Waste plastic and coal tar residue pyrolysis residue co-pyrolysis regenerated coal and regeneration method

Abstract

The invention discloses waste plastic and coal tar residue pyrolysis residue co-pyrolysis regenerated coal and a regeneration method, and belongs to the technical field of solid waste resource utilization. Coal tar residue pyrolysis residues with the high carbon hydrogen ratio (larger than 10) and the large porosity (larger than 50%) and coal tar residue pyrolysis residues with the low carbon hydrogen ratio (lt; according to the present invention, the low-temperature co-pyrolysis is performed on the waste plastics with the coal tar residue content of less than 1.00, such that the hydrocarbon substances generated by the waste plastic pyrolysis are attached to the coal tar residue pyrolysis residue pore structure so as to achieve the synergistic interaction, such that the volatilization loss is reduced, the yield of the regenerated coal is as high as 93%, and the excellent effects of coal tar residue pyrolysis residue carbon-hydrogen ratio optimization and regenerated coal heat value increase are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of solid waste, and particularly relates to a co-pyrolysis method for regenerating coal from waste plastics and pyrolysis residues of coal tar residues and a regeneration method thereof. Background Art

[0002] Plastics are important chemical products and consumer goods in modern life. The output of waste plastics has been growing in tandem with the consumption of plastics, gradually accumulating in the environment to form "white pollution". A large amount of non-degradable plastics entering the environment has had a serious impact on the natural ecosystem and can also pose a serious threat to the human body through the food chain. Against the backdrop of global resource shortages, plastics are regarded as a renewable resource due to their high carbon-hydrogen ratio, high calorific value, and low phosphorus, sulfur, and ash content. The disposal and utilization methods of waste plastics mainly include thermochemical technologies (incineration, pyrolysis, and gasification, etc.), hydrolysis, biodegradation, and landfill.

[0003] Among the above-mentioned plastic comprehensive utilization and disposal technologies, the co-pyrolysis technology of waste plastics and oily sludge can utilize the existing equipment for oily sludge pyrolysis. By controlling the co-pyrolysis ratio of plastics and oily sludge, the carbon-hydrogen ratio of the materials (plastics + oily sludge) in the pyrolysis process is reformed, promoting the generation of hydrogen and increasing the proportion of hydrogen in the gas products. It has the advantages of effectively treating two types of pollutants, reducing the landfill of waste plastics and the treatment cost of oily sludge, and realizing synergistic resource utilization. It is currently a research hotspot for the resource treatment of plastic and oily sludge pollutants. However, the current co-pyrolysis technology of waste plastics has the following problems: First, the components of plastics and oily sludge are complex, and various side reactions may occur during pyrolysis, affecting the composition and quality of the products. Second, higher equipment requirements: The equipment for oily sludge pyrolysis operates at medium and low temperatures (<450°C), but co-pyrolysis requires high temperatures (>500°C) and high-pressure conditions, and is combined with catalysts (metal oxides, activated carbon, etc.) to improve the selectivity of hydrogen, which requires higher corrosion resistance and sealing performance of the equipment. Third, the residue after oily sludge pyrolysis is a hazardous waste. Co-pyrolysis with plastics results in the mixing of plastic residues, which are not originally hazardous wastes, with oily sludge pyrolysis residues, both becoming hazardous wastes, increasing the generation amount of hazardous wastes from oily sludge pyrolysis. Summary of the Invention

[0004] In view of the above problems, the present invention provides a method for co-pyrolyzing waste plastics and pyrolysis residues of coal tar slag to regenerate coal, which effectively solves the technical problems that side reactions occur during the co-pyrolysis of existing plastics and oily sludge, affecting the composition and quality of the products, the high requirements for pyrolysis equipment in the co-pyrolysis of plastics and oily sludge, and the generation of hazardous waste during their pyrolysis. Different from the conventional co-pyrolysis technology of plastics and oily sludge that takes gas production and oil recovery as the inspection indexes and aims at reducing the residue after pyrolysis, the present invention realizes the preparation of regenerated coal based on the pyrolysis residue of coal tar slag by co-pyrolyzing the pyrolysis residue of coal tar slag and waste plastics at low temperature, reducing the generation of pyrolysis gas and condensate oil, and reforming the carbon-hydrogen ratio while improving the quality and calorific value of the co-pyrolysis residue.

