Method for preparing new catalyst from waste tire pyrolytic carbon black

Abstract

Disclosed in the present invention is a method for preparing a new catalyst from waste tire pyrolytic carbon black. Pyrolytic carbon black with low impurities is obtained by subjecting waste tires to low-temperature rapid pyrolysis and high-temperature water vapor water washing, thereby avoiding the waste of waste tires. The pyrolytic carbon black is loaded with an active metal, so as to prepare a new catalyst, which is used for catalyzing the pyrolysis of a hydrocarbon-rich waste plastic (polypropylene and polyethylene) to prepare a hydrogen-rich synthesis gas for hydrogen production, thereby achieving the recycling of solid waste.

Description

A method for preparing a new catalyst by pyrolyzing carbon black from waste tires Technical field:

[0001] The invention relates to the technical field of solid waste treatment, and in particular to a method for preparing a novel catalyst by pyrolyzing carbon black from waste tires. Background technology:

[0002] At present, with the widespread use of plastic products, the amount of waste plastic has increased dramatically, and the increase in the number of cars has also caused an increasing number of waste tires. This not only causes serious pollution to the environment, but also brings about the problem of waste resources. At present, the treatment and utilization technologies of waste plastics and waste tires mainly include landfill, incineration, mechanical recycling, melting and reshaping into low-grade plastics, etc., and the waste recovery rate is only 9%. The treatment and reuse of solid waste has become a focus of global attention. Waste plastics and waste rubber are difficult to degrade. It may take hundreds of years for them to completely decompose in the natural environment, causing ocean, soil and air pollution, and endangering human and animal health. The thermal chemical recovery method of waste tires and waste plastics has gradually attracted widespread attention and in-depth research. Pyrolysis technology can produce energy from solid waste and is one of the ways to utilize resources. Summary of the invention:

[0003] The purpose of the present invention is to provide a method for preparing a novel catalyst by pyrolyzing carbon black from waste tires.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for preparing a novel catalyst by pyrolyzing carbon black from waste tires, the method comprising the following steps:

[0006] (1) Under an inert atmosphere, waste tire rubber particles are pyrolyzed at 420-550°C for 15-45 minutes, then rapidly heated to 550-900°C at a rate of 25-50°C / min, and then steam is introduced at a rate of 3-15 ml / h for 5-20 minutes to obtain pyrolytic carbon;

[0007] (2) The pyrolytic carbon obtained in step (1) and the metal compound are mixed and stirred in water to obtain a pyrolytic carbon-metal mixed solution, and then placed in an oven at 120° C. and dried for 24 hours to obtain a solid mixture, and then the solid mixture is calcined at a high temperature of 600-900° C. under inert gas for 1-4 hours to obtain a new catalyst.

[0008] Because the surface and interior of waste tires contain colloidal impurities, they are rapidly pyrolyzed at a low temperature of 420-550°C and then washed with steam at a high temperature of 550-900°C to obtain pyrolytic carbon. The colloidal impurities on the surface and inside are fully removed, which increases the specific surface area of ​​the pyrolytic carbon and the active sites of metal loading. Then, new catalysts are prepared by selecting loaded metals to achieve the reuse of carbon black.

[0009] Preferably, the inert gas in step (1) is selected from nitrogen, argon and helium; the waste tire rubber particles are solid rubber particles of 2 to 10 mm obtained by washing, magnetic separation and crushing of scrap tires of various automobiles.

[0010] Preferably, the water vapor in step (1) is one of deionized water vapor and ultrapure water vapor.

[0011] Preferably, the metal compound described in step (2) is any one of iron salt, cobalt salt, nickel salt, and copper salt, the mass ratio of the metal compound to the pyrolytic carbon carrier is 2.5% to 32.5%:1, the stirring rate is 400 to 800 r / min, and the stirring time is 5 to 8 hours.

[0012] Preferably, the high-temperature calcination heating rate in step (2) is 5 to 50° C. / min.

[0013] The present invention also protects the use of the catalyst obtained by the above preparation method in catalytic pyrolysis of hydrocarbon-rich waste plastics to produce hydrogen-rich synthesis gas, which specifically includes the following steps: hydrocarbon-rich waste plastics and water vapor are cracked at 500-800°C under the action of the catalyst to produce hydrogen-rich synthesis gas.

