KR20230146210A - Method of treating pyrolysis oil from waste plastics - Google Patents

Abstract

The present disclosure includes a first step of removing moisture after washing waste plastic pyrolysis oil; A second step of producing a mixed oil by mixing the waste plastic pyrolysis oil from which the water has been removed and a sulfur source; A third step of hydrogenating the mixed fraction with hydrogen gas under a hydrogenation catalyst; A fourth step of separating the hydrogenated mixed fraction into a liquid stream and a gas stream to obtain liquid pyrolysis oil; a fifth step of recovering hydrogen gas from the separated gas stream and resupplying it to the third step; It provides a method of processing waste plastic pyrolysis oil, including.

Description

{Method of treating pyrolysis oil from waste plastics}

The present disclosure relates to a method for processing waste plastic pyrolysis oil.

Waste plastic is manufactured using petroleum as a raw material, has a low recyclability rate, and is mostly disposed of as waste. Since these wastes take a long time to decompose in nature, they contaminate the soil and cause serious environmental pollution. As a method for recycling waste plastic, waste plastic can be pyrolyzed and converted into usable oil, which is called waste plastic pyrolysis oil.

However, pyrolysis oil obtained by pyrolyzing waste plastic has a higher content of impurities such as chlorine, nitrogen, and metals compared to oil produced from crude oil by general methods, so it cannot be directly used as high-value fuel such as gasoline and diesel oil.

Purification processes such as hydrogenation are being carried out to remove impurities, but waste plastic pyrolysis oil contains water, chlorine, and nitrogen, so problems such as equipment corrosion, reduced catalyst activity, and deterioration of product properties occur during hydrogenation. In addition, ammonia and hydrogen chloride generated during hydrogenation react to produce ammonium chloride salt (NH ₄ Cl), which not only reduces durability by causing corrosion at the rear end of the reactor, but also causes many process problems such as lowering process efficiency due to differential pressure. It causes problems. In addition, waste plastic pyrolysis oil has a high content of impurities such as metals, which affects the catalyst in the hydrogenation process. As a result, the activity of the catalyst rapidly decreases, making it impossible to carry out the process stably for a long period of time.

Therefore, there is a need for a processing process for waste plastic pyrolysis oil that can obtain high-quality, high-value fuel with minimized impurities stably over a long period of time without process trouble issues from waste plastic pyrolysis oil raw materials containing impurities such as moisture.

The purpose of the present disclosure is to provide a method for treating waste plastic pyrolysis oil that can be operated stably for a long period of time without reducing the activity of the hydrogenation catalyst.

Another object of the present disclosure is to provide a method of treating waste plastic pyrolysis oil that can be operated stably for a long period of time by suppressing or minimizing the production of ammonium chloride salt (NH ₄ Cl) throughout the treatment process of waste plastic pyrolysis oil.

Another object of the present disclosure is to provide a method for processing waste plastic pyrolysis oil that can yield high-quality, high-value fuel with significantly reduced impurity content such as chlorine, nitrogen, oxygen, and metal.

The present disclosure includes a first step of removing moisture after washing waste plastic pyrolysis oil; A second step of producing a mixed oil by mixing the waste plastic pyrolysis oil from which the water has been removed and a sulfur source; A third step of hydrogenating the mixed fraction with hydrogen gas under a hydrogenation catalyst; A fourth step of separating the hydrogenated mixed fraction into a liquid stream and a gas stream to obtain liquid pyrolysis oil; a fifth step of recovering hydrogen gas from the separated gas stream and resupplying it to the third step; It provides a method of processing waste plastic pyrolysis oil, including.

In one embodiment, the waste plastic pyrolysis oil that has undergone the first step may contain 300 to 2,000 ppm of moisture.

In one embodiment, the sulfur source in the second step may include sulfur-containing oil.

In one embodiment, in the second step, the sulfur source may be included in less than 50 parts by weight based on 100 parts by weight of waste plastic pyrolysis oil.

In one embodiment, in the second step, the mixed oil may contain 100 ppm or more of sulfur.