[0005] The first object of the present invention is to provide a method for regenerating coal by co-pyrolyzing waste plastics and pyrolysis residues of coal tar slag, which includes the following steps:

[0006] Using KOH as the activator and the pyrolysis residue of coal tar slag as the raw material, under a protective atmosphere, the temperature is first raised to 500°C - 600°C for activation treatment to increase the pore structure of the pyrolysis residue of coal tar slag, and the activated pyrolysis residue of coal tar slag is obtained.

[0007] Using waste plastics as the raw material and the activated pyrolysis residue of coal tar slag as the carrier and catalyst, under a protective atmosphere, the temperature is secondarily raised to 350°C - 450°C for co-pyrolysis reaction, and the hydrocarbon substances generated by the pyrolysis of waste plastics are attached to the pore structure of the activated pyrolysis residue of coal tar slag, and the co-pyrolysis regenerated coal of waste plastics and pyrolysis residues of coal tar slag is obtained.

[0008] As a preferred embodiment, the mass ratio of the waste plastics to the activated pyrolysis residue of coal tar slag is 1:2.3 - 19.

[0009] As a preferred embodiment, the time of the co-pyrolysis reaction is 1h - 2h.

[0010] As a preferred embodiment, the mass ratio of the pyrolysis residue of coal tar slag to KOH is 1:1 - 4.

[0011] As a preferred embodiment, the time of the activation treatment is 1 - 2h.

[0012] As a preferred embodiment, the porosity of the activated pyrolysis residue of coal tar slag is 80% - 90%.

[0013] As a preferred embodiment, after the activation treatment, it is continuously cooled to room temperature in a protective atmosphere, the excess KOH is neutralized with hydrochloric acid to obtain a primary product, the primary product is rinsed with deionized water until the pH value of the rinsing solution is 6 - 7, and vacuum dried at 100°C - 120°C for 6h - 12h to obtain the activated pyrolysis residue of coal tar slag.

[0014] As a preferred embodiment, before the activation treatment, the pyrolysis residue of the coal tar slag is crushed to a particle size of 1 mm to 5 mm and a porosity of 50% to 65%; the particle size of the waste plastic is 1 mm to 5 mm.

[0015] As a preferred embodiment, the heating rate of the first heating is 5 °C / min to 10 °C / min, and the heating rate of the second heating is 40 °C / min to 60 °C / min.

[0016] The second object of the present invention is to provide a co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag, which is prepared by the above-mentioned regeneration method. The carbon-hydrogen ratio of the co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag is 3 to 8, the calorific value is 25.50 MJ / kg to 34.33 MJ / kg, and the sulfur content is <0.1%.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The present invention provides a regeneration method for co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag. The present invention uses KOH as an activator and the pyrolysis residue of coal tar slag as a raw material. Under a protective atmosphere, the pyrolysis residue of coal tar slag is subjected to high-temperature activation treatment. KOH decomposes into K2O and H2O at high temperature, and at the same time reacts with the pyrolysis residue of coal tar slag, generating CO and CO2 gases to escape, thereby forming a rich microporous and mesoporous structure on the pyrolysis residue of coal tar slag, improving the specific surface area and pore structure of the pyrolysis residue of coal tar slag, and obtaining activated pyrolysis residue of coal tar slag; using waste plastic as a raw material and the activated pyrolysis residue of coal tar slag as a carrier and catalyst, a low-temperature co-pyrolysis reaction is carried out under a protective atmosphere, and the hydrocarbon substances generated by the pyrolysis of the waste plastic are attached to the pore structure of the activated pyrolysis residue of coal tar slag, thereby obtaining co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag. The present invention carries out low-temperature co-pyrolysis of the pyrolysis residue of coal tar slag with a relatively high carbon-hydrogen ratio (>10) and a relatively large porosity (>50%) and waste plastic with a low carbon-hydrogen ratio (<1.00), attaches the hydrocarbon substances generated by the pyrolysis of the waste plastic to the pore structure of the pyrolysis residue of coal tar slag to synergistically increase the efficiency, reduce the volatilization loss, and the yield of the regenerated coal is as high as 93%. It realizes the excellent effect of optimizing the carbon-hydrogen ratio of the pyrolysis residue of coal tar slag and increasing the calorific value of the regenerated coal. At the same time, it solves the problems of few subsequent comprehensive utilization ways of the pyrolysis residue of coal tar slag and the difficult natural degradation of waste plastic, which occupies a large space.