[0014] Waste plastics rich in hydrocarbons include waste polypropylene plastics and waste polyethylene plastics.

[0015] The beneficial effects of the present invention are as follows:

[0016] 1) This invention eliminates waste tire waste by rapidly pyrolyzing waste tires at low temperatures and then washing them with steam at high temperatures to produce low-impurity pyrolytic carbon black. The pyrolytic carbon black is loaded with active metals to prepare a novel catalyst that catalyzes the pyrolysis of hydrocarbon-rich waste plastics (polypropylene, polyethylene) to produce hydrogen-rich syngas, thus enabling the recycling and reuse of solid waste.

[0017] 2) The raw materials of the present invention, waste tires and waste plastics, are widely available, and their full utilization can solve problems such as environmental pollution and resource utilization. The present invention also fully utilizes the excellent properties of waste tire pyrolysis carbon black, such as large specific surface area and excellent active sites, to provide a resource utilization method for waste tires and waste plastics, and also provides a new method for preparing a catalyst for catalyzing the pyrolysis of waste plastics to produce hydrogen. Description of the drawings:

[0018] FIG1 is a thermal field emission scanning electron microscopy test result of the catalyst obtained in Example 1;

[0019] FIG2 is an XRD pattern of the novel catalyst prepared in Example 1. Specific implementation method:

[0020] The following is a further description of the present invention, but not a limitation of the present invention.

[0021] Example 1:

[0022] (1) Under nitrogen atmosphere, waste tire rubber particles were rapidly pyrolyzed at 450°C for 30 min, then rapidly heated to 800°C at a rate of 30°C / min, and washed with deionized water vapor at a rate of 9 ml / h for 15 min to obtain pyrolytic carbon;

[0023] (2) Pyrolytic carbon black and nickel nitrate compound were then mixed in water at a mass ratio of 1:15% and stirred at a rate of 600 r / min for 7 hours to obtain a pyrolytic carbon-metal mixed solution, which was then placed in an oven at 120°C for 24 hours to obtain a solid mixture. The solid mixture was then heated to 800°C at a heating rate of 30°C / min under inert gas and calcined for 2 hours to obtain a new catalyst. The catalyst was characterized. As shown in Figure 1, the obtained catalyst had a clear interface, small metal particles, and was evenly dispersed. As shown in Figure 2, the main structure of the catalyst contains ZnS and Ni as well as a small amount of NiO. The presence of ZnS and Ni not only provides more active sites, which helps the catalytic reaction, but also ensures the stability of the catalyst.

[0024] (3) The new catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production ability. 1g of polypropylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the new catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 800°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 54.85mmol.

[0025] Comparative Example 1:

[0026] (1) Waste tire rubber particles were rapidly pyrolyzed at 450°C for 30 min under nitrogen atmosphere to obtain pyrolytic carbon;

[0027] (2) Pyrolytic carbon black and nickel nitrate compound were then mixed in water at a mass ratio of 1:15% and stirred at 600 rpm for 7 h to obtain a pyrolytic carbon-metal mixed solution, which was then dried in an oven at 120°C for 24 h to obtain a solid mixture. The solid mixture was then heated to 800°C at a heating rate of 30°C / min under inert gas and calcined for 2 h to obtain a catalyst.

[0028] (3) The catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production capacity. 1g of polypropylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 800°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 30.45mmol.

[0029] Comparative Example 2:

[0030] Refer to Example 1, the difference is that the pyrolysis temperature of waste tire rubber particles is relatively high.

[0031] (1) Waste tire rubber pellets were kept at 800°C for 45 min under nitrogen atmosphere, and deionized water vapor was introduced at a rate of 9 ml / h for 15 min to obtain pyrolytic carbon;

[0032] (2) Pyrolytic carbon black and nickel nitrate compound were then mixed in water at a mass ratio of 1:15% and stirred at 600 r / min for 7 h to obtain a pyrolytic carbon-metal mixed solution, which was then dried in an oven at 120°C for 24 h to obtain a solid mixture. The solid mixture was then heated to 800°C at a heating rate of 30°C / min under inert gas and calcined at 800°C for 2 h to obtain a catalyst.

[0033] (3) The catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production capacity. 1g of polypropylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 800°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 41.62mmol.