In one embodiment, the third step includes a 3-1 step of hydrogenating the mixed fraction at a first temperature under a hydrogenation catalyst to produce a fluid from which chlorine has been removed; Step 3-2 of producing refined oil from which impurities have been removed by hydrogenating the fluid at a second temperature higher than the first temperature under a hydrogenation catalyst; may include.

In one embodiment, the first temperature may be greater than 100°C and less than 400°C, and the second temperature may be greater than 300°C and less than 450°C.

In one embodiment, the reaction pressure during the hydrogenation treatment in steps 3-1 and 3-2 may be greater than 10 bar and less than 200 bar.

In one embodiment, the ratio of liquid hourly space velocity (LHSV) during the hydrogenation treatment in steps 3-1 and 3-2 may be 1:0.1 to 1:2.0.

In one embodiment, the fourth step may be to introduce the hydrogenated mixed oil into a high-temperature and high-pressure separator to separate it into a liquid stream and a gas stream.

In one embodiment, the gas stream separated in the high-temperature, high-pressure separator may be sequentially introduced into the low-temperature, high-pressure separator and the low-temperature, low-pressure separator, and the liquid stream separated in the high-temperature, high-pressure separator may be introduced into the high-temperature, low-pressure separator.

In one embodiment, salt production can be suppressed by washing the gas stream separated in the high temperature and high pressure separator with water.

In one embodiment, the method may further include fractional distillation of the liquid pyrolysis oil separated in the fourth step, and salt formation may be suppressed using a salt remover in the fractional distillation step.

In one embodiment, the fifth step may be to purify the recovered hydrogen gas to remove impurities and then re-supply it to the third step.

The method for treating waste plastic pyrolysis oil according to the present disclosure has the effect of enabling stable operation for a long period of time without reducing the activity of the hydrogenation catalyst.

The method for treating waste plastic pyrolysis oil according to the present disclosure is effective in enabling long-term stable operation by suppressing or minimizing the production of ammonium chloride salt (NH ₄ Cl) throughout the process.

The method of treating waste plastic pyrolysis oil according to the present disclosure can obtain high-quality, high-value fuel with significantly reduced impurity content such as chlorine, nitrogen, oxygen, and metal.

The method for treating waste plastic pyrolysis oil according to the present disclosure can improve economic efficiency by recovering and reusing hydrogen gas from separated waste gas.

The singular form of the terms used in this specification may be interpreted to also include the plural form unless otherwise specified.

As used herein, numerical ranges include lower and upper limits and all values within that range, all doubly defined values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specified herein, values outside the numerical range that may occur due to experimental error or rounding of values are also included in the defined numerical range.

'Include' mentioned in this specification is an open description that has the same meaning as expressions such as 'comprises', 'contains', 'has', 'characterized by', etc., and includes elements that are not additionally listed, Does not exclude materials or processes.

The unit of % used without special mention in this specification means weight% unless otherwise defined.

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

The present disclosure includes a first step of removing moisture after washing waste plastic pyrolysis oil; A second step of producing a mixed oil by mixing the waste plastic pyrolysis oil from which the water has been removed and a sulfur source; A third step of hydrogenating the mixed fraction with hydrogen gas under a hydrogenation catalyst; A fourth step of separating the hydrogenated mixed fraction into a liquid stream and a gas stream to obtain liquid pyrolysis oil; a fifth step of recovering hydrogen gas from the separated gas stream and resupplying it to the third step; It provides a method of processing waste plastic pyrolysis oil, including. Through this, high-quality, high-value fuel with minimal impurities can be obtained from waste plastic pyrolysis oil raw materials stably for a long period of time without process trouble issues.

The waste plastic pyrolysis oil may be a hydrocarbon oil mixture produced by high temperature pyrolysis of waste plastic. At this time, 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 waste plastic may be household waste plastic, industrial waste plastic, or agricultural waste plastic.

