Method for producing fuel oil and carbon black from waste tires

Abstract

The present invention provides a method for producing fuel oil and carbon black from waste tires, and the method comprises the following steps: (1) crushing the waste tires into tire particles; (2) mixing the tire particles with a support filler to obtain a tire particle mixture; (3) subjecting the tire particle mixture to pyrolysis treatment in a pyrolysis device, wherein the pyrolysis temperature ranges from 300 °C to 340 °C and the pyrolysis time ranges from 15 hours to 20 hours; (4) condensing and collecting the pyrolysis oil gas generated by the pyrolysis treatment to obtain the fuel oil; and (5) collecting the carbon black from the pyrolysis device. The entire process of the method is in a negative pressure state. The process according to the present invention can produce fuel oil with a very high productivity and co-produce carbon black. In addition, the production process can be implemented in the form of large-scale production by using an existing coke oven, and the whole process is in negative pressure operation, avoiding the impact on the environment.

Description

Technical Field

[0001] The present invention relates to the field of waste tire recycling and treatment processes, and specifically, to a method for producing fuel oil and carbon black from waste tires. Background Art

[0002] With the rapid development of the transportation industry and the sharp growth of the automotive industry, the output of waste tires has been increasing year by year, causing greater and greater harm to the environment. Waste tires are difficult to degrade in the natural state. If stacked outdoors for a long time, they will breed mosquitoes and flies, spread diseases, occupy land, and may cause fires. Due to the lack of effective management, many waste tires have flowed into the hands of illegal oil refiners, wasting resources and polluting the environment. Therefore, the resource utilization of waste tires can not only make up for the shortage of non-renewable petroleum resources, meet the increasingly strict environmental protection requirements, but also improve the added value of waste tires and expand the uses of products.

[0003] At present, there are mainly three ways to recycle waste tires: 1. Retreading waste tires, which requires a relatively high integrity of the tires; 2. Manufacturing recycled rubber and rubber powder from waste tires. Recycled rubber can replace part of the raw rubber and be applied to rubber products, but secondary exhaust gas pollution is generated during the high-temperature, high-pressure dynamic desulfurization process in the production process, and there are risks of combustion and explosion during the production process; 3. "Pyrolysis" recycling of waste tires. The "pyrolysis" technology is an important development direction for the current recycling of waste tires.

[0004] However, in the currently commonly used pyrolysis production process for preparing fuel oil and carbon black from waste tires, the cracking reaction of rubber powder is generally incomplete, the productivity is not high, and if the sealing effect of the production device is not good during the reaction process, there will be leakage, resulting in a decrease in product output and the risk of environmental pollution. In addition, the currently used production devices generally have imperfect safety measures, which are prone to accidents and secondary pollution.

[0005] Therefore, it is of great significance to develop an environmentally friendly process that can use existing equipment to produce fuel oil and carbon black from waste tires in a large-scale production manner with high productivity. Summary of the Invention

[0006] Based on the above-described technical problems, one of the objectives of the present invention is to provide an environmentally friendly process that can produce fuel oil and carbon black from waste tires in a large-scale production manner with high productivity.

[0007] Specifically, the present invention provides a method for producing fuel oil and carbon black from waste tires, and the method includes the following steps:

[0008] (1) Crushing waste tires into tire particles;

[0009] (2) Mix the tire particles with a support filler to obtain a tire particle mixture;

[0010] (3) Subject the tire particle mixture to pyrolysis treatment in a pyrolysis device, wherein the pyrolysis temperature is in the range of 300°C to 340°C, and the pyrolysis time is in the range of 15 hours - 20 hours;

[0011] (4) Condense and collect the pyrolysis oil and gas generated by the pyrolysis treatment to obtain the fuel oil;

[0012] (5) Collect the carbon black from the pyrolysis device.

[0013] According to certain preferred embodiments of the present invention, the pyrolysis device is in a negative pressure state.

[0014] According to certain preferred embodiments of the present invention, the pyrolysis device is in a negative pressure range of -50 Pa to -100 Pa.

[0015] According to certain preferred embodiments of the present invention, in step (1), the waste tire is crushed into tire particles with a particle size less than or equal to 10 mm.

[0016] According to certain preferred embodiments of the present invention, the support filler used in step (2) is alumina ceramic balls.

[0017] According to certain preferred embodiments of the present invention, in step (2), the mixing weight ratio of the tire particles to the support filler is in the range of 0.4 - 1.

[0018] According to certain preferred embodiments of the present invention, the pyrolysis device used in step (3) is a coke oven, and the coke oven includes a carbonization chamber and a combustion chamber, wherein the temperature in the carbonization chamber is in the range of 300°C to 340°C, and the temperature in the combustion chamber is in the range of 600°C to 800°C.

