KR20240155049A - Method and system for producing refined hydrocarbons from waste plastic pyrolysis oil - Google Patents

Abstract

The present disclosure relates to a method and a production system for producing purified hydrocarbons from waste plastic pyrolysis oil.
The method and system for producing refined hydrocarbon according to the present disclosure can minimize the generation of ammonium salt (NH ₄ Cl) in the process of refining waste plastic pyrolysis oil containing impurities including chlorine and nitrogen, and prevent the phenomenon of impurity particles being fixed within a reactor. In addition, refined hydrocarbon having very low impurity content and olefin content and excellent quality can be provided from waste plastic pyrolysis oil.

Description

Method and system for producing refined hydrocarbons from waste plastic pyrolysis oil

The present invention relates to a method and system for producing purified hydrocarbons from waste plastic pyrolysis oil.

Waste plastics are manufactured using petroleum as a raw material, and the recycling rate, such as energy recovery and mechanical recycling, is low, and a significant amount is simply incinerated or landfilled. Since these wastes take a long time to decompose in nature, they pollute the soil and cause serious environmental pollution. As a method for recycling waste plastics, there is a method of converting waste plastics into usable oil by thermal decomposition, and the oil produced by thermal decomposition of waste plastics in this way is called waste plastic pyrolysis oil.

However, waste plastic pyrolysis oil has a higher content of impurities such as chlorine, nitrogen, and metals compared to the oil produced from crude oil by general methods, so waste plastic pyrolysis oil can only be blended in limited amounts into high value-added fuels such as gasoline and diesel. Therefore, in the process of producing refined hydrocarbons from waste plastic pyrolysis oil, it is necessary to remove the impurities contained in the waste plastic pyrolysis oil.

Known methods for removing impurities such as chlorine, nitrogen, oxygen, and metals contained in waste plastic pyrolysis oil include a method of reacting waste plastic pyrolysis oil with hydrogen in the presence of a hydrogenation catalyst to perform dechlorination/denitrogenation/deoxygenation, or a method of adsorbing and removing chlorine contained in waste plastic pyrolysis oil using a chlorine adsorbent.

Specifically, U.S. Patent Publication No. 3,935,295 discloses a technique for removing chloride contaminants from various hydrocarbon oils. The technique is a conventional technique in which oil is hydrogenated under a hydrogenation catalyst in a first reactor, a fluid containing hydrogen chloride (HCl) produced in the process and purified oil is introduced into a second reactor, and then the chlorine component contained in the fluid is removed by adsorption using an adsorbent.

However, as in the conventional technology described above, when oil and hydrogen are reacted under a hydrogenation catalyst, chlorine compounds such as hydrogen chloride and nitrogen compounds generated together with the refined oil react to generate ammonium salts (NH ₄ Cl), and these ammonium salts cause various process problems. Specifically, the ammonium salts generated inside the reactor when oil and hydrogen react not only cause corrosion of the reactor, reducing durability, but also cause many process problems such as differential pressure generation and deactivation of the catalyst, reducing process efficiency. In addition, when the process is operated for a long period of time, impurity particles in the waste plastic pyrolysis oil are fixed inside the reactor, similarly causing various process problems.

Therefore, there is a need for the development of a method and system for producing refined hydrocarbons from waste plastic pyrolysis oil that solves the above-described process problems.

U.S. Patent Publication No. 3935295 (Registration Date: 1976.01.27)

The purpose of the present disclosure is to provide a method and a system for producing purified hydrocarbons from waste plastic pyrolysis oil, which minimizes the production of ammonium salts (NH ₄ Cl) in the process of refining waste plastic pyrolysis oil containing impurities including chlorine and nitrogen.

Another object of the present disclosure is to provide a method and system for producing refined hydrocarbons from waste plastic pyrolysis oil, in which the activity of the catalyst is maintained for a long time, the purification efficiency is excellent, and long-term operation is possible.

Another object of the present disclosure is to provide a method and system for producing purified hydrocarbons from waste plastic pyrolysis oil, which can prevent the phenomenon of impurity particles becoming fixed within a reactor.

Another object of the present disclosure is to provide a method and a production system for producing refined hydrocarbons having excellent quality and very low content of impurities such as chlorine, nitrogen, oxygen, and metals and olefin content from waste plastic pyrolysis oil.

In order to achieve the above object, in one aspect of the present disclosure, a method for producing refined hydrocarbons from waste plastic pyrolysis oil is provided, including: S1) a step of applying voltage to a first mixture comprising waste plastic pyrolysis oil, wash water, and a demulsifier to dehydrate them; S2) a step of first hydrogenating the first mixture dehydrated in step S1) and a second mixture comprising a sulfur source to produce refined oil from which impurities have been removed; and S3) a step of second hydrogenating the refined oil from which impurities have been removed.

In the step S1) according to an example of the present disclosure, the waste plastic pyrolysis oil can be mixed in a larger volume than the wash water.

In the step S1) according to an example of the present disclosure, the first mixture may be a mixture of waste plastic pyrolysis oil and washing water in a volume ratio of 1:0.001 to 0.5.

In the step S1) according to an example of the present disclosure, the first mixture may be a mixture of waste plastic pyrolysis oil and a demulsifier in a volume ratio of 1:0.000001 to 0.001.

The voltage according to an example of the present disclosure may be applied as an alternating current or a combination of alternating current and direct current.

According to one example of the present disclosure, the voltage may be applied through a vertical electrode.

A method for producing refined hydrocarbons from waste plastic pyrolysis oil according to an example of the present disclosure may further include, in the step S1), a step of removing a rag layer from the first mixture after the voltage is applied.

According to an example of the present disclosure, the step S1) can be performed at a temperature of 20° C. to 300° C.

According to an example of the present disclosure, the ratio of the moisture content of the waste plastic pyrolysis oil and the moisture content of the first mixture dehydrated in step S1) may be 1:0.0001 to 0.9.

According to an example of the present disclosure, the step S1) may further dehydrate the dehydrated first mixture by coagulating the moisture.

According to an example of the present disclosure, the second mixture may have a weight ratio of nitrogen to chlorine of 1:1 to 10.

The sulfur source according to one example of the present disclosure may include a sulfur-containing oil.

According to an example of the present disclosure, the sulfur-containing oil may be included in an amount of less than 0.5 parts by weight based on 100 parts by weight of the first mixture dehydrated in step S1).

