JPH04359068A - Carbon black producing furnace - Google Patents

Abstract

PURPOSE:To efficiently obtain carbon black having high specific surface area together with coloring force by lining a specific oxide-based ceramic refractory on a cooling cell of double cylinder structure made of a metal, in which a combustion zone on the upstream side of a crude oil inlet is provided with a heat exchange function. CONSTITUTION:The objective carbon black producing furnace obtained by lining (A) a zirconia/hafnia-based refractory obtained by subjecting a (partially) stabilized zirconia-based layer and hafnia-based layer containing an oxide of calcium or magnesium to solid solution binding in the boundary surface and having laminated two layer structure, (B) zirconia refractory material obtained by laminating and integrating a zirconia-based layer containing yttria and zirconia-based layer containing calcium oxide and having two layer structure and (C) alumina/yttria-based refractory material obtained by laminating and integrating an alumina layer and yttria layer and having two-layer structure on a cooling cell of double cylinder structure made of a metal, in which a combustion zone on the upstream side of a crude oil inlet is provided with heat exchange function, in the form of furnace in which combustion zone reaction zone having a small diameter and reaction stopping zone are provided in rows.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a carbon black manufacturing furnace, and in particular, it is capable of effectively increasing the temperature of combustion gas to thermally decompose carbon black that has both a high specific surface area and coloring power with high productivity. Regarding a carbon black manufacturing furnace.

0002

[Prior Art] In recent years, the high performance of automobiles has placed strict performance requirements on tire components. For example, large tires for trucks, buses, etc. must have improved wear resistance, and Improving grip performance is an important issue for high-performance tires. In order to meet these required rubber performances, it is considered effective to use carbon black, which has a high specific surface area and high coloring power.

[0003]Means for producing carbon black with such a fine particle size and high coloring power include high-speed rotation of combustion gas flow, high-temperature pyrolysis of feedstock hydrocarbon oil, and high gas flow rate at the feedstock oil introduction position. It is known that such matters are important conditional factors. For example, U.S. Patent No. 285
No. 1337 describes a venturi-type carbon black production furnace equipped with a narrowed throat section, in which a feed oil burner is inserted in a direction perpendicular to the furnace axis of the throat section, and the linear velocity of the combustion gas flow in the throat section is adjusted. 150ft/sec (
46m/sec) or more, preferably 200ft/sec
(61m/sec) to 4000ft/sec (121m/sec)
9 m/sec), and high temperature combustion gas flow [combustion flame temperature 2000-3000°F (1093-16
49°C)] and the feedstock oil. Furthermore, U.S. Patent No. 3,490,867 discloses that a venturi-type carbon black manufacturing furnace having the same structure as the above is used, and a raw material oil injection nozzle is installed in the wide area inlet in front of the venturi where two series of furnace combustion chambers converge. A mode of insertion in the axial direction is shown, and in this case, the linear flow velocity at the narrow diameter throat portion is 300 to 2600 ft/sec.
(91-792m/sec), preferably 450
~1600ft/sec (137~487m/sec)
, combustion gas temperature is 3500-2900°F (1929
~1593°C), the throat outlet temperature after introducing the raw oil is 3200~2600°F (1760~1427°C)
It is stated that it should be set to .

However, high-speed swirling of the combustion gas flow,
Applying physical conditions such as a high flow rate at the feedstock introduction point to a carbon black production furnace in actual operation requires a large amount of energy supply equipment, but it is expected that good property improvements will be commensurate with that. That is difficult.

[0005] On the other hand, high-temperature pyrolysis of feedstock hydrocarbon oil does not require the addition of any special energy equipment, and is made possible by increasing the combustion rate. However, in conventional carbon black manufacturing furnaces, the refractory temperature of the lining refractory material used is approximately 1900°C even at the highest temperature part.
Since the brick is made of alumina (high alumina or ultra-high alumina), phenomena such as spalling and melting occur within a short period of time when it comes into contact with a combustion gas flow that exceeds 2000℃. This will cause the furnace to become unable to operate.

[0006] For this reason, some proposals have been made to protect the refractory lining by methods such as circulating a relatively low-temperature combustion gas flow around the furnace wall or forcibly cooling the furnace body. For example, U.S. Pat. No. 4,220,624 discloses that in a venturi-type carbon black manufacturing furnace, two series of pre-combustion chambers are provided in the tangential direction at the furnace head, and a supplementary combustion chamber with a replenishment combustion rate of 150 is provided on the peripheral side of the furnace wall.
% low-temperature combustion gas flow, and a supplementary combustion rate of 1 in the center of the furnace.
A process is disclosed in which a high temperature combustion gas flow of 0.00% is introduced into the furnace as a two-layer flow to generate high temperature combustion gas while protecting the furnace material. However, this method has the disadvantage that it is not possible to generate high temperature combustion gas with a uniform combustion rate.