The waste plastic pyrolysis oil may contain impurities such as chlorine compounds, nitrogen compounds, and metal compounds in addition to hydrocarbon oil, and may contain excessive moisture. The chlorine compound may include both organic chlorine and inorganic chlorine.

The content of chlorine compounds contained in the waste plastic pyrolysis oil may be 50 ppm or more, specifically 300 ppm or more. The upper limit of the chlorine compound content is not particularly limited, but may be, for example, 3,000 ppm or less, specifically 1,500 ppm or less.

The waste plastic pyrolysis oil may contain excessive moisture. Since waste plastics are usually collected or disposed of while still containing moisture, pyrolysis oil generated from the waste plastics contains excessive moisture. The moisture content contained in waste plastic pyrolysis oil may be 300 ppm or more, specifically 500 ppm or more. The upper limit of the moisture content is not particularly limited, but may be, for example, 3000 ppm or less.

As a specific example, the waste plastic pyrolysis oil may contain more than 500 ppm of nitrogen, 100 ppm of chlorine, and more than 2,000 ppm of moisture, more than 20% by volume of olefin (based on 1 atm, 25°C), and conjugated diolefin ( Conjugated diolefin) may contain more than 1% by volume (based on 1 atm, 25°C), but the content of the above impurities is only a specific example of what may be included in waste plastic pyrolysis oil and the composition of waste plastic pyrolysis oil is not limited to this.

Excessive moisture and impurities such as chlorine and nitrogen contained in the waste plastic pyrolysis oil may cause deactivation of catalysts in the hydrogenation reaction process or cause problems such as equipment corrosion. Accordingly, the first step of removing moisture after washing the waste plastic pyrolysis oil with water is performed to simultaneously remove impurities and moisture contained in the pyrolysis oil, thereby improving process stability and the quality of refined oil.

In detail, the first step is to supply washing water to the waste plastic pyrolysis oil, wash it with water, and discharge an aqueous solution containing chlorine and nitrogen to remove impurities including chlorine in the waste plastic pyrolysis oil. Residual moisture in waste plastic pyrolysis oil can be removed by performing a dry dehydration process such as hot air drying, or by oil-water separation, centrifugation, or distillation methods.

The first step may be performed at 30 to 250°C and 2 to 50 bar. It can be performed in an inert atmosphere, for example, a nitrogen atmosphere, and when the water treatment process is performed under these conditions, the impurity removal efficiency can be improved.

In one embodiment, the waste plastic pyrolysis oil that has undergone the first step may contain 300 to 2,000 ppm of moisture. Through the first step, the moisture present in waste plastic pyrolysis oil can be effectively reduced.

In the second step, by mixing the waste plastic pyrolysis oil and the sulfur source to produce a mixed fraction, deactivation of the hydrogenation catalyst due to lack of sulfur source and high temperature operation during the reaction and separation purification process can be suppressed and catalyst activity maintained. . The sulfur source refers to a sulfur source that can continuously supply sulfur components during the refining process.

Here, the hydrogenation catalyst may refer to a commonly used hydrogenation catalyst, but may refer to a molybdenum-based hydrogenation catalyst, specifically a molybdenum-based sulfide hydrogenation catalyst, in terms of improving catalytic activity by a sulfur source, as will be described later.

In one embodiment, the sulfur source may include a sulfur-containing fraction. The sulfur-containing fraction refers to a fraction composed of hydrocarbons containing sulfur obtained from crude oil as a raw material. There are no particular restrictions as long as it is an oil containing sulfur. For example, light gas oil, direct current naphtha, vacuum naphtha, pyrolysis naphtha, direct current kerosene, vacuum kerosene, pyrolysis kerosene, direct current diesel oil, vacuum diesel oil, thermal cracking diesel oil, sulfur-containing waste tire oil, etc. or any mixture thereof.

In one embodiment, the sulfur-containing oil may be included in less than 50 parts by weight based on 100 parts by weight of waste plastic pyrolysis oil. Specifically, sulfur-containing oil may be included in less than 40 parts by weight.

