How to process waste plastic

Abstract

A method for upgrading liquefied waste plastics (LWP) to a refined hydrocarbon mixture is provided according to the present invention, which comprises the steps of providing a feed comprising liquefied waste plastics (LWP) and a vacuum gas oil (VGO) stream and / or a heavy gas oil (HGO) stream to produce a blended stream, subjecting the blended stream to hydrotreating for removal of impurities and to produce a hydrotreated stream, subjecting the hydrotreated stream to hydrocracking to produce a hydrocracked stream comprising a refined hydrocarbon mixture, and fractionating the hydrocracked stream comprising a refined hydrocarbon mixture.

Description

[Technical Field]

[0001] The present invention relates to a method for upgrading waste or recycled plastics. In particular, the present invention relates to a method for producing a refined hydrocarbon mixture, wherein the hydrocarbon is particularly suitable as a base oil component. Thus, a method is provided in which a refined hydrocarbon mixture is produced from liquefied waste plastics (LWP) and vacuum gas oil (VGO) / heavy gas oil (HGO) feed. [Background technology]

[0002] Environmental concerns and the desire to limit the use of fossil-based feedstocks have created a need to develop the potential uses of waste plastics. Waste plastics are a growing environmental concern because many of the polymers that make up plastics are very stable and do not decompose in nature. Incineration of waste plastics increases greenhouse gas emissions and leads to other environmental problems in the form of air and land pollution. Incineration of waste plastics is considered a waste of valuable raw materials, even if energy is recovered in the form of heat.

[0003] Plastics and polymers are primarily composed of carbon, hydrogen, and heteroatoms such as oxygen and / or nitrogen. However, waste plastics also contain many impurities from other sources, such as metals and chlorine. There is growing interest in using waste plastics to produce various hydrocarbon components. While fuels are mixtures of hydrocarbons, producing liquid fuels from waste plastics is not generally considered useful. Direct incineration of waste plastics also produces energy, which can be recovered and used for heating and / or power generation. Therefore, there is a need to upgrade waste plastics to higher hydrocarbon components, which can be used to produce new plastics, chemicals, or other materials.

[0004] Base oils, used for lubrication and other purposes, are potentially hydrocarbon products from waste plastics. However, there are high requirements for the properties of the base oil, especially regarding viscosity and low-temperature fluidity. Based on their properties and potential applications, base oils are divided into different groups.

[0005] Patent Document 1 describes a method for producing an oil base component, which method includes supplying vacuum gas oil (VGO) and wax as minor components in a feed, subjecting the feed to hydrocracking, and further subjecting the bottom fraction to a dewaxing step to provide a base oil and a middle distillate.

[0006] A process for producing hydrocarbon oils from the pyrolysis of waste plastics is described in U.S. Patent No. 5,623,299. The disclosed process involves melting the waste plastics to remove chlorine and organics, and transferring the molten waste plastics to a heated screw pyrolysis reactor to form hydrocarbon gases that are condensed and form hydrocarbon oils.

[0007] Liquefied waste plastics (LWP) are a desirable recycled feedstock in various applications to replace the use of virgin petroleum feedstocks; however, LWP still contains impurities that limit the use of LWP-containing streams as feedstocks, and there is an increasing demand for base oil components with improved properties. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] European Patent No. 3081623 [Patent Document 2] U.S. Patent No. 10,246,643 Summary of the Invention

[0009] The object of the present invention is to provide a method and a refined hydrocarbon product for overcoming the above-mentioned problems. The object of the present invention is achieved by a method and an arrangement characterized in that it is set forth in the independent claims. Preferred embodiments of the invention are disclosed in the dependent claims.

[0010] It is therefore an object of the present invention to provide a method for upgrading liquefied waste plastics (LWP) into a mixture of refined hydrocarbons, the method comprising: providing a feed comprising liquefied waste plastics (LWP) and a vacuum gas oil (VGO) stream and / or a heavy gas oil (HGO) stream to generate a blended stream; subjecting said mixed stream to hydrotreating to remove impurities and to produce a hydrotreated stream; subjecting the hydrotreated stream to hydrocracking to produce a hydrocracked stream comprising a mixture of refined hydrocarbons; Fractionating the hydrocracked stream containing a mixture of refined hydrocarbons Includes:

[0011] A general advantage of the process of the present invention is that it allows waste plastics to be upgraded into valuable products. A further advantage of the process of the present invention is that it provides valuable hydrocarbons suitable for the production of base oil components and middle distillate fuel components.

