Method and device for producing reduced chlorine content waste plastic pyrolysis oil

Abstract

The present disclosure provides a method for producing waste plastic pyrolysis oil with reduced chlorine, comprising a first step of loading waste plastic raw material and modified red mud into a reactor, and a second step of pyrolyzing the waste plastic raw material in the reactor and recovering pyrolysis oil, wherein the modified red mud is characterized in that, upon X-ray diffraction (XRD) analysis, the intensity of a first peak at a 2θ diffraction angle of 14±0.1° is greater than the intensity of a second peak at a 2θ diffraction angle of 14.5±0.1°.

Description

[Technical field]

[0001] The present disclosure relates to a method for producing reduced chlorine pyrolysis oil from waste plastics. [Background technology]

[0002] Waste plastics have a low recycling rate and are mostly disposed of as garbage. Such waste takes a long time to decompose in natural conditions, polluting the soil and causing serious environmental pollution. As a method for recycling the waste plastics, a method of converting them into fractions through a thermal decomposition process is being carried out.

[0003] However, pyrolysis oil obtained by pyrolysis of waste plastics contains a high content of impurities such as chlorine, nitrogen, metals, and solid by-products compared to fractions produced from crude oil by conventional methods, and therefore cannot be immediately used as a high-value-added fuel such as volatile oil or diesel oil. Instead, it must be refined to adsorb the impurities before it can be used as fuel.

[0004] For example, chlorine was converted to hydrogen chloride by hydrogenation treatment in the presence of a hydrogenation catalyst and then adsorbed. However, since waste plastic pyrolysis oil contains a high amount of chlorine, excessive amounts of hydrogen chloride are generated during the hydrogenation treatment, which causes problems such as corrosion of equipment, abnormal reactions, and deterioration of product properties.

[0005] In addition, there is a technology that uses adsorbents such as CaO or waste FCC catalyst (E-cat) to adsorb chlorine, nitrogen, etc., but this has the problem that in order to achieve an adsorption effect, they must be used in very large amounts (2 to 50 times the amount of the fraction to be refined). After chlorine, nitrogen, etc. are adsorbed, the adsorbent loses its adsorption capacity, so there is a problem that the inactivated adsorbent must be continually replaced.

[0006] Therefore, a method is needed that can produce waste plastic pyrolysis oil with reduced chlorine content to a level that can be introduced into a refining process.

[0007] Meanwhile, red mud is a waste material that is generated during the process of extracting alumina from bauxite, and over 120 million tons are discharged in the form of sludge and over 40 million tons in the form of dry powder every year around the world, with the amount continuing to increase. In Korea, over 200,000 tons are discharged in the form of sludge every year.

[0008] As a method for treating the red mud, it is used as a building material or as a heavy metal treatment agent, but since red mud has strong alkaline properties and high water content, there are many restrictions on using it as it is. Currently, a pretreatment process is required to utilize red mud, which requires huge facility and processing costs for drying and crushing, and causes serious problems such as environmental damage due to dust. Since landfilling is also impossible, there is no suitable place to load the denatured red mud, and various problems are caused, such as damage to surrounding crops and human lives due to the outflow of leachate, so there is an urgent need to treat the red mud. Summary of the Invention [Problem to be solved by the invention]

[0009] The present disclosure aims to provide a method for producing waste plastic pyrolysis oil that utilizes red mud, which is a waste material, as a useful resource and can effectively reduce the chlorine content in the pyrolysis oil produced by the thermal decomposition of waste plastic.

[0010] Another object of the present disclosure is to provide a technology for minimizing the chlorine content in pyrolysis oil produced by using modified red mud with maximized chlorine adsorption effect.

[0011] Another object of the present disclosure is to produce a pyrolysis oil having a low impurity content that is applicable to a refining process after pyrolysis of waste plastic raw materials without a separate post-treatment process. [Means for solving the problem]

[0012] The present disclosure provides a method for producing waste plastic pyrolysis oil with reduced chlorine, comprising a first step of loading waste plastic raw material and modified red mud into a reactor, and a second step of pyrolyzing the waste plastic raw material in the reactor and recovering pyrolysis oil, wherein the modified red mud is characterized in that, upon X-ray diffraction (XRD) analysis, the intensity of a first peak at a 2θ diffraction angle of 14±0.1° is greater than the intensity of a second peak at a 2θ diffraction angle of 14.5±0.1°.