The sulfur source may include sulfur-containing organic compounds instead of or in addition to sulfur-containing distillates. Specifically, the sulfur-containing organic compound may be one or two or more compounds selected from disulfide-based compounds, sulfide-based compounds, sulfonate-based compounds, and sulfate-based compounds. Specifically, disulfide, dimethyldisulfide, dimethylsulfide, polysulfide, dimethyl sulfoxide (DMSO), methyl methanesulfonate, and ethyl methanesulfonate. , propyl methanesulfonate, propenyl propenesulfonate, propenyl cyanoethanesulfonate, ethylene sulfate, bicyclo glyoxal sulfate, and It may include one or a mixture of two or more selected from methyl sulfate, but this is only provided as an example and the present disclosure is not limited thereto. The sulfur-containing organic compound may be included in an amount of 0.001 to 50 parts by weight based on 100 parts by weight of waste plastic pyrolysis oil. If it is included in less than 0.01 parts by weight, the effect of preventing deactivation of the hydrogenation catalyst may be minimal due to the low content of the sulfur component supplied.

The third step of hydrogenating the mixed fraction with hydrogen gas under a hydrogenation catalyst refers to a hydrogenation reaction in which hydrogen gas is added to the hydrocarbon fraction contained in the mixed fraction. Specifically, hydrotreatment may refer to conventionally known hydrogenation treatments including hydrodesulfurization reaction, hydrocracking reaction, hydrodechlorination reaction, hydrodenitrification reaction, and hydrodemetallization reaction. Through the hydrogenation treatment, impurities including chlorine (Cl) and nitrogen (N), olefins, and other metal impurities can also be removed.

In one embodiment, the third step includes a 3-1 step of hydrogenating the mixed fraction at a first temperature under a hydrogenation catalyst to produce a fluid from which olefins have been removed; Step 3-2 of producing refined oil from which impurities have been removed by hydrogenating the fluid at a second temperature higher than the first temperature under a hydrogenation catalyst; may include.

The type of each component removed during hydrogenation can be determined by the reaction temperature. The hydrogenation treatment in step 3-1 is performed at a first temperature to mainly remove olefins, and the hydrogenation treatment in step 3-2 is performed at a second temperature higher than the first temperature to mainly remove chlorine and nitrogen. Impurities contained therein can be removed.

The hydrogenation treatment of step 3-1 and step 3-2 is performed sequentially, so that olefins are first removed in step 3-1, and then impurities including chlorine and nitrogen are removed in step 3-2. The production and accumulation of substances that cause differential pressure, such as oligomers, in the reactor can be minimized.

In one embodiment, the first temperature may be greater than 100°C and less than 400°C, and the second temperature may be greater than 300°C and less than 450°C. The difference between the first temperature and the second temperature may be 50 to 350°C, specifically 50 to 280°C, but this is only an example and the difference between the first temperature and the second temperature is not limited to this.

When hydrogenation is performed in the first temperature range, olefins can be intensively removed. Specifically, a hydrogenation reaction of waste plastic pyrolysis oil occurs under a hydrogenation catalyst, and most of the olefins from the waste plastic pyrolysis oil are saturated to produce paraffin. In addition, some impurities such as chlorine are removed from waste plastic pyrolysis oil, and other metal impurities are removed. The first temperature may be 100 to 400°C.

When hydrogenation is performed in the second temperature range, impurities including chlorine and nitrogen can be removed. If the temperature is below 300℃, impurities in waste plastic pyrolysis oil cannot be effectively removed, which reduces product quality. If the temperature is above 450℃, thermal cracking side reactions may occur excessively, causing problems such as coking and other catalyst deactivation. The second temperature is preferably 320 to 420°C in that catalytic activity can be maintained.

In one embodiment, the reaction pressure during the hydrogenation treatment in steps 3-1 and 3-2 may be greater than 10 bar and less than 200 bar. There is a problem that impurities including chlorine and nitrogen cannot be effectively removed under low pressure conditions of 10 bar or less, and there is a problem that the production of ammonium chloride salt (NH ₄ Cl) is promoted under high pressure conditions of 200 bar or more. Specifically, it may be 30 bar to 180 bar.