[0012] In the following, the invention will be explained in more detail by means of preferred embodiments with reference to the accompanying drawings. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 shows a schematic diagram of a specific embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present invention relates to a method for producing a refined hydrocarbon mixture from a feed containing liquefied waste plastics (LWP) and vacuum gas oil (VGO) and / or heavy gas oil (HGO) streams. The term "liquefied waste plastic" refers to a liquid product produced from any waste plastic through a non-oxidative pyrolysis process. Typically, liquefied waste plastics are produced by the thermal decomposition of waste plastics. LWP is a mixture of hydrocarbonaceous organic components with a wide range of carbon chain lengths. The carbon chain length and chemical structure, and therefore the properties, of LWP vary depending on the type of plastic (polymer) used in its production and the liquefaction conditions. A typical waste plastic feedstock for a liquefaction process contains primarily polyethylene with varying amounts of polypropylene, polystyrene, and other minor components, such as polyamide, polyethylene terephthalate, and polyvinyl chloride.

[0015] In one embodiment of the present invention, liquefied waste plastics are obtained by pyrolyzing waste plastics and subsequently fractionating the pyrolyzed waste plastics, where the heavy bottom fraction of the fractionation constitutes the liquefied waste plastics feed for the process of the present invention. LWPs typically have a boiling point range of about 40°C to 550°C, which roughly corresponds to a carbon chain length of C5 to C55. Depending on the conversion technology, the final boiling point of LWPs can be as high as 750°C.

[0016] LWP are the products of thermal decomposition of various polymers and are complex mixtures of primarily paraffins, olefins, naphthenes, and aromatic hydrocarbons. The total amount of olefins is typically high, ranging from 40% to 60% by weight, while the amount of aromatic hydrocarbons is typically below 20% by weight. LWP also contains heteroatoms such as oxygen, nitrogen, chloride, and sulfur in the form of organic compounds with heteroatom substituents. The amount of heteroatoms varies depending on the polymer used to produce LWP. Water is typically removed from LWP products, but dissolved water may remain in LWP.

[0017] The liquefied waste plastics may be subjected to a pretreatment process before hydrotreating according to the present invention.

[0018] The feed subjected to hydrotreating also includes a vacuum gas oil (VGO) stream. The term "vacuum gas oil stream" or "VGO" stream, as used herein, refers to a heavy oil stream recovered as a distillate from a vacuum distillation unit of an oil refinery. In addition to, or as an alternative to, VGO, the feed subjected to hydrotreating can also include heavy gas oil (HGO), which has properties similar to VGO but is obtained from atmospheric crude oil distillation rather than vacuum distillation. Hereinafter, a stream containing VGO and / or HGO is referred to as a "VGO / HGO stream."

[0019] The VGO / HGO stream contains significant amounts of cyclic and aromatic compounds, as well as heteroatoms, such as sulfur and nitrogen, and other heavier compounds. The exact composition of the VGO / HGO stream varies depending on the crude oil source and VGO / HGO cutoff used in petroleum distillation. The term VGO / HGO stream, or more generally VGO and HGO, is well known in petroleum refining technology. Surprisingly, it has been found that LWP mixes well with the VGO / HGO stream and that blending LWP with the VGO / HGO stream improves the refining process and the quality of the final product.

[0020] According to one embodiment of the present invention, the amount of LWP in the total feed of the process according to the present invention is between 1 wt.% and 40 wt.% based on the total feed. Preferably, the amount of LWP in the total feed is between 5 wt.% and 30 wt.%, and more preferably between 5 wt.% and 25 wt.%.

[0021] LWP can contain significant amounts of chlorine in the form of organic or inorganic chlorides, depending on the source of the waste plastic. Chloride-containing compounds can be converted to hydrogen chloride (HCl) during refining operations, and HCl is a well-known corrosive agent. Therefore, the amount of chloride introduced into the refinery process with LWP should be minimized. It has been found that blending LWP streams with VGO / HGO streams requires less pretreatment before hydrotreating and hydrocracking refining processes.

[0022] In addition, it has surprisingly been found that hydrocarbon blends with superior viscosity characteristics can be produced by using a combination of LWP and a VGO / HGO stream that is subjected to a two-stage process involving initial hydrotreating followed by hydrocracking. As shown in the examples below, the addition of an LWP to a VGO / HGO stream, followed by hydrotreating and hydrocracking the blend, provided a product with a significantly higher viscosity index than the product obtained from pure VGO in the same manner. By adding an LWP to a VGO / HGO stream, viscosity indices higher than 130, as required for API Group III+ base oils, could be achieved even at lower hydrocracking conversions.

