A waste tire pyrolysis system and method for producing high toluene transmittance pyrolysis carbon black.

Abstract

This application relates to a waste tire pyrolysis system and method for producing high toluene transmittance pyrolysis carbon black. It comprises a pyrolysis reactor, a primary catalytic pyrolysis section, a gas-phase micro-oxidation section, and a carbon black collector connected in sequence. Catalytic pyrolysis and in-situ micro-oxidation steps are introduced during the pyrolysis process to directly and continuously produce high-value-added pyrolysis carbon black products with high toluene transmittance. The high toluene transmittance pyrolysis carbon black produced by this invention has a toluene transmittance ≥90% measured at a wavelength of 365 nm and a BET specific surface area ≥80 m² / g, demonstrating excellent application effects in the preparation of rubber products, inks, or coatings.

Description

Technical Field

[0001] This application relates to the field of waste tire pyrolysis technology, specifically to a waste tire pyrolysis system and method for producing high toluene transmittance pyrolysis carbon black. Background Technology

[0002] The "black pollution" problem caused by waste tires is becoming increasingly serious, and pyrolysis technology is considered one of the most promising methods for achieving its harmless and resource-based disposal. The pyrolysis process mainly produces pyrolysis oil, pyrolysis gas, and pyrolysis carbon black (CBp). Of these, pyrolysis carbon black accounts for approximately 30%–35% of the yield, but its value is the lowest. The CBp obtained by traditional pyrolysis processes is of low quality, mainly manifested in the following ways: 1. Low toluene transmittance: This is a key indicator for evaluating carbon black as a pigment or high-end filler. Due to the condensation and encapsulation of heavy tar and asphaltenes during the pyrolysis process, as well as the formation of amorphous carbon deposits on the carbon black surface, the surface of pyrolyzed carbon black CBp particles is rough and contains many impurities. When dispersed in toluene, these particles severely scatter and absorb light, resulting in extremely low transmittance, typically below 50%. 2. High ash content: Inorganic additives in tires, such as ZnO, SiO2 and S, ultimately remain in the pyrolysis carbon black CBp; 3. Low surface activity: The surface covered by hydrocarbons lacks active sites and has poor compatibility with the polymer matrix.

[0003] Low-quality pyrolysis carbon black (CBp) is typically only used as a low-grade fuel or inexpensive filler, with limited economic value. To improve its value, existing technologies usually employ methods such as strong acid washing, high-temperature activation, and surface modification to modify CBp. While these methods can improve the performance of CBp to some extent, they also have drawbacks such as long process flows, chemical consumption, secondary pollution, high energy consumption, and significantly increased production costs, severely restricting its industrial application. Summary of the Invention

[0004] The purpose of this invention is to provide a waste tire pyrolysis system and method for producing high toluene transmittance pyrolysis carbon black. The system introduces catalytic pyrolysis and in-situ micro-oxidation steps during the pyrolysis process to directly and continuously produce high-value-added pyrolysis carbon black products with high toluene transmittance.

[0005] The first technical solution adopted in this invention is: a waste tire pyrolysis system for producing high toluene transmittance pyrolysis carbon black, comprising a pyrolysis reactor, a primary catalytic pyrolysis section, a gas-phase micro-oxidation section, and a carbon black collector connected in sequence; the primary catalytic pyrolysis section is located at the gas-phase outlet end of the pyrolysis reactor, adopts a vertical tower structure, and is filled with a solid acid catalyst at the bottom; the gas-phase micro-oxidation section is provided with a connecting pipe, and the pipe wall is provided with an inlet for injecting oxygen-containing inert gas; a secondary catalytic pyrolysis layer is also provided in the primary catalytic pyrolysis section, the secondary catalytic pyrolysis layer is located in the upper middle part of the primary catalytic pyrolysis section, and a metal oxide catalyst supported on inert ceramic balls is uniformly spread on the secondary catalytic pyrolysis layer.

[0006] Furthermore, the solid acid catalyst includes HZSM-5 molecular sieve, HY molecular sieve, or modified waste tire pyrolysis carbon-based catalyst, and its loading volume accounts for 5% to 15% of the effective volume of the pyrolysis reactor.

[0007] Furthermore, the metal oxide catalyst includes single metal oxides, composite metal oxides, and rare earth metal oxides, wherein the single metal oxides include zinc oxide and aluminum oxide, the composite metal oxides include cobalt-molybdenum oxide and nickel-molybdenum oxide, and the rare earth metal oxides include lanthanum oxide and cerium oxide.