In one embodiment, the ratio of liquid hourly space velocity (LHSV) during the hydrogenation treatment in steps 3-1 and 3-2 may be 1:0.1 to 1:2.0. If this is satisfied, impurities can be effectively removed through the hydrogenation treatment in steps 3-1 and 3-2, the activity of the hydrogenation catalyst can be maintained at high activity for a long period of time, and process efficiency is improved.

As the hydrogenation catalyst, various known types can be used as long as it is a catalyst that allows a hydrogenation reaction in which hydrogen is added to the hydrocarbon fraction of waste plastic pyrolysis oil. As a specific example, the hydroprocessing catalyst may include one or two or more selected from hydrodesulfurization catalysts, hydrodenitrification catalysts, hydrodechlorination catalysts, and hydrodemetallization catalysts. This catalyst allows the demetalization reaction to be carried out and simultaneously the denitrification reaction or dechlorination reaction to be carried out according to the above-mentioned conditions such as temperature. Specifically, it may contain an active metal having the catalytic ability for hydrogenation treatment, and preferably, the active metal may be supported on a support. The active metal may be any one having the required catalytic activity, and may include, for example, one or more selected from molybdenum, nickel, etc. The support may be any material that is durable enough to support the active metal.

It may be advantageous for the hydrogenation catalyst to be a molybdenum-based hydrogenation catalyst, specifically a molybdenum-based sulfide hydrogenation catalyst, in terms of improving catalytic activity by the sulfur source. The molybdenum-based hydrogenation catalyst may be a catalyst in which the molybdenum-based metal, or a metal containing one or two 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 can be used alone or, if necessary, in the form of a binary catalyst combined with metals such as nickel, cobalt, and tungsten. Alumina, silica, silica-alumina, titanium oxide, molecular sieve, zirconia, aluminum phosphate, carbon, niobia, or mixtures thereof may be used as the support, but is not limited thereto. The molybdenum-based sulfide hydrogenation catalyst may include, for example, molybdenum sulfide (MoS) or molybdenum disulfide (MoS ₂ ), but is not limited thereto and may include known molybdenum-based sulfide hydrogenation catalysts.

Through the fourth step, the mixed oil hydrotreated in the third step can be separated into a liquid stream and a gas stream to obtain liquid pyrolysis oil.

In one embodiment, the hydrogenated mixed fraction may be introduced into a high-temperature, high-pressure separator and separated into a liquid stream and a gas stream. A liquid stream separated from the gas stream and impurities can be obtained from the mixed stream through a high-temperature and high-pressure separator. A cooling process may be performed before introducing the hydrogenated mixed oil into the high-temperature and high-pressure separator.

In one embodiment, the gas stream separated in the high-temperature, high-pressure separator may be sequentially introduced into the low-temperature, high-pressure separator and the low-temperature, low-pressure separator, and the liquid stream separated in the high-temperature, high-pressure separator may be introduced into the high-temperature, low-pressure separator.

The gas stream separated in the high-temperature, high-pressure separator can be sequentially introduced into the low-temperature, high-pressure separator and the low-temperature, low-pressure separator to finally exhaust and remove the gas. In this process, some of it can be liquefied again and recovered as a liquid stream. The liquid stream separated from the high-temperature and high-pressure separator can be introduced into the high-temperature and low-pressure separator to finally recover a high-quality liquid stream.

In one embodiment, salt production can be suppressed by washing the gas stream separated in the high temperature and high pressure separator with water. By washing the gas stream, the formation of ammonium chloride salt (NH ₄ Cl) by ammonia and hydrogen chloride can be prevented. The washing process can be performed at least twice.