[0013] In one embodiment, the intensity of the first peak (I 1 ) and the intensity of the second peak (I 2 ) and the ratio (I 1 ) / (I 2 ) may be 5 or more.

[0014] In one embodiment, the intensity of the first peak (I 1 ) and the intensity of the third peak (I 3 ) and the ratio (I 1 ) / (I 3 ) may be 5 or more.

[0015] In one embodiment, in the first step, 5 to 30 parts by weight of the modified red mud may be charged into the reactor with respect to 100 parts by weight of the waste plastic raw material.

[0016] In one embodiment, in the first step, the modified red mud may further contain 30 to 80 parts by weight of water based on 100 parts by weight of the modified red mud, and may be charged into the reactor as a paste.

[0017] In one embodiment, the second step may be carried out at a temperature of 300 to 600°C.

[0018] In one embodiment, the second step may be carried out in a non-oxidizing atmosphere. Effect of the Invention

[0019] The method for producing waste plastic pyrolysis oil according to the present disclosure can effectively reduce the chlorine content in the waste plastic pyrolysis oil produced by pyrolyzing waste plastic in the presence of modified red mud.

[0020] The method for producing waste plastic pyrolysis oil according to the present disclosure can produce pyrolysis oil having a low impurity content that is applicable to a refining process after pyrolysis of waste plastic raw material without performing a separate post-treatment process. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a graph showing the results of X-ray diffraction (XRD) analysis of red mud of Example 3 and Comparative Example 1, which are representative examples of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] As used herein, the singular forms of the terms "a," "an," and "the" can be construed as including the plural forms as well, unless otherwise indicated.

[0023] Numerical ranges used herein include lower and upper limits, all values ​​within the range, all values ​​limited therein, and all possible combinations of upper and lower limits of numerical ranges limited in different ways. Unless otherwise specified in the present specification, values ​​outside the numerical ranges that may occur due to experimental error or rounding of values ​​are included in the defined numerical range.

[0024] As referred to in this specification, "comprising" is an open-ended term having the same meaning as terms such as "comprising," "containing," "having," "characterized," and the like, and does not exclude further unrecited elements, materials, or steps.

[0025] In this specification, the unit of % used without special mention means % by weight unless otherwise defined.

[0026] The ppm unit used in this specification without any special mention means ppm by mass unless otherwise defined.

[0027] Waste plastics include polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polyvinyl chloride (PVC), and polystyrene (PS), and contain organic and inorganic chlorine. Pyrolysis oil produced by the thermal decomposition process of waste plastics cannot be used immediately as high-value-added fuel such as volatile oil or diesel oil due to its high impurity content, but can be used as fuel after the impurities are adsorbed through a refining process. Therefore, technology is needed to produce waste plastic pyrolysis oil with minimized chlorine content from waste plastics.

[0028] Meanwhile, red mud is a waste product generated in the process of extracting alumina from bauxite, and is generally discharged in a sludge state with a moisture content of about 30 to 50%. The generally high moisture red mud is usually dried in a pretreatment process and used for construction materials, heavy metal treatment agents, etc. This pretreatment process requires huge facility and processing costs, and in particular, the physical and chemical properties of the red mud change during the drying process, which places many limitations on the use of the red mud.

[0029] Therefore, the present disclosure provides a method for effectively reducing chlorine in pyrolysis oil produced by using modified red mud with maximized selectivity and adsorption properties for chlorine in a waste plastic pyrolysis process.

