Method for resource utilization of tire decomposition carbon black

Abstract

The application discloses a method for recycling and utilizing tire decomposition carbon black resources, characterized by using the zinc oxide-containing carbon black raw material after tire decomposition and heavy oil, stirring and mixing, mechanically pressing into carbon rods, directly feeding into a fixed bed, feeding in mixed gas of pure oxygen and carbon dioxide, carbon rod combustion, carbon dioxide conversion and tar cracking gasification combined action, producing combustible gas containing light tar, hydrocarbons, carbon oxides and zinc vapor, and further obtaining high-purity metal zinc without tar after quenching of the combustible gas; the tar-containing combustible gas after zinc removal is directly fed into a carbon black production line as carbon-rich fuel. The method has the advantages of simple and safe process, high product utilization rate, low cost and energy consumption, and can better play the roles of recycling, cost reduction and energy consumption reduction.

Description

Technical Field

[0001] This method relates to the field of waste tire decomposition technology, and more specifically, to a method for the resource utilization of carbon black from tire decomposition. Background Technology

[0002] Automobile tires are a composite material of rubber and carbon black. Carbon black, as an important additive in tires, enhances the overall hardness, strength and wear resistance of tires. The two main products of waste tire pyrolysis and oil refining are pyrolysis oil and carbon black. The carbon black produced by pyrolysis is crude carbon black with a calorific value of 7000 kcal / kg, which is comparable to that of coal and has high industrial utilization value.

[0003] CN115446096A discloses a method for preparing blast furnace pulverized coal fuel and zinc carbonate from waste tire pyrolysis carbon black. The method involves adding waste tire pyrolysis carbon black to an acid solution to obtain filtrate I and solid product I. Solid product I is then treated to obtain dezincified pyrolysis carbon black, which is then mixed with blast furnace pulverized coal to produce blast furnace pulverized coal fuel. Simultaneously, filtrate I is treated to obtain basic zinc carbonate, and other products are treated and recycled. This invention controls the concentration, time, and temperature of the acid solution to adjust the composition of the obtained dezincified pyrolysis carbon black, ensuring it meets the requirements for preparing blast furnace pulverized coal fuel. Dezincified pyrolysis carbon black possesses advantages such as high fixed carbon, low ash content, low harmful elements, high calorific value, and excellent blast furnace pulverized coal injection process performance. It can partially or completely replace coal in blast furnace pulverized coal injection, thus realizing the application of waste tire pyrolysis carbon black in blast furnace pulverized coal injection. This not only improves the utilization value of waste materials but also reduces the consumption of fossil fuels in ironmaking production, achieving better economic benefits. This method uses acid to treat zinc-containing carbon black, which carries a high risk of accidents and makes the waste liquid difficult to treat, thus contradicting the environmental protection goals of energy conservation and emission reduction.

[0004] CN105001913A provides an apparatus and method for producing combustible gas from tire pyrolysis carbon black. The apparatus includes a combustion chamber at the bottom and a gasification chamber at the top, with a steam secondary heating device between the combustion chamber and the gasification chamber. The method includes: (1) burning carbon black with combustion air in the combustion chamber to generate high-temperature flue gas containing carbon dioxide; (2) the high-temperature flue gas, after gas-solid separation and carbon dioxide absorption, enters the gasification chamber, where carbon black reacts with carbon dioxide and steam to generate high-temperature combustible gas containing hydrogen and carbon monoxide; (3) the high-temperature combustible gas enters a waste heat boiler to generate steam, which then enters the secondary heating device to be converted into superheated steam and enters the gasification chamber. This invention uses the high-temperature carbon dioxide flue gas generated from the combustion of tire pyrolysis carbon black as the direct heating source and carbon source for carbon black gasification. The equipment has high thermal efficiency, the entire process is compact, and the equipment investment cost is low. However, this method involves incomplete combustion of carbon black, requiring additional adsorption of the generated carbon dioxide to reduce its concentration, thus reducing the carbon black utilization rate and adding extra process steps.