The fifth step is a step of recovering hydrogen gas from the separated gas stream and resupplying it to the third step, wherein the gas stream contains unreacted hydrogen gas, a very small amount of methane (CH ₄ ) or ethane (C ₂ H ₆ ), etc., and in addition, hydrogen sulfide gas (H ₂ S) and hydrogen chloride (HCl) produced by the reaction of chlorine (Cl), nitrogen (N), sulfur (S) or oxygen (O) with hydrogen gas. , ammonia (NH ₃ ), or water vapor (H ₂ O). By recovering hydrogen gas from the gas stream and resupplying it to the third step, economic efficiency can be improved and reaction efficiency can be improved.

In one embodiment, the fifth step may purify the recovered hydrogen gas to remove impurities and then re-supply it to the third step. The recovered hydrogen gas may contain other impurities such as chlorine (Cl), nitrogen (N), hydrogen chloride (HCl), and ammonia (NH ₃ ). Accordingly, by performing a purification step, the purity of hydrogen gas can be improved to more than 90% and re-supplied in the third step. Purification can be performed by washing the hydrogen gas with water, and the washing process can be performed at least once.

In one embodiment, the method further includes fractional distillation of the liquid pyrolysis oil separated in the fourth step, and salt formation can be suppressed by using a salt remover in the fractional distillation step. Specifically, the liquid pyrolysis oil separated in the fourth step has minimal impurities and may contain less than 10 ppm of chlorine (Cl), less than 10 ppm of nitrogen (N), and less than 2,000 ppm of moisture. It may contain less than 3% by weight of olefins, and may contain less than 0.5% by weight of conjugated diolefins. The pyrolysis oil is introduced into the fractionator and fractional distillation is performed to ultimately recover a petroleum product with minimal impurities. Petroleum products can be recovered by boiling point, for example, Naphtha (bp ~150℃) 5~35% by weight, Kero (bp 150~265℃) 10~60% by weight, LGO (bp 265~380℃) 20~ It can be recovered at 40% by weight and AR (bp 380℃~) 5~40% by weight, but is not necessarily limited thereto. By using a salt remover in the fractional distillation step, the gas stream can be washed with water to prevent the formation of ammonium chloride salt (NH ₄ Cl) by ammonia and hydrogen chloride. The salt remover may be a known salt remover capable of suppressing the formation of ammonium chloride salt (NH ₄ Cl).

Hereinafter, the present invention will be described in detail through examples. However, these are intended to illustrate the present invention in more detail, and the scope of the present invention is not limited to the following examples.

Example 1

Waste plastic was pyrolyzed to prepare 1000g of waste plastic pyrolysis oil raw material. The waste plastic pyrolysis oil raw material contains 560ppm chlorine, 1080ppm nitrogen, and 2200ppm moisture.

The waste plastic pyrolysis oil was washed with 200 g of washing water. Afterwards, moisture was removed by hot air drying at 130°C and 5 bar, and only the oil was recovered.

A mixed fraction was prepared by mixing 100 parts by weight of the recovered pyrolysis oil fraction with 0.1 part by weight of the hydrocarbon fraction containing 20,000 ppm sulfur.

The prepared mixed fraction and hydrogen gas were put into the reactor and operated for hydrogenation treatment. The mixed fraction was hydrogenated with a reaction gas containing hydrogen gas (H ₂ ) at 350°C and 60 bar under a NiMo hydrogenation catalyst.

The hydrotreated mixed fraction was separated into a liquid stream and a gas stream. Specifically, the hydrogenated mixed fraction was put into a high-temperature, high-pressure separator, separated into a liquid stream and a gas stream, and the liquid stream was recovered to obtain refined oil with minimized impurities. In addition, hydrogen gas was recovered from the separated gas stream and re-supplied to the hydrogenation reactor for use.

Comparative Example 1

In Example 1, the waste plastic pyrolysis oil raw material was directly put into the reactor and hydrogenation treatment was performed. That is, the reaction was performed under the same conditions as in Example 1, except that the water washing and moisture removal processes and the mixing process with the sulfur-containing hydrocarbon fraction were omitted.

Evaluation example

The chlorine (Cl) content (ppm) in the finally obtained refined oil was measured and expressed using IC analysis.