[0008] The second technical solution adopted by this invention is: using the waste tire pyrolysis system for producing high toluene transmittance pyrolysis carbon black as described in the first technical solution, including the following steps: S1: The crushed waste tire material is fed into the pyrolysis reactor and heated to 450-550℃ at a rate of 10-25℃ / min under an inert atmosphere, and kept at a constant temperature for 1-3 hours to carry out atmospheric pressure pyrolysis. S2: The gas-solid mixture produced by pyrolysis is passed through a solid acid catalyst and a metal oxide catalyst to obtain high-temperature oil and gas and solid carbon black particles; the heavy hydrocarbon macromolecules entrained in the gas-solid mixture are catalytically pyrolyzed into light small molecules, reducing condensation and deposition on the carbon black surface. S3: The high-temperature oil and gas and solid carbon black particles after catalytic cracking enter the gas phase micro-oxidation section. At the same time, preheated oxygen-containing inert gas is introduced into the gas phase micro-oxidation section through the air inlet. The oxygen volume concentration is controlled at 1%~5% and the gas residence time is 0.5~5 seconds to perform instantaneous and gentle oxidation activation on the carbon black particles. S4: High-temperature oil and gas and oxidized activated solid carbon black particles are fed into a carbon black collector for gas-solid separation. The collected solid is pyrolysis carbon black with high toluene transmittance.

[0009] Furthermore, the ratio of the total number of oxygen moles in the oxygen-containing inert gas introduced in step S3 to the mass of waste tire material added in step S1 is (0.05~0.3) mol: 1 kg.

[0010] Furthermore, the volume ratio of inert gas to oxygen in the oxygen-containing inert gas is 95%~99%:1%~5%, wherein the inert gas includes nitrogen.

[0011] The third technical solution adopted in this invention is: a waste tire pyrolysis carbon black with high toluene transmittance obtained by the waste tire pyrolysis method for producing high toluene transmittance pyrolysis carbon black as described in the second technical solution, wherein the toluene transmittance is ≥90% and the BET specific surface area is ≥80 m² / g as measured at a wavelength of 365nm.

[0012] The fourth technical solution adopted in this invention is: the application of high toluene transmittance pyrolysis carbon black as described in the third technical solution in the preparation of rubber products, inks or coatings.

[0013] The beneficial effects of this invention are as follows: (1) The present invention uses a two-stage catalytic cracking method. A solid acid catalyst is set at the bottom of the first-stage catalytic cracking section at the back end of the cracking reactor, and a metal oxide catalyst is set in the middle and upper part. The solid acid catalyst is in direct contact with the waste tire material and can initially crack macromolecules. The second-stage catalytic layer performs deep catalytic cracking on the entire gas-solid mixture, selectively converting the heavy tar that is easy to condense and deposit into light oil and gaseous products, reducing the condensation and deposition on the surface of carbon black. (2) Before the high-temperature oil and gas and carbon black particles enter the collection system, the present invention injects a small amount of oxygen with a precisely controlled concentration in the gas phase micro-oxidation section. At a high temperature of more than 450°C, the oxygen can selectively react with the amorphous carbon and residual hydrocarbons attached to the surface of the carbon black particles to undergo combustion reaction, while causing minimal damage to the core graphitized structure. This effectively cleans the surface of the carbon black in an instant, making the carbon black cleaner and the pores more unobstructed. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0016] Explanation of reference numerals in the attached diagram: 1-Pyrolysis reactor, 2-Primary catalytic pyrolysis section, 3-Secondary catalytic pyrolysis layer, 4-Gas phase micro-oxidation section, 5-Air inlet, 6-Carbon black collector. Detailed Implementation

[0017] To better understand the above-described objects, features, and advantages of the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the invention; however, the invention may be practiced in other ways different from those described herein, and therefore, the invention is not limited to the specific embodiments disclosed below.

[0018] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art described herein. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” etc., are used only to indicate relative positional relationships, which change accordingly when the absolute position of the described object changes.

[0019] like Figure 1 As shown, a waste tire pyrolysis system for producing high toluene transmittance pyrolyzed carbon black includes a pyrolysis reactor 1, a primary catalytic pyrolysis section 2, a gas-phase micro-oxidation section 4, and a carbon black collector 6 connected in sequence. The primary catalytic pyrolysis section 2 is located at the gas-phase outlet of the pyrolysis reactor 1, adopts a vertical tower structure, and is filled with a solid acid catalyst at the bottom. The gas-phase micro-oxidation section 4 is provided with a connecting pipe, and the pipe wall is provided with an inlet 5 for injecting oxygen-containing inert gas. The primary catalytic pyrolysis section 2 is also provided with a secondary catalytic pyrolysis layer 3, which is located in the upper middle part of the primary catalytic pyrolysis section 2, and is uniformly covered with a metal oxide catalyst supported on inert ceramic balls. In this embodiment of the invention, the gas-phase micro-oxidation section 4 is provided with a spiral connecting pipe, and the inlet 5 is located on the spiral connecting pipe.

