Method for producing modified recycled carbon black and modified recycled carbon black

Abstract

A method for producing modified recycled carbon black, characterized in that it comprises the following main burner modification step: a main burner fuel, an oxygen-containing gas and raw recycled carbon black are continuously supplied to a main burner that burns the fuel to generate a flame, the main burner fuel is burned, a flame is continuously generated in the main burner, and the raw recycled carbon black is introduced into the flame, and the main burner total carbon combustion rate shown in the following formula (1): main burner total carbon combustion rate (%) = (A / (B+C)) × 100 (1) is lower than 100.0% by the flame. According to the present invention, a method for producing modified recycled carbon black that can effectively remove rubber residue attached to the surface of the raw recycled carbon black and can be continuously performed can be provided.

Description

Technical Field

[0001] The present invention relates to recycled carbon black having a modified surface state, a method for producing the same, and a rubber composition using the same. Background Art

[0002] In recent years, efforts such as carbon neutrality and sustainability have become popular in order to reduce the impact on the global environment. In addition, the carbon black industry has been studying the use of recycled carbon black obtained by thermal cracking of waste tires as part of sustainable activities.

[0003] As a method for producing recycled carbon black based on thermal cracking of waste tires, for example, Patent Document 1 discloses that waste tires are thermally cracked at about 500° C. while circulating nitrogen gas, and Patent Document 2 discloses that waste rubber is treated in a two-stage thermal cracking process and the obtained material is crushed.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 5813985

[0007] Patent Document 2: WO2013 / 095145A1 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] However, rubber residues mainly composed of rubber carbonized products adhere to the surface of recycled carbon black obtained by thermal cracking of rubber products such as waste tires. When the rubber residues are mixed in the rubber composition, the adsorption of carbon black and rubber components is hindered.

[0010] Therefore, in the recycled carbon black, the bonding with the rubber component is weak, so there is a problem that the reinforcement of the rubber product is low.

[0011] Therefore, recycled carbon black with high reinforcing property for rubber products is sought. Furthermore, from an industrial point of view, a method for producing recycled carbon black with high reinforcing property for rubber products continuously rather than batchwise is required.

[0012] Therefore, an object of the present invention is to provide a method for producing modified recycled carbon black which can effectively remove rubber residues adhering to the surface of recycled carbon black and can be performed continuously.

[0013] Solutions for solving problems

[0014] The present inventors have conducted intensive research and found that: a main burner fuel, an oxygen-containing gas and recycled carbon black with carbides attached thereto are continuously supplied to a main burner that burns the fuel to generate a flame, the main burner fuel is burned, and a flame is continuously generated in the main burner, and the recycled carbon black with rubber carbides attached thereto is introduced into the flame, and when passing through the flame, the rubber residue attached to the surface of the recycled carbon black is rapidly oxidized and decomposed by the high-temperature flame, thereby completing the present invention.

[0015] That is, the present invention provides the following solutions:

[0016] (1) A method for producing modified recycled carbon black, characterized in that it comprises the following main burner modification step: a main burner fuel, an oxygen-containing gas, and recycled carbon black with rubber carbide attached thereto are continuously supplied to a main burner that burns the fuel to generate a flame, the main burner fuel is burned, a flame is continuously generated in the main burner, and the recycled carbon black with rubber carbide attached thereto is introduced into the flame, and the recycled carbon black with rubber carbide attached thereto is passed through the flame,

[0017] The total carbon combustion rate of the main burner shown in the following formula (1) is made lower than 100.0%:

[0018] Total carbon combustion rate of main burner (%) = (A / (B+C)) × 100 (1)

[0019] (In formula (1), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of the recycled carbon black with rubber carbide attached to the main burner, and C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner.).

[0020] (2) The method for producing modified and recycled carbon black according to (1) is characterized in that the main burner modification step is a main burner modification step (1) in which the main burner flame combustion rate represented by the following formula (2) is 100.0% or more:

[0021] Main burner flame combustion rate (%) = (A / C) × 100 (2)

[0022] (In the formula (2), A is the amount of oxygen supplied to the main burner, and C is the theoretical amount of oxygen required to completely burn the main burner fuel supplied to the main burner.)

[0023] (3) The method for producing modified and recycled carbon black according to (1) is characterized in that the main burner modification step is a main burner modification step (2) in which the main burner flame combustion rate represented by the following formula (2) is lower than 100.0%:

[0024] Main burner flame combustion rate (%) = (A / C) × 100 (2)

[0025] (In the formula (2), A is the amount of oxygen supplied to the main burner, and C is the theoretical amount of oxygen required to completely burn the main burner fuel supplied to the main burner.)

[0026] (4) The method for producing modified recycled carbon black according to (2) is characterized in that it comprises the following auxiliary burner modification step: an auxiliary burner is provided at a rear stage closer to the main burner than the main burner to burn fuel for the auxiliary burner to generate flame, a flame is continuously generated in the auxiliary burner, and recycled carbon black subjected to the main burner modification step (1) is introduced into the flame generated in the auxiliary burner, and the recycled carbon black is passed through the flame.

[0027] The auxiliary burner reforming step is an auxiliary burner reforming step (1) for making the auxiliary burner flame combustion rate represented by the following formula (3) to be 100.0% or more and making the total carbon combustion rate of all burners represented by the following formula (4) to be less than 100.0%:

[0028] Auxiliary burner flame combustion rate (%) = (D / E) × 100 (3)

[0029] (In formula (3), D is the amount of oxygen supplied to the auxiliary burner, and E is the theoretical amount of oxygen required to completely burn the auxiliary burner fuel supplied to the auxiliary burner.)

[0030] Total carbon combustion rate of all burners (%) = ((A+D) / (B+C+E)) × 100 (4)

[0031] (In formula (4), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, D refers to the amount of oxygen supplied to the auxiliary burner, and E refers to the theoretical amount of oxygen required for complete combustion of the auxiliary burner fuel supplied to the auxiliary burner.).

[0032] (5) The method for producing modified recycled carbon black according to (2) is characterized in that it comprises the following auxiliary burner modification step: an auxiliary burner is provided at a rear stage closer to the main burner than the main burner to burn fuel for the auxiliary burner to generate flame, a flame is continuously generated in the auxiliary burner, and recycled carbon black subjected to the main burner modification step (1) is introduced into the flame generated in the auxiliary burner, and the recycled carbon black is passed through the flame.

[0033] The auxiliary burner reforming step is an auxiliary burner reforming step (2) for making the auxiliary burner flame combustion rate represented by the following formula (3) lower than 100.0%, and making the total carbon combustion rate of all burners represented by the following formula (4) lower than 100.0%:

[0034] Auxiliary burner flame combustion rate (%) = (D / E) × 100 (3)

[0035] (In formula (3), D is the amount of oxygen supplied to the auxiliary burner, and E is the theoretical amount of oxygen required to completely burn the auxiliary burner fuel supplied to the auxiliary burner.)

[0036] Total carbon combustion rate of all burners (%) = ((A+D) / (B+C+E)) × 100 (4)

[0037] (In formula (4), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, D refers to the amount of oxygen supplied to the auxiliary burner, and E refers to the theoretical amount of oxygen required for complete combustion of the auxiliary burner fuel supplied to the auxiliary burner.).

[0038] (6) The method for producing modified recycled carbon black according to (3) is characterized in that it comprises the following auxiliary burner modification step: an auxiliary burner is provided at a rear stage closer to the main burner than the main burner to burn fuel for the auxiliary burner to generate flame, a flame is continuously generated in the auxiliary burner, and recycled carbon black subjected to the main burner modification step (2) is introduced into the flame generated in the auxiliary burner, and the recycled carbon black is passed through the flame.

[0039] The auxiliary burner reforming step is an auxiliary burner reforming step (1) for making the auxiliary burner flame combustion rate represented by the following formula (3) to be 100.0% or more and making the total carbon combustion rate of all burners represented by the following formula (4) to be less than 100.0%:

[0040] Auxiliary burner flame combustion rate (%) = (D / E) × 100 (3)

[0041] (In formula (3), D is the amount of oxygen supplied to the auxiliary burner, and E is the theoretical amount of oxygen required to completely burn the auxiliary burner fuel supplied to the auxiliary burner.)

[0042] Total carbon combustion rate of all burners (%) = ((A+D) / (B+C+E)) × 100 (4)

[0043] (In formula (4), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, D refers to the amount of oxygen supplied to the auxiliary burner, and E refers to the theoretical amount of oxygen required for complete combustion of the auxiliary burner fuel supplied to the auxiliary burner.).

[0044] (7) The method for producing modified recycled carbon black according to (3) is characterized in that it comprises the following auxiliary burner modification step: an auxiliary burner is provided at a rear stage closer to the main burner than the main burner to burn fuel for the auxiliary burner to generate flame, a flame is continuously generated in the auxiliary burner, and recycled carbon black subjected to the main burner modification step (2) is introduced into the flame generated in the auxiliary burner, and the recycled carbon black is passed through the flame.

