Conversion of Waste Plastic and Oil Blend with a Contaminant Removal Step

This application claims priority to U.S. Provisional Application Ser. No. 63/645,299 filed May 10, 2024, the complete disclosure of which is incorporated herein by reference in its entirety.

This disclosure relates to a process for effectively converting waste plastics into petroleum products and suitable feedstock for cracker or chemical production. More specifically, for waste plastic with a high contamination level, a filtration step is used to control the feedstock quality.

The production of plastics has more than doubled since the turn of the century, and more plastic than ever is being used and discarded. The bulk of this discarded plastic accumulates in landfills, with less than 10% of plastics being successfully recycled. One reason underlying the lack of recycling rests in the currently anemic market for recycled plastics.

Much has been done in attempting to advance the recycled plastics market. Indeed, the production of items made from secondary plastics (plastic made using recycled waste plastics) has more than quadrupled from 2000 to 2019. Yet despite this, secondary plastics account for only about 6% of the total plastics produced. Thus, while the increase in items manufactured from secondary plastics represents noble progress, more must be done to create a separate and well-functioning market for recycled waste plastics.

Beyond their use in the creation of secondary plastic, waste plastics are generally well known to be suitable in the production of value-added chemical and fuel products. However, the ability to use waste plastics in the creation of value-added chemicals and fuel products remains limited. As such, chemical recycling accounts for only a small amount of total waste plastic recycling.

The typical chemical recycling process involves cleaning waste plastics, turning said plastics into polymer pellets, and pyrolyzing said plastics in a pyrolysis unit to make fuels (naphtha, diesel), steam cracker feed, or slack wax. However, this current practice of pyrolysis operation produces poor-quality fuel components. Moreover, the current volume of chemical recycling remains too small to function as a substantial independent market for recycled waste plastics, limiting a potentially positive impact on the environment and plastics industry. Expanding the volume of the chemical recycling of single use plastics to an industrially significant quantity requires more robust processes. Thus, improved processes establishing a circular economy for waste plastic where spent waste plastics are not only recycled effectively but generate high value byproducts would be of great interest to the industry.

A summary of certain embodiments disclosed herein is sets forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are note intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

The present process provides a new, useful, and efficient process for the conversion of waste plastics via cofeeding a blend of waste plastic and a refinery feedstock. Contaminants are captured during the blend preparation. In one embodiment, a hot blend of plastic and petroleum oil, such as VGO, is prepared, which blend is then filtered to remove solids. The temperature used for preparing the blend of plastic and petroleum oil is in the range of from about 300-450° F., and the hot blend is filtered while still hot.

In one embodiment the process comprises sorting a feedstock of mixed waste plastic into desirable and undesirable plastics. The desirable plastics can be polyolefins, for example polypropylene and polyethylene. These desirable plastics can then be cleaned. A refinery feedstock can then be added to a blend preparation unit. In one embodiment the refinery feedstock comprises vacuum gas oil. In another embodiment the refinery feedstock comprises atmospheric gas oil. In another embodiment the refinery feedstock comprises atmospheric resid. In still another embodiment the refinery feedstock comprises vacuum resid. The desirable waste plastic can then be added to the blend preparation unit where the plastic and feedstock are heated and mixed to prepare a homogenous blend. The residence time for the desirable plastic and refinery feedstock in the blend preparation unit is sufficiently long to melt the plastic and have the refinery feedstock and desirable plastic mixed until a homogeneously mixed product is achieved. In one embodiment the blend preparation unit comprises a filter for filtering the mixed product to remove any remaining solids. In one embodiment these solids are removed as a filter cake. In another embodiment the solids are removed as a slurry.

The mixed product can be collected from the blend preparation unit and supplied to a refinery conversion unit. In one embodiment the refinery conversion unit comprises a fluid catalytic cracker. In one embodiment the refinery conversion unit comprises a hydrocracker. In one embodiment the refinery unit comprises a high-production compact reactor. In one embodiment the refinery unit comprises a coker. In one embodiment the product of the refinery conversion unit can be used in the creation of high value petroleum products and sustainable feedstock for cracker reactions or chemicals production.