[0019] According to certain preferred embodiments of the present invention, step (4) includes: condensing the pyrolysis oil and gas generated by the pyrolysis treatment to obtain a condensate, and sequentially standing and dehydrating the condensate to obtain the fuel oil.

[0020] According to certain preferred embodiments of the present invention, the method further includes further fractionating the fuel oil to separately obtain heavy fuel oil and light fuel oil.

[0021] According to certain preferred embodiments of the present invention, step (5) includes:

[0022] Collecting the bottom residue from the pyrolysis device; and

[0023] Separate the support filler from the bottom residue to obtain the carbon black.

[0024] According to certain preferred embodiments of the present invention, the non-condensable gas generated in step (4) is introduced into the combustion chamber.

[0025] Compared with the prior art waste tire pyrolysis treatment process, the advantages of the process for producing fuel oil and carbon black from waste tires according to the present invention are as follows:

[0026] 1. By adopting the medium-temperature and slightly negative-pressure pyrolysis technology, especially by specifically controlling the process conditions (including pyrolysis temperature and pyrolysis time) in the pyrolysis device, fuel oil can be produced with a very high productivity and carbon black can be co-produced;

[0027] 2. The existing coking furnace process can be used to treat waste tires, thereby realizing large-scale continuous treatment of waste tires, reducing production costs and improving production efficiency; and

[0028] 3. The waste tire treatment process according to the present invention is in negative pressure operation throughout the process, avoiding the leakage of pyrolysis gas generated during the pyrolysis process into the ambient atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Shows a schematic diagram of a process for producing fuel oil and carbon black from waste tires according to a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It will be understood that other embodiments are contemplated and can be practiced without departing from the scope or spirit of the present invention. Accordingly, the following detailed description is non-limiting.

[0031] Unless otherwise specified, all numbers representing characteristic dimensions, quantities, and physical and chemical properties used in this specification and claims should be understood to be modified by the term "about" in all cases. Therefore, unless there is a contrary indication, the numerical parameters set forth in the above specification and appended claims are approximate values, and those skilled in the art can appropriately change these approximate values in seeking to obtain the desired characteristics using the teachings disclosed herein. The use of numerical ranges expressed with endpoints includes all numbers within that range and any range within that range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, and so on.

[0032] The present invention provides a method for producing fuel oil and carbon black from waste tires, the method comprising the following steps:

[0033] (1) Crushing waste tires into tire particles;

[0034] (2) Mix the tire particles with a support filler to obtain a tire particle mixture;

[0035] (3) Subject the tire particle mixture to pyrolysis treatment in a pyrolysis device, wherein the pyrolysis temperature ranges from 300 °C to 340 °C, and the pyrolysis time ranges from 15 hours to 20 hours;

[0036] (4) Condense and collect the pyrolysis oil and gas generated by the pyrolysis treatment to obtain the fuel oil;

[0037] (5) Collect the carbon black from the pyrolysis device.

[0038] Preferably, the pyrolysis temperature in the pyrolysis device ranges from 300 °C to 340 °C, preferably from 320 °C to 330 °C, and the pyrolysis time ranges from 15 hours to 20 hours, preferably from 15 hours to 17 hours. The inventors of the present invention have found that by specifically controlling the pyrolysis temperature and pyrolysis time in the pyrolysis device within the above ranges, a thorough pyrolysis reaction can be achieved to the greatest extent, reducing the production of by-products in the pyrolysis reaction, thereby significantly improving the productivity of fuel oil and carbon black. Specifically, based on the weight of the waste tires as raw materials being 100%, the amount of the obtained fuel oil can be as high as more than 30%, and the amount of the obtained carbon black can be as high as more than 43%. Such high productivity results are unexpected for the common techniques in the field of waste tire pyrolysis recovery. When the pyrolysis temperature is lower than 300 °C and / or the pyrolysis time is less than 15 hours, the pyrolysis reaction in the pyrolysis device is insufficient, and too many by-products are generated, reducing the yields of fuel oil and carbon black; when the pyrolysis temperature is higher than 340 °C and / or the pyrolysis time is greater than 17 hours, an excessive amount of non-condensable gas is generated in the pyrolysis reaction, resulting in a reduction in the yields of fuel oil and carbon black.

[0039] Preferably, the pyrolysis device is in a negative pressure state. The pyrolysis device is within a negative pressure range of -50 Pa to -100 Pa, preferably -80 Pa to -90 Pa. By controlling the pyrolysis device under the micro-negative pressure condition of -50 Pa to -100 Pa, on the one hand, the pyrolysis efficiency of the tire particle mixture in the pyrolysis device can be improved, significantly increasing the productivity of fuel oil and carbon black, and on the other hand, it can prevent the pyrolysis gas generated during the pyrolysis process from leaking out of the pyrolysis device and polluting the environment. Preferably, in order to further improve the productivity of the process for producing fuel oil and carbon black from waste tires, the entire production process is within a negative pressure range of -50 Pa to -100 Pa, preferably -80 Pa to -90 Pa.