According to one example of the present disclosure, the sulfur source may include one or more sulfur-containing organic compounds selected from a disulfide compound, a sulfide compound, a sulfonate compound, and a sulfate compound.

The first hydrogenation treatment according to an example of the present disclosure can be performed in the presence of a molybdenum-based hydrogenation catalyst.

The molybdenum-based hydrogenation catalyst according to one example of the present disclosure may be a catalyst in which a molybdenum-based metal or a metal including one or more selected from nickel, cobalt, and tungsten and the molybdenum-based metal are supported on a support.

The molybdenum-based hydrogenation catalyst according to one example of the present disclosure may include a molybdenum-based sulfide hydrogenation catalyst.

The first hydrogenation treatment according to an example of the present disclosure can be performed under pressure conditions of 50 bar to 150 bar.

A method for producing refined hydrocarbons from waste plastic pyrolysis oil according to an example of the present disclosure may further include, after step S2), a step of subjecting a stream containing refined oil from which the impurities have been removed to gas-liquid separation and then washing.

According to an example of the present disclosure, the step S3) may be a second hydrogenation treatment of a mixed oil in which refined oil from which impurities have been removed in the step S2) is mixed with petroleum-based hydrocarbons.

The method and system for producing refined hydrocarbon according to the present disclosure can minimize the production of ammonium salt (NH ₄ Cl) in the process of refining waste plastic pyrolysis oil containing impurities including chlorine and nitrogen.

The method and system for producing refined hydrocarbons according to the present disclosure have excellent purification efficiency and enable long-term operation of the process since deactivation of the catalyst used in the process is prevented.

The method and system for producing refined hydrocarbon according to the present disclosure can provide refined hydrocarbon having excellent quality with very low content of impurities such as chlorine, nitrogen, oxygen, and metals and olefin content from waste plastic pyrolysis oil.

The method and system for producing refined hydrocarbons according to the present disclosure can be used in the production of environmentally friendly refined oil and petrochemical products using waste plastics as raw materials.

FIG. 1 is a process diagram of a method for producing purified hydrocarbons from waste plastic pyrolysis oil according to one embodiment of the present disclosure.

The advantages and features of the present invention, and the method for achieving them, will become clear with reference to the embodiments described in detail below. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and these embodiments are provided only to make the disclosure of the present invention complete and to fully inform a person having ordinary skill in the art to which the present invention belongs of the scope of the invention, and the present invention is defined only by the scope of the claims.

Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used in a commonly understood meaning to a person of ordinary skill in the art to which the present invention belongs.

As used herein, the singular forms of terms are to be construed to include the plural forms as well, unless otherwise specified.

The numerical range used in this specification includes the lower and upper limits and all values within that range, increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of the upper and lower limits of a numerical range defined in different shapes. Unless otherwise specifically defined in the specification of the present invention, values outside the numerical range that may arise due to experimental error or rounding of values are also included in the defined numerical range.

The term "includes" as used herein is an open-ended description that has the equivalent meaning of expressions such as "comprises," "contains," "has," and "is characterized by," and does not exclude additional elements, materials, or processes not listed herein.

The term 'reactor' used in this specification may mean a device that can be used in processes such as production, refining, separation, and mixing of waste plastic pyrolysis oil. For example, 'reactor' may be interpreted to mean devices such as a dehydrator, a coalescer, a hydrotreating reactor, and a separator used in a process of refining waste plastic pyrolysis oil.

As used herein, the term 'vertical electrode' may mean an electrode erected vertically with respect to the ground, and the term 'horizontal electrode' may mean an electrode laid horizontally with respect to the ground.

The method and system for producing refined hydrocarbons from waste plastic pyrolysis oil according to the present disclosure include a dehydration step that includes washing, demulsification, and voltage application, etc., to reduce problems such as catalyst deactivation due to moisture dispersed in the waste plastic pyrolysis oil in an emulsion form, corrosion of a reactor due to chlorine contained in the moisture and low pH of the moisture. In addition, the method includes a first hydrogenation treatment step for removing impurities contained in the waste plastic pyrolysis oil through a hydrogenation reaction, and a second hydrogenation treatment step for the refined oil from which the impurities have been removed. The method for producing refined hydrocarbons from waste plastic pyrolysis oil according to the present disclosure can stably produce high-quality refined hydrocarbons from waste plastic pyrolysis oil for a long period of time since the above series of sequential steps are organically combined.

Below, a method and system for producing refined hydrocarbons from waste plastic pyrolysis oil are described in detail.

The present disclosure provides a method for producing refined hydrocarbons from waste plastic pyrolysis oil, including the steps of S1) applying voltage to a first mixture comprising waste plastic pyrolysis oil, wash water, and a demulsifier to dehydrate them; S2) performing a first hydrogenation treatment on the first mixture dehydrated in step S1) and a second mixture comprising a sulfur source to produce refined oil from which impurities have been removed; and S3) performing a second hydrogenation treatment on the refined oil from which impurities have been removed in step S2).

First, step S1) is a step of dehydrating by applying voltage to a first mixture containing waste plastic pyrolysis oil, washing water, and a demulsifier.

Waste plastic pyrolysis oil contains moisture, and problems such as deactivation of a hydrogenation catalyst and corrosion of a reactor may occur due to moisture in the pyrolysis oil, and water-soluble impurities are contained in the moisture, so it is necessary to remove moisture. By going through the above step S1), moisture existing in the form of an emulsion in the waste plastic pyrolysis oil can be easily removed.

The waste plastic pyrolysis oil according to one embodiment of the present disclosure may be a hydrocarbon oil mixture produced by pyrolyzing waste plastic, wherein the waste plastic may include solid or liquid waste related to synthetic polymer compounds such as waste synthetic resin, waste synthetic fiber, waste synthetic rubber, and waste vinyl.

The hydrocarbon oil mixture according to one embodiment of the present disclosure may include impurities such as chlorine compounds, nitrogen compounds, oxygen compounds, metal compounds, char-derived particles, etc., in addition to hydrocarbon oil, and may include impurities in the form of compounds in which chlorine, nitrogen, oxygen, or metals are combined within the hydrocarbon, and may include hydrocarbons in the form of paraffins, olefins, naphthene, or aromatics.