[0034] Example 2

[0035] (1) Under nitrogen atmosphere, waste tire rubber particles were rapidly pyrolyzed at 470°C for 40 min, then rapidly heated to 700°C at a rate of 25°C / min, and washed with deionized water vapor at a rate of 8 ml / h for 10 min to obtain pyrolytic carbon;

[0036] (2) Pyrolytic carbon black and ferric nitrate were then mixed in water at a mass ratio of 1:20% and stirred at 700 rpm for 5 h to obtain a pyrolytic carbon-metal mixed solution. The solution was then dried in an oven at 120°C for 24 h to obtain a solid mixture. The solid mixture was then heated to 750°C at a heating rate of 15°C / min under an inert gas atmosphere and calcined at 750°C for 2.5 h to obtain a novel catalyst.

[0037] (3) The new catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production ability. 1g of polyethylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the new catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 750°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 44.54mmol.

[0038] Example 3

[0039] (1) Under nitrogen atmosphere, waste tire rubber particles were rapidly pyrolyzed at 420°C for 20 min, then rapidly heated to 600°C at a rate of 35°C / min, and washed with deionized water vapor at a rate of 7 ml / h for 13 min to obtain pyrolytic carbon;

[0040] (2) Pyrolytic carbon black and nickel nitrate were then mixed in water at a mass ratio of 1:25% and stirred at 400 rpm for 8 h to obtain a pyrolytic carbon-metal mixed solution. The solution was then dried in an oven at 120°C for 24 h to obtain a solid mixture. The solid mixture was then heated to 700°C at a heating rate of 20°C / min under inert gas and calcined at 700°C for 3.5 h to obtain a novel catalyst.

[0041] (3) The new catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production ability. 1g of polyethylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the new catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 700°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 53.83mmol.

[0042] Example 4

[0043] (1) Under nitrogen atmosphere, waste tire rubber particles were rapidly pyrolyzed at 510°C for 30 min, then rapidly heated to 750°C at a rate of 25°C / min, and washed with deionized water vapor at a rate of 6 ml / h for 20 min to obtain pyrolytic carbon;

[0044] (2) Pyrolytic carbon black and nickel nitrate and copper nitrate compounds were then mixed in water at a mass ratio of 1:15%:15% and stirred at 650 r / min for 6 h to obtain a pyrolytic carbon-metal mixed solution. The solution was then dried in an oven at 120°C for 24 h to obtain a solid mixture. The solid mixture was then heated to 850°C at a heating rate of 25°C / min under inert gas and calcined at 850°C for 2 h to obtain a novel catalyst.

[0045] (3) The new catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production ability. 1g of polypropylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the new catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 850°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 51.68mmol.

[0046] Example 5

[0047] (1) Under nitrogen atmosphere, waste tire rubber particles were rapidly pyrolyzed at 500°C for 27 min, then rapidly heated to 900°C at a rate of 35°C / min, and washed with deionized water vapor at a rate of 5 ml / h for 5 min to obtain pyrolytic carbon;

[0048] (2) Pyrolytic carbon black and cobalt nitrate compound were then mixed in water at a mass ratio of 1:17.5% and stirred at 450 r / min for 8 h to obtain a pyrolytic carbon-metal mixed solution. The solution was then dried in an oven at 120°C for 24 h to obtain a solid mixture. The solid mixture was then heated to 900°C at a heating rate of 23°C / min under an inert gas atmosphere and calcined at 900°C for 3 h to obtain a novel catalyst.

[0049] (3) The new catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production ability. 1g of polypropylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the new catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 900°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 48.96mmol.

[0050] Example 6

[0051] (1) Under nitrogen atmosphere, waste tire rubber particles were rapidly pyrolyzed at 475°C for 25 min, then rapidly heated to 650°C at a rate of 25°C / min, and washed with deionized water vapor at a rate of 6 ml / h for 10 min to obtain pyrolytic carbon;

[0052] (2) Pyrolytic carbon black, cobalt nitrate, and copper nitrate were then mixed in water at a mass ratio of 1:12.5%:12.5% ​​and stirred at 700 r / min for 8 hours to obtain a pyrolytic carbon-metal mixed solution. The solution was then dried in an oven at 120°C for 24 hours to obtain a solid mixture. The solid mixture was then heated to 600°C at a heating rate of 10°C / min under inert gas and calcined at 600°C for 4 hours to obtain a novel catalyst.