[0040] Preferably, in step (1), the waste tires are crushed into tire particles with a particle size less than or equal to 10 mm, preferably less than or equal to 3 mm. A tire particle size less than or equal to 10 mm is beneficial for sufficient thermal cracking. In addition, a smaller tire particle size facilitates the collection of carbon black from the cracking device in step (5).

[0041] Preferably, in order to uniformly disperse the tire particles and provide support for them, the tire particles are mixed with a support filler in step (2). Preferably, the support filler used is alumina ceramic balls, and the particle size of the support filler is in the range of 3 mm to 10 mm. Preferably, the mixing weight ratio of the tire particles to the support filler is in the range of 0.4 - 1.

[0042] According to a preferred embodiment of the present invention, in order to achieve large-scale production of the above process and reduce production costs, an existing coke oven can be used as the cracking device. There is no particular limitation on the specific structure of the coke oven. A coke oven is usually built with refractory bricks and includes at least a carbonization chamber and a combustion chamber. A coke oven can include multiple carbonization chambers and multiple combustion chambers, which are arranged alternately and separated by refractory materials (silica bricks). The combustion chamber provides heat to the carbonization chamber, and the cracking reaction of the tire particles takes place in the carbonization chamber.

[0043] Preferably, in order to improve the productivity of fuel oil and carbon black, the temperature in the carbonization chamber is in the range of 300°C to 340°C, preferably 320°C to 330°C, and the temperature in the combustion chamber is in the range of 600°C to 800°C, preferably 700°C to 800°C, and most preferably 800°C. The inventors of the present invention have found that by specifically controlling the temperature of the fuel chamber and carbonization chamber in the coke oven and the cracking time within the range of the present invention, a thorough cracking reaction can be achieved to the greatest extent, reducing the production of by-products in the cracking reaction, thereby significantly improving the productivity of fuel oil and carbon black. Specifically, based on the weight of the waste tires as raw materials being 100%, the amount of fuel oil obtained can be as high as more than 30%, and the amount of carbon black obtained can be as high as more than 43%. Such high productivity results are unexpected for those of ordinary skill in the field of waste tire thermal cracking recovery. When the temperature in the carbonization chamber is lower than 300°C, the temperature in the combustion chamber is lower than 600°C, and / or the cracking time is less than 15 hours, the cracking reaction in the coke oven is insufficient, and too many by-products are generated, reducing the yield of fuel oil and carbon black; when the temperature in the carbonization chamber is higher than 340°C, the temperature in the combustion chamber is higher than 800°C, and / or the cracking time is greater than 17 hours, excessive non-condensable gases are generated in the cracking reaction, resulting in a reduction in the yield of fuel oil and carbon black.

[0044] Preferably, step (4) described above includes: condensing the pyrolysis oil-gas generated by the pyrolysis treatment to obtain a condensate, and successively subjecting the condensate to static stratification and dehydration to obtain the fuel oil.

[0045] Preferably, the method further includes fractionating the fuel oil to separately obtain heavy fuel oil and light fuel oil.

[0046] Preferably, step (5) includes:

[0047] collecting bottom residues from the pyrolysis device; and

[0048] separating the support packing from the bottom residues to obtain the carbon black.

[0049] The recovered support packing can be introduced into step (2) to be mixed with new tire particles.

[0050] Preferably, the non-condensable gas generated in step (4) is introduced into the combustion chamber as fuel.

[0051] The method for producing fuel oil and carbon black from waste tires according to the present invention can be implemented by using existing coke oven facilities.

[0052] Figure 1 Shows a schematic diagram of the process for producing fuel oil and carbon black from waste tires according to a preferred embodiment of the present invention.

[0053] Specifically, the process according to the present invention includes the following operations:

[0054] (1) Waste tire crushing operation

[0055] Cut waste tires (with or without steel wires) into pieces, wash them on site, and crush them through crusher 1 to crush the rubber blocks into tire particles with a particle size less than or equal to 10 mm. The tire particles are conveyed by conveyor belt 2 through magnetic separator 3 to remove steel wires. Then, support packing 4 (aluminum oxide ceramic balls with a diameter of 10 mm, where the mixing weight ratio of tire particles to support packing is 1:1) is added to the tire particles to obtain a tire particle mixture. The tire particle mixture is conveyed by conveyor belt 2 to crusher 5 for crushing, and further conveyed by conveyor belt 2 to tire particle tower 6.