Among other factors the present process permits the effective conversion of waste plastics via cofeeding waste plastic melt with a refinery feed, for example VGO. Before sending the feed stream containing waste plastic to refinery units, the contaminants are captured in the blend preparation process. With a lower contamination level, the refinery conversion units will operate more effectively. The plastic/petroleum oil blend is upgraded with appropriate refinery units with conversion processes. The final transportation fuels produced by the integrated process will be higher quality and will meet the fuels quality requirements. Our process will produce valuable products, such as high quality gasoline, jet, diesel and base oil, and valuable intermediate/feedstocks for chemicals production. The integrated process will generate a much cleaner naphtha stream for steam cracker feedstock for ethylene generation for polyethylene production or a propane/propylene stream ultimately for polypropylene production. These large productions would allow a “circular economy” for plastics recycle. The use of the present process offers significant economic and environmental benefits if adopted in industrial refineries.

Before the processes of the conversion of waste plastics and oil blend with contaminant removal step is disclosed and described, it is to be understood that this disclosure is not limited to the particular structures, process steps, or materials disclosed herein, but is extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in this specification, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a step” may include multiple steps, reference to “producing” or “products” of a reaction or treatment should not be taken to be all of the products of a reaction/treatment, and reference to “treating” may include reference to one or more of such treatment steps. As such, the step of treating can include multiple or repeated treatment of similar materials/streams to produce identified treatment products.

Numerical values with “about” include typical experimental variances. As used herein, the term “about” means within a statistically meaningful range of a value, such as a stated particle size, concentration range, time frame, molecular weight, temperature, or pH. Such a range can be within an order of magnitude, typically within 10%, and more typically within 5% of the indicated value or range. Sometimes, such a range can be within the experimental error typical of standard methods used for the measurement and/or determination of a given value or range. The allowable variation encompassed by the term “about” will depend upon the particular system under study, and can be readily appreciated by one of ordinary skill in the art. Whenever a range is recited within this application, every whole number integer within the range is also contemplated as an embodiment of the invention.

The present application, in one embodiment, relates to the conversion of waste plastics via cofeeding waste plastic melt with a refinery feedstock. In one embodiment the waste plastics can be sorted into desirable and undesirable waste plastics. Polyethylene (PE) and polypropylene (PP) plastics are particularly attractive options for processing in refinery units. However, waste plastics with PE and PP plastic sometimes contain substantial amounts of undesirable materials such as other undesirable plastics (polyvinyl chloride, polyethylene terephthalate, nylon, etc.), inorganic filler materials (CaCO, MgO, silica, talc, TiOetc.), additives and colors. The amount of undesirable material can be in the range of 0.1 to 30 wt. %. Contamination with polyvinyl chloride (PVC) is highly undesirable since its decomposition product, HCl, could corrode the refinery equipment and cause serious reliability issues if water is present in the process streams. Other unwanted plastic that are common in the waste plastic feed sources may include polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), variety of nylon polymers (e.g., nylon 66, nylon 6). In one embodiment the desirable waste plastics can be washed to further remove any contaminants.

For recycling of polyethylene and polypropylene plastic, an advanced recycling process utilizing a catalytic conversion process is the most energy efficient and effective recycling process. However, due to impurities in the waste plastic feedstock, it is difficult to use catalysts for advanced recycling. In order to feed the plastic/VGO blend to the catalytic processes such as fluid catalytic cracking (FCC) or hydrocracking (HCR), impurities in the blend need to be removed before feeding the plastic/VGO blend to the catalytic conversion unit.

The source of impurities in the waste plastic feedstocks can be classified broadly into two different groups. The first group of impurities were originated during manufacturing of plastic resins or plastic products, such as plastic films, molds, etc. Plastic resins contain additives, catalyst residue from the polymer manufacturing, and inorganic filler materials such as talc, silica, alumina, diatomaceous earth, nepheline syenite, and calcium carbonate, which were added to improve the manufacturing process or properties of plastic resins. Plastic product manufacturers add more inorganic filler materials, pigments or create multi-layer films with different plastic mixes or with metallic layering materials. These additives and filler materials cannot be removed by a mechanical cleaning process and can cause a serious problem for advanced recycling processes utilizing catalytic conversion units. In particular, those impurities may deactivate the catalyst in the conversion unit prematurely and/or cause downstream processing issues with fines generation.

The second group of impurities are undesirable plastics coming from imperfect sorting of recycling process. Sorting and mechanical cleaning processes still leave undesirable plastics in the recycled plastic feed. Undesirable plastic materials include, but are not limited to, nylon, polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and polyethylene terephthalate (PET). These undesirable plastic materials may cause issues in plant operation and equipment reliability. The presence of PVC is particularly harmful as it evolves HCl that could cause corrosion in refinery equipment. High nitrogen containing plastic, such as nylon and ABS may deactivate the catalyst in the conversion unit.