[0020] In this embodiment of the invention, the solid acid catalyst includes HZSM-5 molecular sieve, HY molecular sieve, or modified waste tire pyrolysis carbon-based catalyst, with a loading volume accounting for 5% to 15% of the effective volume of pyrolysis reactor 1. The metal oxide catalyst includes single metal oxides, composite metal oxides, and rare earth metal oxides, wherein the single metal oxides include zinc oxide (ZnO) and aluminum oxide (Al2O3), the composite metal oxides include cobalt-molybdenum oxide (Co-Mo-O) and nickel-molybdenum oxide (Ni-Mo-O), and the rare earth metal oxides include lanthanum oxide (La2O3) and cerium oxide (CeO2).

[0021] This invention also provides a waste tire pyrolysis method for producing high toluene transmittance pyrolysis carbon black, using the aforementioned waste tire pyrolysis system for producing high toluene transmittance pyrolysis carbon black, and includes the following steps: S1: The crushed waste tire material is fed into pyrolysis reactor 1, and under an inert atmosphere, the temperature is programmed to rise to 450~550℃ at a rate of 10~25℃ / min, and then kept at a constant temperature for 1~3 hours to carry out atmospheric pressure pyrolysis.

[0022] S2: The gas-solid mixture produced by pyrolysis is passed through a solid acid catalyst and a metal oxide catalyst to obtain high-temperature oil and gas and solid carbon black particles; the heavy hydrocarbon macromolecules entrained in the gas-solid mixture are catalytically pyrolyzed into light small molecules, reducing condensation and deposition on the carbon black surface.

[0023] S3: The high-temperature oil and gas and solid carbon black particles after catalytic cracking enter the gas-phase micro-oxidation section 4. Simultaneously, preheated oxygen-containing inert gas is introduced into the gas-phase micro-oxidation section 4 through the air inlet 5, controlling the oxygen volume concentration to 1%~5% and the gas residence time to 0.5~5 seconds, to perform instantaneous and gentle oxidation activation on the carbon black particles. The ratio of the total oxygen moles in the introduced oxygen-containing inert gas to the mass of waste tire material added in step S1 is (0.05~0.3) mol: 1 kg. The volume ratio of inert gas to oxygen in the oxygen-containing inert gas is 95%~99%: 1%~5%, wherein the inert gas includes nitrogen.

[0024] S4: High-temperature oil and gas and oxidized activated solid carbon black particles are fed into carbon black collector 6 for gas-solid separation. The collected solid is pyrolysis carbon black with high toluene transmittance.

[0025] The high toluene transmittance pyrolysis carbon black prepared by the method described in the embodiments of the present invention has a toluene transmittance ≥90% and a BET specific surface area ≥80 m² / g as measured at a wavelength of 365 nm. It can be widely used in the preparation of rubber products, inks or coatings, etc.

[0026] The following comparative experiments illustrate the performance of the high toluene transmittance pyrolysis carbon black prepared according to the embodiments of the present invention: Using the system described in this embodiment of the invention, 1 kg of shredded waste tires was added to pyrolysis reactor 1. After the system was purged with nitrogen to replace the air, the temperature was increased to 500°C at a rate of 15°C / min and held at that temperature for 2 hours. HZSM-5 molecular sieve was used as the solid acid catalyst, and Co-Mo / Al2O3 catalyst was used as the metal oxide catalyst. A nitrogen-nitrogen mixture preheated to 500°C and containing 2% oxygen was introduced through inlet 5, controlling the total oxygen content to be 0.15 mol.

[0027] In addition, pyrolysis carbon black was directly collected under the same pyrolysis conditions, but without any catalytic pyrolysis or micro-oxidation steps, as a comparative example. The performance of the pyrolysis carbon black prepared by the two methods was compared, and the results are shown in Table 1.

[0028] Table 1 Product Performance Comparison Table

[0029] The product of the present invention and the comparative product were respectively filled into natural rubber in the same number of parts (50 phr) to prepare compound rubber. The test results showed that the vulcanizate filled with the product of the present invention had significantly higher tensile strength and tear strength than the comparative product, and a higher blackness in appearance, proving that the product of the present invention has better reinforcing and pigmenting properties.

[0030] This invention employs a two-stage catalytic cracking method. A solid acid catalyst directly contacts the waste tire material, enabling preliminary cracking of macromolecules. A metal oxide catalyst then performs deep catalytic cracking on the entire gas-solid mixture, selectively converting easily condensable and deposited heavy tar into light oil and gaseous products, reducing condensation and deposition on the carbon black surface. Before the high-temperature oil, gas, and carbon black particles enter the collection system, a precisely controlled amount of oxygen is injected into the gas-phase micro-oxidation section 4. At a high temperature greater than 450°C, the oxygen selectively reacts with the amorphous carbon and residual hydrocarbons attached to the surface of the carbon black particles, causing minimal damage to the core graphitized structure. This effectively cleans the carbon black surface instantly, making the carbon black cleaner and its pores more open.