[0045] The auxiliary burner reforming step is an auxiliary burner reforming step (2) for making the auxiliary burner flame combustion rate represented by the following formula (3) lower than 100.0%, and making the total carbon combustion rate of all burners represented by the following formula (4) lower than 100.0%:

[0046] Auxiliary burner flame combustion rate (%) = (D / E) × 100 (3)

[0047] (In formula (3), D is the amount of oxygen supplied to the auxiliary burner, and E is the theoretical amount of oxygen required to completely burn the auxiliary burner fuel supplied to the auxiliary burner.)

[0048] Total carbon combustion rate of all burners (%) = ((A+D) / (B+C+E)) × 100 (4)

[0049] (In formula (4), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, D refers to the amount of oxygen supplied to the auxiliary burner, and E refers to the theoretical amount of oxygen required for complete combustion of the auxiliary burner fuel supplied to the auxiliary burner.).

[0050] (8) The method for producing modified and recycled carbon black according to (2) or (3), characterized in that it comprises the following auxiliary fuel thermal cracking step: a fuel nozzle is provided at a later stage than the aforementioned main burner, and an auxiliary fuel is introduced from the fuel nozzle into the flame generated in the aforementioned main burner or in the vicinity thereof, thereby thermally cracking the auxiliary fuel,

[0051] The auxiliary fuel thermal cracking process is an auxiliary fuel thermal cracking process in which the total carbon combustion rate of the entire reaction represented by the following formula (5) is lower than 100.0%:

[0052] Total carbon combustion rate of all reactions (%) = (A / (B+C+F)) × 100 (5)

[0053] (In formula (5), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of main burner fuel supplied to the main burner, and F refers to the theoretical amount of oxygen required for complete combustion of auxiliary fuel supplied from the fuel nozzle.)

[0054] (9) The method for producing modified recycled carbon black according to (1) is characterized in that, before the main burner modification step, a particle size adjustment step of crushing and / or classifying the recycled carbon black to which the rubber carbide is attached is provided.

[0055] (10) A modified recycled carbon black obtained by carrying out the method for producing a modified recycled carbon black according to any one of (1) to (9).

[0056] Effects of the Invention

[0057] According to the present invention, a method for producing modified recycled carbon black can be provided, which can effectively and continuously remove rubber residues adhering to the surface of recycled carbon black. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A manufacturing apparatus for modified and recycled carbon black is provided for implementing an example of a method for manufacturing modified and recycled carbon black according to the present invention.

[0059] Figure 2 This is a schematic diagram showing an example of a main burner reforming process.

[0060] Figure 3 It is a schematic diagram showing an example of a main burner reforming step and an auxiliary burner reforming step.

[0061] Figure 4 This is a schematic end view showing the structure of an example of a main burner.

[0062] Figure 5 This is a schematic end view showing the structure of another embodiment of the main burner.

[0063] Figure 6 This is a Raman spectrum of an example of the modified and recycled carbon black of the present invention.

[0064] Figure 7This is a Raman spectrum of an example of recycled carbon black before modification. DETAILED DESCRIPTION

[0065] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings as appropriate. The following detailed description of the present invention is one example of the embodiments, and the present invention is not to be construed as being limited to the embodiments.

[0066] Figure 1 This is a schematic diagram of a manufacturing apparatus for modified recycled carbon black, which is an example of a method for implementing the manufacturing method of modified recycled carbon black of the present invention. Figure 1 In the present invention, the manufacturing device 1 for modified and recycled carbon black comprises: a main burner 3, a burner modification section 2 provided with an auxiliary burner 4 and a supply pipe 5 for cooling water, and a collecting section 7 provided with a bag filter inside. The burner modification section 2 and the collecting section 7 are connected by a connecting pipe 6. The main burner 3 is arranged on the upper side of the burner modification section 2, and the main burner 3 is connected with a supply pipe for the main burner fuel 11, a supply pipe for the oxygen-containing gas 12, and a supply pipe for the raw material recycled carbon black and the conveying gas 13. In addition, the auxiliary burner 4 is connected with a supply pipe for the auxiliary burner fuel 14 and the oxygen-containing gas 15.

[0067] like Figure 2 As shown, in the burner reforming section 2, when the fuel is burned in the main burner 3 to generate the flame 21, the main burner fuel 11, the oxygen-containing gas 12, the raw material recycled carbon black, and the conveying gas 13 are continuously supplied to the main burner 3 from the fuel supply side to the flame 21 while the flame 21 is generated in the main burner 3, so that the flame 21 is continuously generated in the main burner 3, and the raw material recycled carbon black is introduced from the fuel supply side into the flame 21 generated in the main burner 3 and passes through the flame 21. Then, when the raw material recycled carbon black passes through the flame 21 generated in the main burner 3, the surface of the recycled carbon black is modified. Figure 2 , the moving direction 22 of the raw material recycled carbon black is shown, and the recycled carbon black moves from the fuel supply side to the front end side of the flame 21 generated in the main burner 3.

[0068] like Figure 3 As shown, in the burner reforming section 2, in addition to the reforming using the main burner 3, reforming using the auxiliary burner 4 can also be performed. Figure 2Similarly, after the recycled carbon black is introduced into the flame 21 generated in the main burner 3 and passes through the flame 21, the fuel is burned in the auxiliary burner 4 to generate the flame 23. In the state where the flame 23 is generated in the auxiliary burner 4, the recycled carbon black that has passed through the flame 21 generated in the main burner 3 is introduced into the flame 23 generated in the auxiliary burner 4 and passes through the flame 23. Then, when the recycled carbon black that has passed through the flame 21 generated in the main burner 3 passes through the flame 23 generated in the auxiliary burner 4, the surface of the recycled carbon black is further modified. Figure 3 The moving direction 22 of the recycled carbon black is shown in the figure, but the recycled carbon black passes through the flame 21 generated in the main burner 3, is introduced into the flame 23 generated in the auxiliary burner 4, and passes through the flame 23.

[0069] It should be noted that in the burner reforming section 2, reforming of the recycled carbon black using the main burner 3 is essential, and reforming of the recycled carbon black using the auxiliary burner 4 is performed as necessary.

[0070] After the raw material recycled carbon black passes through the flame generated in the main burner 3 in the burner modification section 2, or passes through the flame generated in the main burner 3 and the flame generated in the auxiliary burner 4, cooling water is supplied from the cooling water supply pipe 5 arranged below the burner modification section 2 to the burner modification section 2, so that the recycled carbon black contacts the cooling water 16 and is cooled.

[0071] Next, the cooled recycled carbon black and gases such as combustion gas, decomposition gas and water vapor are introduced into the collecting section 7 through the connecting pipe 6, and are separated into gas 17 and modified recycled carbon black 18 by a bag filter provided in the collecting section 7 to obtain modified recycled carbon black 18.

[0072] The method for producing modified recycled carbon black of the present invention is characterized in that it comprises the following main burner modification step: a main burner fuel, an oxygen-containing gas and recycled carbon black with rubber carbide attached are continuously supplied to a main burner that burns the fuel to generate a flame, the main burner fuel is burned, a flame is continuously generated in the main burner, and the recycled carbon black with rubber carbide attached is introduced into the flame, and the recycled carbon black with rubber carbide attached is passed through the flame.

[0073] The total carbon combustion rate of the main burner shown in the following formula (1) is made lower than 100.0%:

[0074] Total carbon combustion rate of main burner (%) = (A / (B+C)) × 100 (1)

[0075] (In the formula, A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of the recycled carbon black with rubber carbide attached to the main burner, and C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner.).

[0076] The main burner modification step of the method for manufacturing modified recycled carbon black of the present invention is the following step: main burner fuel, oxygen-containing gas and recycled carbon black with carbides attached are continuously supplied to the main burner that burns the fuel to generate flame, thereby modifying the surface of the recycled carbon black with carbides attached.

[0077] In the main burner modification process, the recycled carbon black with carbide attached as the raw material for modification (hereinafter, also referred to as raw material recycled carbon black) is a carbon black obtained by thermal cracking rubber products such as waste tires, and is a carbon black with rubber residues with rubber carbide as the main component attached to the surface. For example, the raw material recycled carbon black used as the raw material for modification includes: PB365 manufactured by Enrestec, Inc., BolderBlack manufactured by Bolder Industries, DE-Black manufactured by DeltaEnergy LLC., MondoBlack manufactured by ECOLOMONDO, etc. This raw material recycled carbon black can be manufactured by any manufacturing method without special restrictions, for example, the method described in Patent Document 2 can be cited.