The present process offers a superior blend preparation process for plastic with a petroleum feed such as VGO for advanced recycling of waste plastic comprising polyethylene (PE) and polypropylene (PP). The process comprises the preparation of a plastic and oil blend at a temperature around 300-450° F., followed by hot filtration at a similar temperature range. This process purifies the PE or PP plastic/oil blend by removing undissolved, undesirable plastics and inorganic filler materials from the plastic/oil blend.

In one embodiment of the present process, waste plastic and a petroleum refinery feed are fed to a blend preparation unit and mixed until the waste plastic has melted and essentially dissolved in and combined with the refinery feedstock to form a mixed product. In one embodiment the refinery feedstock can comprise vacuum gas oil (VGO). In another embodiment the refinery feedstock can comprise atmospheric gas oil (AGO). In another embodiment the refinery feedstock can comprise atmospheric resid (AR). In still another embodiment the refinery feedstock can comprise vacuum resid (VR). The amount of polyethylene (PE) and polypropylene (PP) added to the refinery feedstock in the blend preparation unit can range from 1-20 wt. % of the mixed product and in one embodiment from 1-10 wt. % of the mixed product, and in another embodiment from 1-5 wt. %. The amount of plastic in the blend is generally less than 20 wt. %. The amount of high-density PP or high-density PE added to the refinery feedstock in the blend preparation unit can generally range from 1-10 wt. % of the mixed product.

In one embodiment the operating temperature of the blend preparation melting unit is about 300-450° F., and in another embodiment about 300-400° F., and in another embodiment about 350-400° F. At this temperature, all PE and PP plastics can be dissolved while the decomposition of PVC is minimized. PVC, which decomposes at 450-600° F. and produces a substantial amount of HCl and some organic chlorides. PE is stable up to 800° F. and PP is stable up to 700° F., at which temperatures they begin to decompose. Hydrocarbons in VGO are stable for the entire temperature window up to 1100° F., but it contains light hydrocarbon components that start to boil at 400° F. and above. Unwanted plastics such as nylon, PET, PVC, and ABS can be further minimized using this operating temperature as these plastics do not melt in petroleum oil at 450° F. or below. Thus, the operating temperature maximizes the melting of PE and PP while at the same time minimizing contamination from other plastics and organic chlorides in the blend.

In one embodiment the blend preparation unit can contain a filtration unit to further remove solid contaminants. Solid removals can be done via filtration using continuous slurry removal or use of a filter press or a centrifuge. The filtration unit can also remove solid contaminants and unwanted plastics (nylon, PET, ABS, PVC) from the hot blend of plastic and petroleum oil. This filtration step is particularly critical if the hot homogeneous blend is fed to a refinery conversion unit such as an FCC or HCR unit, where the catalyst stability will be negatively affected by the solid contaminants in the hot homogeneous blend of plastic and petroleum oil. In one embodiment the bottom stream containing solids (the reject stream containing solids) can be sent to a coker unit for additional hydrocarbon recovery, or further filtered. The solids can be disposed of as a filter cake. In one embodiment the plastic/VR blend can be fed to coker unit. A coker unit does not contain any catalyst that needs to be protected, thus the coker unit can handle the plastic/VR feed with a higher amount of solids and an additional solid removal step may not be necessary. If the solid content of the plastic/VR feed is too high to cause an issue for the coke quality, then, a portion of the solids in the plastic/VR feed can be removed to control the residual solid content of the coke. In one embodiment the plastic/VR feed can be sent to a visbreaker or deasphalting unit.