According to one embodiment of the present disclosure, the wash water can serve to increase the probability of contact between waste plastic pyrolysis oil and the water in the form of an emulsion. In addition, a basic compound can be added to the wash water so as to remove a water-soluble acidic substance contained in the water, and the basic compound can be sodium hydroxide (NaOH), but is not particularly limited. According to one embodiment of the present disclosure, the waste plastic pyrolysis oil can be mixed in a larger volume than the wash water, and specifically, the first mixed solution can be a mixture of waste plastic pyrolysis oil and wash water in a volume ratio of 1:0.001 to 0.5, more specifically in a volume ratio of 1:0.005 to 0.4, and most specifically in a volume ratio of 1:0.01 to 0.3. When the above range is satisfied, washing is sufficiently performed so that impurities in the pyrolysis oil can be significantly reduced, and the cost required for removing the mixed wash water can be minimized.

According to one embodiment of the present disclosure, the demulsifier may be one or a mixture of two or more selected from the group consisting of polyethylene glycol, tert-butanol, acetone, alkylnaphthalenesulfonate, alkylbenzenesulfonate, nonionic alkoxylated alkyl phenol resin, polyalkylene oxide, and polyoxyethylene sorbitan ester, but is not limited thereto.

According to one embodiment of the present disclosure, the first mixture may be a mixture of waste plastic pyrolysis oil and a demulsifier in a volume ratio of 1:0.000001 to 0.001, specifically, a volume ratio of 1:0.000002 to 0.0005, and more specifically, a volume ratio of 1:0.000003 to 0.0001. When the above range is satisfied, the emulsion can be decomposed while minimizing the impact on the quality of the pyrolysis oil.

According to one embodiment of the present disclosure, the emulsifier may have a weight average molecular weight of 200 to 2,000, specifically, a weight average molecular weight of 300 to 1,000, and more specifically, a weight average molecular weight of 400 to 800. When the above range is satisfied, mixing with waste plastic pyrolysis oil and washing water under conditions in which a dehydration process is performed can be easily performed, thereby increasing the decomposition efficiency of the water emulsion.

The emulsion-type moisture contained in the first mixture containing waste plastic pyrolysis oil, washing water, and a demulsifier is still difficult to remove because it is stable. Therefore, the moisture can be easily removed by applying voltage to the first mixture.

According to one embodiment of the present disclosure, the voltage may be applied as an alternating current or a combination of an alternating current and a direct current. Some impurity particles contained in waste plastic pyrolysis oil exhibit polarity, and when a direct current voltage is applied, polar impurity particles may accumulate on a specific electrode, and when the process is performed for a long period of time, a phenomenon in which the impurities are fixed on the electrode may occur. However, when an alternating voltage is applied, the polarity of the electrode changes periodically, so that the fixation phenomenon of the impurity particles can be prevented. In addition, the frequency of the alternating current according to one embodiment of the present disclosure may be a single frequency or a combination of two or more frequencies. As a specific example, in the case of a single frequency, an alternating current having a frequency of 60 Hz may be applied, and in the case of a combination of two or more frequencies, an alternating current having frequencies of 50 Hz and 60 Hz may be applied alternately, but is not limited thereto.

According to one embodiment of the present disclosure, the voltage may be applied via a vertical electrode. If impurity particles accumulate on the electrode during the process of preparing the mixture or applying the voltage, if they are not artificially washed, the phenomenon of the impurity particles being fixed on the electrode may occur after a long period of time. However, if a vertical electrode is used, the impurity particles fall to the bottom of the reactor without being accumulated on the electrode due to gravity without performing a separate washing operation, so the phenomenon of the impurity particles being fixed can be prevented in advance.

The magnitude of the voltage according to one embodiment of the present disclosure may be, but is not limited to, 0.1 to 50 kV, specifically 1 to 30 kV, and more specifically 5 to 20 kV.

The dehydration according to one embodiment of the present disclosure may be performed by any method known in the art. As a non-limiting example, the water may be removed by following the separated water layer after voltage application. The water may also be removed in a gas-liquid separator.

Metal impurities in the waste plastic pyrolysis oil stabilize the emulsion, hindering the oil-water separation, and help form a stable emulsion layer, commonly called a rag layer. This rag layer can be formed between the demineralized oil layer on the upper side of the first mixture and the water layer below, and can gradually thicken during the continuous dehydration process. The excessively thick rag layer can be discharged to the hydrogenation treatment stage equipment together with the demineralized oil. This reduces the demineralization effect of the demineralized oil, thereby reducing the efficiency of the process. In addition, the rag layer can be discharged together with the water, causing problems in the wastewater treatment process. Therefore, it is desirable to remove the rag layer formed between the demineralized oil layer and the water layer.

Thus, the method for producing refined hydrocarbons from waste plastic pyrolysis oil according to one embodiment of the present disclosure may further include a step of removing a rag layer from the first mixture after applying voltage in step S1). The removal of the rag layer may be performed through a pipe that penetrates the wall of the dehydrator and is connected to the outside after measuring a change in the density of the mixture through a density meter in the dehydrator to determine the formation location and thickness of the rag layer, but is not necessarily limited thereto.

According to one embodiment of the present disclosure, the step S1) may be to dehydrate the first mixture, and then further dehydrate the dehydrated first mixture by coagulating the moisture.

The additional dehydration according to one embodiment of the present disclosure may be performed by supplying the dehydrated first mixture to a coalescer. Specifically, the residual moisture contained in the dehydrated first mixture may be removed by being coagulated by a collection filter in the coalescer, but this is only a specific example and is not necessarily limited thereto. As the moisture content in the waste plastic pyrolysis oil is further reduced through the additional dehydration, the deactivation of the catalyst due to moisture is prevented, and the stability of the process and the quality of the refined hydrocarbon can be improved.

According to one embodiment of the present disclosure, the ratio of the moisture content of the waste plastic pyrolysis oil and the moisture content of the dehydrated first mixture may be 1:0.0001 to 0.9, specifically 1:0.0005 to 0.5, and more specifically 1:0.001 to 0.1. When the above range is satisfied, the risk of trouble occurring in subsequent processes including hydrogenation treatment is significantly reduced, and high-quality refined oil satisfying the specifications as a raw material can be produced, but is not necessarily limited thereto.