[0019] The present invention utilizes the characteristics that the pyrolysis slag of coal tar slag has a porous structure and a high carbon-hydrogen ratio, as well as the low carbon-hydrogen ratio of waste plastics. By controlling the pyrolysis process of waste plastics, using the pyrolysis slag of coal tar slag as a carrier and catalyst, the waste plastics are pyrolyzed at a low temperature (350°C - 450°C) and adsorbed in the pores of the pyrolysis slag of coal tar slag. By adjusting the mass ratio of waste plastics to the pyrolysis slag of coal tar slag, the carbon-hydrogen ratio of the pyrolysis slag of coal tar slag is regulated to be 3 - 8, which is used for coal blending in coal gasification and fuel coal, and has various uses. The calorific value of the regenerated coal of the present invention is 25.50 - 34.33 MJ / kg, which is significantly higher than the original calorific value of 20 MJ / kg of the pyrolysis slag of coal tar slag. The sulfur content of the regenerated coal is <0.1%, and the combustion pollution is lower than that of raw coal. The regeneration method of co-pyrolyzing waste plastics and the pyrolysis slag of coal tar slag to regenerate coal provided by the present invention has low requirements for reaction equipment, can utilize the existing coal tar slag pyrolysis equipment, is compatible with the existing pyrolysis furnace, and the obtained regenerated coal has the characteristics of high gasification efficiency, high calorific value, and adjustable carbon-hydrogen ratio.

[0020] The present invention simultaneously realizes the goals of reducing, recycling, and harmless treatment of solid wastes in the coal chemical industry and the plastic industry. Incorporating the regenerated coal obtained by the present invention into raw coal can replace part of the raw coal for coal blending in coal chemical enterprises or as a heat source for high-temperature furnaces such as power plants and incinerators. The present invention not only expands the recycling ways of current waste plastics and the pyrolysis slag of coal tar slag, but also effectively reduces the difficulty and cost of co-pyrolyzing waste plastics with other solid wastes, and has the characteristics of low cost, high preparation efficiency, simple process technology, and less pollution. Brief Description of the Drawings

[0021] Figure 1 It is the morphology diagram of coal tar slag, the pyrolysis slag of coal tar slag, and regenerated coal of the present invention. Among them, Figure a is coal tar slag, Figure b is the pyrolysis slag of coal tar slag, and Figure c is regenerated coal. Detailed Embodiments

[0022] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the specific embodiments cited do not limit the present invention. The following test methods and detection methods are all conventional methods without special instructions; the reagents and raw materials are all commercially available without special instructions.

[0023] Currently, there are the following problems in the co-pyrolysis of waste plastics and oily sludge: the components of plastics and oily sludge are complex, and various side reactions may occur during the pyrolysis process, affecting the composition and quality of the products. The requirements for pyrolysis equipment are relatively high. The pyrolysis equipment for oily sludge operates at medium and low temperatures, but co-pyrolysis requires high temperature and high pressure conditions, and is combined with catalysts such as metal oxides and activated carbon to improve the hydrogen selectivity, and has relatively high requirements for the corrosion resistance and sealing performance of the equipment. The residue after the pyrolysis of oily sludge belongs to hazardous waste, and the co-pyrolysis with plastics causes the plastic residues that were not originally hazardous waste to become hazardous waste after being mixed with the pyrolysis residues of oily sludge. In view of the above technical problems, the present invention provides a co-pyrolysis regeneration coal and regeneration method of waste plastics and pyrolysis residues of coal tar slag.

[0024] The technical solution of the present invention will be described in detail below.

[0025] The present invention first provides a regeneration method for co-pyrolysis regeneration coal of waste plastics and pyrolysis residues of coal tar slag, including the following steps:

[0026] Using KOH as an activator and taking the pyrolysis residues of coal tar slag as raw materials, under a protective atmosphere, the temperature is first raised to 500°C - 600°C for activation treatment to increase the pore structure of the pyrolysis residues of coal tar slag, and activated pyrolysis residues of coal tar slag are obtained.

[0027] Using waste plastics as raw materials and the activated pyrolysis residues of coal tar slag as a carrier and catalyst, under a protective atmosphere, the temperature is secondarily raised to 350°C - 450°C to carry out a co-pyrolysis reaction, and the hydrocarbon substances generated by the pyrolysis of waste plastics are attached to the pore structure of the activated pyrolysis residues of coal tar slag, and co-pyrolysis regeneration coal of waste plastics and pyrolysis residues of coal tar slag is obtained.