In one embodiment the upgraded mixed product produced can be high-quality gasoline, jet, diesel, and base oil, and valuable intermediates/feedstocks for chemical production. The final transportation fuel produced by the integrated process can be high quality and meet fuel quality requirements. In one embodiment, a naphtha fraction is recovered from the refinery conversion unit. The integrated process generates a much cleaner naphtha stream for steam cracker feedstock for ethylene generation for polyethylene production or a propane/propylene stream ultimately for the polypropylene production. The naphtha fraction can also be further processed in the refinery to gasoline, diesel, base oil, or jet fuel. In another embodiment, a gasoline fraction can be recovered from the conversion unit which is then sent to a gasoline blending pool in the refinery. This large on-spec production would allow a feasible “circular economy” for plastics recycling.

shows a diagram of the pyrolysis of waste plastics fuel or wax that is generally operated in the industry today. Generally, the waste plastics are sorted together 1. The cleaned plastic wasteis converted in a pyrolysis unitto off gasand pyrolysis oil (liquid product). The off gasfrom the pyrolysis unitis used as fuel to operate the pyrolysis unit. An on-site distillation unit separates the pyrolysis oil to produce naphtha and dieselproducts which are sold to fuel markets. The heavy pyrolysis oil fractionis recycled back to the pyrolysis unitto maximize the fuel yield. Charis removed from the pyrolysis unit. The heavy fractionis rich in long chain, linear hydrocarbons, and is very waxy (i.e., forms paraffinic wax upon cooling to ambient temperature). Wax can be separated from the heavy fractionand sold to the wax markets.

Use of the present blend, however, avoids the pyrolysis of the waste plastic. Rather, a stable blend of petroleum feedstock and the waste plastic is prepared, which can be fed to the refinery conversion units. Thus, the pyrolysis can be avoided, which is a significant energy savings as well as equipment cost savings.

The preferred plastic starting material for use in the present blend is sorted waste plastics containing predominantly polyethylene and polypropylene (plastics recycle classification types 2, 4, and 5). The pre-sorted waste plastics are washed and shredded or pelleted to feed to a blend preparation unit.depicts the plastic type classification for waste plastics recycling. Classification types 2, 4, and 5 are high density polyethylene, low density polyethylene and polypropylene, respectively. Any combination of the polyethylene and polypropylene waste plastics can be used. Polystyrene, classification, can also be present in a limited amount.

Sorting of waste plastics is important in order to minimize contaminants such as N, Cl, and S. Plastics waste containing polyethylene terephthalate (plastics recycle classification type 1), polyvinyl chloride (plastics recycle classification type 3) and other polymers (plastics recycle classification type 7) need to be sorted out to less than 5%, preferably less than 1% and most preferably less than 0.1%. The present process can tolerate a moderate amount of polystyrene (plastics recycle classification type 6). Waste polystyrene needs to be sorted out to less than 20%, preferably less than 10% and most preferably less than 5%.

Washing of waste plastics can remove metal contaminants such as sodium, calcium, magnesium, aluminum, and non-metal contaminants coming from other waste sources. Non-metal contaminants include contaminants coming from the IUPAC Periodic Table Group 14, such as silica, contaminants from Group 15, such as phosphorus and nitrogen compounds, contaminants from Group 16, such as sulfur and oxygen compounds, and halide contaminants from Group 17, such as fluoride, chloride, and iodide. The residual metals, non-metal contaminants, and halides need to be removed to less than 50 ppm, preferentially less than 30 ppm and most preferentially to less than 5 ppm.

The petroleum with which the waste plastic is blended is generally a petroleum based feedstock for the refinery. It is preferred that the petroleum blending oil is the same as the petroleum feedstock for the refinery. The petroleum can also comprise any petroleum derived oil or petroleum based material. In one embodiment, the petroleum feedstock oil can comprise atmospheric gas oil, vacuum gas oil (VGO), atmospheric residue, or heavy stocks recovered from other refinery operations. In one embodiment, the petroleum feedstock oil with which the waste plastic is blended comprises VGO. In one embodiment, the petroleum feedstock oil with which the waste plastic is blended comprises light cycle oil (LCO), heavy cycle oil (HCO), FCC naphtha, gasoline, diesel, toluene, and/or an aromatic solvent derived from petroleum.

In one embodiment, the petroleum feedstocks for the blend preparation include vacuum gas oil, atmospheric gas oil, reformate, light cycle oil, heavy fuel oil, refinery hydrocarbon streams containing toluene, xylene, heptane or benzene, or pure toluene, pure xylene, coker naphtha, C5-C6 isomerized paraffinic naphtha, FCC naphtha, hydrocracker bottom, gasoline, jet fuel, diesel, or mixtures of some these.

In one embodiment, an alternative hydrocarbon feedstock or hydrocarbon solvent can be used for the blend preparation. The alternative feedstock can be derived from other hydrocarbon sources such as from bio feedstock, coal, natural gas, or plastic pyrolysis.