[0078] The raw material recycled carbon black is the following carbon black: in the Raman spectrum obtained by measuring at an excitation wavelength of 532 nm according to laser Raman spectroscopy, the carbon black at 1350±10 cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 A carbon black having a peak intensity (G band) having a peak top within a range of 112 to 200, preferably 112 to 190 (hereinafter, referred to as the G band intensity when the D band intensity is 100). The G band intensity when the D band intensity is 100 will be described later.

[0079] The raw material recycled carbon black is obtained by modifying the recycled carbon black obtained by thermal cracking rubber products such as waste tires, and therefore the ash content of the raw material recycled carbon black is, for example, 3.0% to 50.0%, preferably 5.0% to 35.0%.

[0080] In addition, in this invention, an ash content means the value measured by the method defined in JIS K 6218-2.

[0081] The fuel for the main burner in the main burner modification process is not particularly limited as long as it burns and generates a flame through the oxygen in the oxygen-containing gas when it comes into contact with the flame generated in the main burner. For example, methane, ethane, propane, natural gas, hydrocarbon gases such as ethylene and acetylene, hydrogen, ammonia, their mixed gases, gases generated by thermal cracking of rubber and plastics, etc., in addition, as liquid fuels, aromatic hydrocarbons such as naphthalene and anthracene, coal-based hydrocarbons such as creosote and tall oil, petroleum-based heavy oils such as FCC residue oil and ethylene heavy oil, acetylene-based unsaturated hydrocarbons, aliphatic hydrocarbons such as hexane, vegetable oils such as rapeseed oil and soybean oil, oils generated by thermal cracking of rubber and plastics, etc., are preferably methane, ethane, propane, natural gas, ethylene, acetylene and other hydrocarbon gases in terms of higher flame temperature.

[0082] Examples of the oxygen-containing gas in the main burner reforming step include oxygen, oxygen-containing gas, and air. From the viewpoint of economic efficiency, air is preferred.

[0083] Then, in the main burner modification process, the main burner fuel, oxygen-containing gas and recycled carbon black with carbides attached are continuously supplied to the flame from the fuel supply side into the main burner that burns the fuel to generate a flame, thereby burning the main burner fuel, continuously generating a flame in the main burner, and introducing the raw material recycled carbon black into the flame generated in the main burner and passing through the flame.

[0084] In the main burner reforming process, the raw material recycled carbon black is supplied to the main burner using a transport gas. The transport gas may be an inert gas such as nitrogen, argon, helium, or an oxygen-containing gas such as oxygen, oxygen-containing gas, or air. As the transport gas, an oxygen-containing gas is preferably used because the raw material recycled carbon black is easily oxidized.

[0085] In the main burner reforming step, the raw material recycled carbon black, the oxidizing gas, and the main burner fuel conveyed by the conveying gas can be supplied to the main burner through respective paths. In addition, in the main burner reforming step, first, the raw material recycled carbon black and the oxidizing gas can be mixed, and the obtained mixed flow and the main burner fuel can be supplied to the main burner.

[0086] In the main burner modification process, when the raw material recycled carbon black and the oxygen-containing gas are introduced into the flame, a mixed flow of the raw material recycled carbon black and the oxygen-containing gas is formed and introduced into the flame, so that the oxygen-containing gas can be present in the vicinity of the raw material recycled carbon black when introduced into the flame. Therefore, the contact between the raw material recycled carbon black and the oxygen-containing gas can take precedence over the contact between the raw material recycled carbon black and the fuel gas, thereby easily causing oxidation of the raw material recycled carbon black.

[0087] In the main burner reforming step, (i) when the raw material recycled carbon black and the transport gas, the oxygen-containing gas and the main burner fuel are introduced into the flame, the raw material recycled carbon black is present in the center when the raw material recycled carbon black is observed from a plane perpendicular to the moving direction of the raw material recycled carbon black, the oxygen-containing gas is present so as to surround the raw material recycled carbon black, and the main burner fuel is present so as to surround the oxygen-containing gas. The raw material recycled carbon black and the transport gas, the oxygen-containing gas and the main burner fuel can be introduced into the flame, and further, (ii) when the raw material recycled carbon black and the transport gas, the oxygen-containing gas and the main burner fuel are introduced into the flame, the main burner fuel is present in the center when the raw material recycled carbon black is observed from a plane perpendicular to the moving direction of the raw material recycled carbon black. In the center, oxygen-containing gas is present in a manner surrounding the fuel for the main burner, and raw material recycling carbon black is present in a manner surrounding the oxygen-containing gas, and raw material recycling carbon black and conveying gas, oxygen-containing gas and fuel for the main burner can be introduced into the flame, (iii) for the flame, when raw material recycling carbon black and conveying gas, oxygen-containing gas and fuel for the main burner are introduced, when the surface is observed perpendicular to the moving direction of the raw material recycling carbon black, raw material recycling carbon black is present in the center, and fuel for the main burner is present in a manner surrounding the raw material recycling carbon black, and oxygen-containing gas is present in a manner surrounding the fuel for the main burner, and raw material recycling carbon black and conveying gas, oxygen-containing gas and fuel for the main burner can be introduced into the flame. Moreover, among these, when introducing into the flame, oxygen-containing gas can be present near the raw material recycling carbon black, so that the contact between the raw material recycling carbon black and the oxygen-containing gas can be prioritized over the contact between the raw material recycling carbon black and the fuel gas, so that the oxidation of the raw material recycling carbon black can be easily caused, preferably (i) and (ii).

[0088] In the main burner reforming process, the temperature of the flame generated in the main burner is high. Therefore, when the raw material recycled carbon black passes through the flame generated in the main burner, the rubber residue mainly composed of rubber carbide attached to the surface of the raw material recycled carbon black is rapidly oxidized and decomposed and removed. In addition, in the main burner reforming process, the raw material recycled carbon black is exposed to high temperature only during the period when the main burner fuel and the oxygen-containing gas are simultaneously supplied to the main burner and the raw material recycled carbon black passes through the flame generated in the main burner. Therefore, the exposure time to high temperature is short. Therefore, the surface of the raw material recycled carbon black is selectively oxidized.

[0089] On the other hand, when the raw recycled carbon black and the oxidizing gas are simultaneously supplied to the heating furnace and the raw recycled carbon black is subjected to oxidation treatment in the heating furnace, the temperature to which the raw recycled carbon black is exposed does not become higher than the temperature of the flame, and the time for which the raw recycled carbon black is heated becomes longer. Furthermore, if the temperature to which the raw recycled carbon black is exposed is low, oxidation proceeds from the portion that is easily oxidized and decomposed, and if the time is long, oxidation proceeds inside the raw recycled carbon black particles, forming pores in the raw recycled carbon black.

[0090] In the main burner reforming step, the main burner total carbon combustion rate represented by the following formula (1) is made lower than 100.0%:

[0091] Total carbon combustion rate of main burner (%) = (A / (B+C)) × 100 (1)

[0092] (In the formula, A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of the recycled carbon black with rubber carbide attached to the main burner, and C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner.).

[0093] It should be noted that A is the amount of oxygen supplied to the main burner per unit time, and B is the amount of theoretical oxygen required per unit time for complete combustion of the carbon component by treating all components other than ash of the recycled carbon black with rubber carbide attached to the main burner as carbon and calculating the carbon component, and C is the amount of theoretical oxygen required per unit time for complete combustion of the main burner fuel supplied to the main burner.

[0094] In the main burner modification process, controlling the main burner total carbon combustion rate to be lower than 100.0% means that the main burner fuel and the raw material recycled carbon black supplied to the main burner are not completely burned. When the main burner fuel and the raw material recycled carbon black supplied to the main burner are completely burned, the recycled carbon black will be oxidized and disappear, and the modified recycled carbon black cannot be obtained. Therefore, by making the main burner total carbon combustion rate lower than 100.0%, modification based on oxidative decomposition of the surface of the raw material recycled carbon black can be performed. From the viewpoint of the balance between the amount of recovered modified particles obtained and the amount of rubber carbide that needs to be removed, the main burner total carbon combustion rate is preferably 10.0% or more and 90.0% or less, and more preferably 15.0% or more and 80.0% or less.

[0095] In the method for producing modified recycled carbon black of the present invention, as a main burner modification step, there can be cited a main burner modification step (1) in which the main burner flame combustion rate represented by the following formula (2) is 100.0% or more:

[0096] Main burner flame combustion rate (%) = (A / C) × 100 (2)

[0097] (In the formula, A refers to the amount of oxygen supplied to the main burner, and C refers to the theoretical amount of oxygen required to completely burn the main burner fuel supplied to the main burner.)