[0030] In detail, one embodiment of the present disclosure provides a method for producing waste plastic pyrolysis oil with reduced chlorine, comprising a first step of charging a waste plastic raw material and modified red mud into a reactor, and a second step of pyrolyzing the waste plastic raw material in the reactor and recovering a pyrolysis oil, wherein the modified red mud is characterized in that, upon X-ray diffraction (XRD) analysis, the intensity of a first peak at a 2θ diffraction angle of 14±0.1° is greater than the intensity of a second peak at a 2θ diffraction angle of 14.5±0.1°. The X-ray diffraction (XRD) analysis refers to an X-ray diffraction pattern using CuKα radiation.

[0031] Specifically, the modified red mud in which the intensity of the first peak at a 2θ diffraction angle of 14±0.1° is greater than the intensity of the second peak at 14.5±0.1° in X-ray diffraction (XRD) analysis has the effect of having very excellent chlorine selectivity and chlorine adsorption properties in the pyrolysis process. Conventionally, red mud is dried at 110°C for 24 hours and used in the form of dried red mud, but the modified red mud of the present disclosure has peak characteristics unique to modified red mud that are not present in dried red mud in X-ray diffraction (XRD) analysis, specifically, the modified red mud in which the intensity of the first peak at a 2θ diffraction angle of 14±0.1° is greater than the intensity of the second peak at 14.5±0.1° can exhibit excellent chlorine adsorption effects.

[0032] In one embodiment, the intensity of the first peak (I 1 ) and the intensity of the second peak (I 2 ) and the ratio (I 1 ) / (I 2 ) may be 5 or more. 1 ) / (I 2 When (I) satisfies the above range, the thermal decomposition efficiency and the chlorine adsorption effect can be very excellent. 1 ) / (I 2 When the (I) is 7 or more, the chlorine adsorption effect is more excellent, and 1 ) / (I 2When the ratio of (I) to (Ig) is 10 or more, the catalyst exhibits uniform dispersibility with the waste plastics, and the thermal conduction to the waste plastics is uniform, which can improve the yield of the pyrolysis oil. 1 ) / (I 2 ) may be 30 or less.

[0033] The modified red mud may be a red mud modified to satisfy the peak ratio. Specifically, for example, a modified red mud satisfying the peak ratio may be produced by compressing a general red mud in an atmosphere containing water vapor or in an atmosphere containing a polar alcohol, but this is merely an example and is not necessarily limited thereto. Any method for modifying red mud to satisfy the peak ratio may be used without limitation.

[0034] In one embodiment, the modified red mud may have an intensity of a first peak at a 2θ diffraction angle of 14±0.1° greater than an intensity of a third peak at a 2θ diffraction angle of 28.2±0.1° upon X-ray diffraction (XRD) analysis.

[0035] In one embodiment, the intensity of the first peak (I 1 ) and the intensity of the third peak (I 3 ) and the ratio (I 1 ) / (I 3 ) may be 5 or more. In particular, when the intensity of the first peak at a 2θ diffraction angle of 14±0.1° is greater than the intensity of the third peak at a 2θ diffraction angle of 28.2±0.1°, the intensity of the first peak (I 1 ) and the intensity of the third peak (I 3 ) and the ratio (I 1 ) / (I 3 When (I) is 5 or more, the selectivity to chlorine and the chlorine adsorption characteristics in the thermal decomposition process can be more excellent. 1 ) / (I 3 ) may be 7 or more, and more specifically, 1 ) / (I 3) may be 10 or more, and, without limitation, may be 30 or less.

[0036] During the X-ray diffraction (XRD) analysis of the modified red mud, the peak intensity (I 1 ) / (I 2 ) is 5 or more, and (I 1 ) / (I 3 ) is 5 or more, the chlorine adsorption effect can be maximized. That is, the modified red mud that satisfies all of the peak characteristics has a very high chlorine adsorption rate, and when a thermal decomposition process of waste plastic is performed in the presence of the modified red mud, a high-quality pyrolysis oil with minimized impurities can be recovered. Even with a simple process of contacting the waste plastic raw material to be treated with the modified red mud and pyrolyzing it, a high-quality pyrolysis oil can be produced, and due to the excellent chlorine adsorption rate, the amount of modified red mud used can be less than that of conventional adsorbents, thereby reducing process costs and improving energy efficiency. Furthermore, considering the reality that the environment is polluted by waste plastic waste and red mud waste and that they need to be reused, there is an advantage in that resources can be effectively recycled and high-value-added oil can be effectively produced by using both waste materials.