The step S1) according to one embodiment of the present disclosure can be performed at a pressure of 50 bar or less. When performed at a pressure of 50 bar or less, moisture in the pyrolysis oil can be easily removed, and process stability can be secured. Specifically, it can be performed at a pressure of 30 bar or less, more specifically, it can be performed at a pressure of 20 bar or less, and, without limitation, it can be performed at a pressure of 5 bar or more.

The step S1) according to one embodiment of the present disclosure may be performed at a temperature of 20° C. to 300° C. When the above range is satisfied, emulsion decomposition and moisture coagulation may occur well, thereby improving dehydration efficiency. Specifically, it may be performed at a temperature of 50° C. to 250° C., and more specifically, 80° C. to 200° C.

In order to improve the dehydration efficiency in step S1) according to one embodiment of the present disclosure, one or more additional processes selected from the group consisting of centrifugation and distillation may be performed before and/or after dehydration. The above-described additional processes may be performed by methods known in the art and are not particularly limited.

Next, step S2) is a step of producing refined oil from which impurities have been removed by first hydrogenation of the first mixture obtained by dehydrating in step S1) and the second mixture obtained by mixing the sulfur source.

The second mixture according to one embodiment of the present disclosure may have a concentration of chlorine (Cl) of 10 ppm or more, specifically 100 ppm or more, more specifically 200 ppm or more, and an upper limit may be, but is not limited to, 3000 ppm or less.

According to one embodiment of the present disclosure, the second mixture may have a weight ratio of nitrogen to chlorine of 1:0.1 to 10, specifically 1:0.5 to 5, and more specifically 1:1 to 2. However, the weight ratio is only a specific example that may be included in the waste plastic pyrolysis oil, and the composition of the waste plastic pyrolysis oil is not limited thereto.

The first hydrogenation treatment according to one embodiment of the present disclosure can be performed under a condition where the ratio of hydrogen to the second mixture is 100 Nm ³ /Sm ³ to 5000 Nm ³ /Sm ³ , specifically 500 Nm ³ /Sm ³ to 3000 Nm ³ /Sm ³ , and more specifically 1000 Nm ³ /Sm ³ to 1500 Nm ³ /Sm ³ . When this is satisfied, impurities can be effectively removed, the activity of the hydrogenation catalyst can be maintained at a high level for a long period of time, and the process efficiency can be improved.

The above sulfur source refers to a sulfur source that can continuously supply sulfur components during the refining process.

The above step S2) can suppress deactivation of a molybdenum-based hydrogenation catalyst due to insufficient sulfur source and high-temperature operation during the purification process and maintain catalytic activity by producing a second mixture containing the sulfur source.

According to one embodiment of the present disclosure, the sulfur supply source may include a sulfur-containing oil fraction. The sulfur-containing oil fraction refers to an oil fraction composed of hydrocarbons containing sulfur obtained using crude oil as a raw material. There is no particular limitation on the sulfur-containing oil fraction, and examples thereof may include light gas oil, straight run naphtha, vacuum naphtha, thermal cracking naphtha, straight run kerosene, vacuum kerosene, thermal cracking kerosene, straight run light oil, vacuum kerosene, thermal cracking light oil, sulfur-containing waste tire oil, or any mixture thereof.

According to one embodiment of the present disclosure, by including waste tire oil as the sulfur-containing oil, the high content of sulfur contained in the waste tire is converted into oil together with hydrocarbons, so that it can preferably function as a sulfur source for waste plastic pyrolysis oil. In addition, by using waste tire oil as a sulfur source for waste plastic pyrolysis oil, it is advantageous in terms of reducing the environmental load due to recycling of waste tires and maintaining catalytic activity for a long period of time.

Specifically, the sulfur-containing fraction may be light gas oil (LGO) having a specific gravity of 0.7 to 1. When this is used, it can be uniformly mixed with the dehydrated first mixture, and has the advantage of high hydrogenation efficiency. Specifically, the specific gravity may be 0.75 to 0.95, and more specifically, may be 0.8 to 0.9. The sulfur-containing fraction may contain sulfur in an amount of 100 ppm or more. When the sulfur component is contained in an amount of 100 ppm or less, the content of the supplied sulfur component may be small, and the effect of preventing deactivation of the molybdenum-based hydrogenation catalyst may be minimal. Specifically, the sulfur component may be contained in an amount of 800 ppm or more, more specifically, 8,000 ppm or more, and, but not limited to, 200,000 ppm or less.

The second mixture according to one embodiment of the present disclosure may contain sulfur in an amount of 100 ppm or more. As in the case of the sulfur-containing oil, if the sulfur component in the second mixture is contained in an amount of 100 ppm or less, the content of the supplied sulfur component may be small, and thus the effect of preventing deactivation of the molybdenum-based hydrogenation catalyst may be minimal. Specifically, the sulfur component may be contained in an amount of 800 ppm or more, more specifically, in an amount of 8,000 ppm or more, and, without limitation, in an amount of 200,000 ppm or less.

According to one embodiment of the present disclosure, the sulfur-containing oil may be included in an amount of less than 0.5 parts by weight based on 100 parts by weight of the first mixture dehydrated in step S1). Specifically, the sulfur-containing oil may be included in an amount of less than 0.1 parts by weight, more specifically, less than 0.05 parts by weight, and, without limitation, more than 0.01 parts by weight. Since the sulfur-containing oil is included in an amount of less than 0.5 parts by weight, the concentration of chlorine (Cl) or nitrogen (N) included in the waste plastic pyrolysis oil is diluted, thereby controlling the production rate of ammonium salt (NH ₄ Cl) and improving process stability.

According to one embodiment of the present disclosure, the sulfur source may include one or more sulfur-containing organic compounds selected from a disulfide compound, a sulfide compound, a sulfonate compound, and a sulfate compound. Specifically, it may include one or a mixture of two or more selected from dimethyldisulfide, dimethylsulfide, polysulfide, dimethyl sulfoxide (DMSO), methyl methanesulfonate, ethyl methanesulfonate, propyl methanesulfonate, propenyl propenesulfonate, propenyl cyanoethansulfonate, ethylene sulfate, bicyclo glyoxal sulfate, and methyl sulfate, which is provided by way of example only and the present disclosure is not limited thereto.