[0056] (2) Feeding operation

[0057] During the initial start-up, the tire particle mixture is transported by a charging vehicle (not shown) to the charging furnace hole position of coke oven 7, the charging hole is opened, the tire particle mixture is unloaded from the charging vehicle bin into coke oven 7, and the upper part of the raw material is leveled by a leveling rod at the end of charging.

[0058] (3) Pyrolysis operation

[0059] The coke oven 7 includes alternately arranged carbonization chambers and combustion chambers with a height of 4.3 meters, wherein the temperature in the combustion chambers is in the range of 600 °C to 700 °C, thereby ensuring that the central temperature range of the carbonization chambers is 320 °C. The cracking time lasts for 17 hours. After the cracking is completed, the temperature of the combustion chambers is reduced to 600 °C. During the production process of the coke oven, the inside of the coke oven is slowly evacuated by a Roots blower to create a slight negative pressure (-100 Pa) inside the coke oven to prevent the cracked gas from leaking out of the furnace.

[0060] (4) Fuel oil collection process

[0061] The cracked oil and gas generated in the carbonization chambers of the coke oven 7 are sucked by a blower into the primary cooler 8, where the inhaled gas is cooled to below 32 °C. Condensed liquid is generated at the bottom of the primary cooler 8 and non-condensable gas exists in the upper part.

[0062] Subsequently, the condensed liquid is introduced into the distillation column 13 by a pump 12 for fractionation, wherein: the upper fraction of the distillation column 13 is condensed by a condenser 15 and collected as light fuel oil 15, while the lower fraction of the distillation column 13 is collected as heavy fuel oil 14. Optionally, a heavy oil intermediate tank 11 (with a volume of 400 m 3 ) for storing oil can also be provided between the primary cooler 8 and the distillation column 13. Optionally, the condensed liquid is allowed to stand for layering and dehydration in sequence.

[0063] In addition, the non-condensable gas in the upper part of the primary cooler 8 is transported by a blower 10 to the desulfurization tower 9 for desulfurization, and the desulfurized non-condensable gas is further transported to the fuel chamber of the coke oven 7 as fuel.

[0064] (5) Carbon black collection process

[0065] After it is detected that no gas volatilizes in the carbonization chamber, the residue (i.e., carbon black) in the carbonization chamber is pushed out into the carbon black silo 17 by the coke pusher in the coke pusher mode and cooled by nitrogen circulation. Then, the carbon black is pulverized in the carbon black pulverizer 18 and further collected in the carbon black packing machine 19. Optionally, in the above process, the carbon black can be screened in a carbon black screening machine to separate out the support filler. The support filler can be reused in the waste tire recycling process according to the present invention.

[0066] Although specific embodiments have been shown and described in the present invention, those skilled in the art will understand that various alternative and / or equivalent embodiments can be used to replace the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any improvements or changes to the specific embodiments discussed in the present invention. Therefore, the present invention is only limited by the claims and their equivalents.

[0067] Those skilled in the art should understand that various modifications and changes can be made without departing from the scope of the present invention. Such modifications and changes are intended to fall within the scope of the present invention as defined by the appended claims.

Claims

1. A method for producing fuel oil and carbon black from waste tires, the method comprising the following steps: (1) crushing waste tires into tire particles with a particle size less than or equal to 3 mm; (2) mixing the tire particles with alumina ceramic balls to obtain a tire particle mixture, wherein the mixing weight ratio of the tire particles to the alumina ceramic balls is in the range of 0.4-1, and the particle size of the alumina ceramic balls is in the range of 3 mm to 10 mm; (3) the tire particle mixture is subjected to cracking treatment in a coking oven, wherein the coking oven comprises a carbonization chamber and a combustion chamber which are alternately arranged, the temperature in the carbonization chamber is in the range of 320° C. to 330° C., the temperature in the combustion chamber is in the range of 700° C. to 800° C., the coking oven is slowly evacuated by a Roots blower so that the coking oven is in the negative pressure range of -80 Pa to -90 Pa, and the cracking time is in the range of 15 hours to 17 hours; (4) The cracked oil gas generated in the carbonization chamber of the coke oven is sucked into a primary cooler by a fan and cooled to below 32° C., so as to condense at the bottom of the primary cooler to obtain a condensate and generate a non-condensable gas at the upper part of the primary cooler, the condensate is sequentially statically layered and dehydrated to obtain the fuel oil, and the non-condensable gas is transported to a desulfurization tower by a fan for desulfurization, and the desulfurized non-condensable gas is further transported to the combustion chamber of the coke oven as fuel; and (5) collecting bottom residue from the carbonization chamber of the coke oven, and separating the alumina ceramic balls from the bottom residue by screening in a carbon black screening machine to obtain the carbon black.

2. The method for producing fuel oil and carbon black from waste tires according to claim 1, further comprising further fractionating the fuel oil to obtain heavy fuel oil and light fuel oil, respectively.

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