[0098] In the main burner modification step (1), controlling the main burner flame combustion rate to 100.0% or more means that the main burner fuel supplied to the main burner is completely burned. In the main burner modification step (1), by making the main burner flame combustion rate 100.0% or more, the surface of the raw material recycled carbon black becomes easy to be oxidized, thereby improving the oxidation removal of the residual rubber component attached to the raw material recycled carbon black. From the viewpoint of the balance between the flame temperature and the amount of rubber carbonized matter to be removed, the main burner flame combustion rate is preferably 105.0% or more and 500.0% or less, more preferably 110.0% or more and 400.0% or less. It should be noted that the main burner modification step (1) is a scheme of the main burner modification step, and therefore, the main burner total carbon combustion rate is lower than 100.0%, preferably 15.0% or more and 90.0% or less, and more preferably 20.0% or more and 80.0% or less.

[0099] In the method for producing modified recycled carbon black of the present invention, as a main burner modification step, there can be cited a main burner modification step (2) in which the main burner flame combustion rate represented by the following formula (2) is lower than 100.0%:

[0100] Main burner flame combustion rate (%) = (A / C) × 100 (2)

[0101] (In the formula, A refers to the amount of oxygen supplied to the main burner, and C refers to the theoretical amount of oxygen required to completely burn the main burner fuel supplied to the main burner.)

[0102] In the main burner modification step (2), controlling the main burner flame combustion rate to be lower than 100.0% means that the main burner fuel supplied to the main burner is not completely burned. Moreover, the main burner fuel is heated under the condition that the main burner fuel supplied to the main burner is not completely burned, so that the main burner fuel undergoes thermal cracking to generate carbides. Therefore, by attaching the generated carbides to the surface-modified recycled carbon black when the flame is generated in the main burner, the specific surface area of ​​the modified recycled carbon black can be adjusted. From the viewpoint of the appropriate value of the specific surface area for improving the reinforcement of rubber, the main burner flame combustion rate is preferably 20.0% or more and 99.0% or less, and more preferably 30.0% or more and 95.0% or less. It should be noted that the main burner reforming step (2) is one embodiment of the main burner reforming step, and therefore the main burner total carbon combustion rate is lower than 100.0%, preferably 15.0% to 90.0%, and more preferably 20.0% to 80.0%.

[0103] The manufacturing method of modified and recycled carbon black of the present invention may include the following auxiliary burner modification step: an auxiliary burner is provided at a rear section closer to the main burner to burn fuel for the auxiliary burner to generate flame, flame is continuously generated in the auxiliary burner, and recycled carbon black subjected to the main burner modification step is introduced into the flame generated in the auxiliary burner and passed through the flame. In the manufacturing method of modified and recycled carbon black of the present invention, the auxiliary burner modification step is performed as needed.

[0104] The auxiliary burner modification process of the manufacturing method of modified recycled carbon black of the present invention is the following process: at a rear section closer to the flame generated in the main burner, the auxiliary burner is used to burn fuel to generate a flame, and the recycled carbon black that has undergone the main burner modification process is continuously supplied to be introduced into the flame generated in the auxiliary burner, and the surface of the recycled carbon black is modified by the flame.

[0105] What is reformed in the auxiliary burner reforming step is the recycled carbon black after the main burner reforming step, that is, the recycled carbon black that passes through the flame generated in the main burner or the recycled carbon black that passes near the front end of the flame generated in the main burner.

[0106] In the auxiliary burner reforming step, auxiliary burner fuel and oxygen-containing gas are continuously supplied to the auxiliary burner to continuously generate flames. The position of the flame generated in the auxiliary burner is at the front end of the flame generated in the main burner, inside the flame generated in the main burner and near the front end of the flame, and outside the flame generated in the main burner and near the front end of the flame, preferably outside the flame generated in the main burner and near the front end of the flame.

[0107] The auxiliary burner fuel in the auxiliary burner modification process is not particularly limited as long as it burns and generates a flame through the oxygen in the oxygen-containing gas when it comes into contact with the flame generated in the auxiliary burner. For example, methane, ethane, propane, natural gas, hydrocarbon gases such as ethylene and acetylene, hydrogen, ammonia, their mixed gases, gases generated by thermal cracking of rubber and plastics, etc., in addition, as liquid fuels, aromatic hydrocarbons such as naphthalene and anthracene, coal-based hydrocarbons such as creosote and tall oil, petroleum-based heavy oils such as FCC residual oil and ethylene heavy oil, acetylene-based unsaturated hydrocarbons, aliphatic hydrocarbons such as hexane, vegetable oils such as rapeseed oil and soybean oil, oils generated by thermal cracking of rubber and plastics, etc., are preferred. In terms of the higher flame temperature, hydrocarbon gases such as methane, ethane, propane, natural gas, ethylene, acetylene, etc. are preferred.

[0108] Examples of the oxygen-containing gas used in the auxiliary burner reforming step include oxygen, oxygen-containing gas, and air. From the viewpoint of economic efficiency, air is preferred.

[0109] Then, in the auxiliary burner modification process, the auxiliary burner is burned with fuel to generate a flame in the auxiliary burner, a flame is continuously generated in the auxiliary burner, and recycled carbon black after the main burner modification process is introduced into the flame generated in the auxiliary burner and passes through the flame.

[0110] As the auxiliary burner reforming step, there can be mentioned an auxiliary burner reforming step (1) in which the auxiliary burner flame combustion rate represented by the following formula (3) is made 100.0% or more and the total carbon combustion rate of all burners represented by the following formula (4) is made less than 100.0%:

[0111] Auxiliary burner flame combustion rate (%) = (D / E) × 100 (3)

[0112] (Wherein, D is the amount of oxygen supplied to the auxiliary burner, and E is the theoretical amount of oxygen required to completely burn the auxiliary burner fuel supplied to the auxiliary burner.)

[0113] Total carbon combustion rate of all burners (%) = ((A+D) / (B+C+E)) × 100 (4)

[0114] (Wherein, A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of the recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, D refers to the amount of oxygen supplied to the auxiliary burner, and E refers to the theoretical amount of oxygen required for complete combustion of the auxiliary burner fuel supplied to the auxiliary burner.).

[0115] It should be noted that D is the amount of oxygen supplied to the auxiliary burner per unit time.

[0116] In addition, E refers to the amount per unit time of the theoretical amount of oxygen required to completely burn the auxiliary burner fuel supplied to the auxiliary burner.

[0117] In the auxiliary burner modification step (1), controlling the total carbon combustion rate of all burners to be less than 100.0% means that the auxiliary burner fuel and recycled carbon black supplied to the auxiliary burner are not completely burned. When the auxiliary burner fuel and recycled carbon black supplied to the auxiliary burner are completely burned, the recycled carbon black will be oxidized and disappear, and the modified recycled carbon black cannot be obtained. From the viewpoint of the balance between the amount of recovered modified particles obtained and the amount of rubber carbide to be removed, the total carbon combustion rate of all burners is preferably 15.0% or more and 90.0% or less, and more preferably 20.0% or more and 80.0% or less.

[0118] In the auxiliary burner modification step (1), controlling the auxiliary burner flame combustion rate to 100.0% or more means that the auxiliary burner fuel supplied to the auxiliary burner is completely burned. In the auxiliary burner modification step (1), by making the auxiliary burner flame combustion rate 100.0% or more, the surface of the recycled carbon black after the main burner modification step becomes easy to be oxidized, thereby improving the oxidation removal of the residual rubber component attached to the recycled carbon black after the main burner modification step. That is, the auxiliary burner modification step (1) can improve the oxidation removal of the residual rubber component that is not completely removed even after the main burner modification step (1). From the viewpoint of the balance between the flame temperature and the amount of rubber carbide to be removed, the auxiliary burner flame combustion rate is preferably 105.0% or more and 600.0% or less, and more preferably 110.0% or more and 500.0% or less. It should be noted that the auxiliary burner reforming step (1) is one embodiment of the auxiliary burner reforming step, and therefore the total carbon combustion rate of all burners is lower than 100.0%, preferably 15.0% to 90.0%, and more preferably 20.0% to 80.0%.

[0119] As the auxiliary burner reforming step, there can be mentioned an auxiliary burner reforming step (2) in which the auxiliary burner flame combustion rate represented by the following formula (3) is lower than 100.0%, and the total carbon combustion rate of all burners represented by the following formula (4) is lower than 100.0%:

[0120] Auxiliary burner flame combustion rate (%) = (D / E) × 100 (3)

[0121] (Wherein, D is the amount of oxygen supplied to the auxiliary burner, and E is the theoretical amount of oxygen required to completely burn the auxiliary burner fuel supplied to the auxiliary burner.)

[0122] Total carbon combustion rate of all burners (%) = ((A+D) / (B+C+E)) × 100 (4)

[0123] (Wherein, A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of the recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, D refers to the amount of oxygen supplied to the auxiliary burner, and E refers to the theoretical amount of oxygen required for complete combustion of the auxiliary burner fuel supplied to the auxiliary burner.).