[0028] For the above activation treatment, KOH is a strong base. Using it as an activator can react with the carbon in the pyrolysis residues of coal tar slag to generate basic active sites and improve the catalytic performance of the material. Its mechanism of action is as follows: KOH decomposes at 500°C - 600°C to generate K2O and H2O, and at the same time reacts with the carbon material, and CO and CO2 gases escape, thereby forming a rich microporous and mesoporous structure on the pyrolysis residues of coal tar slag, increasing the specific surface area, and enhancing the catalytic activity of the activated pyrolysis residues of coal tar slag.

[0029] The types of the above hydrocarbon substances generated by the pyrolysis of waste plastics are shown in Table 1 below.

[0030] Table 1 Gas Chromatographic Analysis of Low-Temperature Pyrolysis Products of Waste Plastics (Unit: %)

[0031]

[0032]

[0033] In the above technical solution, by performing low-temperature co-pyrolysis on coal tar slag pyrolysis residue and waste plastics, the hydrocarbon substances generated by the pyrolysis of waste plastics are attached to the pore structure of the coal tar slag pyrolysis residue, achieving the excellent effects of optimizing the carbon-hydrogen ratio of the coal tar slag pyrolysis residue and increasing the calorific value of the recycled coal. No side reactions occur during the pyrolysis process, no hazardous waste is generated, and there is no need to modify the existing coal tar slag pyrolysis equipment. The carbon-hydrogen ratio of the co-pyrolysis recycled coal of waste plastics and coal tar slag pyrolysis residue obtained by the present invention is 3-8, the calorific value is 25.50 MJ / kg - 34.33 MJ / kg, and the sulfur content is <0.1%. The present invention simultaneously solves the problems of few subsequent comprehensive utilization routes for coal tar slag pyrolysis residue, difficult natural degradation of waste plastics, and large occupied space.

[0034] It should be noted that the present invention controls the co-pyrolysis temperature at 350°C - 450°C, effectively controlling the excessive volatilization of waste plastics.

[0035] In order to effectively match the raw material (waste plastics) with the carrier and catalyst (coal tar slag pyrolysis residue), thereby increasing the yield of recycled coal, the mass ratio of the waste plastics to the activated coal tar slag pyrolysis residue is 1:2.3 - 19. When the mass ratio of the activated coal tar slag pyrolysis residue is less than 2.3 or greater than 19 defined herein, it will affect the carbon-hydrogen ratio of the overall reaction, resulting in the carbon-hydrogen ratio of the prepared recycled coal being less than 3 or greater than 8, which is not conducive to the subsequent comprehensive utilization of the recycled coal as a blending coal raw material.

[0036] In order to promote the full reaction of waste plastics and activated coal tar slag pyrolysis residue, the co-pyrolysis reaction time is 1 h - 2 h. If the co-pyrolysis reaction time is less than 1 h, the reaction will be incomplete. If it exceeds 2 h, the continuous reaction may cause the hydrocarbon substances attached to the surface of the recycled coal to decompose into gases, resulting in a decrease in the yield of the recycled coal.

[0037] In order to increase the porosity of the coal tar slag pyrolysis residue, the mass ratio of the coal tar slag pyrolysis residue to KOH is 1:1 - 4. If the dosage of the activator KOH is less than 1 defined herein, the obtained activated coal tar slag pyrolysis residue has fewer pore structures, and the amount of hydrocarbon substances attached by the pyrolysis of waste plastics is small, resulting in a still high carbon-hydrogen ratio and a decrease in calorific value of the recycled coal. If the dosage of the activator KOH is greater than 4 defined herein, it will lead to excessive use of KOH and cannot continue to improve the coal tar pyrolysis residue.

[0038] In order to further control the pore structure of the coal tar slag pyrolysis residue within a suitable range, the activation treatment time is 1 h - 2 h.

[0039] It should be noted that through the above activation treatment of the pyrolysis residue of coal tar slag, the porosity of the activated pyrolysis residue of coal tar slag in the present invention is 80% - 90%, thereby increasing the adhesion amount of hydrocarbon substances generated by the pyrolysis of waste plastics to the activated pyrolysis residue of coal tar slag, thereby reducing the carbon-hydrogen ratio of the pyrolysis residue of coal tar slag and increasing the calorific value of the regenerated coal.