[0007] As a method for forcibly cooling the furnace body, the main body of the carbon black manufacturing furnace is made of two cylinders made of steel, the inner cylinder is lined with bricks, and air is introduced into the gap between the double cylinders. A process in which the preheated air is circulated and used as combustion air (U.S. Pat. No. 30877).
No. 96), a process in which a steel coil is placed inside the lining brick of a tapered carbon black production furnace and cooling water is fed into the coil (US Pat. No. 4619).
No. 812 Specification), etc. have been proposed.

[0008]

[Problem to be solved by the invention] The method of forcibly cooling the furnace body described above can effectively extend the life of the refractory lining, but in both cases, the furnace structure uses alumina refractory bricks. There is a limit to the high temperature level of the combustion gas because it is lined inside the furnace body. Furthermore, it is usually necessary to install two to three layers of alumina/silica-based insulating bricks on the outer wall side of the alumina-based brick lining layer, which creates a work and economic burden during furnace construction and repair. In addition to the increase, heat loss due to the heat storage effect of the insulation layer is also unavoidable.

The object of the present invention is to provide a structure in which the outer peripheral surface of the combustion zone of the furnace is forcibly air-cooled, and is lined with a specific oxide-based ceramic refractory material that can withstand high temperatures of 2000°C or more. The purpose of the present invention is to provide a carbon black production furnace that can produce high-temperature combustion gas and operate stably over a long period of time, thereby producing carbon black with high specific surface area and coloring power with good operability.

0010

[Means for Solving the Problems] A carbon black production furnace according to the present invention for achieving the above object has a combustion zone in which fuel is combusted to produce high-temperature combustion gas, and a subsequent narrow diameter section in which high-temperature combustion gas flows. In a furnace configuration consisting of a reaction zone where feedstock oil is injected into the reactor and converted into carbon black through a pyrolysis reaction, and a reaction stop zone where the reaction gas is rapidly cooled to terminate the pyrolysis reaction, the feedstock oil introduction position is The combustion zone part on the more upstream side consists of a metal double cylinder cooling cell with a heat exchange function, lined with one of the following oxide ceramic refractory materials (1) to (3). This is a structural feature. (1) Partially stabilized or fully stabilized zirconia (ZrO2) layer and hafnia (HfO2) containing one or more stabilizers selected from oxides of calcium, magnesium, yttrium, and cerium.
A zirconia/hafnia-based refractory material with a laminated two-layer structure in which the layers are solid-solution bonded at the interface. (2) Partially stabilized or fully stabilized zirconia layer containing yttria (Y2O3) and calcium oxide (
A zirconia refractory material with a two-layer structure consisting of partially or fully stabilized zirconia layers containing CaO). (3) An alumina/yttria-based refractory material with a two-layer structure in which an alumina (Al2O3) layer and an yttria layer are laminated and integrated.

The first structural requirement of the present invention is that in the above-mentioned furnace configuration, the outer periphery of the combustion zone portion upstream from the raw oil introduction position is configured as a cooling cell having a double cylinder structure made of metal and having a heat exchange function. At the point. The cooling cell is formed in the form of a steel jacket with an inlet pipe and a discharge pipe for the cooling medium, and its specifications are such that the cell surface in contact with the refractory lining layer will not melt and that air, etc. The pipe is designed appropriately, taking into account the flow velocity in the pipe, etc., so that the refrigerant can efficiently exchange heat. At this time, in order to prevent local heating within the cell, it is preferable to design the shape to have as little dead space as possible.

[0012] In addition, the cooling medium is air or oxygen-enriched air, and a cooling medium discharge pipe is provided so that the medium, which is fed into the cooling cell and heated by the heat exchange function, can be used as combustion supporting gas for fuel oil. Combustion efficiency can be further increased by installing a circulation path from the fuel oil supply system to the fuel oil supply system.

A second component of the present invention is that the bricks lining the inner surface of the cooling cell are made of any one selected from a specific zirconia/hafnia refractory material, a zirconia refractory material, and an alumina/yttria refractory material. It consists of an oxide-based ceramic refractory material. The lining made of this oxide-based ceramic refractory material can be formed in a single layer, and there is no need to install an insulating brick layer on the outer peripheral surface. In addition, the reaction zone and reaction termination zone downstream of the combustion zone are as follows:
The lining is made of commonly used alumina firebrick.