[0124] In the auxiliary burner modification step (2), controlling the total carbon combustion rate of all burners to be less than 100.0% means that the auxiliary burner fuel and recycled carbon black supplied to the auxiliary burner are not completely burned. When the auxiliary burner fuel and recycled carbon black supplied to the auxiliary burner are completely burned, the recycled carbon black will be oxidized and disappear, and the modified recycled carbon black cannot be obtained. From the viewpoint of the balance between the amount of recovered modified particles obtained and the amount of rubber carbide to be removed, the total carbon combustion rate of all burners is preferably 15.0% or more and 90.0% or less, and more preferably 20.0% or more and 80.0% or less.

[0125] In the auxiliary burner modification step (2), controlling the auxiliary burner flame combustion rate to be lower than 100.0% means that the auxiliary burner fuel supplied to the auxiliary burner is not completely burned. Moreover, under the condition that the auxiliary burner fuel supplied to the auxiliary burner is not completely burned, the auxiliary burner fuel is heated, so that the auxiliary burner fuel undergoes thermal cracking to generate carbides. Therefore, by attaching the generated carbides to the surface-modified recycled carbon black when the flame is generated in the auxiliary burner, the specific surface area of ​​the modified recycled carbon black can be adjusted. From the viewpoint of the appropriate value of the specific surface area for improving the reinforcement of rubber, the auxiliary burner flame combustion rate is preferably greater than 2.0% and less than 90.0%, and more preferably greater than 5.0% and less than 80.0%. It should be noted that the auxiliary burner reforming step (2) is one embodiment of the auxiliary burner reforming step, and therefore the total carbon combustion rate of all burners is lower than 100.0%, preferably 15.0% to 90.0%, and more preferably 20.0% to 80.0%.

[0126] The manufacturing method of modified and recycled carbon black of the present invention may include the following auxiliary fuel thermal cracking step: a fuel nozzle is arranged at a rear stage closer to the main burner, and an auxiliary fuel is introduced into the flame generated in the main burner or in the vicinity thereof, thereby thermally cracking the auxiliary fuel. In the manufacturing method of modified and recycled carbon black of the present invention, the auxiliary fuel thermal cracking step is performed as needed.

[0127] In the method for producing modified recycled carbon black of the present invention, as an apparatus for implementing the scheme having the auxiliary fuel thermal cracking step, for example, Figure 1 In the manufacturing apparatus 1 for modified recycled carbon black shown, no auxiliary burner is provided, and a fuel nozzle for introducing auxiliary fuel is provided in the flame generated in the main burner or in the vicinity thereof.

[0128] The auxiliary fuel thermal cracking step of the method for producing modified recycled carbon black of the present invention is a step of introducing an auxiliary fuel into the flame generated in the main burner or in the vicinity thereof, thermally cracking the auxiliary fuel to generate carbides, and using the generated carbides to modify the surface of the recycled carbon black after the main burner modification step. The auxiliary fuel is supplied at the front end of the flame generated in the main burner, inside the flame generated in the main burner and near the front end of the flame, and outside the flame generated in the main burner and near the front end of the flame.

[0129] The carbon black reformed in the auxiliary fuel thermal cracking step is the recycled carbon black that has been subjected to the main burner reforming step, that is, the recycled carbon black that has passed through the flame generated in the main burner or the recycled carbon black that has passed through the flame generated in the main burner.

[0130] In the auxiliary fuel thermal cracking process, the auxiliary fuel is introduced from a fuel nozzle arranged closer to the rear stage than the main burner. At this time, when the auxiliary fuel is supplied to the fuel nozzle and the auxiliary fuel is introduced from the flame generated in the main burner or in the vicinity thereof, the oxygen-containing gas may not be mixed in the auxiliary fuel supplied to the fuel nozzle. The auxiliary fuel in the auxiliary fuel thermal cracking process is not particularly limited as long as it is thermally cracked under the heat of the flame of the main burner. For example, methane, ethane, propane, natural gas, ethylene, acetylene and other hydrocarbon gases, their mixed gases, rubber, plastics and other gases generated by thermal cracking, and aromatic hydrocarbons such as naphthalene and anthracene as liquid fuels, creosote, tall oil and other coal-based hydrocarbons, FCC residual oil, ethylene heavy oil and other petroleum-based heavy oils, acetylene unsaturated hydrocarbons, hexane and other aliphatic hydrocarbons, rapeseed oil, soybean oil and other vegetable oils, rubber, Plastics and other oils generated by thermal cracking, etc., in terms of uniformly modifying and recycling carbon black, methane, ethane, propane, natural gas, ethylene, acetylene and other hydrocarbon gases are preferred.

[0131] In the auxiliary fuel thermal cracking step, the total carbon combustion rate of all reactions represented by the following formula (5) is made lower than 100.0%:

[0132] Total carbon combustion rate of all reactions (%) = (A / (B+C+F)) × 100 (5)

[0133] (Wherein, A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of the recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, and F refers to the theoretical amount of oxygen required for complete combustion of the auxiliary fuel supplied from the fuel nozzle.).

[0134] It should be noted that F is the amount per unit time of the theoretical amount of oxygen required to completely burn the pilot fuel supplied from the fuel nozzle.

[0135] In the auxiliary fuel thermal cracking process, controlling the total carbon combustion rate of all reactions to be less than 100.0% means that the main burner fuel, recycled carbon black and auxiliary fuel supplied to the main burner are not completely burned. When the main burner fuel, recycled carbon black and auxiliary fuel supplied to the main burner are completely burned, the recycled carbon black will be oxidized and disappear, and the modified recycled carbon black cannot be obtained. Moreover, under the condition that the auxiliary fuel supplied from the auxiliary nozzle is not completely burned, the auxiliary fuel is heated, so that the auxiliary fuel is thermally cracked to generate carbides. Therefore, the generated carbides are attached to the recycled carbon black that has been surface-modified, and the specific surface area of ​​the modified recycled carbon black can be adjusted. From the viewpoint of the balance between the amount of recovered modified particles obtained and the amount of rubber carbides that need to be removed, the total carbon combustion rate of all reactions is preferably 5.0% or more and 90.0% or less, and more preferably 20.0% or more and 80.0% or less.

[0136] In the main burner reforming step, the supply amounts of the raw material recycled carbon black, the oxygen-containing gas, and the main burner fuel are appropriately selected so as to achieve a predetermined main burner total carbon combustion rate.

[0137] In the main burner reforming step (1), the main burner total carbon combustion rate and the main burner flame combustion rate are appropriately selected so as to achieve a predetermined main burner total carbon combustion rate and a main burner flame combustion rate. For example, the air supply amount as the oxygen-containing gas is set to 100.0 Nm 3 / hour, the supply rate of city gas (composition: methane 88%, ethane 6%, propane 5%, butane 1%) as the main burner fuel is 1.8Nm 3 / hour and above and 8.7Nm 3 / hour or less, preferably 2.3Nm 3 / hour and above and 8.3Nm 3 / hour or less, and the supply amount of raw material recycled carbon black is 3kg / hour or more and 80kg / hour or less, preferably 5kg / hour or more and 60kg / hour or less.

[0138] In the main burner reforming step (2), the main burner total carbon combustion rate and the main burner flame combustion rate are appropriately selected so as to achieve a predetermined main burner total carbon combustion rate and a main burner flame combustion rate. For example, the air supply amount as the oxygen-containing gas is set to 100.0 Nm 3 / hour, the supply rate of city gas as the main burner fuel is 9.2Nm 3 / hour or more and 45.0Nm 3 / hour or less, preferably 9.6Nm 3 / hour and above and 30Nm 3 / hour or less, and the supply amount of raw material recycled carbon black is 2 kg / hour or more and 75 kg / hour or less, preferably 3 kg / hour or more and 55 kg / hour or less.

[0139] In the auxiliary burner reforming step, the supply amounts of the oxygen-containing gas and the auxiliary burner fuel are appropriately selected so as to achieve a predetermined total carbon combustion rate of all burners and an auxiliary burner flame combustion rate.

[0140] In the auxiliary burner reforming step (1), the total carbon combustion rate of all burners and the auxiliary burner flame combustion rate are appropriately selected so as to achieve a predetermined total carbon combustion rate of all burners and a flame combustion rate of the auxiliary burner. For example, the air supply amount of the oxygen-containing gas used as the main burner is 100.0 Nm 3 / hour, the supply amount of air as the oxygen-containing gas for the auxiliary burner is 5.0 Nm 3 / hour and above and 100.0Nm 3 / hour or less, preferably 10.0Nm 3 / hour and above and 90.0Nm 3 / hour or less, the supply rate of city gas as fuel for the auxiliary burner is 0.2Nm 3 / hour and above and 8.7Nm 3 / hour or less, preferably 0.5Nm 3 / hour and above and 7.5Nm 3 / hour or less.