According to one embodiment of the present disclosure, the sulfur-containing organic compound may be included in an amount of 0.01 to 0.1 parts by weight based on 100 parts by weight of the first mixture dehydrated in step S1). Specifically, it may be included in an amount of 0.02 to 0.08 parts by weight, and more specifically, it may be included in an amount of 0.03 to 0.06 parts by weight. If it is included in an amount of less than 0.01 parts by weight, the content of the supplied sulfur component may be low, and thus the effect of preventing deactivation of the molybdenum-based hydrogenation catalyst may be minimal.

The above first hydrogenation treatment means a hydrogenation reaction in which a reaction gas containing hydrogen gas (H ₂ ) is added to a second mixture containing a sulfur source and a first mixture dehydrated in the step S1) under a molybdenum-based hydrogenation catalyst. Specifically, the first hydrogenation treatment may mean a conventionally known hydrogenation treatment including a hydrodesulfurization reaction, a hydrocracking reaction, a hydrodechlorination reaction, a hydrodenitrogenation reaction, a hydrodeoxygenation reaction, and a hydrodemetallation reaction. Through the first hydrogenation treatment, impurities including chlorine (Cl), nitrogen (N), and oxygen (O) and a portion of olefins are removed, and other metal impurities can also be removed, and by-products including the above impurities are generated.

The above by-product is generated by the reaction of hydrogen gas (H ₂ ) with impurities contained in the waste plastic pyrolysis oil, such as chlorine (Cl), nitrogen (N), sulfur (S), or oxygen (O), and specifically, may include hydrogen sulfide gas (H ₂ S), hydrogen chloride (HCl), ammonia (NH ₃ ) or water vapor (H ₂ O), and in addition, may include unreacted hydrogen gas (H ₂ ), trace amounts of methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ) or butane (C ₄ H ₁₀ ).

The molybdenum-based hydrogenation catalyst according to one embodiment of the present disclosure may be a catalyst in which a molybdenum-based metal, or a metal including one or more selected from nickel, cobalt, and tungsten, and the molybdenum-based metal are supported on a support. The molybdenum-based hydrogenation catalyst has high catalytic activity during hydrogenation treatment, and may be used alone or, if necessary, in the form of a binary system catalyst combined with a metal such as nickel, cobalt, or tungsten.

According to one embodiment of the present disclosure, the support may be, but is not limited to, alumina, silica, silica-alumina, titanium oxide, molecular sieve, zirconia, aluminum phosphate, carbon, niobia or a mixture thereof.

The molybdenum-based hydrogenation catalyst according to one embodiment of the present disclosure may include a molybdenum-based sulfide hydrogenation catalyst. For example, it may include molybdenum sulfide (MoS) or molybdenum disulfide (MoS ₂ ), but is not limited thereto, and may include a known molybdenum-based sulfide hydrogenation catalyst.

The reaction gas according to one embodiment of the present disclosure may further include hydrogen sulfide gas (H ₂ S). The hydrogen sulfide gas (H ₂ S) included in the reaction gas may act as a sulfur source and regenerate the activity of a molybdenum-based hydrogenation catalyst that has been deactivated during a purification process, such as a sulfur source mixed with waste plastic pyrolysis oil.

The first hydrogenation treatment according to one embodiment of the present disclosure can be performed at a pressure of 150 bar or less. Specifically, it can be performed at a pressure of 120 bar or less, more specifically, 100 bar or less, and, but not limited to, it can be performed at a pressure of 50 bar or more. When the first hydrogenation treatment is performed under a pressure condition exceeding 150 bar, since ammonia and hydrogen chloride are generated in excess during the first hydrogenation treatment, the ammonium salt formation temperature increases, which can easily cause a differential pressure within the process such as a reactor, and the process stability can be significantly reduced. By controlling the contents of nitrogen and chlorine in the waste plastic pyrolysis oil, the increase in the ammonium salt formation temperature can be partially suppressed even under a pressure condition exceeding 150 bar; however, in this case, the waste plastic pyrolysis oil that is the target of the purification process according to the present disclosure can be extremely limited, which is not appropriate.

The first hydrogenation treatment according to one embodiment of the present disclosure may be performed at a temperature of 150° C. to 500° C. When the above range is satisfied, the efficiency of the first hydrogenation treatment may be improved. Specifically, it may be performed at a temperature of 200° C. to 400° C.

The first hydrogenation treatment according to one embodiment of the present disclosure may be performed in multiple stages, and as a specific example, may be performed in two stages. When the first hydrogenation treatment is performed in two stages, the first stage may be performed at a lower temperature than the second stage. In this case, the first stage may be performed at a temperature of 150° C. to 300° C., specifically 200° C. to 250° C., and the second stage may be performed at a temperature of 300° C. to 500° C., specifically 350° C. to 400° C., but is not limited thereto.

The first hydrogenation treatment according to one embodiment of the present disclosure may be performed at a fluid space velocity (LHSV) of 0.1 to 5 h ^-1 . When the LHSV satisfies the above range, there is an effect of more stably obtaining refined oil from which impurities such as chlorine, nitrogen, or metals are removed. Specifically, it may be performed at an LHSV of 0.3 to 3 h ^-1 , more specifically, 0.5 to 1.5 h ^-1 .

A method for purifying waste plastic pyrolysis oil according to one embodiment of the present disclosure may further include, after step S2), a step of washing a stream containing purified oil from which impurities have been removed after gas-liquid separation.

The stream containing the refined oil from which the impurities have been removed according to one embodiment of the present disclosure may include the refined oil from which the impurities have been removed, discharged from the rear end of the reactor where the step S2) is performed, as well as hydrogen chloride, ammonia, and unreacted hydrogen gas.

According to one embodiment of the present disclosure, ammonia and hydrogen chloride generated by hydrogenation can be removed from a stream containing refined oil from which impurities have been removed through the gas-liquid separation, and unreacted hydrogen gas can be recovered.

The gas-liquid separation according to one embodiment of the present disclosure can be performed using a separator by a method known in the art and is not particularly limited.

According to one embodiment of the present disclosure, the gas-liquid separation may be performed 2 to 4 times, specifically 3 to 4 times, and more specifically 4 times. When the above range is satisfied, since the refined oil contains trace amounts of NH ₃ and HCl, the generation of ammonium salts may be minimized even under low-temperature conditions for oil-water separation. In addition, without adding a separate salt remover to the refined oil in the future, an oil refining process using this as a raw material may be stably performed.