[0037] In one embodiment, in the first step, the modified red mud may be charged into the reactor in an amount of 5 to 30 parts by weight per 100 parts by weight of the waste plastic raw material. In this range, chlorine can be effectively adsorbed, pyrolysis efficiency can be improved, and high-quality pyrolysis oil can be obtained. Specifically, the modified red mud may be charged in an amount of 5 to 25 parts by weight, more specifically, 5 to 20 parts by weight per 100 parts by weight of the waste plastic raw material.

[0038] In one embodiment, in the first step, the modified red mud may be charged into the reactor in the form of a paste further containing 30 to 80 parts by weight of water per 100 parts by weight of the modified red mud. When the modified red mud is charged into the reactor in the form of a paste further containing water in the above range, the water can capture chlorine dissociated from the waste plastic in the pyrolysis process, thereby obtaining a further chlorine adsorption effect. Specifically, the modified red mud may contain 30 to 60% by weight of the water based on the total weight of the modified red mud.

[0039] The thermal process of the second decomposition step may be carried out in a non-oxidizing atmosphere as described below, and when the modified red mud contains moisture in the above range, the non-oxidizing atmosphere can be realized as water vapor evaporated from the moisture contained in the red mud. This solves the problems of the conventional use of red mud, which requires processing steps such as calcination, drying, and crushing, expensive facilities, and high processing costs, and also improves process efficiency.

[0040] In one embodiment, the second step may be performed at a temperature of 300 to 600° C. Within this range, it is possible to prevent fusion of chlorine-containing waste plastics and improve the efficiency with which chlorine dissociated from the waste plastics is adsorbed onto the modified red mud. Specifically, the temperature may be 300 to 550° C., more specifically, 350 to 500° C.

[0041] In one embodiment, the second step may be performed in a non-oxidizing atmosphere. The non-oxidizing atmosphere is an atmosphere in which waste plastics do not burn, for example, an atmosphere in which the oxygen concentration is adjusted to 1% by volume or less, and may be an atmosphere of an inert gas such as nitrogen, water vapor, carbon dioxide, or argon. The pyrolysis process can be stably performed in a low-oxygen atmosphere in which the oxygen concentration is 1% by volume or less.

[0042] As described above, when the modified red mud contains moisture in the above range, the non-oxidizing atmosphere may be a water vapor atmosphere generated by vaporization of the moisture contained in the red mud. In particular, in order to improve the reaction efficiency, a melting process may be performed before the pyrolysis process. After the waste plastic raw material and the modified red mud are charged into a reactor, a process of uniformly melting them at 100 to 130°C for 1 to 2 hours may be performed. During this process, water vapor is generated from the moisture contained in the modified red mud, and the water vapor is used for pressure purging to remove oxygen. That is, a non-oxidizing atmosphere can be formed by water vapor from the moisture contained in the raw material, and a separate inert gas purging process does not need to be performed.

[0043] The second step may be carried out in a non-oxidizing atmosphere for 150 to 350 minutes, and when the maintenance time is satisfied, activation of the non-oxidizing atmosphere composition and sufficient pyrolysis may be carried out. Specifically, it may be 170 to 330 minutes, and more specifically, it may be 200 to 300 minutes.

[0044] The reactor may be a batch reactor or a continuous reactor. In the case of a batch reactor, any type of batch reactor capable of controlling stirring and temperature rise is possible, for example, a rotary kiln type batch reactor may be selected. In the case of a continuous reactor, a continuous fixed bed reactor may be used.

[0045] When the modified red mud is dispersed in water, the dispersed aqueous solution may have a pH of 8 to 13. The strongly alkaline modified red mud satisfying the above range can effectively adsorb chlorine dissociated from waste plastics. Specifically, the pH may be 9 to 12.