[0141] In the auxiliary burner reforming step (2), the total carbon combustion rate of all burners and the auxiliary burner flame combustion rate are appropriately selected so as to achieve a predetermined total carbon combustion rate of all burners and a flame combustion rate of the auxiliary burner. For example, the air supply amount of the oxygen-containing gas used as the main burner is 100.0 Nm 3 / hour, the supply rate of air as oxygen-containing gas for the auxiliary burner is 2Nm 3 / hour or more and 50.0Nm 3 / hour or less, preferably 5.0Nm 3 / hour or more and 40.0Nm 3 / hour or less, the supply rate of city gas as fuel for the auxiliary burner is 0.5Nm 3 / hour or more and 50.0Nm 3 / hour or less, preferably 1.0Nm 3 / hour or more and 30.0Nm 3 / hour or less.

[0142] In the auxiliary fuel thermal cracking step, the amount of air supplied as the oxygen-containing gas for the main burner is appropriately selected so as to achieve a predetermined total carbon combustion rate for the entire reaction. For example, the amount of air supplied as the oxygen-containing gas for the main burner is 100.0 Nm 3 / hour, the supply rate of city gas as auxiliary fuel is 0.5Nm 3 / hour or more and 50.0Nm 3 / hour or less, preferably 1.0Nm 3 / hour or more and 30.0Nm 3 / hour or less.

[0143] When the auxiliary burner reforming step is not performed or when the auxiliary fuel thermal cracking step is not performed, the reformed and recycled carbon black obtained after the main burner reforming step, that is, by the flame generated in the main burner, is brought into contact with water, nitrogen, a metal wall of a heat exchanger, etc., and is cooled. In addition, when the auxiliary burner reforming step is performed, the reformed and recycled carbon black obtained after the main burner reforming step and the auxiliary burner reforming step, that is, by the flame generated in the main burner and the flame generated in the auxiliary burner, is brought into contact with water, nitrogen, a metal wall of a heat exchanger, etc., and is cooled. In addition, when the auxiliary fuel thermal cracking step is performed, the reformed and recycled carbon black obtained after the main burner reforming step and the auxiliary fuel thermal cracking step, that is, by the flame generated in the main burner, is brought into contact with water, nitrogen, a metal wall of a heat exchanger, etc., and is cooled. At this time, the reformed and recycled carbon black after passing through the flame is at a high temperature, so when water is brought into contact, the water becomes water vapor.

[0144] After the modified recycled carbon black is cooled, the cooled modified recycled carbon black is separated from combustion gas, decomposition gas, water vapor and other gases using a solid and gas separation device such as a bag filter and a cyclone separator to obtain the modified recycled carbon black.

[0145] The manufacturing method of modified recycled carbon black of the present invention may include a particle size adjustment step of crushing and / or classifying the raw recycled carbon black before the main burner modification step. By performing the particle size adjustment step before the main burner modification step, the fluctuation of the particle size of the raw recycled carbon black supplied to the main burner modification step becomes smaller, thereby reducing the fluctuation of the surface modification of the raw recycled carbon black in the main burner modification step.

[0146] The pulverizing device used in the particle size adjustment process is not particularly limited, and examples thereof include a roller mill, a jet mill, a hammer mill, a pin mill, a shredder, a roller crusher, a pounding mill, a ring mill, etc. In addition, the classifying device used in the particle size adjustment process is not particularly limited, and examples thereof include: a mechanical classifier equipped with a classifying rotor, etc. to achieve centrifugal classification; a classifier that achieves centrifugal classification based on a vortex (free vortex or even semi-free vortex) generated by the supply of a high-speed airflow; a classifier that utilizes the inertial force and the wall effect of particles accelerated by a curved high-speed airflow; etc.

[0147] There are no special restrictions as long as the main burner can generate flame by burning the main burner fuel, and the main burner fuel, oxygen-containing gas and raw material recycling carbon black can be continuously supplied from the fuel supply side to burn the main burner fuel, flame is continuously generated in the main burner, and raw material recycling carbon black is introduced into the flame and passes through the flame.

[0148] For example, as the main burner, there can be cited Figure 4 The main burner of the embodiment shown. Figure 4 Schematic end view of an example of a main burner. Figure 4 In the main burner 30a, a supply path 33 for raw material recycled carbon black and a conveying gas is provided in the center of the burner, and a jet port 37 for raw material recycled carbon black and a conveying gas is formed on the flame generation side. In addition, the main burner 30a has a supply path 32 for oxygen-containing gas in a manner surrounding the supply path 33 for raw material recycled carbon black and a conveying gas, and a jet port 36 for oxygen-containing gas is formed on the flame generation side. In addition, the main burner 30a has a supply path 31 for fuel for the main burner in a manner surrounding the supply path 32 for oxygen-containing gas, and a jet port 35 for fuel for the main burner is formed on the flame generation side. When viewed from a plane perpendicular to the moving direction of the raw material recycled carbon black, a circular supply path for raw material recycled carbon black and a conveying gas is formed in the center, a cylindrical supply formation for oxygen-containing gas is formed in a manner surrounding the supply path for raw material recycled carbon black and a conveying gas, and a cylindrical supply formation for fuel for the main burner is formed in a manner surrounding the supply path for oxygen-containing gas. Figure 4 In the embodiment of the present invention, the supply paths for the raw material recycling carbon black and the transport gas, the supply path for the oxygen-containing gas, and the supply path for the main burner fuel are open at the end portion on the flame side of the main burner.

[0149] Then, raw material recycled carbon black, conveying gas, oxygen-containing gas, and main burner fuel are supplied from the fuel supply side of the main burner 30a, so that in the flame, the raw material recycled carbon black is present in the center, the oxygen-containing gas is present in a manner surrounding the raw material recycled carbon black, and the main burner fuel is present in a manner surrounding the oxygen-containing gas, and the raw material recycled carbon black, conveying gas, oxygen-containing gas, and main burner fuel can be introduced. By using the main burner 30a, when the raw material recycled carbon black, conveying gas, oxygen-containing gas, and main burner fuel are introduced into the flame, the oxygen-containing gas can be present near the raw material recycled carbon black, so that the contact between the raw material recycled carbon black and the oxygen-containing gas can be prioritized over the contact between the raw material recycled carbon black and the fuel gas, thereby easily causing the oxidation of the raw material recycled carbon black.

[0150] In addition, as the main burner, there can be cited Figure 5 The main burner of the embodiment shown. Figure 5 Schematic end view of an example of a main burner. Figure 5 In the main burner 30b, a supply path 33 for raw material recycled carbon black and conveying gas is provided in the center of the burner, and a jet port 37 for raw material recycled carbon black and conveying gas is formed on the flame generation side. In addition, the main burner 30b has a supply path 32 for oxygen-containing gas in a manner surrounding the supply path 33 for raw material recycled carbon black and conveying gas, and a jet port 36 for oxygen-containing gas is formed on the flame generation side. In addition, the main burner 30b has a supply path 31 for main burner fuel in a manner surrounding the supply path 32 for oxygen-containing gas, and a jet port 35 for main burner fuel is formed on the flame generation side. Moreover, the jet port 37 for raw material recycled carbon black and conveying gas, the jet port 36 for oxygen-containing gas, and the jet port 35 for main burner fuel are opened in a mixing chamber 38, and a mixed flow is ejected from the mixing chamber 38 toward the flame. Figure 5 In the scheme example, at the end on the flame side of the main burner, the supply paths for raw material recycling carbon black and conveying gas, the supply path for oxygen-containing gas and the supply path for main burner fuel are opened in a mixing chamber formed closer to the observer than the end on the flame side of the main burner, and the mixing chamber opens at the end on the flame side of the main burner.

[0151] In addition, as the structure of the main burner, there can be cited the structures of the burners described in Japanese Patent No. 3001561, Japanese Patent No. 5367471, Japanese Patent No. 3312228, Japanese Patent No. 4769276, Japanese Patent Unexamined Publication No. 2021-50897, Japanese Patent Unexamined Publication No. 2010-156025, Japanese Patent No. 6580710, etc.

[0152] In the method for producing modified recycled carbon black of the present invention, by performing a main burner modification step, or performing a main burner modification step and an auxiliary burner modification step, the G band intensity and the nitrogen adsorption specific surface area N of the modified recycled carbon black when the D band intensity is set to 100 can be obtained. 2 SA is the modified recycled carbon black in the range shown below. When the D band intensity is 100, the G band intensity and the nitrogen adsorption specific surface area N 2 The modified recycled carbon black having SA in the range shown below has strong bonding with the rubber component and does not have excessively high aggregation, so the reinforcement of the rubber product becomes high. Therefore, the method for producing the modified recycled carbon black of the present invention can continuously produce the modified recycled carbon black that can improve the reinforcement of the rubber product.