The gas stream generated as a result of the gas-liquid separation according to one embodiment of the present disclosure may include off-gas including light hydrocarbons, hydrogen sulfide, ammonia, or hydrogen chloride, and unreacted hydrogen gas. The off-gas and unreacted hydrogen gas are separated according to a method known in the art, and the unreacted hydrogen gas is recycled within the process, and the off-gas is treated through the steps described below and can be used as fuel or discharged into the atmosphere.

According to one embodiment of the present disclosure, the washing may be performed to dissolve and remove salts contained in the gas stream, or to dissolve gases capable of forming salts, thereby inhibiting salt formation. The washing may be performed by a method known in the art, and is not particularly limited.

The washing according to one embodiment of the present disclosure may be performed 2 to 4 times, specifically 2 to 3 times. When the above range is satisfied, the salt removal and salt formation inhibition effects are sufficiently exerted, so that high-quality refined oil can be obtained, and the stability of the process can be secured.

A method for purifying waste plastic pyrolysis oil according to one embodiment of the present disclosure may further include, after the step of separating a stream containing the purified oil from which the impurities have been removed and then washing it, the step of combusting the separated off-gas; and the step of treating the uncombusted off-gas.

According to one embodiment of the present disclosure, the waste gas may include light hydrocarbons of C1-C4, hydrogen sulfide (H ₂ S), ammonia (NH ₃ ), etc. Therefore, in order to use the waste gas as fuel, it is necessary to remove hydrogen sulfide (H ₂ S), ammonia (NH ₃ ), etc. The exhaust gas containing sulfur dioxide (SO ₂ ), nitrogen dioxide (NO ₂ ), etc. generated by the combustion of the waste gas may be discharged into the atmosphere after performing caustic scrubbing to meet emission standards.

In addition, after the step of combusting the waste gas, the uncombusted waste gas can be discharged as waste water after being treated by sour water stripping, adsorption, biological treatment, oxidation, amine scrubbing, or caustic scrubbing.

Next, step S3) is a step of second hydrogenation treatment of the refined oil from which the above impurities have been removed.

The contents described in the first hydrogenation treatment above can be equally applied to the second hydrogenation treatment to the overlapping extent.

The second hydrogenation treatment according to one embodiment of the present disclosure means a hydrogenation reaction that occurs by adding a reaction gas containing hydrogen gas (H ₂ ) to the refined oil from which impurities have been removed in the step S2) under a molybdenum-based hydrogenation catalyst.

The molybdenum-based hydrogenation catalyst according to one embodiment of the present disclosure may be a catalyst in which a molybdenum-based metal or a metal including one or more selected from nickel, cobalt, and tungsten and the molybdenum-based metal are supported on a support. The molybdenum-based hydrogenation catalyst has high catalytic activity during hydrogenation treatment, and may be used alone or, if necessary, in the form of a binary system catalyst combined with a metal such as nickel, cobalt, or tungsten.

According to one embodiment of the present disclosure, the support may be, but is not limited to, alumina, silica, silica-alumina, titanium oxide, molecular sieve, zirconia, aluminum phosphate, carbon, niobia or a mixture thereof.

The molybdenum-based hydrogenation catalyst according to one embodiment of the present disclosure may include a molybdenum-based sulfide hydrogenation catalyst. For example, it may include molybdenum sulfide (MoS) or molybdenum disulfide (MoS ₂ ), but is not limited thereto, and may include a known molybdenum-based sulfide hydrogenation catalyst.

The reaction gas according to one embodiment of the present disclosure may further include hydrogen sulfide gas (H ₂ S). The hydrogen sulfide gas (H ₂ S) included in the reaction gas may act as a sulfur source and regenerate the activity of a molybdenum-based hydrogenation catalyst that has been deactivated during a purification process, such as a sulfur source mixed with waste plastic pyrolysis oil.

The second hydrogenation treatment according to one embodiment of the present disclosure may be performed at a pressure of 200 bar or less. Specifically, it may be performed at a pressure of 150 bar or less, more specifically, 120 bar or less, and, without limitation, it may be performed at a pressure of 10 bar or more.

The second hydrogenation treatment according to one embodiment of the present disclosure may be performed at a temperature of 150° C. to 500° C. Specifically, it may be performed at a temperature of 200° C. to 400° C., but is not limited thereto.

The second hydrogenation treatment according to one embodiment of the present disclosure may be performed at a fluid space velocity (LHSV) of 0.1 to 5 h ^-1 . Specifically, it may be performed at an LHSV of 0.3 to 3 h ^-1 , more specifically, 0.5 to 1.5 h ^-1 , but is not necessarily limited thereto.

According to one embodiment of the present disclosure, the step S3) may be a second hydrogenation treatment of the purified oil fraction separated by distillation from the refined oil from which impurities have been removed in the step S2). According to one embodiment of the present disclosure, the purified oil fraction may be naphtha, kerosene, light gas oil, vacuum gas oil (VGO), or residue, but is not limited thereto.

According to one embodiment of the present disclosure, the step S3) may be a second hydrogenation treatment of a mixed oil mixture in which refined oil from which impurities have been removed in the step S2) and petroleum-based hydrocarbons are mixed. In addition, it goes without saying that the mixed oil mixture in which the refined oil fraction and petroleum-based hydrocarbons are mixed may be subjected to a second hydrogenation treatment.

The above petroleum hydrocarbons are a general term for a mixture of naturally occurring hydrocarbons or a compound separated from the mixture, and specifically, may be any one or a mixture of two or more selected from the group consisting of naphtha, kerosene, light gas oil, vacuum gas oil (VGO), and residue derived from crude oil, but are not limited thereto.

In the past, when hydrogenation was performed using only petroleum hydrocarbons as feedstock, the hydrogenation catalyst was quickly deactivated due to impurities such as high sulfur (S) and nitrogen (N), so the hydrogenation efficiency did not last long. However, this problem can be solved by including refined oil from which impurities have been removed.

According to one embodiment of the present disclosure, the mixed oil may contain refined oil from which impurities have been removed in the step S2) in an amount of 5 wt% or more, 10 wt% or more, 20 wt% or more, 40 wt% or more, or 50 wt% or more, relative to the total weight of the mixed oil, and may have an upper limit of, but not limited to, 95 wt% or less. Although the present disclosure is not necessarily limited to the above range, generally, the lower the impurity content in the refined oil, the higher the proportion of refined oil that can be included in the mixed oil.