[0023] Those skilled in the art will appreciate that the exact composition and properties of VGO and HGO, and any mixtures prepared therefrom, will depend on the type of crude oil being processed and the overall configuration of the crude oil distillation process (including both atmospheric and vacuum distillation steps). Furthermore, individual distillation steps may be configured or optimized in a particular way due to specific requirements from downstream processing units. Nevertheless, VGO and HGO are very similar streams, and therefore, adding LWP to either of these streams, or to mixtures thereof, is expected to have similar effects.

[0024] The American Petroleum Institute (API) has classified base oils into five major groups based on both their properties and manufacturing methods. API Group III is the base oil group derived from VGO / HGO and has the highest viscosity index requirements. Group III viscosity index is 120 or greater. Group III+ is not an official API group, but is well established. Group III+ viscosity index requirement is 130 or greater.

[0025] It has been surprisingly discovered that components capable of producing high-quality base oils can be obtained from LWP, which is typically of lower quality compared to many other feeds due to the amount of impurities contained in waste plastics. LWP contains significant amounts of impurities, such as chlorides, compared to, for example, slack wax feed. Despite the high amount of impurities in LWP, high-quality components can be obtained using the claimed method. This is achieved even when the bottoms fraction from LWP fractionation is used as the feed. The method of the present invention is flexible and can be easily modified depending on the quality and characteristics of the feed.

[0026] According to the method of the present invention, a feed containing LWP and a VGO / HGO stream is subjected to hydrotreating to produce a hydrotreated stream. Hydrotreating can be carried out under conditions that remove any heteroatoms that may be present in the LWP, such as oxygen, sulfur, and / or nitrogen. In addition to removing heteroatoms, hydrotreating also results in the complete or partial saturation of unsaturated compounds (aromatic and olefinic), if present. Hydrotreating is performed on the feed to remove impurities, such as nitrogen, sulfur, halogens, and metals, that may be present in the feed. It has surprisingly been found that initially performing hydrotreating on a feed containing VGO / HGO and LWP facilitates optimization of the hydrocracking process.

[0027] Hydrotreating is typically carried out in the presence of a catalyst. The catalyst may, for example, comprise at least one component selected from IUPAC Group 6, 8, or 10 of the Periodic Table of the Elements. When a supported catalyst is employed, the catalyst preferably comprises Mo and at least one additional transition metal on a support. Examples of such supported catalysts include supported NiMo catalysts or supported CoMo catalysts, or a mixture of both. In supported catalysts, the support preferably comprises alumina and / or silica. These catalysts are usually implemented as sulfided catalysts to ensure that the catalyst is in the active (sulfided) form. This can be achieved by sulfiding the catalyst beforehand (i.e., before starting the hydrotreating reaction) and / or by adding a sulfur-containing feed (e.g., containing sulfur as an organic or inorganic sulfide). The feed may initially contain sulfur, or a sulfur additive may be mixed into the feed. In a preferred embodiment, the hydrotreating uses a catalyst, and the catalyst is a supported NiMo catalyst, and the support comprises alumina (NiMo / Al2O3), and / or the catalyst is a supported CoMo catalyst, and the support comprises alumina (CoMo / Al2O3).

[0028] Hydrotreating can be carried out by placing a hydrotreating catalyst in one or more layers in a fixed-bed reactor and passing the LWP-containing feed through the catalyst layers along with hydrogen. The catalyst can also be placed in a graded catalyst bed. Alternative catalyst placements and conditions suitable for hydrotreating are well known to those skilled in the art.

[0029] Hydrotreating can be carried out using any suitable hydrotreating conditions. In one embodiment of the present invention, hydrotreating is carried out using the following conditions: a temperature of 250-450°C, preferably 330-420°C, and more preferably 390-410°C; a pressure of 30-250 bar (3-25 MPa), preferably 130-180 bar (13-18 MPa), and more preferably 145-155 bar (14.5-15.5 MPa); a hydrogen to oil ratio of 500-2000 l:l, preferably about 900-1300 l:l, and more preferably about 1000-1200 l:l; and a hydrocarbon liquid hourly space velocity (LHSV) of about 0.2-10.0 l / h, preferably 1.5-2.7 l / h, and more preferably 1.8-2.5 l / h.