[0040] In order to further increase the porosity of the pyrolysis residue of coal tar slag, after the activation treatment, it is continuously cooled to room temperature in a protective atmosphere, and hydrochloric acid is used to neutralize the excess KOH to obtain a primary product. The primary product is rinsed with deionized water until the pH value of the rinsing solution is 6 - 7, and vacuum dried at 100°C - 120°C for 6h - 12h to obtain the activated pyrolysis residue of coal tar slag.

[0041] It should be emphasized that according to the carbon-hydrogen ratio required for the regenerated coal, before the activation treatment, the pyrolysis residue of coal tar slag is crushed to a particle size of 1mm - 5mm; furthermore, in order to improve the mixing uniformity of the waste plastics and the pyrolysis residue of coal tar slag, the waste plastics are crushed to a particle size of 1mm - 5mm.

[0042] In the activation reaction and the subsequent co-pyrolysis reaction, the heating rate of the first heating is 5°C / min - 10°C / min, and the heating rate of the second heating is 40 - 60°C / min.

[0043] For the heating rate of the first heating, if it is lower than 5°C / min, it will cause the reaction between KOH and the residue to be too slow, resulting in a decrease in the pore formation efficiency and insufficient increase in porosity; when the heating rate of the first heating is higher than 10°C / min, it will cause the reaction between KOH and the residue to be too fast, resulting in the relevant chemical reactions occurring only on the surface of the coal tar pyrolysis residue and unable to further penetrate into the interior to form a large number of uniform pores, resulting in a decrease in porosity.

[0044] For the heating rate of the second heating, if it is lower than 40°C / min, it will cause the time to reach the reaction temperature to be too long, and the waste plastics will melt during the heating process and block the pores of the coal tar pyrolysis residue, affecting the subsequent entry of hydrocarbon substances, resulting in too high a carbon-hydrogen ratio and a decrease in the yield of the regenerated coal; when the heating rate of the second heating is higher than 60°C / min, it will cause the cracking speed of the waste plastics to increase, and some of the cracked petroleum hydrocarbons will not have time to adhere to the coal tar pyrolysis residue and further crack into non-condensable gases, that is, volatile substances with less than 10 carbon atoms.

[0045] The technical effects of the present invention will be described below with specific examples.

[0046] Example 1

[0047] A regeneration method for co-pyrolyzing waste plastics and pyrolysis residue of coal tar slag to regenerate coal, comprising the following steps:

[0048] S1. Crush the pyrolysis residue of coal tar slag to a particle size of <5 mm. Mix the crushed pyrolysis residue of coal tar slag with KOH powder at a mass ratio of 1:4. Under a nitrogen atmosphere, first heat it up to 500 °C at a rate of 8 °C / min for activation treatment for 1.5 h to increase the pore structure of the pyrolysis residue of coal tar slag. After the activation treatment, continue to cool it to room temperature in a nitrogen atmosphere. Neutralize the excess KOH with 5% hydrochloric acid to obtain a primary product. Wash the primary product with deionized water until the pH value is neutral, and dry it in vacuum at 100 °C for 10 h to obtain an activated pyrolysis residue of coal tar slag with a porosity of 89.76% to obtain the activated pyrolysis residue of coal tar slag.

[0049] S2. Mix waste plastic polystyrene and the activated pyrolysis residue of coal tar slag at a mass ratio of 3:7. Under a nitrogen atmosphere, second heat it up to 350 °C at a rate of 40 °C / min and carry out co-pyrolysis reaction for 1 h to attach the hydrocarbon substances generated by the pyrolysis of the waste plastic to the pore structure of the activated pyrolysis residue of coal tar slag, obtaining a co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag with a yield of 92.78%, a carbon-hydrogen ratio of 3.22, and a calorific value of 33.03 MJ / kg.

[0050] Example 2

[0051] A regeneration method for co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag, comprising the following steps:

[0052] S1. Crush the pyrolysis residue of coal tar slag to a particle size of <5 mm. Mix the crushed pyrolysis residue of coal tar slag with KOH powder at a mass ratio of 1:1. Under a nitrogen atmosphere, first heat it up to 500 °C at a rate of 8 °C / min for activation treatment for 1.5 h to increase the pore structure of the pyrolysis residue of coal tar slag. After the activation treatment, continue to cool it to room temperature in a nitrogen atmosphere. Neutralize the excess KOH with 5% hydrochloric acid to obtain a primary product. Wash the primary product with deionized water until the pH value is neutral, and dry it in vacuum at 100 °C for 10 h to obtain an activated pyrolysis residue of coal tar slag with a porosity of 82.59% to obtain the activated pyrolysis residue of coal tar slag.