In addition, the present disclosure provides a system for producing refined hydrocarbons from waste plastic pyrolysis oil, including a dehydrator that performs dehydration by applying voltage to a first mixture containing waste plastic pyrolysis oil, wash water, and a demulsifier; a first hydrogenation reactor into which the first mixture dehydrated in the dehydrator and hydrogen gas are introduced and refined oil from which impurities are removed is generated by hydrogenation treatment under a hydrogenation treatment catalyst; and a second hydrogenation reactor that performs a second hydrogenation treatment on the refined oil subjected to the first hydrogenation treatment.

The description of the method for producing refined hydrocarbons from waste plastic pyrolysis oil can be equally applied to the description of the system for producing refined hydrocarbons from waste plastic pyrolysis oil within the overlapping scope.

The dehydrator according to one embodiment of the present disclosure may be equipped with vertical electrodes. The number of vertical electrodes equipped in the dehydrator according to one embodiment of the present disclosure may be at least 2 or more, specifically 4 or more, more specifically 6 or more, and may be 20 or less as an upper limit, but is not necessarily limited thereto.

The dehydrator according to one embodiment of the present disclosure may include a coalescer therein. The coalescer is a device that collects fine droplets to form large droplets, and a device commonly used in the industry can be used, and is not particularly limited.

According to one embodiment of the present disclosure, the first mixture dehydrated in the dehydrator may be introduced into the coagulator to produce a first mixture that has been further dehydrated. When a dehydrator including the coagulator is used, it goes without saying that the first mixture that has been further dehydrated is introduced into the first hydrogenation treatment reactor together with hydrogen gas.

The system for producing refined hydrocarbons from the waste plastic pyrolysis oil according to one embodiment of the present disclosure may further include a separator for gas-liquid separation of refined oil from which impurities have been removed, generated from the hydrogenation treatment reactor.

The number of the separators according to one embodiment of the present disclosure may be 2 to 4, specifically 3 to 4, and more specifically 4. When the above range is satisfied, since the refined oil contains trace amounts of NH ₃ and HCl, the generation of ammonium salts can be minimized even under low-temperature conditions for oil-water separation. In addition, a process using the refined oil as a raw material can be stably performed without adding a separate salt remover to the refined oil in the future.

The system for producing refined hydrocarbons from the waste plastic pyrolysis oil according to one embodiment of the present disclosure may further include a recycle gas compressor for recovering unreacted hydrogen gas from the gas stream separated from the separator and feeding it into a hydrogenation reactor.

Hereinafter, the method and system for producing refined hydrocarbons from waste plastic pyrolysis oil according to the present disclosure will be described in more detail through examples. However, the following examples are only one reference for describing the present disclosure in detail, and the present disclosure is not limited thereto, and may be implemented in various forms. In addition, unless otherwise defined, all technical terms and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In addition, the terminology used in the description of this disclosure is only for the purpose of effectively describing specific embodiments, and is not intended to limit the present disclosure.

[Example 1]

Under the conditions of 150 ℃ and 10 bar, waste plastic pyrolysis oil, washing water, and polyethylene glycol having a weight average molecular weight of 500 were introduced into a dehydrator in a volume ratio of 1:0.25:0.0001 and stirred to prepare a first mixture. The first mixture was separated into oil and water by applying an AC voltage of 15 kV through a vertical electrode, and then the water layer was removed to perform dehydration.

At this time, the waste plastic pyrolysis oil had a moisture content of about 5,000 ppm or more and contained high concentrations of impurities such as nitrogen (N) of 500 ppm or more, chlorine (Cl) of 200 ppm or more, and olefin of 20 volume% or more.

A second mixture was prepared by mixing 0.04 parts by weight of dimethyl disulfide with 100 parts by weight of the first mixture dehydrated in the above dehydrator, and then subjected to a first hydrogenation treatment under conditions of 300°C and 70 bar to produce refined oil from which impurities were removed.

A mixed oil, in which the refined oil from which the above impurities were removed and the light gas oil derived from crude oil and having a boiling point of 230 to 380°C were mixed in a weight ratio of 9:1, was subjected to a second hydrogenation treatment under the conditions of 350°C and 60 bar to obtain refined hydrocarbons.

[Examples 2 and 3]

In Example 1, the same conditions as in Example 1 were performed, except that waste plastic pyrolysis oil, washing water, and polyethylene glycol were added to the dehydrator in the volume ratios shown in Table 1 below, to obtain purified hydrocarbons.

[Example 4]

A purified hydrocarbon was obtained by performing the same process as in Example 1 except that a direct current voltage was applied through a horizontal electrode.

[Example 5]

In Example 1, dehydration of the first mixture was performed under the same conditions as in Example 1, except that it was performed at a temperature of 120°C, to obtain a purified hydrocarbon.

[Example 6]

In Example 5, waste plastic pyrolysis oil and polyethylene glycol were introduced in a volume ratio of 1:0.00001, and the first hydrogenation treatment was performed under the same conditions as Example 1, except that the pressure was 180 bar, to obtain a purified hydrocarbon.

[Example 7]

In Example 1, the same conditions as in Example 1 were performed, except that additional dehydration was performed through a coagulant after dehydration of the first mixture, to obtain a purified hydrocarbon.

[Comparative Example 1]

A purified hydrocarbon was obtained by performing the process under the same conditions as in Example 1, except that no washing water was added.

[Comparative Example 2]

A purified hydrocarbon was obtained by performing the same process as in Example 1 except that polyethylene glycol was not added.

[Comparative Example 3]

A purified hydrocarbon was obtained by performing the same process as in Example 1 except that no voltage was applied.

[Comparative Example 4]

A purified hydrocarbon was obtained under the same conditions as in Example 1, except that dimethyl disulfide was not mixed into the dehydrated first mixture in Example 1.

Evaluation example

measurement method

The moisture and chlorine contents in the mixture obtained after the dehydration process and the chlorine content in the refined oil from which impurities were removed were measured and displayed using ICP and XRF analysis methods.

The catalytic activity retention time was measured in hours based on the point at which the nitrogen content in the refined oil exceeded 10 ppm through Total Nitrogen & Sulfur (TNS element) analysis on refined oil.