Among the oxide ceramics that are selectively used as lining refractories, zirconia/hafnia refractories are:
A molding binder is added to the raw material whose particle size has been adjusted by pulverizing a partially or completely stabilized electro-fused ingot of zirconia and hafnia, granulation of fine powder, calcining, etc. to form a zirconia layer and a hafnia layer. It can be manufactured by a method in which one layer is molded to form a layer and then sintered at a temperature of 1500° C. or higher, and a cooling cell is lined with the hafnia layer exposed on the inner surface of the furnace. Regarding the zirconia/hafnia-based refractory material, Japanese Patent Application No. 1-33983
It is described in detail in the specification of No. 1.

The zirconia refractory material is made by laminating a partially stabilized or fully stabilized zirconia composition containing yttria and a partially stabilized or fully stabilized zirconia composition containing calcium oxide in a predetermined layer thickness and shape. It can be manufactured by a method in which the yttria-containing zirconia layer is integrally formed into a shape and then sintered at a temperature of 1500° C. or higher, and a cooling cell is lined with the yttria-containing zirconia layer exposed on the inner surface of the furnace. This zirconia-based refractory material is described in detail in Japanese Patent Application No. 1-339829.

[0016] Furthermore, the alumina/yttria-based refractory material is
Alumina and yttria powder particles whose particle size has been adjusted are calcined in air, and after kneading a binder component into each powder particle, the alumina component and yttria component are sequentially stacked and filled into a mold, and then the compact is heated to 1500 ml. It is manufactured using a method of sintering at temperatures above ℃ and is lined in a cooling cell so that the yttria layer is exposed on the inner surface of the furnace. This alumina/yttria-based refractory material is described in detail in Japanese Patent Application No. 1-339830.

[0017]

[Operation] The alumina bricks (high alumina or ultra-high alumina) lined in the combustion zone of conventional carbon black manufacturing furnaces have a fire resistance limit of approximately 1900°C, and if they come into contact with combustion gas above this temperature, they will melt. It causes loss phenomenon and deteriorates. In the present invention, the oxide ceramic refractory material selected as the lining brick for the combustion zone is
It has a fire resistance temperature exceeding 0°C and excellent spalling resistance. For this reason, the temperature of the combustion gas generated in the combustion zone is 200%
Even when the temperature exceeds 0°C, stable usage conditions are ensured for a long period of time.

Furthermore, all of the oxide ceramic refractories used in the present invention have a high melting point and low thermal conductivity, resulting in a large temperature gradient in the thickness direction of the brick. For this reason, compared to alumina bricks, the wall thickness can be made thinner to maintain a constant temperature gradient, and this material is directly lined with the inner surface of a cooling cell with a double metal cylinder structure for forced cooling. With this structure, it is possible to form a lightweight and compact combustion zone in which situations such as overheating and melting of the metal cylinder do not occur. In addition, by using air or oxygen-enriched air as the cooling medium flowing in the cooling cell, and by using a structural design that uses the medium preheated by the heat exchange effect as a combustion-supporting gas, the fuel It can effectively function to promote the combustion of oil and raise the temperature.

Through the above-mentioned effects, it is possible to produce carbon black having both a high specific surface area and a high coloring power under efficient and stable operating conditions.

[0020]

【Example】

Example 1 Furnace head equipped with combustion burners in the axial direction of the furnace, inner diameter 500 m
m, an outer diameter of 530 mm, a length of 500 mm, a steel double cylinder structure cooling cell is lined with 70 mm thick oxide ceramic refractory bricks to form a combustion zone,
An inner diameter of 60 mm, equipped with a raw oil introduction nozzle in this combustion area,
100 mm inner diameter, 1000 mm length with a narrow throat reaction zone of 200 mm length and a quench device at the rear.
A carbon black production furnace was installed with a continuous reaction stop zone of mm. At this time, the exhaust pipe of the cooling cell was connected to the combustion chamber, and the preheated cooling medium was designed in a circulation path where the entire amount was consumed as combustion-supporting gas.

[0021] As the oxide ceramic refractory brick, a zirconia layer (60 m
Using a zirconia/hafnia-based material with a laminated two-layer structure in which a hafnia layer (10 mm) is bonded with solid solution, the hafnia layer is placed inside the cooling cell in the combustion area including the raw material introduction position, with the hafnia layer as the exposed surface in the furnace. I tensed. The furnace body on the downstream side was constructed using ordinary high alumina bricks.