[0030] In one embodiment of the present invention, hydrotreating includes the use of at least one guard bed prior to the actual hydrotreating, which can facilitate the removal of impurities such as silicon, phosphorus, chlorides and / or iron.

[0031] The hydrotreating stage, which optionally includes the use of guard beds, essentially serves two functions: to remove impurities and to saturate double bonds. By removing impurities and saturating double bonds prior to the essential hydrocracking stage, the feedstock is standardized, meaning that the hydrotreating step eliminates variations in the hydrocracking feed. This allows conditions in the hydrocracking stage to remain stable and eliminates the need to change conditions in response to changes in the overall feedstock. The hydrocracking step performed prior to hydrocracking ensures that hydrocracking conditions can be optimized to produce high-quality hydrocarbons that can then be converted into base oil components with superior properties.

[0032] The resulting hydrotreated stream is subjected to hydrocracking to obtain a refined hydrocarbon mixture, also referred to as a hydrocracked stream. The hydrocracking process removes heteroatoms, such as N and S, that were not removed during hydrotreating. Hydrocracking primarily involves the cleavage of larger long-chain hydrocarbons into smaller short-chain hydrocarbons and / or the opening of cyclic hydrocarbons to form linear and / or branched hydrocarbons. Hydrocracking is typically carried out in the presence of a hydrocracking catalyst. Suitable hydrocracking catalysts for this process include, but are not limited to, bifunctional catalysts comprising an acidic support, such as alumina, amorphous silica-alumina, or zeolite, and at least one active hydrogenation component selected from IUPAC Groups 6, 8, or 10 of the Periodic Table of the Elements. Typical examples of hydrocracking catalysts include NiW / Al2O3, NiW / zeolite, NiW / Al2O3-SiO2, Pt / zeolite or Pd / zeolite, and Pt / Al2O3-SiO2 or Pt / Al2O3-SiO2.

[0033] The hydrocracking catalyst can be arranged in one or more layers in a fixed bed reactor. The hydrotreated stream is passed through a fixed bed having layered hydrocracking catalyst along with hydrogen to form a hydrocracked stream. Suitable catalyst arrangements and conditions for hydrocracking hydrocarbon hydrotreating streams are well known to those skilled in the art.

[0034] Hydrocracking can be carried out using any suitable hydrocracking conditions. In one embodiment of the present invention, hydrocracking is carried out using the following conditions: a temperature of 330-450°C, preferably 370-420°C, and more preferably 390-410°C; a pressure of 50-250 bar (5-25 MPa), preferably 140-160 bar (14-16 MPa), and more preferably 145-155 bar (14.5-15-5 MPa); a hydrogen to oil ratio of 500-2000 l:l, preferably about 900-1300 l:l, and more preferably 1000-1200 l:l; and a hydrocarbon liquid hourly space velocity (LHSV) of about 0.5-5.0 l / h, preferably 1.0-2.5 l / h, and more preferably 1.4-1.9 l / h.

[0035] Hydrocracking may be followed by removal of light ends before further processing. Other processes, such as fractionation, are also possible.

[0036] The hydrotreating and hydrocracking steps can be carried out in a single reactor or in separate reactors. When these two steps are carried out in separate reactors, the hydrotreating reactor is located immediately upstream of the hydrocracking reactor, with no additional steps between hydrotreating and hydrocracking. In one option, hydrotreating and hydrocracking are carried out in a single unit, located in a single vessel, with a hydrotreating section followed by a hydrocracking section. The unit can also include one or more hydrotreating guard beds before the hydrotreating section.

[0037] The method according to the present invention further comprises a step of fractionating the hydrocracked stream containing the purified hydrocarbon mixture. When the method further comprises an isomerization step, the fractionation step can be carried out either before or after the isomerization step. The fractionation of the hydrocarbon mixture formed in hydrocracking can be carried out by a typical distillation method, and one or several fractions can be obtained in the distillation. In one embodiment of the present invention, the hydrocarbon mixture is subjected to fractionation to obtain at least two fractions, a light fraction and a heavy fraction, wherein the heavy fraction consists of hydrocarbons suitable for the production of base oil components, and the light fraction contains hydrocarbons suitable for use as fuel components or as feed for steam cracking and subsequent polymer production.