In one embodiment, the petroleum feedstocks are gas oil, heavy reformate, or various recycle streams that will be fed to a catalytic conversion unit. In one embodiment, the blend is sent to the conversion unit at a temperature above the melting point of the highest melting plastic in the blend. The volume flow of the blend to the refinery unit can comprise up to 100 vol. % of the total flow of hydrocarbons to the conversion unit, and in one embodiment up to 50 vol. %, and in another embodiment up to 25 vol. % of the total hydrocarbon flow to the conversion unit. Then, the plastic and petroleum feedstock in the blend are converted together to a higher value product via catalytic conversion.

depicts the thermal stability of PE, PP, and PVC as shown by thermal gravimetric analysis. PVC decomposes at 450-600° F. and produces a substantial amount of HCl, and may generate organic chlorides. PE is stable up to 800° F. and PP is stable up to 700° F. The hydrocarbons in VGO, for example, are stable for the entire temperature window up to 1100° F., but it does contain light hydrocarbon components that start to boil at 400° F. and above.

shows one embodiment of the integrated process. Mixed waste plastic is sorted to obtain post-consumer or post-industrial PE/PP. Post-consumer or post-industrial PE/PP is then cleaned producing clean plastic, which is fed to a blend preparation unit, along with a refinery feedstock. The blend preparation unit melts plastic and prepares a hot homogeneous blend of plastic and petroleum oilthat can be fed to a refinery unitto produce high value petroleum products and sustainable feedstock for cracker or chemicals production.

depicts a detailed view of one embodiment of the blend preparation unit. Clean wasteand oil feedstockare added to the blend preparation unit. The clean wasteand oil feedstockare heated and mixedproducing a hot homogeneous liquid blend of plastic and oil. The hot homogeneous liquid blend of plastic and oilis filtered for solid removal using filter, producing a filtered homogeneous blend of plastic and oiland removed solids. The temperature of the filtrationis about the same as the temperatures used in the heating and mixing, and is in the range of about 300-450° F. The filtered homogenous blend of plastic and oilis then passed to a hydrocarbon conversion unitto produce high value hydrocarbon products and sustainable feedstock for cracker or chemicals production. The oil feedstock can be a refinery feedstock or hydrocarbon solvent derived from other feedstock sources such as from bio feedstock, coal, natural gas, or plastic pyrolysis. The blend preparation unit and hydrocarbon conversion unit may be located near the waste collection facility, near plastic recycling facility or near a chemical production plant.

depicts a detailed view of one embodiment of the blend preparation unit. Clean wasteand vacuum gas oilare added to the blend preparation unit. The clean wasteand vacuum gas oilare heated and mixedproducing a hot homogeneous liquid blend of plastic and oil. The hot homogeneous liquid blend of plastic and oilis filtered for solid removal using filter, producing a filtered homogeneous blend of plastic and oiland removed solids. The filtered homogenous blend of plastic and oilis then passed to a refinery conversion unitto produce high value petroleum products and sustainable feedstock for cracker or chemicals production. The removed solidsare removed as a slurry steamwhich can be sent to a coker, or a filter cake. The filter cakecan be sent to a waste handling facility for disposal or to a cement manufacturing facility to be used as fuel.

depicts a detailed view of one embodiment of the blend preparation unit. Clean wasteand atmospheric gas oilare added to the blend preparation unit. The clean wasteand atmospheric gas oilare heated and mixedproducing a hot homogeneous liquid blend of plastic and oil. The hot homogeneous liquid blend of plastic and oilis filtered for solid removal using filter, producing a filtered homogeneous blend of plastic and oiland removed solids. The filtered homogenous blend of plastic and oilis then passed to a refinery conversion unitto produce high value petroleum products and sustainable feedstock for cracker or chemicals production. The removed solidsare removed as a slurry steamwhich can be sent to a coker, or a filter cake. The filter cakecan be sent to a waste handling facility or to a cement manufacturing facility.

depicts a detailed view of one embodiment of the blend preparation unit. Clean wasteand vacuum residare added to the blend preparation unit. The clean wasteand vacuum residare heated and mixedproducing a hot homogeneous liquid blend of plastic and oil. Solids are not removed in this embodiment. The homogenous blend of plastic and oilis then passed to a refinery conversion unitto produce high value petroleum products and sustainable feedstock for cracker or chemicals production. Optionally, a portion of the hot homogeneous liquid blend of plastic and oilis filtered for solid removal using filteras needed, producing a filtered homogeneous blend of plastic and oilto improve the quality of the petroleum products and sustainable feedstock for cracker or chemicals production. If the filter unit is used, then solids are removed either as a slurry steam or as a filter cake.