Propane was used as a fuel and supplied from a combustion burner, and oxygen-enriched air was used as a cooling medium for the cooling cell. The feedstock oil was atomized and injected radially into the combustion gas stream from the periphery together with atomizing nitrogen gas through external mixing type introduction nozzles (two). A quench for stopping the reaction was set at a position 900 mm downstream from the entrance of the reaction stopping area. The raw material oil has a specific gravity (15/4 °C) of 1.046, a toluene insoluble content of 0.14%, and a correlation coefficient (BMCI) of 134.
, sulfur content 0.1%, initial boiling point 195℃, Na ion 3
．． An aromatic hydrocarbon oil containing 0 ppm of K ions and 0.3 ppm of K ions was used.

Table 1 shows the characteristics of carbon black produced using the above-mentioned production furnace in comparison with the production conditions.

Example 2 Oxide-based ceramic refractory bricks were prepared using a zirconia layer containing yttria with a stabilization rate of 90% (10 mm) and a zirconia layer containing calcium oxide with a stabilization rate of 84% (60 mm).
Instead of using zirconia with an integrated two-layer structure in the case of m), an yttria-containing zirconia layer was used as an exposed surface in the furnace to line the cooling cell in the combustion area including the raw oil introduction position. Carbon black was manufactured using a manufacturing furnace having the same furnace shape as in Example 1 in all other respects, and the characteristics of the obtained carbon black are listed in Table 1 in comparison with the manufacturing conditions.

Example 3 An oxide ceramic refractory brick was coated with an alumina layer (50 m
Instead of using a two-layer alumina/yttria refractory material that has a laminated and integrated yttria layer (m) and a yttria layer (20 mm), the yttria layer was used as an exposed surface inside the furnace to line the cooling cell in the combustion zone, including the raw oil introduction position. . Carbon black was manufactured using a manufacturing furnace having the same furnace shape as in Example 1 in all other respects, and the characteristics of the obtained carbon black are listed in Table 1 in comparison with the manufacturing conditions.

Comparative Example 1 The combustion chamber was made of high alumina refractory bricks with a wall thickness of 200 mm (
It was constructed using a fireproof/insulating three-layer structure, with an inner diameter of 400 mm, an outer diameter of 800 mm, and a length of 500 mm, with no cooling cell installed. Other than that, carbon black was manufactured using a manufacturing furnace having the same furnace configuration as in Example 1, and the characteristics of the obtained carbon black are listed in Table 1 in comparison with the manufacturing conditions.

[0027]

From the results in Table 1, Examples 1 to 3 that meet the requirements of the present invention enable a more stable thermal decomposition reaction under high-temperature combustion gas than Comparative Example 1. It is recognized that the properties such as coloring strength and 24M4DBP are relatively increased. Further, in the carbon black production furnaces of each example, no evidence of melting damage or cracks was observed on the furnace walls after operation, and no damage was found in the cooling cells.

[0029]

[Effects of the Invention] As described above, by using the carbon black production furnace of the present invention, it is possible to generate combustion gas of 2000°C or higher, and to operate the furnace stably, resulting in high 24M4DBP and coloring power. High quality carbon black can be efficiently produced. Therefore, it is extremely useful as a carbon black production furnace for large tires that require high wear resistance, high-performance tires for passenger cars that require excellent grip performance, and high-grade color tires.

Claims (2)

[Claims] Claim 1: A combustion zone in which fuel is combusted to produce high-temperature combustion gas, a reaction zone in which feedstock oil is injected into the high-temperature combustion gas stream in a subsequent narrow diameter section and converted into carbon black by a pyrolysis reaction, In a furnace configuration consisting of a reaction stop zone that rapidly cools the gas and terminates the thermal decomposition reaction, the combustion zone upstream of the feedstock oil introduction position has a metal double cylinder structure with a heat exchange function. In the cell below (1) ~
A carbon black manufacturing furnace characterized in that it is lined with the oxide ceramic refractory material according to any one of (3). (1) Partially stabilized or fully stabilized zirconia (ZrO2) layer and hafnia (HfO2) containing one or more stabilizers selected from oxides of calcium, magnesium, yttrium, and cerium.
A zirconia/hafnia-based refractory material with a laminated two-layer structure in which the layers are solid-solution bonded at the interface. (2) Partially stabilized or fully stabilized zirconia layer containing yttria (Y2O3) and calcium oxide (
A zirconia refractory material with a two-layer structure consisting of partially or fully stabilized zirconia layers containing CaO). (3) An alumina/yttria-based refractory material with a two-layer structure in which an alumina (Al2O3) layer and an yttria layer are laminated and integrated. Claim 2: A claim comprising a circulation path for flowing air or oxygen-enriched air as a cooling medium into the cooling cell and using the air or oxygen-enriched air preheated by a heat exchange function as a combustion supporting gas for fuel oil. Item 1. Carbon black production furnace according to item 1.