[0038] In another embodiment, the hydrocarbon mixture is fractionated to obtain at least three fractions, of which the first and second fractions are heavier fractions containing hydrocarbons suitable for producing base oil components, and the third fraction is a lighter fraction suitable for use as a fuel component or as a feed for steam cracking and subsequent polymer production. The first heavier fraction may be a fraction containing components with a 5 wt.% distillation point above 380°C, the second heavier fraction may be a fraction containing components with a 5 to 95 wt.% distillation range in the range of 330 to 410°C, and the third fraction may be a fraction lighter than the first and second heavier fractions and having a boiling point distribution with a 95 wt.% distillation point below 370°C, suitable for use as a fuel component or as a feed for steam cracking and subsequent polymer production.

[0039] According to one embodiment of the present invention, the process further comprises hydroisomerizing the mixture of hydrocarbons produced by the two-step process comprising first hydrotreating followed by hydrocracking. The hydrocracked hydrocarbon stream may be subjected to an isomerization or dewaxing step. Alternatively, the fraction recovered in the fractionation step after the hydrocracking step may be subjected to a hydroisomerization step.

[0040] In the isomerization step, normal n-paraffins are isomerized to provide branched paraffins, so-called isoparaffins (also called i-paraffins). Isomerization of n-paraffins or hydrocarbons of hydrocracking streams is desirable and generally improves the cold flow properties of the hydrocarbon mixture. Isomerization is generally carried out in the presence of an isomerization catalyst. Suitable isomerization catalysts and conditions for carrying out this process are well known to those skilled in the art.

[0041] Isomerization produces a mixture of hydrocarbons, which may optionally be further fractionated after isomerization. The isomerized hydrocarbons may be fractionated by distillation, such that light ends are removed from the stream. The remaining stream, from which the light ends have been removed, is subjected to further fractionation. A distillation or fractionation step after the isomerization step is particularly useful when the mixture of hydrocarbons obtained after hydrocracking has not been subjected to a distillation or fractionation step.

[0042] According to one embodiment of the present invention, liquefied waste plastics (LWP) are produced by the pyrolysis of waste plastics. The waste plastics can be any waste plastics, but are preferably waste plastics collected for recycling from industrial or municipal sources. The types of polymers contained in the waste plastics include, but are not limited to, low-density polyethylene, high-density polyethylene, and polypropene. Other polymers, such as polystyrene, polyamide, polyethylene terephthalate, and Teflon, may also be present in the waste. Overall, it is desirable to maximize the amount of polymers containing only carbon and hydrogen, but varying amounts of heteroatom impurities may also be tolerated depending on the liquefaction process and subsequent downstream operations.

[0043] According to one embodiment of the present invention, the formed LWP is fractionated, preferably by distillation, before subjecting the feed to hydrotreating. In fractionating the LWP, a light fraction is removed from the LWP, and a bottoms fraction is recovered to form a feed containing LWP that is subjected to hydrotreating and hydrocracking. In one embodiment, the formed LWP is also subjected to a pretreatment process to remove impurities.

[0044] Additionally, the present invention also includes a purified hydrocarbon product produced by the process of the present invention, which contains hydrocarbon components having impurity levels suitable for use in steam cracking, which is used to produce olefins and other hydrocarbons suitable for the polymerization and production of polymers.

[0045] A specific embodiment of the present invention is depicted as a schematic process in Figure 1. The LWP (10) is mixed (15) with the VGO / HGO stream (12) to form a feed containing the LWP and the VGO / HGO stream. Mixing (15) can be performed in a separate vessel for mixing the streams, or simply by combining the piping for the LWP (10) with the piping for the VGO / HGO stream (12), whereby mixing occurs in the piping and in hydrotreating (20). The combined stream (17) is subjected to hydrotreating (20). After hydrotreating (20), a hydrotreated stream (25) is produced, which is subjected to hydrocracking (30). The hydrocracked stream (35) produced by hydrocracking contains a mixture of hydrocarbons. The hydrocracked stream (35) is subjected to a distillation step (36) to separate a light end fraction (37) from the hydrocracked stream. The bottoms fraction (38) of the distillation step (36) is subjected to isomerization (42) of the bottoms fraction (38). The isomerized bottoms stream (47) is a stream containing a mixture of purified hydrocarbons and is subjected to further fractionation (52) to obtain various fractions. [Example]

[0046] Example 1 LWP production and distillation In this example, two separate LWP samples were used for illustration. One was produced from a polyethylene-rich waste plastic feedstock, and the other was produced from a polypropylene-rich waste plastic feedstock. The original waste plastic feedstock was converted in a batch pyrolysis process to obtain two LWP crude oils. The plastic was fed into a horizontal kiln-type pyrolysis reactor, which was then gradually heated to approximately 440°C. The pyrolysis process was continued until no visible steam / gas evolution occurred. The average reaction temperature was approximately 400°C. The pyrolysis vapors were cooled and condensed to produce crude LWP samples.