[0153] The modified recycled carbon black obtained by the method for producing modified recycled carbon black of the present invention is obtained by modifying the surface of recycled carbon black obtained by thermally cracking rubber products such as waste tires. More specifically, the modified recycled carbon black of the present invention is obtained by removing all or part of the rubber residues mainly composed of rubber carbide attached to the surface of recycled carbon black obtained by thermally cracking rubber products such as waste tires.

[0154] For recycled carbon black with rubber carbide attached to the surface, the Raman spectrum obtained by measuring at an excitation wavelength of 532 nm by laser Raman spectroscopy was quantified at 1350±10cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak having a peak top in the range of is 112 or more.

[0155] For such recycled carbon black with rubber carbide attached to the surface, the modified recycled carbon black is obtained by removing the rubber residue with rubber carbide as the main component attached to the surface. Therefore, according to the Raman spectrum obtained by measuring at an excitation wavelength of 532nm by laser Raman spectroscopy, the modified recycled carbon black is obtained by removing the rubber residue with rubber carbide as the main component attached to the surface. -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm -1 The peak intensity of the peak (G band) with a peak top within the range of 84 or more and 111 or less. When the D band intensity of the recycled carbon black is set to 100, the G band intensity is within the above range, so that there is no or very little rubber residue attached to the surface of the recycled carbon black, and the bonding between the recycled carbon black and the rubber component becomes higher, so the reinforcement of the rubber product becomes higher. From the viewpoint of improving the reinforcement by performing a proper reaction with the rubber, the G band intensity when the D band intensity is set to 100 is preferably 85 or more and 110 or less, and more preferably 90 or more and 105 or less. On the other hand, if the G band intensity when the D band intensity of the recycled carbon black is set to 100 exceeds the above range, there are many rubber residues attached to the surface of the recycled carbon black, and the bonding between the recycled carbon black and the rubber component becomes lower. In addition, if it is lower than the above range, there are many defects in the graphite structure of the black surface, and the surface activity becomes too high, the aggregation of carbon blacks in the rubber is promoted, and the reinforcement of the rubber is reduced.

[0156] In the present invention, the G band intensity and the D band intensity when the D band intensity is 100 are values ​​calculated from the Raman spectrum obtained by performing the data processing (2) after measurement under the following measurement conditions (1).

[0157] (1) As a laser Raman spectrometer, HR-800 manufactured by Horiba, Ltd. is used, and a plurality of carbon black sample particles to be measured are placed on a glass slide, rubbed several times with a spatula to make the surface flat, and the state is measured under the following measurement conditions.

[0158] YAG laser (excitation wavelength): 532nm

[0159] Number of engraved lines: 600gr / mm

[0160] Filter: D0.6

[0161] Objective lens magnification: 100 times

[0162] Exposure time: 150 seconds

[0163] Cumulative times: 2 times

[0164] (2) The measurement wavelength (Raman Shift) of the obtained spectrum was 2100 cm -1 The signal intensity under the condition of 0 is set, and the average value of every 39 adjacent points in the data points constituting the spectrum is calculated. Then, smoothing is performed to obtain a spectrum curve connecting the above average values. Next, in order to make it easier to compare each sample, the measurement wavelength is 1350±10cm -1 The peak intensity observed in the range of 100 is set as 100. The spectrum obtained at this time is shown in FIG. Figure 6 .

[0165] like Figure 6 As shown, for the modified recycled carbon black, according to the Raman spectrum obtained by measuring at an excitation wavelength of 532 nm by laser Raman spectroscopy, a peak at 1350±10 cm -1 The peak with a peak top in the range of 1580±20cm (D band) and -1 A peak (G band) having a peak top in the range of .

[0166] Furthermore, from the peak intensity values ​​of the D band and the G band, the peak intensity of the G band was calculated when the peak intensity of the D band was set to 100. According to the research of the present inventors, the greater the amount of rubber carbide attached to the recycled carbon black, the greater the intensity of the G band. Therefore, the removal state of the rubber carbide from the recycled carbon black can be grasped based on the magnitude of the peak intensity of the G band when compared with the peak intensity of the D band.

[0167] Figure 6 In the Raman spectrum of the modified and recycled carbon black example, when the peak intensity of the D band is set to 100, the peak intensity of the G band is 93, which is within the range of 84 to 111. Figure 7The Raman spectrum of the example of recycled carbon black before modification shows that when the peak intensity of the D band is 100, the peak intensity of the G band is 113, which is above 84 and below 111. This shows that Figure 7 In the recycled carbon black before modification shown in the figure, rubber carbide is attached to the surface. Figure 6 In the modified recycled carbon black shown above, rubber carbonization adhering to the surface is removed by modifying the carbon black.

[0168] Nitrogen adsorption specific surface area N of modified recycled carbon black 2 SA is 15m 2 / g and above and 350m 2 / g or less. Then use the nitrogen adsorption specific surface area N of carbon black 2 When SA is within the above range, the aggregation force of the recycled carbon black can be suppressed to a low level, thereby improving the reinforcement of the rubber product. From the perspective of optimizing the contact area with the rubber and improving the reinforcement of the rubber, the nitrogen adsorption specific surface area N of the recycled carbon black is 2 SA preferred 20m 2 / g and above and 300m 2 / g or less, more preferably 30m 2 / g and above and 250m 2 / g or less. On the other hand, the nitrogen adsorption specific surface area N of carbon black is used again. 2 If SA is lower than the above range, the surface in contact with the rubber is small, the reinforcing effect cannot be fully exerted, and the reinforcing property of the rubber is reduced. On the other hand, if it exceeds the above range, the aggregation force of the recycled carbon black becomes excessively high, so the reinforcement property of the rubber product is reduced.

[0169] It should be noted that, in the present invention, the nitrogen adsorption specific surface area N 2 SA is a value measured based on the nitrogen adsorption amount according to the method defined in JIS K6217-2 2001 "Test methods for basic properties of carbon black for rubber use".

[0170] From the viewpoint of improving the reinforcement of rubber, the DBP (dibutylphthalate) absorption of the modified recycled carbon black is preferably 60 cm 3 / 100g or more and 200cm 3 / 100g or less, more preferably 70cm 3 / 100g or more and 195cm 3 / 100g or less, more preferably 80cm 3 / 100g or more and 190cm 3On the other hand, if the DBP absorption is below the above range, the dispersibility of carbon black deteriorates when mixed with the rubber composition, and the reinforcement of the obtained rubber becomes easy to decrease. In addition, if it exceeds the above range, the processability of the rubber obtained when mixed with the rubber composition is sometimes reduced.

[0171] In the present invention, the DBP absorption refers to a value measured according to the method defined in JIS K6217-4 "Carbon black for rubber - Basic properties - Part 4. Method for determining DBP absorption".

[0172] Modified recycled carbon black is obtained by modifying recycled carbon black obtained by thermal cracking of rubber products such as waste tires. Therefore, the ash content of the modified recycled carbon black is 3.0% to 50.0%, more preferably 5.0% to 35.0%.

[0173] In addition, in this invention, an ash content means the value measured by the method defined in JIS K 6218-2.

[0174] Example

[0175] The invention is illustrated by the following examples.

[0176] (Example 1)

[0177] use Figure 1 The manufacturing apparatus 1 of the modified recycled carbon black shown in the figure. First, city gas (composition: methane 88%, ethane 6%, propane 5%, butane 1%) as the main burner fuel is heated at 16.0 Nm 3 / hour, air as oxygen-containing gas at 215.0Nm 3 / hour to the main burner to generate flame. Then, continue to supply city gas and air, and use 10.0Nm 3 / hour of conveying air, the raw material recycled carbon black is supplied to the main burner at 15kg / hour, and the main burner modification process is carried out through the flame. The raw material recycled carbon is crushed in advance with a chopper mixer. The modified recycled carbon black that has passed through the flame is cooled with cooling water, and the gas is separated in a bag filter to obtain the modified recycled carbon black. At this time, the total carbon combustion rate of the main burner is 79.0%. In addition, the main burner flame combustion rate is 128.0%.

[0178] Next, the nitrogen adsorption specific surface area N of the modified recycled carbon black was measured. 2 SA, G band intensity when D band intensity is set to 100. As a result, the nitrogen adsorption specific surface area N 2 SA is 202m 2 / g, and the G band intensity was 93 when the D band intensity was set to 100.

[0179] It should be noted that in Example 1, the auxiliary burner reforming step was not performed.

[0180] Raw material recycling carbon black

[0181] Recycled carbon black obtained by thermal cracking of waste tires

[0182] PB365 made by Enrestec, Inc.

