tube. After the above operation was performed for three consecutive months, water was flowed through the choke at a pressure of 10 kg / m ² , and the presence or absence of breakage of the choke was confirmed by a water pressure test. Was.

The physical properties of the obtained carbon black,
Tables 2 and 3 show the results of the structural inspection of the chalk after the test. Particle size of carbon black is 15 nm
Thus, a particle having a small particle size and high blackness is stably obtained.
This is because it is possible to flow a high-temperature and high-velocity gas flow as a combustion gas flow flowing through the choke portion while maintaining the chalk wall at a temperature that can be maintained according to the material. It is considered that high quality carbon black was obtained. In addition, the measuring method of each physical property in Table 2 is as follows.

(Particle Size) According to electron microscopy. Electron microscopy is a method described below. The carbon black is put into chloroform, irradiated with ultrasonic waves of 200 KHz for 20 minutes to be dispersed, and then the dispersed sample is fixed to a supporting film.
This is photographed with a transmission electron microscope, and the particle diameter is calculated from the diameter on the photograph and the magnification of the photograph. This operation is 1
The measurement is performed 500 times, and an arithmetic average of those values is obtained. (Specific surface area) The specific surface area (N ₂ SA) is ASTM D30
37-88. (CrDBP) Crushed DBP absorption number (CrDBP) is AS
Determined according to TM D-3493-88.

(D _mod , D _1/2 ) The maximum frequency Stokes equivalent diameter (D _mod ) and the Stokes equivalent diameter _half width (D _1/2 ) are:
The decision was made as follows. Using a 20% ethanol solution as a spin solution, a Stokes equivalent diameter is measured by a centrifugal sedimentation type particle size distribution analyzer (DCF3 type manufactured by JL Automation), a Stokes equivalent diameter is measured, and a Stokes equivalent diameter versus a given sample is measured. Make a histogram of the relative frequency of occurrence in A straight line L is drawn from the histogram peak to Y
Draw parallel to the axis to the X axis and end at a point on the X axis of the histogram. The Stokes equivalent diameter at the X-axis point of this histogram is the maximum frequency Stokes equivalent diameter D _mod . Further, a line M is drawn in parallel with the X axis through the midpoint of the straight line L. Line M
Intersects the distribution curve of the histogram at two points O and P,
The absolute value of the difference between the two Stokes equivalent diameters at the two points O and P of the carbon black particles is the Stokes equivalent diameter half width D
_1/2 value.

(D ₇₅ ) The volume 75% diameter (D ₇₅ ) was determined as follows. In the method of determining the maximum frequency Stokes diameter, from the histogram of the Stokes equivalent diameter versus the relative frequency of occurrence of the sample, obtain the volume from each Stokes equivalent diameter and frequency, and obtain the Stokes equivalent diameter versus its equivalent diameter. Make a graph showing the total volume of the sample. On this graph, a perpendicular line is drawn from the point of 75% of the total volume to the X axis, and the diameter at the point of intersection with the X axis is the volume 75% diameter (D ₇₅ ). (PVC blackness) The PVC blackness was measured using the sample carbon black 1
Parts by weight were added to 100 parts by weight of the PVC resin, dispersed and sheeted by two rolls, and the blackness of carbon black “# 40” and “# 45” of Mitsubishi Chemical Corporation was set to 1 point, 10 points and the reference value, respectively. Then, the blackness of the sample was evaluated by visual evaluation.

(Dispersion index) The dispersion index was evaluated by the following method. The state of dispersion in the LDPE resin was observed, the number of undispersed aggregates was counted, and the larger the number, that is, the higher the dispersion index, the worse the dispersibility was evaluated. 250c
c Using a Banbury mixer, mix 40% by weight of the sample carbon black with the LDEP resin and knead at 115 ° C for 4 minutes. Mixing conditions LDPE resin 101.89 g Calcium stearate 1.39 g Irganox 1010 0.87 g Sample carbon black 69.43 g Next, the mixture is diluted with a two-roll mill at 120 ° C. so that the carbon black concentration becomes 1% by weight. Diluting compound preparation conditions LDPE resin 58.3 g Calcium stearate 0.2 g Carbon black 40% compounding resin 1.5%

The sheet is formed into a sheet with a slit width of 0.3 mm, cut into chips, and formed into a film of 65 ± 3 μm on a hot plate at 240 ° C. 0.2 mm in a visual field of 3.6 mm x 47 mm with an optical microscope with a magnification of 20 times.
The diameter distribution of the undispersed mass having the above diameter is measured, and the total area is calculated. This area is calculated by dividing the total area by the reference area based on the area of the undispersed aggregate having a diameter of 0.35 mm as the number of reference particles. This is observed in 16 or more visual fields, and the average value is used as the dispersion index.