[0047] The crude LWP samples were vacuum distilled using a 20-liter batch distillation apparatus, and two fractions were collected as distillates: a naphtha range cut (approximately 30°C to approximately 190°C) and a middle cut (approximately 165°C to 350°C). A heavy fraction (above 350°C) was collected as the distillation bottoms product for both LWP samples. The yields of the heavy fraction were 37 wt.% for the PE-rich LWP and 23 wt.% for the PP-rich LWP. The two LWP heavy fractions were mixed in equal proportions (by weight) before further processing.

[0048] Methods and product analysis For illustrative purposes, a VGO / HGO feed alone and a feed containing 90 wt.% VGO / HGO and 10 wt.% LWP heavy ends were subjected to the process of the present invention, i.e., hydrotreating using an alumina-supported transition metal sulfide catalyst (NiMo / Al2O3) followed by hydrocracking using a typical bifunctional hydrocracking catalyst (NiW on a zeolite support). The conditions, which were the same for both the hydrotreating (HT) and hydrocracking (HC) steps except for the weight hourly space velocity (WHSV), are shown in Table 1.

[0049] The resulting hydrocracking products were analyzed using simulated distillation (EN 15199-2) to determine the conversion of the fraction above 343°C. Both feeds were hydrocracked at two different conversion levels (60% and 75%) and then physically distilled into different product fractions (185-350°C, 350-405°C, and >405°C). The 350-405°C and >405°C product fractions were subsequently dewaxed using a 50 / 50 mixture of toluene and methyl ethyl ketone. The viscosity of the solvent-dewaxed products was determined according to EN ISO 3104, the viscosity index according to ASTM D2270, and the pour point according to ASTM D5950.

[0050] The overall product distribution for this experiment is shown in Table 1 and indicates that incorporating 10 wt.% LWP into the hydrocracking process does not adversely affect the yield of the most desirable product fractions, i.e., the cut above 405°C and the 385–405°C cut.

[0051] Conversion was calculated as follows with a 343°C cut point (343+°C): Conversion %[343℃]: 100 - [100 x (product boiling above 343°C) / (fraction in the feed boiling above 343°C)].

[0052] Conversion therefore indicates the proportion of feed components that originally had boiling points above 343°C that are converted during the process to compounds boiling below 343°C. Higher conversion therefore means that more gaseous and liquid hydrocarbons with boiling points in the naphtha / gasoline / middle distillate range will be produced. As a result, less hydrocarbon suitable for base oil production will be produced. Conversion can be influenced primarily by changing the reaction temperature; i.e., increasing the temperature will increase the conversion.

[0053] [Table 1]

[0054] Table 2 shows the properties of the fraction above 405°C after solvent dewaxing. The results clearly demonstrate that the addition of 10 wt.% LWP significantly increased the viscosity index of the product. When combined with the fact that the yield of this particular fraction remained essentially the same compared to when only VGO / HGO was used as the feed, the overall benefit of LWP addition to product quality is clear. Those skilled in the art will also recognize that by processing LWP-containing feeds at lower conversion levels, products with viscosity indices greater than 130 can be obtained in higher yields than those reported in Tables 1 and 2.

[0055] [Table 2]

[0056] In contrast to the situation for the fractions above 405°C, the properties of the fractions between 350 and 405°C did not show any clear changes. As can be seen from Table 3, the viscosity index after solvent dewaxing was very similar with or without LWP addition.

[0057] [Table 3]

[0058] In addition to the two heavier product fractions, a middle distillate fraction (185-360°C) was analyzed using a different method. The results, shown in Table 4, indicate that the addition of LWP reduced the density and increased the cetane number of this product. Therefore, in some respects, the LWP-containing product may be considered to have better properties, for example, when used as a diesel fuel component.

[0059] [Table 4]

[0060] It will be obvious to those skilled in the art that with the advancement of technology, the concept of the present invention can be implemented in various ways. The present invention and its embodiments are not limited to the examples described above, but can be modified in various ways within the scope of the claims.