[0046] The modified red mud may further contain inorganic components within a range in which the sum of the components is 100% by weight. 2 O 3 10~30% by weight, Al 2 O 3 5~20% by weight, SiO 21~30wt%, CaO 0~15wt%, TiO 2 1-25% by weight and Na 2 O 0 to 15 wt %. More specifically, Fe 2 O 3 10~25% by weight, Al 2 O 3 5~15% by weight, SiO 2 1~25% by weight, CaO 0~10% by weight, TiO 2 1-20% by weight and Na 2 At least two or more components selected from the group consisting of 0 to 10% by weight of O may be further included.

[0047] The first step may be carried out by further including a compatibilizer. The compatibilizer can improve the efficiency of the pyrolysis reaction with waste plastics without impairing the inherent physical properties of the modified red mud, particularly the peak characteristics of XRD. By further including a compatibilizer, the modified red mud can be more easily mixed with the waste plastic raw material, and the long-term dispersion stability can be improved. The compatibilizer may be, for example, a cellulose ether compound such as methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, or carboxymethyl cellulose. The compatibilizer may be included in an amount of 0.01 to 5 parts by weight, specifically 0.01 to 3 parts by weight, based on 100 parts by weight of the modified red mud.

[0048] The thermal decomposition reaction may be carried out by further charging an additive into the reactor. For example, by further charging at least one desalting agent selected from metal oxides, metal hydroxides, and metal carbonates and carrying out the thermal decomposition process, the chlorine adsorption effect can be further improved. The metal may be an alkali metal or an alkaline earth metal. Specifically, it may be sodium, magnesium, potassium, or calcium, and more specifically, it may be potassium hydroxide, sodium hydroxide, magnesium hydroxide, potassium hydroxide, calcium oxide, magnesium oxide, calcium carbonate, sodium carbonate, or potassium carbonate. The desalting agent may be charged in an amount of 1 to 10 parts by weight per 100 parts by weight of the waste plastic raw material. Specifically, it may be charged in an amount of 1 to 5 parts by weight. In addition, additives such as a stabilizer, an antifoaming agent, or a dispersing agent may be charged.

[0049] The waste plastic raw material may be a domestic waste plastic waste or an industrial waste plastic waste, or a mixed waste plastic of these. The domestic waste plastic waste is a plastic mixed with PVC, PS, PET, PBT, etc. other than PE and PP, and in the present disclosure, as an example, it may be a waste plastic containing 3% by weight or more of PVC together with PE and PP. The chlorine content may be 5,000 ppm or more, specifically 5,000 to 15,000 ppm, per 100 parts by weight of the domestic waste plastic, but this is an example and is not limited thereto.

[0050] The industrial waste plastic is industrial waste generated during the manufacturing process in an industrial entity, and may be waste plastic containing PE and PP as main components. The industrial waste plastic maintains a relatively clean state and has a low chlorine content compared to household waste plastic. However, it has a high content of organic chlorine resulting from adhesive or dye components, and is particularly characterized by a high ratio of chlorine contained in aromatic rings. The chlorine content may be 100 to 1,000 ppm, specifically 500 to 1,000 ppm, more specifically 700 to 1,000 ppm, per 100 parts by weight of waste plastic, but is not limited thereto.

[0051] The second step is to pyrolyze the waste plastic material to recover pyrolysis oil, and the waste plastic material is converted into hydrocarbon products, which may include pyrolysis gas. After the pyrolysis gas is discharged from the reactor, it can be cooled and liquefied in a condenser, and the liquid pyrolysis oil can be recovered in a storage tank.