[0005] CN111040796A relates to a production process for preparing fuel oil and crude carbon black from waste tires. The process includes: crushing waste tires into powder with a particle size ≤10mm, feeding it into a feed trough via a tubular chain elevator, and then conveying it to a pyrolysis furnace via a screw conveyor; the pyrolysis furnace is externally heated, with a pyrolysis temperature of 480-500℃ and a pressure of -50Pa; the pyrolysis chamber is divided into three chambers, with the generated carbon black discharged from the slag outlet at the end of the third pyrolysis chamber and conveyed to the next process via a screw conveyor; the pyrolysis furnace has two oil and gas outlets, which converge and sequentially enter a secondary oil and gas separator and a secondary condenser. The separated and condensed fuel oil is pumped to an oil storage tank, while the pyrolysis gas from the outlet of the second condenser is sent to a pyrolysis gas buffer tank, and then pumped to a hot air furnace for use as fuel gas. Excess pyrolysis gas is sent to a combustion chamber for combustion treatment to meet emission standards. This invention makes full use of waste tires, avoids environmental pollution and resource waste, and the process technology is green, environmentally friendly, continuous, and intelligent. This method sends carbon black and fuel oil obtained from pyrolysis to other equipment for processing and storage, without direct utilization. The pyrolysis gas needs to be heated before being used as fuel after passing through a buffer tank, which will significantly increase equipment costs and process energy consumption, and increase recovery costs.

[0006] According to existing technical documents, the zinc oxide contained in tire decomposition carbon black cannot be directly used for carbon black production. Waste engine oil, asphalt, and waste recycled oil are waste materials that require multiple processes for separation and treatment to optimize carbon black quality and make effective use, which increases the process steps and equipment costs. Pyrolysis oil is usually stored or processed in other ways before being produced, without applying its high calorific value to the combustion pyrolysis process. The process usually requires the addition of fuel gas from the outside and preheating of the fuel gas, making the recovery cost high. Therefore, the following method has been invented. Summary of the Invention

[0007] A method for the resource utilization of carbon black from tire decomposition is characterized by using coarse zinc oxide-containing carbon black from tire decomposition and heavy oil, mixing them at a solid-liquid ratio of 1:0.02~0.1, and mechanically pressing them into carbon rods with a diameter of 20~40 mm and a length of 40~80 mm. The carbon rods are not cooled or stored, but are directly fed into a fixed bed. At a temperature of 1100~1400℃, a mixture of pure oxygen and carbon dioxide with a volume ratio of 1:0.2~2.5 is introduced. The carbon rods are combusted, carbon dioxide is converted, and tar is cracked and gasified in combination to produce combustible gas containing light tar, hydrocarbons, carbon oxides, and zinc vapor. The combustible gas is quenched to 650~750℃ to separate liquid zinc, and then further high-purity metallic zinc without tar is obtained. The tar-containing combustible gas after zinc removal is directly sent to the carbon black production line as carbon-rich fuel without cooling, thereby maximizing the utilization of tire decomposition carbon black in the manufacturing process.

[0008] In one possible implementation, the heavy oil includes one or more of the following: carbon black feedstock tar, waste engine oil, asphalt, and waste recycling oil.

[0009] Compared with the prior art, the present invention has the following characteristics: 1. The carbon rods are assembled and processed through a fixed-bed gasification process. The resulting elemental carbon and carbon monoxide can react with zinc oxide powder (ZnO + CO = Zn + CO2, ZnO + C = Zn + CO) to complete the separation of crude zinc smelting. At the same time, high-temperature pyrolysis is generated, and heavy waste oil is used to produce fuel gas that can be used to produce carbon black. The combination of gasification and crude smelting simultaneously completes the separation of crude carbon black from tire decomposition, the utilization of heavy waste oil, and the smelting of metallic zinc, reducing equipment costs and production energy consumption. 2. The traditional process of adding all the raw material tar in the carbon black production process from the cracking chamber has been changed to adding part of it from the coal briquette making process. The tar can be used as both a binder and a raw material. 3. Carbon black combustion gas is usually cold coal gas, but this invention uses hot combustible gas, which reduces the coal gas cooling and heating process and saves energy. Attached Figure Description