Claims

1. 1. A method for upgrading liquefied waste plastics (LWP) to a mixture of refined hydrocarbons, comprising: providing a feed comprising liquefied waste plastics (LWP) and a vacuum gas oil (VGO) stream and / or a heavy gas oil (HGO) stream to generate a mixed stream; subjecting said mixed stream to hydrotreating to remove impurities and to produce a hydrotreated stream; subjecting the hydrotreated stream to hydrocracking to produce a hydrocracked stream comprising a mixture of refined hydrocarbons; fractionating said hydrocracked stream containing a mixture of purified hydrocarbons. A method comprising:

2. 2. The method of claim 1, wherein the mixed stream comprises 1 to 40 wt. % LWP, with the balance being the total stream and the VGO and / or HGO stream.

3. 2. The method of claim 1, wherein the mixed stream comprises 5 to 30 wt. % LWP, with the balance being the total stream and the VGO and / or HGO stream.

4. 3. The method according to claim 1 or 2, wherein the LWP is produced by pyrolysis of waste plastics.

5. 5. The method of claim 4, wherein the pyrolyzed waste plastic is fractionated into one or more LWP fractions, and at least one LWP fraction is used in the feed to be hydrotreated.

6. 10. The method of claim 1, wherein said LWP is subjected to a pretreatment prior to said hydrotreating step.

7. 10. The method of claim 1, wherein said hydrotreating comprises the use of at least one guard bed prior to hydrotreating said mixed stream.

8. 2. The process of claim 1, wherein said hydrotreating and said hydrocracking are carried out in a single unit located in a single vessel having a hydrotreating section followed by a hydrocracking section.

9. The hydrogenation treatment is carried out on an alumina support (Al 2 O 3 2. The process of claim 1, conducted in the presence of a catalyst selected from sulfided NiMo, CoMo, and combinations thereof supported on a catalyst carrier.

10. The hydrotreating is carried out under the following conditions: a temperature of 250 to 450°C; a pressure of 30 to 250 bar (3 to 25 MPa); a hydrogen to oil ratio of 500 to 2000 l:l; and Hydrocarbon Liquid Hourly Space Velocity (LHSV) of about 0.2 to 10.0 1 / h The method according to claim 1 or 9, wherein the method is carried out by

11. The hydrotreating is carried out under the following conditions: a temperature of 330 to 420°C; a pressure of 130-180 bar (13-18 MPa); a hydrogen to oil ratio of about 900 to 1300 l:l; and Hydrocarbon Liquid Hourly Space Velocity (LHSV) of 1.5 to 2.7 1 / h The method according to claim 1 or 9, wherein the method is carried out by

12. 10. The process of claim 1, wherein the hydrocracking is carried out in the presence of a bifunctional catalyst comprising an acidic support and an active hydrogenation component.

13. The hydrocracking is carried out under the following conditions: a temperature of 330 to 450°C; a pressure of 50 to 250 bar (5 to 25 MPa); a hydrogen to oil ratio of 500 to 2000 l:l; and Hydrocarbon Liquid Hourly Space Velocity (LHSV) of about 0.5 to 5.0 1 / h The method according to claim 1 or 12, wherein the method is carried out by

14. The hydrocracking is carried out under the following conditions: a temperature of 370 to 420°C; a pressure of 140-160 bar (14-16 MPa); a hydrogen to oil ratio of about 900 to 1300 l:l; and Hydrocarbon Liquid Hourly Space Velocity (LHSV) of 1.0 to 2.5 1 / h The method according to claim 1 or 12, wherein the method is carried out by

15. 10. The method of claim 1, wherein said fractionation of said hydrocracked stream containing said mixture of refined hydrocarbons is carried out to form at least two fractions: a lighter fraction and a heavier fraction.

16. 16. The method of claim 1 or 15, wherein the fractional distillation is carried out to form at least three fractions, wherein a first heavier fraction is a fraction of components having a 5 wt. % distillation point above 380°C, a second heavier fraction is a fraction of components having a 5 to 95 wt. % distillation range in the range of 330 to 410°C, and a third fraction is a fraction having a 95 wt. % distillation point below 370°C.

17. 10. The method of claim 1, wherein the method comprises isomerizing the produced refined hydrocarbon mixture either before the step of fractionating the produced refined hydrocarbon mixture or after the step of fractionating the produced refined hydrocarbon mixture.

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