[0031] This invention directly solves the problem of low toluene transmittance in pyrolysis carbon black (CBp) from a production process perspective, achieving product specifications that meet high-end application requirements without complex post-processing. It realizes continuous and automated production of high-quality pyrolysis carbon black (CBp) with high efficiency and low cost. The high toluene transmittance pyrolysis carbon black (CBp) produced can significantly increase its selling price, greatly enhancing the economic feasibility of the entire waste tire pyrolysis project. The production process avoids the use of strong acids and alkalis, generating no corresponding wastewater or waste residue. The micro-oxidation process utilizes the heat energy from pyrolysis itself, resulting in low energy consumption and effectively achieving green production, energy conservation, and environmental protection.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A waste tire pyrolysis system for producing high toluene transmittance pyrolysis carbon black, characterized in that, The system comprises a pyrolysis reactor, a primary catalytic pyrolysis section, a gas-phase micro-oxidation section, and a carbon black collector connected in sequence. The primary catalytic pyrolysis section is located at the gas-phase outlet of the pyrolysis reactor and adopts a vertical tower structure, with a solid acid catalyst packed at the bottom. The gas-phase micro-oxidation section is equipped with connecting pipes, and the pipe walls have inlets for injecting oxygen-containing inert gas. The primary catalytic pyrolysis section also includes a secondary catalytic pyrolysis layer, which is located in the upper middle part of the primary catalytic pyrolysis section. The secondary catalytic pyrolysis layer is uniformly coated with a metal oxide catalyst supported on inert ceramic balls.

2. The waste tire pyrolysis system for producing high toluene transmittance pyrolysis carbon black according to claim 1, characterized in that, The solid acid catalyst includes HZSM-5 molecular sieve, HY molecular sieve, or modified waste tire pyrolysis carbon-based catalyst, and its loading volume accounts for 5% to 15% of the effective volume of the pyrolysis reactor.

3. The waste tire pyrolysis system for producing high toluene transmittance pyrolysis carbon black according to claim 1, characterized in that, The metal oxide catalyst includes single metal oxides, composite metal oxides, and rare earth metal oxides. The single metal oxides include zinc oxide and aluminum oxide, the composite metal oxides include cobalt-molybdenum oxide and nickel-molybdenum oxide, and the rare earth metal oxides include lanthanum oxide and cerium oxide.

4. A method for producing high toluene transmittance pyrolysis carbon black from waste tires, characterized in that, The production process using the waste tire pyrolysis system for producing high toluene transmittance pyrolysis carbon black as described in any one of claims 1 to 3 includes the following steps: S1: The crushed waste tire material is fed into the pyrolysis reactor and heated to 450-550℃ at a rate of 10-25℃ / min under an inert atmosphere, and kept at a constant temperature for 1-3 hours to carry out atmospheric pressure pyrolysis. S2: The gas-solid mixture produced by pyrolysis is passed through a solid acid catalyst and a metal oxide catalyst to obtain high-temperature oil and gas and solid carbon black particles; the heavy hydrocarbon macromolecules entrained in the gas-solid mixture are catalytically pyrolyzed into light small molecules, reducing condensation and deposition on the carbon black surface. S3: The high-temperature oil and gas and solid carbon black particles after catalytic cracking enter the gas phase micro-oxidation section. At the same time, preheated oxygen-containing inert gas is introduced into the gas phase micro-oxidation section through the air inlet. The oxygen volume concentration is controlled at 1%~5% and the gas residence time is 0.5~5 seconds to perform instantaneous and gentle oxidation activation on the carbon black particles. S4: High-temperature oil and gas and oxidized activated solid carbon black particles are fed into a carbon black collector for gas-solid separation. The collected solid is pyrolysis carbon black with high toluene transmittance.

5. The waste tire pyrolysis method for producing high toluene transmittance pyrolysis carbon black according to claim 5, characterized in that, The ratio of the total number of oxygen moles in the oxygen-containing inert gas introduced in step S3 to the mass of waste tire material added in step S1 is (0.05~0.3) mol: 1 kg.

6. The waste tire pyrolysis method for producing high toluene transmittance pyrolysis carbon black according to claim 5, characterized in that, The volume ratio of inert gas to oxygen in the oxygen-containing inert gas is 95%~99%:1%~5%, wherein the inert gas includes nitrogen.

7. A high-toluene-transmittance pyrolysis carbon black obtained by the waste tire pyrolysis method for producing high-toluene-transmittance pyrolysis carbon black according to any one of claims 4 to 6, characterized in that, The transmittance of toluene measured at a wavelength of 365 nm is ≥90%, and the BET specific surface area is ≥80 m² / g.

8. The use of the high toluene transmittance pyrolysis carbon black as described in claim 7 in the preparation of rubber products, inks or coatings.

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