The following examples are provided to aid in illustrating the present process and its advantages. The examples are meant to be illustrative and not limiting.

Four commercial plastic samples, low density polyethylene (LDPE, Plastic A), high density polyethylene (HDPE, Plastic B), two polypropylene samples with average molecular weight of ˜12,000 (PP, Plastic C) and ˜250,000 (PP, Plastic D), were purchased and their properties are summarized in Table 1.

Petroleum feedstocks that can be used to prepare stable blends with plastic include hydrotreated vacuum gas oil (VGO), Aromatic 100 solvent, and light cycle oil (LCO), and diesel. Their properties are shown in Table 2. Aromatic 100 is a commercially available aromatic solvent manufactured from petroleum-based material, mainly containing C-Cdialkyl and trialkyl benzenes.

Several blends of vacuum gas oil (VGO) and the two plastic samples (Plastic A and C from Table 1) were prepared by adding the plastic pellets to a hydrotreated vacuum gas oil (Petroleum Feed #1 of Table 2) using an autoclave unit.

The following procedure was used. At ambient temperature, pre-weighed plastic pellets (solids) and the VGO feed (waxy solids) were added to a batch autoclave unit. The autoclave was purged with Ngas to remove air in the vessel, and then the inlet and outlet valves were closed. The mixture was stirred with an impeller at 1600 RPM while the mixture was heated with an external heating jacket to the target temperature of 177° C. (350° F.) or 232° C. (450° F.) by raising the temperature set point by 10° C. for every 10 minutes. Then, the temperature was held at the target temperature for 1 to 2 hours, then cooled down to ambient temperature with the stirring maintained. The pressure was monitored for the entire time. Typically, the pressure was built up to as high as 8 psig at 450° F., and then back to 1 psig upon cooling, indicating no reaction between plastic and VGO. The slight pressure build-up near the target heating temperature was due to vaporization of light material in VGO.

Upon cooling, the hot homogeneous liquid blend of plastic and VGO became a waxy solid that has the typical look of VGO's waxy solids. The blend product at ambient temperature showed no visible separate phase of plastic and looked completely homogeneous per visual observation. The blend of plastic and VGO was stable at ambient conditions, and no change was observed for a 3-month period of observation.

To assess material handling, a pour point (per ASTM D5950-14) and viscosity (per ASTM D445) of the blend were measured. The hot heptane insoluble test method (ASTM D3279) was used to determine the weight percent of plastic in oils as plastic is insoluble in hot heptane at 80° C. The method isolates the plastic material using a 0.8-micron membrane filter. Table 3 below summarizes the list of samples prepared and their properties.

The blends made with the addition of PE or PP plastic showed moderate increases of pour point and viscosity compared with the pure VGO base case. These changes can be handled with typical refinery operating equipment with minor or no modifications. The blend tank needs to be heated above the melting point of plastic to keep the blend as an easily transferable liquid. Then, the liquid blend can be transferred to a transportation vessel or to a refinery conversion unit via pumping, gravity force or via pressure differential.

At 80° C., all the wax in VGO was dissolved in the heptane solvent and the weight percent of heptane insoluble was only 0.01% (Example 2-1). The hot heptane insoluble test separated the plastic from the stable blend. For the blend material (Examples 2-2 through 2-7), the weight percent of heptane insoluble was coming from undissolved plastic that was filtered out with the 0.8-micron membrane filter. The amount of recovered plastic as solid material matched well with the amount of plastic added to the blend preparations. The heptane insoluble results in Table 3 clearly indicate that the blend was a physical mixture of solid plastic particles dispersed in VGO and that the bulk of plastic particles can be re-separated from the VGO.

Four pure plastic samples were purchased to study the effectiveness of the present process in removing undesirable plastic components in recycled plastic materials. Polyvinyl chloride (PVC, Plastic E), acrylonitrile butadiene styrene (ABS, Plastic F), nylon (Nylon-6, Plastic G), and polyethylene terephthalate (PET, Plastic H) are commonly present in waste PE and PP streams as undesirable plastic components. Properties of these four plastic samples are summarized in Table 4.