[0053] (3) The new catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production ability. 1g of polyethylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the new catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 600°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 47.86mmol.

[0054] Example 7

[0055] (1) Under nitrogen atmosphere, waste tire rubber particles were rapidly pyrolyzed at 550°C for 20 min, then rapidly heated to 650°C at a rate of 40°C / min, and washed with deionized water vapor at a rate of 5 ml / h for 8 min to obtain pyrolytic carbon;

[0056] (2) Pyrolytic carbon black and ferric nitrate were then mixed in water at a mass ratio of 1:27.5% and stirred at 700 rpm for 5 h to obtain a pyrolytic carbon-metal mixed solution. The solution was then dried in an oven at 120°C for 24 h to obtain a solid mixture. The solid mixture was then heated to 850°C at a heating rate of 8°C / min under an inert gas atmosphere and calcined at 850°C for 3 h to obtain a novel catalyst.

[0057] (3) The new catalyst prepared in step (2) was used in a catalytic pyrolysis experiment to verify its hydrogen production ability. 1g of polyethylene particles was weighed as a reaction raw material and placed in the pyrolysis section hanging basket of the upper section of the pyrolysis reactor. 1g of the new catalyst powder prepared in step (2) was weighed and placed in the catalytic section of the lower section of the pyrolysis reactor. Under a nitrogen atmosphere, the catalytic section of the lower section of the pyrolysis reactor was slowly heated from room temperature to 850°C at a heating rate of 30°C / min and maintained until the catalytic reaction was completed. The pyrolysis section of the upper section of the pyrolysis reactor was slowly heated from room temperature to 500°C at a heating rate of 30°C / min and maintained for 30 minutes. During this period, deionized water vapor was introduced at a rate of 6ml / h through a peristaltic pump. The gas generated by the pyrolysis catalysis was collected and detected, and the hydrogen yield was 48.55mmol.

[0058] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a new catalyst by pyrolyzing carbon black from waste tires, characterized in that: The method comprises the following steps: (1) Under an inert atmosphere, waste tire rubber particles are pyrolyzed at 420-550°C for 15-45 minutes, then rapidly heated to 550-900°C at a rate of 25-50°C / min, and then steam is introduced at a rate of 3-15 ml / h for 5-20 minutes to obtain pyrolytic carbon; (2) The pyrolytic carbon obtained in step (1) and the metal compound are mixed and stirred in water to obtain a pyrolytic carbon-metal mixed solution, and then placed in an oven at 120° C. and dried for 24 hours to obtain a solid mixture, and then the solid mixture is calcined at a high temperature of 600-900° C. under inert gas for 1-4 hours to obtain a new catalyst.

2. The method according to claim 1, characterized in that In step (1), the inert gas is selected from one of nitrogen, argon and helium.

3. The method according to claim 1, characterized in that The waste tire rubber particles are solid rubber particles of 2 to 10 mm obtained from scrap tires of various vehicles after cleaning, magnetic separation and crushing.

4. The method according to claim 1, wherein The water vapor described in step (1) is one of deionized water vapor and ultrapure water vapor.

5. The method according to claim 1, wherein The metal compound described in step (2) is any one of iron salt, cobalt salt, nickel salt, and copper salt, the mass ratio of the metal compound to the pyrolytic carbon carrier is 2.5% to 32.5%:1, the stirring rate is 400 to 800 r / min, and the stirring time is 5 to 8 hours.

6. The method according to claim 1, characterized in that The high temperature calcination heating rate in step (2) is 5 to 50° C. / min.

7. Use of the catalyst obtained by the method according to claim 1 in catalytic pyrolysis of hydrocarbon-rich waste plastics to produce hydrogen-rich synthesis gas, characterized in that: The specific steps include: The hydrocarbon-rich waste plastics and water vapor are cracked at 500-800°C under the action of a catalyst to produce hydrogen-rich synthesis gas.

8. The use according to claim 7, characterized in that The hydrocarbon-rich waste plastics are waste polypropylene plastics or waste polyethylene plastics.

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