[0010] Figure 1 This is a process flow diagram of the tire decomposition carbon black resource utilization method of the present invention. Specific implementation methods

[0011] Example 1: Zinc oxide-containing carbon black crude material from tire decomposition is mixed with heavy oil at a solid-liquid ratio of 1:0.04 and mechanically pressed into carbon rods with a diameter of 20 mm and a length of 40 mm. The carbon rods are not cooled or stored and are directly fed into a fixed bed. At a temperature of 1100°C, a mixture of pure oxygen and carbon dioxide with a volume ratio of 1:0.8 is introduced. The combined action of carbon rod combustion, carbon dioxide conversion, and tar cracking and gasification produces combustible gas containing light tar, hydrocarbons, carbon oxides, and zinc vapor. The combustible gas is quenched to 700°C to separate liquid zinc and further obtain tar-free high-purity metallic zinc. The tar-containing combustible gas after zinc removal is directly sent to the carbon black production line as carbon-rich fuel without cooling, thereby maximizing the utilization of tire decomposition carbon black in the manufacturing process.

[0012] Example 2: Zinc oxide-containing carbon black crude material from tire decomposition is mixed with heavy oil at a solid-liquid ratio of 1:0.06 and mechanically pressed into carbon rods with a diameter of 30 mm and a length of 50 mm. The carbon rods are not cooled or stored and are directly fed into a fixed bed. At a temperature of 1200°C, a mixture of pure oxygen and carbon dioxide with a volume ratio of 1:1.2 is introduced. The combined action of carbon rod combustion, carbon dioxide conversion, and tar cracking and gasification produces combustible gas containing light tar, hydrocarbons, carbon oxides, and zinc vapor. The combustible gas is quenched to 700°C to separate liquid zinc and further obtain tar-free high-purity metallic zinc. The tar-containing combustible gas after zinc removal is directly sent to the carbon black production line as carbon-rich fuel without cooling, thereby maximizing the utilization of tire decomposition carbon black in the manufacturing process.

[0013] Example 3: Zinc oxide-containing carbon black crude material from tire decomposition is mixed with heavy oil at a solid-liquid ratio of 1:0.08 and mechanically pressed into carbon rods with a diameter of 40 mm and a length of 60 mm. The carbon rods are not cooled or stored and are directly fed into a fixed bed. At a temperature of 1300°C, a mixture of pure oxygen and carbon dioxide with a volume ratio of 1:2 is introduced. The combined action of carbon rod combustion, carbon dioxide conversion, and tar cracking and gasification produces combustible gas containing light tar, hydrocarbons, carbon oxides, and zinc vapor. The combustible gas is quenched to 700°C to separate liquid zinc and further obtain tar-free high-purity metallic zinc. The tar-containing combustible gas after zinc removal is directly sent to the carbon black production line as carbon-rich fuel without cooling, thereby maximizing the utilization of tire decomposition carbon black in the manufacturing process.

Claims

1. A method for the resource utilization of carbon black from tire decomposition, characterized in that... The zinc oxide-containing carbon black crude material from tire decomposition is mixed with heavy oil at a solid-liquid ratio of 1:0.02~0.1 and mechanically pressed into carbon rods with a diameter of 20~40 mm and a length of 40~80 mm. The carbon rods are not cooled or stored, but directly fed into a fixed bed. At a temperature of 1100~1400℃, a mixture of pure oxygen and carbon dioxide with a volume ratio of 1:0.2~2.5 is introduced. The carbon rods are burned, carbon dioxide is converted, and tar is cracked and gasified in combination to produce combustible gas containing light tar, hydrocarbons, carbon oxides and zinc vapor. The combustible gas is quenched to 650~750℃ to separate liquid zinc, and then further high-purity metallic zinc without tar is obtained. The tar-containing combustible gas after zinc removal is directly sent to the carbon black production line as carbon-rich fuel without cooling, thereby maximizing the utilization of tire decomposition carbon black in the manufacturing process.

2. The method for resource utilization of carbon black from tire decomposition according to claim 1, characterized in that... Heavy oils include one or more of the following: carbon black raw material tar, waste engine oil, asphalt, and waste recycled oil.

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