[0052] The pyrolysis gas may contain 5-35% by weight of naphtha (bp-150°C), 10-60% by weight of Kero (bp 150-265°C), 20-40% by weight of LGO (bp 265-380°C), and 5-40% by weight of UCO-2 / AR (bp 380°C or higher) based on the total weight of the waste plastic raw material. Specifically, it may contain 5-30% by weight of naphtha (bp-150°C), 15-50% by weight of Kero (bp 150-265°C), 20-35% by weight of LGO (bp 265-380°C), and 10-40% by weight of UCO-2 / AR (bp 380°C or higher). In addition, methane (CH 4 ), ethane (C 2 H 6 ), propane (C 3 H 8 ) may also contain residual amounts of low boiling point hydrocarbon compounds such as

[0053] Before the pyrolysis gas is introduced into the condenser, methane (CH 4 ), ethane (C2 H 6 ), propane (C 3 H 8 ) may be separately recovered. The pyrolysis gas generally contains combustible substances such as hydrogen, carbon monoxide, and low molecular weight hydrocarbon compounds. Examples of the hydrocarbon compounds include methane, ethane, ethylene, propane, propene, butane, and butene. Since the pyrolysis gas contains combustible substances, the pyrolysis gas can be reused as fuel for heating a batch reactor or a continuous reactor.

[0054] The condenser includes a region where cooling water flows, and the pyrolysis gas flowing into the condenser can be liquefied by the cooling water and converted into pyrolysis oil. When the pyrolysis oil produced in the condenser rises to a predetermined water level, it can be transported and collected in a storage tank.

[0055] A heat exchanger may be further provided between the condenser and the storage tank. The pyrolysis gas not condensed in the condenser flows into the heat exchanger and is condensed again, and the generated pyrolysis oil can be collected in the storage tank. By collecting the uncondensed pyrolysis gas again, the reaction yield can be improved.

[0056] The liquid pyrolysis oil collected in the storage tank may include an oil layer and a water layer. The water vapor generated from the modified red mud together with the pyrolysis gas is also liquefied and collected in the storage tank, and oil-water separation is performed to form an oil layer and a water layer in the liquid pyrolysis oil.

[0057] The water layer contains chlorine compounds, which may cause corrosion of the storage tank. To prevent this, a neutralizing agent may be added to the water layer. The neutralizing agent may include an alkali metal compound or an alkaline earth metal compound having a pH value of 7 or more when dissolved in water. Specifically, the neutralizing agent may include a hydroxide, oxide, carbonate, hydrogen carbonate, basic carbonate, or fatty acid salt of an alkali metal or alkaline earth metal. The alkali metal or alkaline earth metal may be a metal commonly used in the art. For example, the alkali metal may include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), or francium (Fr), and the alkaline earth metal may include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), or radium (Ra). The neutralizing agent may be added alone or mixed with a solvent such as alcohol to improve neutralization efficiency.

[0058] When adding a neutralizing agent to the water layer, the neutralizing agent may be added in an appropriate amount by measuring the pH of the water layer using a pH meter located at the bottom of the storage tank.

[0059] When the oil layer and the water layer are separated, the oil layer can be collected immediately or the water layer can be adsorbed and then collected to collect the oil layer with minimized chlorine (waste plastic pyrolysis oil). The water layer can be discharged and adsorbed, or the discharged water can be purified and then recycled to the first step to be reused as water to be mixed with the waste plastic.

[0060] An electric field may be applied to effectively separate the oil layer and the water layer, and the oil layer and the water layer may be separated in a short time by electrostatic adhesion due to the application of an electric field. In addition, an additive may be added as necessary to improve the efficiency of the oil-water separation, and the additive may be a conventional demulsifier well known in the art.

[0061] When the water layer is discharged and adsorbed, a density profiler is used to detect the density, so that the oil layer can be prevented from being adsorbed together with the water layer, and only the water layer can be effectively adsorbed.

[0062] The chlorine content in the recovered pyrolysis oil may be 300 ppm or less. The chlorine content in the waste plastic pyrolysis oil produced by effectively adsorbing the chlorine dissociated from the waste plastic raw material using the modified red mud may be 300 ppm or less. In particular, the chlorine content in the waste plastic pyrolysis oil may be 300 ppm or less, as expressed by the relational expression 1 (I 1D / I 1W ) / (I 2D / I 2W ) and relation 2 (I 2W / I 1W ) all of the peak characteristics are satisfied, the chlorine adsorption effect is maximized, and the chlorine content may be 150 ppm or less, more specifically, 100 ppm or less.