[0053] S2. Mix waste plastic polystyrene and the activated pyrolysis residue of coal tar slag at a mass ratio of 3:7. Under a nitrogen atmosphere, second heat it up to 350 °C at a rate of 40 °C / min and carry out co-pyrolysis reaction for 60 min to attach the hydrocarbon substances generated by the pyrolysis of the waste plastic to the pore structure of the activated pyrolysis residue of coal tar slag, obtaining a co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag with a yield of 83.2%, a carbon-hydrogen ratio of 3.85, and a calorific value of 29.79 MJ / kg.

[0054] Example 3

[0055] A regeneration method for co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag, comprising the following steps:

[0056] S1. Crush the pyrolysis residue of coal tar slag to a particle size of <5 mm. Mix the crushed pyrolysis residue of coal tar slag with KOH powder at a mass ratio of 1:4. Under a nitrogen atmosphere, increase the heating rate to 500 °C at a rate of 8 °C / min for the first activation treatment for 1.5 h to increase the pore structure of the pyrolysis residue of coal tar slag. After the activation treatment, continue to cool to room temperature in a nitrogen atmosphere. Neutralize the excess KOH with 5% hydrochloric acid to obtain a primary product. Wash the primary product with deionized water until the pH value is neutral, and vacuum dry it at 100 °C for 10 h to obtain an activated pyrolysis residue of coal tar slag with a porosity of 89.98% to obtain the activated pyrolysis residue of coal tar slag.

[0057] S2. Mix waste plastic polystyrene and the activated pyrolysis residue of coal tar slag at a mass ratio of 1:3. Under a nitrogen atmosphere, increase the heating rate to 350 °C at a rate of 40 °C / min for the second time and carry out a co-pyrolysis reaction for 60 min to attach the hydrocarbon substances generated by the pyrolysis of the waste plastic to the pore structure of the activated pyrolysis residue of coal tar slag, obtaining a co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag with a yield of 93.11%, a carbon-hydrogen ratio of 5.11, and a calorific value of 33.03 MJ / kg.

[0058] Example 4

[0059] A regeneration method for co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag, comprising the following steps:

[0060] S1. Crush the pyrolysis residue of coal tar slag to a particle size of <5 mm. Mix the crushed pyrolysis residue of coal tar slag with KOH powder at a mass ratio of 1:4. Under a nitrogen atmosphere, increase the heating rate to 500 °C at a rate of 8 °C / min for the first activation treatment for 1.5 h to increase the pore structure of the pyrolysis residue of coal tar slag. After the activation treatment, continue to cool to room temperature in a nitrogen atmosphere. Neutralize the excess KOH with 5% hydrochloric acid to obtain a primary product. Wash the primary product with deionized water until the pH value is neutral, and vacuum dry it at 100 °C for 10 h to obtain an activated pyrolysis residue of coal tar slag with a porosity of 89.76% to obtain the activated pyrolysis residue of coal tar slag.

[0061] S2. Mix waste plastic polystyrene and the activated pyrolysis residue of coal tar slag at a mass ratio of 1:4. Under a nitrogen atmosphere, increase the heating rate to 350 °C at a rate of 40 °C / min for the second time and carry out a co-pyrolysis reaction for 60 min to attach the hydrocarbon substances generated by the pyrolysis of the waste plastic to the pore structure of the activated pyrolysis residue of coal tar slag, obtaining a co-pyrolysis regenerated coal of waste plastic and pyrolysis residue of coal tar slag with a yield of 93.31%, a carbon-hydrogen ratio of 6.01, and a calorific value of 27.84 MJ / kg.

[0062] Example 5

[0063] A method for regenerating coal by co-pyrolysis of waste plastics and pyrolysis residues of coal tar slag, comprising the following steps:

[0064] S1. Crush the pyrolysis residue of coal tar slag to a particle size of <5 mm. Mix the crushed pyrolysis residue of coal tar slag with KOH powder according to a mass ratio of 1:4. Under a nitrogen atmosphere, first heat it up to 500 °C at a rate of 8 °C / min for activation treatment for 1.5 h to increase the pore structure of the pyrolysis residue of coal tar slag. After the activation treatment, continue to cool it to room temperature in a nitrogen atmosphere. Neutralize the excess KOH with 5% hydrochloric acid to obtain a primary product. Wash the primary product with deionized water until the pH value is neutral, and vacuum dry it at 100 °C for 10 h to obtain an activated pyrolysis residue of coal tar slag with a porosity of 89.76% to obtain the activated pyrolysis residue of coal tar slag.