The catalytic activity maintenance time was measured and expressed in days based on the time when the nitrogen content in the refined oil exceeded 10ppm by conducting Total Nitrogen & Sulfur (TNS element) analysis on the refined oil.

Example 1 confirmed that by performing the waste plastic pyrolysis oil treatment method of the present disclosure, the chlorine content in the finally obtained waste plastic pyrolysis oil was removed to several ppm or less and that high-quality refined oil with minimized impurities could be obtained. You can. In addition, it can be confirmed that the catalyst activity is maintained continuously for more than 18 days.

On the other hand, in the case of Comparative Example 1, as the water washing and moisture removal process and the mixing process with sulfur-containing hydrocarbon oil were omitted, it was confirmed that the chlorine content in the pyrolysis oil was greatly reduced to 320 ppm and the catalyst activity retention time was reduced to 4 days or less. there is.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be implemented in various different forms, and those skilled in the art will understand the technical idea of the present invention. It will be understood that it can be implemented in other specific forms without changing the essential features. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive.

Claims (14)

A first step of removing moisture after washing the waste plastic pyrolysis oil with water;
A second step of producing a mixed oil by mixing the waste plastic pyrolysis oil from which the water has been removed and a sulfur source;
A third step of hydrogenating the mixed fraction with hydrogen gas under a hydrogenation catalyst;
A fourth step of separating the hydrogenated mixed fraction into a liquid stream and a gas stream to obtain liquid pyrolysis oil;
a fifth step of recovering hydrogen gas from the separated gas stream and resupplying it to the third step; Including,
Method for processing waste plastic pyrolysis oil. According to paragraph 1,
A method of treating waste plastic pyrolysis oil, wherein the waste plastic pyrolysis oil that has passed the first step contains 300 to 2,000 ppm of moisture. According to paragraph 1,
A method of treating waste plastic pyrolysis oil, wherein the sulfur source in the second step includes sulfur-containing oil. According to paragraph 1,
In the second step, the sulfur source is included in less than 50 parts by weight based on 100 parts by weight of waste plastic pyrolysis oil. In paragraph 1
In the second step, the mixed oil contains 100 ppm or more of sulfur. According to paragraph 1,
The third step includes a 3-1 step of hydrogenating the mixed fraction at a first temperature under a hydrogenation catalyst to produce a fluid from which chlorine has been removed; Step 3-2 of producing refined oil from which impurities have been removed by hydrogenating the fluid at a second temperature higher than the first temperature under a hydrogenation catalyst; Including, a method of processing waste plastic pyrolysis oil. According to clause 6,
The first temperature is greater than 100°C and less than 400°C, and the second temperature is greater than 300°C and less than 450°C. According to clause 6,
A method of treating waste plastic pyrolysis oil, wherein the reaction pressure during hydrogenation in steps 3-1 and 3-2 is more than 10 bar and less than 200 bar. According to clause 6,
A method of treating waste plastic pyrolysis oil, wherein the ratio of liquid hourly space velocity (LHSV) during the hydrogenation treatment in steps 3-1 and 3-2 is 1:0.1 to 1:2.0. According to paragraph 1,
The fourth step is to introduce the hydrogenated mixed oil into a high-temperature and high-pressure separator to separate it into a liquid stream and a gas stream. According to clause 10,
The gas stream separated in the high-temperature and high-pressure separator is sequentially introduced into the low-temperature and high-pressure separator and the low-temperature and low-pressure separator, and the liquid stream separated in the high-temperature and high-pressure separator is introduced into the high-temperature and low-pressure separator. According to clause 10,
A method of treating waste plastic pyrolysis oil, wherein salt production is suppressed by washing the gas stream separated in the high-temperature and high-pressure separator with water. According to paragraph 1,
A method of treating waste plastic pyrolysis oil, further comprising fractional distillation of the liquid pyrolysis oil separated in the fourth step, and suppressing salt production in the fractional distillation step using a salt remover. According to paragraph 1,
The fifth step is a method of treating waste plastic pyrolysis oil in which the recovered hydrogen gas is purified to remove impurities and then re-supplied to the third step.