In addition, the purification process of the above examples and comparative examples was operated for 3 months, and the particle fixation rate was measured according to Equation 1 below.

[Formula 1]

Particle fixation rate (%) = (amount of impurity particles fixed on the electrode/amount of impurity particles in the pyrolysis oil)*100

The above measurement results are shown in Table 1 below.

As shown in Table 1 above, Comparative Examples 1 to 3 showed poor moisture and Cl removal results as a result of changing the presence or absence of washing water, presence or absence of demulsifier, and presence or absence of voltage application in the dehydration step, respectively, from the Examples. As the waste plastic pyrolysis oil containing many impurities was hydrogenated, the Cl content in the refined oil was high, and the hydrogenation catalyst was deactivated relatively quickly. Although in Comparative Example 4, the moisture and some impurities in the waste plastic pyrolysis oil were sufficiently removed in the dehydration step, the hydrogenation catalyst was deactivated in a short period of time due to the insufficient sulfur content, and if the refining process was maintained for a long period of time, the Cl content in the refined oil was high, as in the other Comparative Examples. Cl included in a large amount in the refined oil can be toxic to the catalyst used in the second hydrogenation step and can cause the problem of corroding the second hydrogenation treatment reactor, so it can be expected that the content of refined oil in the mixed oil subjected to the second hydrogenation treatment cannot but be limited.

However, in Examples 1 to 7 according to the method for producing refined hydrocarbons from waste plastic pyrolysis oil of the present disclosure, a significant amount of moisture contained in the waste plastic pyrolysis oil was removed through the dehydration step, and a sulfur source was added, thereby significantly prolonging the activity of the hydrogenation catalyst. In addition, since some water-soluble impurities were preemptively removed in the dehydration step and the excellent activity of the catalyst was prolonging for a long period of time, it was possible to obtain high-quality refined hydrocarbons with a very low impurity content.

Meanwhile, when an AC voltage was applied using a vertical electrode, it was confirmed that the rate of fixation of impurity particles derived from char in the pyrolysis oil on the electrode surface was very low even after the process was conducted for more than 3 months. Through this, it was found that applying an AC voltage or using a vertical electrode can exhibit better process efficiency because there is no need to stop the process for cleaning the inside of the reactor.

In addition, in the case of Example 6, although the dehydration result was poor compared to other examples, the Cl content of impurities in the purified hydrocarbon was very low because the first hydrogenation treatment was performed under high pressure conditions. However, it was confirmed that a relatively large amount of ammonium salts were generated even at the temperature at which the first hydrogenation treatment was performed because ammonia and hydrogen chloride were generated in excess due to the high pressure.

In Example 7, as additional dehydration was performed using a coagulant, the moisture and chlorine contents after dehydration were lower than in other examples. Therefore, it can be expected that the activation time of the catalyst, process stability, and quality of purified hydrocarbons are relatively better than in other examples.

While the exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited thereto, and those skilled in the art will understand that various changes and modifications can be made thereto without departing from the concept and scope of the claims set forth below.

Claims (20)

S1) A step of dehydrating by applying voltage to a first mixture containing waste plastic pyrolysis oil, washing water, and a demulsifier;
S2) a step of producing refined oil from which impurities have been removed by first hydrogenation of the first mixture obtained by dehydrating in step S1) and the second mixture obtained by mixing the sulfur source; and
S3) A step of performing a second hydrogenation treatment on the refined oil from which the above impurities have been removed;
A method for producing purified hydrocarbons from waste plastic pyrolysis oil, comprising:
In the first paragraph,
In the above step S1),
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the waste plastic pyrolysis oil is mixed in a larger volume than the wash water.
In the second paragraph,
In the above step S1),
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the first mixture is a mixture of waste plastic pyrolysis oil and washing water in a volume ratio of 1:0.001 to 0.5.
In the first paragraph,
In the above step S1),
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the first mixture is a mixture of waste plastic pyrolysis oil and a demulsifier in a volume ratio of 1:0.000001 to 0.001.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the voltage is applied as an alternating current or a combination of alternating current and direct current.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the above voltage is applied through a vertical electrode.
In the first paragraph,
In the above step S1),
A step of removing a rag layer from the first mixture after applying the voltage;
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, which further comprises:
In the first paragraph,
A method for producing purified hydrocarbon from waste plastic pyrolysis oil, wherein the step S1) is performed at a temperature of 20°C to 300°C.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the ratio of the moisture content of the waste plastic pyrolysis oil and the moisture content of the first mixture dehydrated in step S1) is 1:0.0001 to 0.9.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the step S1) comprises further dehydrating the dehydrated first mixture by coagulating moisture.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the second mixture has a weight ratio of nitrogen to chlorine of 1:1 to 10.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the sulfur source includes a sulfur-containing oil component.
In Article 12,
A method for refining waste plastic pyrolysis oil, wherein the sulfur-containing oil is contained in an amount of less than 0.5 parts by weight based on 100 parts by weight of the first mixture dehydrated in step S1).
In the first paragraph,
A method for producing refined hydrocarbon from waste plastic pyrolysis oil, wherein the sulfur source comprises one or more sulfur-containing organic compounds selected from disulfide compounds, sulfide compounds, sulfonate compounds, and sulfate compounds.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the first hydrogenation treatment is performed in the presence of a molybdenum-based hydrogenation catalyst.
In Article 15,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the above molybdenum-based hydrogenation catalyst is a catalyst in which a molybdenum-based metal or a metal including one or more selected from nickel, cobalt and tungsten and the molybdenum-based metal are supported on a support.
In Article 15,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the above molybdenum-based hydrogenation catalyst comprises a molybdenum-based sulfide hydrogenation catalyst.
In the first paragraph,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, wherein the first hydrogenation treatment is performed under pressure conditions of 50 bar to 150 bar.
In the first paragraph,
After the above step S2),
A step of washing a stream containing refined oil from which the above impurities have been removed after gas-liquid separation;
A method for producing purified hydrocarbons from waste plastic pyrolysis oil, further comprising:
In the first paragraph,
The above step S3) is,
A method for producing refined hydrocarbons from waste plastic pyrolysis oil, comprising second hydrogenation of a mixed oil in which refined oil from which impurities have been removed and petroleum hydrocarbons are mixed in the above step S2).