[0065] S2. Mix waste plastic polystyrene and the activated pyrolysis residue of coal tar slag according to a mass ratio of 3:17. Under a nitrogen atmosphere, secondarily heat it up to 350 °C at a rate of 40 °C / min for a co-pyrolysis reaction for 60 min, and attach the hydrocarbon substances generated by the pyrolysis of the waste plastic to the pore structure of the activated pyrolysis residue of coal tar slag to obtain a co-pyrolysis regenerated coal of waste plastics and pyrolysis residues of coal tar slag with a yield of 93.94%, a carbon-hydrogen ratio of 6.94, and a calorific value of 26.72 MJ / kg.

[0066] Example 6

[0067] A method for regenerating coal by co-pyrolysis of waste plastics and pyrolysis residues of coal tar slag, comprising the following steps:

[0068] S1. Crush the pyrolysis residue of coal tar slag to a particle size of <5 mm. Mix the crushed pyrolysis residue of coal tar slag with KOH powder according to a mass ratio of 1:4. Under a nitrogen atmosphere, first heat it up to 500 °C at a rate of 5 °C / min - 10 °C / min for activation treatment for 1 h - 3 h to increase the pore structure of the pyrolysis residue of coal tar slag. After the activation treatment, continue to cool it to room temperature in a nitrogen atmosphere. Neutralize the excess KOH with 5% - 7% hydrochloric acid to obtain a primary product. Wash the primary product with deionized water until the pH value is neutral, and vacuum dry it at 100 °C for 10 h to obtain an activated pyrolysis residue of coal tar slag with a porosity of 80% - 90% to obtain the activated pyrolysis residue of coal tar slag.

[0069] S2. Mix waste plastic polystyrene and the activated pyrolysis residue of coal tar slag according to a mass ratio of 1:19. Under a nitrogen atmosphere, secondarily heat it up to 350 °C at a rate of 40 °C / min for a co-pyrolysis reaction for 60 min, and attach the hydrocarbon substances generated by the pyrolysis of the waste plastic to the pore structure of the activated pyrolysis residue of coal tar slag to obtain a co-pyrolysis regenerated coal of waste plastics and pyrolysis residues of coal tar slag with a yield of 94.52%, a carbon-hydrogen ratio of 8.13, and a calorific value of 25.63 MJ / kg.

[0070] In order to further illustrate the technical effect of the present invention, the present invention also sets a comparative example, which is as follows:

[0071] Comparative Example 1

[0072] Compared with Example 1, the difference is that the coal tar residue pyrolysis residue is not activated.

[0073] A method for regenerating coal by co-pyrolysis of waste plastics and coal tar residue pyrolysis residue, comprising the following steps:

[0074] S1, crushing the coal tar residue pyrolysis residue into a particle size of <5mm.

[0075] S2, mixing waste plastic polystyrene and crushed coal tar residue pyrolysis residue in a mass ratio of 3:7, heating to 350°C for the second time at a rate of 40°C / min under a nitrogen atmosphere, and co-pyrolyzing for 60 minutes, so that hydrocarbon substances produced by pyrolysis of the waste plastics are attached to the pore structure of the activated coal tar residue pyrolysis residue, and obtaining waste plastics and coal tar residue pyrolysis residues with a yield of 78%, a carbon-hydrogen ratio of 4.5, a calorific value of 21.45MJ / kg, and no sulfur detected. Regenerated coal is obtained by co-pyrolysis of the waste plastics and coal tar residue pyrolysis residue.

[0076] Figure 1 The morphology of the coal tar residue, coal tar residue pyrolysis residue and regenerated coal of the present invention is shown in Figure a, where Figure b is coal tar residue pyrolysis residue, and Figure c is regenerated coal. Figure 1 As can be seen from Figure a, coal tar residue is a black viscous paste containing a large amount of tar and other components. After pyrolysis to recover the volatile and cracked components such as tar, the coal tar residue pyrolysis residue becomes a block with a smooth surface. Due to the high content of fixed carbon, it has a certain metallic luster. Figure 1 Figure b: After the coal tar residue pyrolysis residue was activated with KOH and co-pyrolyzed with waste plastics, a large number of pores appeared on the surface of the regenerated coal and molten substances were attached, indicating that KOH activation significantly improved the porosity of the coal tar residue pyrolysis residue, and a large amount of waste plastics were attached to the surface of the coal tar residue pyrolysis residue.