[0063] Preferred examples and comparative examples of the present disclosure are described below. However, the following examples are preferred embodiments of the present disclosure, and the present disclosure is not limited to the following examples.

[0064] Example 1 A household waste plastic pellet containing 3% by weight or more of PVC along with PE and PP was extruded at 250°C to produce 400g of household waste plastic pellets. The total chlorine content of the household waste plastic pellets was 4,000ppm.

[0065] Alumina was produced from bauxite, and general red mud was recovered from the residue. The composition of the general red mud is shown in Table 1 below.

[0066] [Table 1]

[0067] The general red mud was put into a pressure device containing a steam atmosphere and pressurized at 5 bar for 60 minutes at 25° C. Then, the pressure was adjusted to normal pressure and the mixture was stabilized at 60° C. for 60 minutes to produce modified red mud.

[0068] 400g of the produced household waste plastic pellets and 20g of modified red mud were put into a batch reactor and heated at 110°C for 1 hour to carry out a melting process. A non-oxidizing atmosphere was formed using steam generated from the modified red mud in the melting process, and full-scale pyrolysis was carried out for 250 minutes at 400°C. Pyrolysis gas generated during the pyrolysis process was collected from an outlet at the top of the reactor and captured in a condenser, and finally, waste plastic pyrolysis oil was collected from a recovery tank.

[0069] In order to confirm the peak characteristics of the modified red mud, an X-ray diffraction (XRD) analysis was performed, and the results are shown in Table 2. 1 , I 2 and I 3 is as defined above.

[0070] [Table 2]

[0071] Example 2 A reaction was carried out under the same conditions as in Example 1 to recover waste plastic pyrolysis oil, except that modified red mud having the properties shown in Table 3 below was used in Example 1. Specifically, the general red mud was put into a pressure device containing a steam atmosphere, and pressurized at a pressure of 7 bar and a temperature of 25°C for 60 minutes to produce modified red mud.

[0072] [Table 3]

[0073] Example 3 In Example 1, instead of the general red mud having the composition of Table 1, the general red mud having the composition of Table 4 below was placed in a pressure device containing an ethanol atmosphere and pressurized at a pressure of 5 bar and a temperature of 25° C. for 60 minutes.

[0074] [Table 4]

[0075] Thus, the reaction was carried out under the same conditions as in Example 1, except that the modified red mud having the properties in Table 5 below was produced and used, and waste plastic pyrolysis oil was recovered.

[0076] [Table 5]

[0077] Example 4 In Example 3, a reaction was carried out under the same conditions as in Example 1 to recover waste plastic pyrolysis oil, except that modified red mud having the properties shown in Table 6 below was used. Specifically, the general red mud was put into a pressure device containing an ethanol atmosphere, and pressurized at a pressure of 15 bar and a temperature of 25°C for 60 minutes to produce modified red mud.

[0078] [Table 6]

[0079] Comparative Example 1 The reaction was carried out under the same conditions as in Example 1, except that dried red mud obtained by drying the general red mud in Example 1 was used, and waste plastic pyrolysis oil was recovered. Specifically, the modified red mud was heat-treated at 110°C for 24 hours to produce dried red mud.

[0080] To confirm the peak characteristics of the dried red mud, X-ray diffraction (XRD) analysis was performed and the results are shown in FIG. 1 and Table 7 below.

[0081] [Table 7]

[0082] Comparative Example 2 In Example 1, the reaction was carried out under the same conditions as in Example 1, except that red mud having the properties shown in Table 8 below was used, and waste plastic pyrolysis oil was recovered.

[0083] [Table 8]

[0084] Evaluation example 1 Representatively, the red muds of Example 3 and Comparative Example 1 were subjected to X-ray diffraction (XRD) analysis to measure peak intensities at 2θ diffraction angles of 14±0.1°, 14.5±0.1°, and 28.2±0.1°. The results are shown in Table 9 below.