[0183] Ash content: 18.6%,

[0184] G band intensity when D band intensity is set to 100: 113

[0185] N 2 SA: 76m 2 / g

[0186] (Example 2)

[0187] Change city gas to 26.0Nm 3 / hour, the air as oxygen-containing gas was changed to 205.0Nm 3 / hour, and the raw material recycling carbon black was changed to 33kg / hour. The modification treatment was carried out under the same conditions as in Example 1. At this time, the main burner total carbon combustion rate was 39.0%. In addition, the main burner flame combustion rate was 72.0%. As a result, the nitrogen adsorption specific surface area N 2 SA is 62m 2 / g, and the G band intensity was 99 when the D band intensity was 100.

[0188] (Example 3)

[0189] In addition to the conditions of Example 2, 3.0 Nm of city gas was supplied as auxiliary fuel from the auxiliary burner. 3 / hour, air containing oxygen as auxiliary burner 85.0Nm 3 / hour, the flame is generated, and additional treatment based on the flame of the auxiliary burner is performed. At this time, the total carbon combustion rate of the main burner is 39.0%. In addition, the main burner flame combustion rate is 72.0%. In addition, the auxiliary burner flame combustion rate is 258.0%, and the total carbon combustion rate of all burners is 52.0%. As a result, the nitrogen adsorption specific surface area N 2 SA is 162m 2 / g, and the G band intensity was 94 when the D band intensity was set to 100.

[0190] That is, in Example 3, the main burner reforming step and the auxiliary burner reforming step were performed.

[0191] (Example 4)

[0192] In addition to the conditions of Example 1, 12.0 Nm of city gas was supplied as auxiliary fuel from the auxiliary burner. 3 / hour, air containing oxygen as auxiliary burner 30.0Nm 3 / hour, the flame is generated, and additional treatment based on the flame of the auxiliary burner is performed. At this time, the total carbon combustion rate of the main burner is 79.0%. In addition, the main burner flame combustion rate is 128.0%. In addition, the auxiliary burner flame combustion rate is 23.0%, and the total carbon combustion rate of all burners is 61.0%. As a result, the nitrogen adsorption specific surface area N 2 SA is 113m 2 / g, and the G band intensity was 97 when the D band intensity was set to 100.

[0193] That is, in Example 4, the main burner reforming step and the auxiliary burner reforming step were performed.

[0194] (Example 5)

[0195] Use Figure 1 The auxiliary burner 4 of the manufacturing apparatus 1 for modified recycled carbon black shown in the figure is replaced with a fuel nozzle. First, city gas (composition: methane 88%, ethane 6%, propane 5%, butane 1%) as the fuel for the main burner is heated at 16.0 Nm 3 / hour, air as oxygen-containing gas at 215.0Nm 3 / hour is supplied to the main burner to generate flame. Then, the supply of city gas and air is continued, and while the flame is continuously generated, 10.0 Nm 3 / hour of conveying air, the raw material recycled carbon black is supplied to the main burner at 15 kg / hour, and the main burner reforming process is carried out through the flame, and the city gas 12.0 Nm as fuel is supplied from the fuel nozzle 3 / hour, the auxiliary fuel thermal cracking process is carried out. At this time, the total carbon combustion rate of the main burner is 79.0%. In addition, the flame combustion rate of the main burner is 128.0%. In addition, the total carbon combustion rate of the entire reaction is 54.0%. As a result, the nitrogen adsorption specific surface area N 2 SA is 90m 2 / g, and the G band intensity was 96 when the D band intensity was set to 100.

[0196] That is, in Example 5, the main burner reforming step and the auxiliary fuel thermal cracking step were performed.

[0197] Industrial Applicability

[0198] According to the present invention, recycled carbon black having strong bonding with rubber components and high reinforcing properties for rubber products can be continuously manufactured. Therefore, by using recycled carbon black obtained by thermal cracking rubber products such as waste tires, rubber products having performance equivalent to that of unused carbon black can be manufactured industrially advantageously.

[0199] Description of Reference Numerals

[0200] 1. Manufacturing device for modified and recycled carbon black

[0201] 2 Burner modification department

[0202] 3 Main burners

[0203] 4 Auxiliary burner

[0204] 5 Cooling water supply pipe

[0205] 6 Connecting pipe

[0206] 7 Collection Department

[0207] 11 Main burner fuel

[0208] 12.15 Oxygen-containing gas

[0209] 13 Raw material recycling Carbon black and conveying gas

[0210] 14 Fuel for auxiliary burner

[0211] 16 Cooling water

[0212] 17 Gas

[0213] 18 Modified and recycled carbon black

[0214] 21 Flame generated in the main burner

[0215] 22 Direction of movement of raw material recycling carbon black

[0216] 23 Flame generated in the auxiliary burner

[0217] 30a, 30b Main burner

[0218] 31 Main burner fuel supply path

[0219] 32 Supply path of oxygen-containing gas

[0220] 33 Supply route of raw material recycling carbon black and transport gas

[0221] 35 Main burner fuel outlet

[0222] 36 Oxygen-containing gas outlet

[0223] 37 Raw material recycling carbon black and conveying gas outlet

[0224] 38 Mixing chamber

Claims

1. A method for producing modified and recycled carbon black, characterized in that: The invention comprises the following main burner reforming step: a main burner fuel, an oxygen-containing gas and recycled carbon black with rubber carbide attached are continuously supplied to a main burner that burns the fuel to generate a flame, the main burner fuel is burned, a flame is continuously generated in the main burner, and the recycled carbon black with rubber carbide attached is introduced into the flame, and the recycled carbon black with rubber carbide attached is passed through the flame, The recycled carbon black with rubber carbonized material attached thereto is carbon black as follows: in a Raman spectrum obtained by measuring at an excitation wavelength of 532 nm using laser Raman spectroscopy, the carbon black having a carbon content of 1350±10 cm -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm-1 is set to 100, that is, the peak intensity of the D band is 100. -1 A carbon black having a peak with a peak top within a range of 112 to 200, that is, a peak intensity of the G band, The total carbon combustion rate of the main burner represented by the following formula (1) is set to 10.0% or more and 90.0% or less: Total carbon combustion rate of main burner (%) = (A / (B+C)) × 100 (1) In the formula (1), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required to completely burn the recycled carbon black with rubber carbide attached to the main burner, and C refers to the theoretical amount of oxygen required to completely burn the main burner fuel supplied to the main burner. The modified recycled carbon black obtained was measured by laser Raman spectroscopy at an excitation wavelength of 532 nm. -1 When the peak intensity of the peak with a peak top in the range of 1580±20cm-1 is set to 100, that is, the peak intensity of the D band is 100. -1 The peak with a peak top in the range of , that is, the peak intensity of the G band is greater than 84 and less than 111, and the nitrogen adsorption specific surface area N2SA is 15m 2 / g and above and 350m 2 / g or less.

2. The method for producing modified recycled carbon black according to claim 1, characterized in that: The main burner modification step is a main burner modification step (1) in which the main burner flame combustion rate represented by the following formula (2) is 100.0% or more: Main burner flame combustion rate (%) = (A / C) × 100 (2) In the formula (2), A is the amount of oxygen supplied to the main burner, and C is the theoretical amount of oxygen required to completely burn the main burner fuel supplied to the main burner.

3. The method for producing modified recycled carbon black according to claim 1, characterized in that: The main burner modification step is a main burner modification step (2) for making the main burner flame combustion rate represented by the following formula (2) lower than 100.0%: Main burner flame combustion rate (%) = (A / C) × 100 (2) In the formula (2), A is the amount of oxygen supplied to the main burner, and C is the theoretical amount of oxygen required to completely burn the main burner fuel supplied to the main burner.

4. The method for producing modified recycled carbon black according to claim 2 or 3, characterized in that: The auxiliary fuel thermal cracking step includes: providing a fuel nozzle at a rear stage closer to the main burner, introducing the auxiliary fuel from the fuel nozzle into the flame generated in the main burner or in the vicinity thereof, thereby thermally cracking the auxiliary fuel; The auxiliary fuel thermal cracking process is an auxiliary fuel thermal cracking process in which the total carbon combustion rate of the entire reaction represented by the following formula (5) is lower than 100.0%: Total carbon combustion rate of all reactions (%) = (A / (B+C+F)) × 100 (5) In formula (5), A refers to the amount of oxygen supplied to the main burner, B refers to the theoretical amount of oxygen required for complete combustion of the recycled carbon black with rubber carbide attached to the main burner, C refers to the theoretical amount of oxygen required for complete combustion of the main burner fuel supplied to the main burner, and F refers to the theoretical amount of oxygen required for complete combustion of the auxiliary fuel supplied from the fuel nozzle.

5. The method for producing modified recycled carbon black according to claim 1, characterized in that: Before the main burner reforming step, a particle size adjustment step of pulverizing and / or classifying the recycled carbon black to which the rubber carbonized matter is attached is provided.

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