[0077] In summary, the present invention uses waste plastics as raw materials and the pyrolysis residue of coal tar slag as a carrier and catalyst, enabling the waste plastics to pyrolyze at low temperature and adsorb in the pores of the pyrolysis residue of coal tar slag. By adjusting the mass ratio of waste plastics to the pyrolysis residue of coal tar slag, the carbon-hydrogen ratio of the pyrolysis residue of coal tar slag is regulated to be 3-8, which is used for coal blending in coal gasification and fuel coal, with diverse uses. The calorific value of the regenerated coal of the present invention is 25.50-34.33 MJ / kg, significantly higher than the original calorific value of 20 MJ / kg of the pyrolysis residue of coal tar slag. The sulfur content of the regenerated coal is <0.1%, and the combustion pollution is lower than that of raw coal. The regeneration method of the co-pyrolysis of waste plastics and the pyrolysis residue of coal tar slag to regenerate coal provided by the present invention has low requirements for reaction equipment, can utilize the existing pyrolysis equipment of coal tar slag, is compatible with the existing pyrolysis furnace, and the obtained regenerated coal has the characteristics of high gasification efficiency, high calorific value, and adjustable carbon-hydrogen ratio.

[0078] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims

1. A method for regenerating coal by co-pyrolyzing waste plastics and pyrolysis residues of coal tar slag, characterized in that, It includes the following steps: Using KOH as the activator and the pyrolysis residue of coal tar slag as the raw material, under a protective atmosphere, it is first heated to 500°C - 600°C for activation treatment to increase the pore structure of the pyrolysis residue of coal tar slag, and the activated pyrolysis residue of coal tar slag is obtained; Using waste plastics as the raw material, and the activated pyrolysis residue of coal tar slag as the carrier and catalyst, under a protective atmosphere, it is secondarily heated to 350°C - 450°C for a co-pyrolysis reaction, and the hydrocarbon substances generated by the pyrolysis of waste plastics are attached to the pore structure of the activated pyrolysis residue of coal tar slag to obtain the co-pyrolysis regenerated coal of waste plastics and pyrolysis residue of coal tar slag.

2. The regeneration method according to claim 1, characterized in that, The mass ratio of the waste plastics to the activated pyrolysis residue of coal tar slag is 1:2.3 - 19.

3. The regeneration method according to claim 1, characterized in that, The time of the co-pyrolysis reaction is 1h - 2h.

4. The regeneration method according to claim 1, wherein The mass ratio of the pyrolysis residue of coal tar slag to KOH is 1:1 - 4.

5. The regeneration method according to claim 1, characterized in that The time of the activation treatment is 1h - 3h.

6. The regeneration method according to claim 1, characterized in that, The porosity of the activated pyrolysis residue of coal tar slag is 80% - 90%.

7. The regeneration method according to claim 1, wherein After the activation treatment, it is continuously cooled to room temperature in a protective atmosphere, and the excess KOH is neutralized with hydrochloric acid to obtain a primary product. The primary product is rinsed with deionized water until the pH value of the rinsing solution is 6 - 7, and vacuum dried at 100°C - 120°C for 6h - 12h to obtain the activated pyrolysis residue of coal tar slag.

8. The regeneration method according to claim 1, wherein Before the activation treatment, the pyrolysis residue of coal tar slag is crushed to a particle size of 1mm - 5mm with a porosity of 50% - 65%; the particle size of the waste plastics is 1mm - 5mm.

9. The regeneration method according to claim 1, wherein The heating rate of the first heating is 5°C / min - 10°C / min, and the heating rate of the second heating is 40°C / min - 60°C / min.

10. A co-pyrolysis regenerated coal from waste plastics and pyrolysis slag of coal tar residue, characterized in that, Prepared by using the regeneration method described in any one of claims 1 - 9, the carbon-hydrogen ratio of the co-pyrolysis regenerated coal of waste plastics and pyrolysis residue of coal tar slag is 3 - 8, the calorific value is 25.50MJ / kg - 34.33MJ / kg, and the sulfur content is <0.1%.

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