(Example 2) A production furnace in which an alumina ceramic coating was applied without using a nickel-chromium base coating as an intermediate layer on the inner wall surface of the chalk portion used in the first embodiment, butane supply amount, Combustion gas temperature (value from the above simulation program)
As shown in Table 1, carbon black was produced by performing the same operation as in Example 1 except that KOH was added to the raw material hydrocarbon. The amount of KOH added in the raw material hydrocarbon is described as "potassium concentration" in Table 1. During operation of the furnace, the measured value of the temperature of the thermocouple at a position 10.5 mm downstream from the chalk inlet and 8 mm from the inner wall surface of the choke tube to the inner wall surface of the tube was 122.8 ° C. The physical properties of the obtained carbon black and the structural inspection results of the chalk portion after the test are shown in Tables 2 and 3, respectively. Carbon black has a particle size of 15 nm, and a small particle size and high blackness are stably obtained. This is because it is possible to flow a high-temperature and high-velocity gas flow as a combustion gas flow flowing through the choke portion while maintaining the chalk wall at a temperature that can be maintained according to the material. It is considered that high quality carbon black was obtained.

Comparative Example 1 Example 1 was repeated except that the same manufacturing furnace as in Example 1 was used except that no coating was applied.
The same operation as described above was performed. The physical properties of the obtained carbon black and the structural inspection results of the chalk portion after the test are shown in Tables 2 and 3, respectively. When the obtained carbon black is compared with those obtained in Examples, the PVC blackness is low and the dispersibility is inferior. This is considered to be because the heat energy of the combustion gas flow in the choke portion was deprived by cooling the choke portion made of the good heat conductive material from the outside, and the temperature of the combustion gas flow in the choke portion decreased. In addition, the appearance inspection shows that abrasion occurs. this is,
It is considered to be erosion due to the generated carbon black. By comparing the examples and comparative examples, it is understood that the coating according to the present invention keeps the inside of the choke at a higher temperature and also has the effect of preventing erosion.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

The operation was further continued for three months, and the appearance inspection was carried out. As a result, the production furnace of Example 1 was still sound without peeling, cracking, abrasion and the like. In the production furnace of Example 2, minute cracks were increased. The production furnace of Comparative Example 1 was further worn.

[0059]

As described above, by using the carbon black producing apparatus of the present invention, it has been considered that the use of the carbon black producing apparatus as a black pigment in a resin colorant, a printing ink, or a paint is inconsistent with the prior art, and it is difficult to achieve both. Carbon black satisfying the desired blackness and dispersibility can be obtained. Therefore, carbon black, which is very useful as a black pigment in resin colorants, printing inks and paints, can be produced, which is industrially very useful.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a main part showing an example of an apparatus for producing carbon black.

FIG. 2 is a schematic view showing a specific example of a choke section of the carbon black producing apparatus of the present invention.

Claims (14)

[Claims] 1. A first reaction zone for forming a combustion gas flow, a second reaction zone having a choke section for mixing a raw material hydrocarbon with the obtained combustion gas flow to generate carbon black, and a second reaction zone. A carbon black producing apparatus having a third reaction zone for stopping the reaction, which is located downstream of the apparatus, wherein the inner wall surface of the choke portion is formed of a good heat conductive material having a coating made of a poor heat conductive material. Carbon black production equipment. 2. A first reaction zone for forming a combustion gas stream, a second reaction zone having a choke section for mixing a raw material hydrocarbon with the obtained combustion gas stream to produce carbon black, and a second reaction zone. A carbon black producing apparatus having a third reaction zone for stopping a reaction, which is located downstream of the apparatus, wherein the inner wall surface of the choke portion is a non-good heat conductive material, and the heat conductive material is a non-good heat conductive material. An apparatus for producing carbon black, comprising an intermediate layer made of a member having a coefficient of thermal expansion intermediate between that of the good thermal conductive material and the coating of the poor thermal conductive material, between the coating made of the good thermal conductive material. 3. The carbon black producing apparatus according to claim 1, wherein the choke portion has a jacket. 4. The apparatus for producing carbon black according to claim 3, wherein the high-temperature side surface of the flange constituting the jacket is coated with a poor heat conductive material. 5. The choke portion is made of metal.
The carbon black production apparatus according to any one of the above. 6. The carbon black producing apparatus according to claim 1, wherein the thickness of the coating is 5 mm or less. 7. The carbon black producing apparatus according to claim 1, wherein the coating surface is smooth, and the coating surface is cracked in a thickness direction. 8. The carbon black producing apparatus according to any one of claims 1 to 7, wherein the coated portion does not have an edge of 90 degrees or less. 9. A method for producing carbon black, comprising performing a carbon book forming reaction in the apparatus for producing carbon black according to any one of claims 1 to 8. 10. A method for producing carbon black, comprising using the apparatus for producing carbon black according to any one of claims 1 to 8 to allow a liquid to flow through a jacket of a chalk portion during a carbon black generation reaction. 11. A method for producing carbon black, comprising using the apparatus for producing carbon black according to any one of claims 1 to 8 to flow a gas through a jacket of a choke portion during a carbon black production reaction. 12. The temperature of the coating surface is 500 to 1
The method for producing carbon black according to any one of claims 9 to 11, wherein the carbon black production reaction is performed under a temperature of 600 ° C. 13. The film coefficient on the cooling medium side is 2000 kcal.
The method for producing carbon black according to claim 10 or 12, wherein the carbon black formation reaction is carried out under a condition of not less than / m ² hr ° C. 14. The film coefficient on the cooling medium side is 200 kcal / m.
13. The method for producing carbon black according to claim 11, wherein the carbon black formation reaction is performed under a condition of ² hr ° C. or higher.