[0085] [Table 9]

[0086] Referring to Table 9 and FIG. 1, Example 3 is 1 I 2 In contrast, in the case of Comparative Example 1, I 1 I 2 I can confirm that it is lower than 3 It can be confirmed that Example 3 has a lower value than Comparative Example 2.

[0087] As a result, in Example 3, (I 1 ) / (I 2 ) and (I 1 ) / (I 3 ) each satisfies 5 or more, whereas Comparative Example 1 does not satisfy this requirement. It can be seen that the chlorine removal properties of red mud differ due to the difference in peak characteristics, as shown in Table 10 below.

[0088] Evaluation example 2 The chlorine content of the recovered waste plastic pyrolysis oil was measured by ICP and XRF analysis. The results are summarized in Table 10 below.

[0089] [Table 10]

[0090] Examples 1 and 2 show the results of the (I 1 ) / (I 2 ) values ​​were 7.38 and 9.92, respectively, which are greater than 5, confirming that the chlorine content in the recovered pyrolysis oil was approximately 250 to 270 ppm, effectively reducing the chlorine content.

[0091] In particular, with reference to Examples 3 and 4, 1 ) / (I 2 ) values ​​are 11.74 and 13.89, respectively, and satisfy 5 or more, and (I 1 ) / (I 3 ) values ​​are 12.51 and 17.64, respectively, and when they meet 5 or more, it can be confirmed that the chlorine content in the pyrolysis oil is 200 ppm or less, and the chlorine removal properties of the modified red mud are further improved.

[0092] On the other hand, the commonly used dried red mud of Comparative Example 1 (I 1 ) / (I 2 ) value is 1 or less, (I 1 ) / (I 3 ) value was found to be very low at less than 3, which indicates that the chlorine removal properties of the modified red mud have decreased and that the chlorine content in the pyrolysis oil is excessive at 530 ppm.

[0093] Comparative Example 2 (I 1 ) / (I 2 ) value is 1 or less, (I 1 ) / (I 3 ) value is low at 5 or less, which confirms that the chlorine removal properties of the modified red mud are reduced.

[0094] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and may be implemented in various different forms, and a person having ordinary skill in the art to which the present invention belongs can understand that the present invention may be implemented in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the embodiments described above are illustrative in all respects and are not limiting.

Claims

1. A first step of charging waste plastic raw materials and modified red mud into a reactor; A second step of pyrolyzing the waste plastic raw material in a reactor and recovering pyrolysis oil; The modified red mud is characterized in that, in X-ray diffraction (XRD) analysis, the intensity of a first peak at a 2θ diffraction angle of 14±0.1° is greater than the intensity of a second peak at a 2θ diffraction angle of 14.5±0.1°.

2. The intensity of the first peak (I １ ) and the intensity of the second peak (I ２ ) and the ratio (I １ ) / (I ２ 2. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1, wherein the ratio of the chlorine content to the total chlorine content is 5 or more.

3. 2. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1, wherein the intensity of the first peak at a 2θ diffraction angle of 14±0.1° of the modified red mud is greater than the intensity of the third peak at a 2θ diffraction angle of 28.2±0.1° when analyzed by X-ray diffraction (XRD).

4. The intensity of the first peak (I １ ) and the intensity of the third peak (I ３ ) and the ratio (I １ ) / (I ３ 2. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1, wherein the ratio of the chlorine content to the total chlorine content is 5 or more.

5. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1, wherein in the first step, 5 to 30 parts by weight of the modified red mud is charged into the reactor per 100 parts by weight of the waste plastic raw material.

6. 2. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1, wherein in the first step, the modified red mud further contains 30 to 80 parts by weight of water per 100 parts by weight of the modified red mud, and is charged into the reactor as a paste.

7. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1, wherein the second step is carried out at a temperature of 300 to 600°C.

8. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1 , wherein the second step is carried out in a non-oxidizing atmosphere.

9. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 1 , wherein the first step is carried out further containing an admixture.

10. The method for producing waste plastic pyrolysis oil with reduced chlorine content according to claim 9, wherein the admixture is a cellulose ether compound.

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