Systems and methods for stabilizing, storing, and transporting pyrolysis oils

Abstract

This document provides systems and methods for limiting gum formation in pyrolysis oils and removing gum impurities from pyrolysis oils during storage and / or transportation, as well as improved techniques for removing gum deposits from the inner surfaces of sealed containers during storage and / or transportation. One such method includes loading a sealed container with a dispersant, which is a polar surfactant immiscible with the pyrolysis oil. The steps include contacting the pyrolysis oil with the dispersant inside the sealed container to produce a stabilized pyrolysis oil and form water-dispersible gum deposits on the inner surface of the sealed container. In some examples, after removing the stabilized pyrolysis oil from the sealed container, the step includes applying an aqueous fluid to the inner surface of the sealed container to disperse and remove the water-dispersible gum deposits from the inner surface of the sealed container.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit from European application No. EP23205932.9, filed on 25 October 2023. The contents of the referenced application are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to systems and methods for stabilizing, storing, and transporting pyrolysis oils. More specifically, this disclosure relates to systems and methods for limiting gum formation in pyrolysis oils and removing gum impurities from pyrolysis oils during storage and / or transportation, as well as improved techniques for removing gum deposits from the inner surfaces of sealed containers used for storage and / or transportation. Background Technology

[0004] Pyrolysis oil originates from the chemical recycling of mixed plastic waste (MPW). For example, pyrolysis oil can be formed by pyrolyzing MPW under anaerobic conditions at sufficiently elevated temperatures (e.g., 400°C to 500°C). Pyrolysis oil primarily consists of small hydrocarbon molecules, which may include various heteroatoms such as oxygen, nitrogen, and halogen (e.g., chlorine, bromine, fluorine) atoms, depending on the composition of the MPW and the pyrolysis process. Additionally, atmospheric gases, including oxygen (O2), can dissolve in the pyrolysis oil, for example, when it is transferred to containers for storage or transport. It is currently recognized that the heteroatom content and / or dissolved oxygen content of the pyrolysis oil can lead to the formation of undesirable gums within the oil during storage and / or transport. Typically, these heteroatoms are more electronegative than carbon, which reduces the electron density of the carbon atoms bonded to the heteroatoms, making them more susceptible to oxidation.

[0005] When pyrolysis oil is oxidized during storage or transport, it begins to form a gum, which consists of solid particles of oxidized pyrolysis oil that are insoluble in the remaining liquid pyrolysis oil. When the pyrolysis oil is subsequently removed from the container after storage or transport, most of this gum remains as deposits on the inner surfaces of the storage or transport container, and these containers are typically cleaned to remove the gum deposits before they can be used for other purposes. Cleaning storage or transport containers for pyrolysis oil takes approximately three times longer than cleaning storage or transport containers after the use of other hydrocarbons, undesirably increasing operating costs and causing delays. Furthermore, a considerable volume of organic solvents (such as acetone) is often used after the pyrolysis oil has been removed to dissolve and remove the gum deposits from the interior of these containers, undesirably increasing the operating costs associated with the purchase, application, and disposal of organic solvents. In some cases, depending on the organic solvents used, certain protective, ventilated, and monitoring devices may be used to limit and / or monitor organic solvent exposure, further increasing operating costs. Summary of the Invention

[0006] The applicant recognizes the need to limit the formation of gum deposits within pyrolysis oils during storage and transportation, and to facilitate cheaper and easier cleaning of gum deposits from storage and transportation containers used for storing or transporting pyrolysis oils. This document provides systems and methods for addressing these deficiencies in the art, and offers other additional or alternative advantages. Examples include systems and methods for limiting the formation of gum deposits in pyrolysis oils and removing gum impurities from pyrolysis oils during storage and / or transportation, and improved techniques for removing gum deposits from the inner surfaces of sealed storage and / or transportation containers. One such method includes the step of loading a sealed container with a dispersant and pyrolysis oil, the dispersant being a polar surfactant immiscible with the pyrolysis oil. The step includes contacting the pyrolysis oil with the dispersant inside the sealed container to extract gum impurities from the pyrolysis oil, thereby producing a stabilized pyrolysis oil and forming a water-dispersible gum deposit on the inner surface of the sealed container. In some examples, the step includes pumping or draining the stabilized pyrolysis oil from the sealed container, wherein the water-dispersible gum deposit remains on the inner surface of the sealed container. In some examples, after removing the stabilized pyrolysis oil from the sealed container, the step includes applying an aqueous fluid to the inner surface of the sealed container to disperse and remove water-dispersible colloidal deposits from the inner surface. For example, applying the aqueous fluid may include water jetting or pressure washing of the inner surface of the sealed container to remove water-dispersible colloidal deposits. In some examples, the aqueous fluid does not contain acetone or other organic solvents.

[0007] In some examples, the pyrolysis oil is derived from the pyrolysis of mixed plastic waste. In some examples, the stabilized pyrolysis oil removed from sealed containers contains fewer than 1% to 10 wt% heteroatoms relative to the pyrolysis oil, wherein the heteroatoms include oxygen, nitrogen, or halogen atoms, or combinations thereof. In some examples, the stabilized pyrolysis oil contains less than 1 wt% gum impurities. In some examples, the dispersant comprises a polyoxyolefin block copolymer having a hydrophilic-lipophilic balance (HLB) value greater than 10. In some examples, the dispersant comprises a poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEO-PPO-PEO) block copolymer having an HLB of 18 to 23.

[0008] One such system or apparatus is a sealed container for storing or transporting pyrolysis oil, wherein the sealed container contains pyrolysis oil and a dispersant, the dispersant being a polar surfactant immiscible with the pyrolysis oil. In some examples, the inner surface of the sealed container is coated with a dispersant before the sealed container is loaded with pyrolysis oil for storage or transport. In some examples, the inner surface of the sealed container contains water-dispersible colloidal deposits formed when colloidal impurities of the pyrolysis oil come into contact with the dispersant. In some examples, the dispersant is a polyoxyolefin block copolymer having a hydrophilic-lipophilic balance (HLB) value of 18 to 23. In some examples, the sealed container is a road tanker, rail tanker, or marine tanker.

[0009] This document discusses in detail the aspects and advantages of these exemplary examples and other examples. Furthermore, it should be understood that the foregoing information and the following detailed description are merely illustrative examples of various aspects and examples, and are intended to provide an overview or framework for understanding the nature and characteristics of the claimed aspects and examples. Therefore, these and other objects of this disclosure, along with its advantages and features, will become apparent from the following description and accompanying drawings. Moreover, it should be understood that the features of the various examples described herein are not mutually exclusive and can exist in various combinations and arrangements. Attached Figure Description

[0010] The accompanying drawings are included to provide a further understanding of the examples of this disclosure, are incorporated into and form part of this specification, illustrate the examples of this disclosure, and, together with the detailed description, serve to explain the principles of the examples discussed herein. No attempt is made to show the structural details of this disclosure in more detail than is necessary for a basic understanding of the examples discussed herein and their various implementable forms. By convention, the various features in the drawings discussed below are not necessarily drawn to scale. The dimensions of the various features and elements in the drawings may be enlarged or reduced to illustrate the examples of this disclosure more clearly.

[0011] Figure 1 This is a schematic diagram of a method for stabilizing pyrolysis oil stored in a sealed container and subsequently cleaning water-dispersible colloidal deposits from the sealed container, according to an example.

[0012] Figure 2 This is a schematic diagram of an example method for stabilizing pyrolysis oil in a sealed container during transport and subsequently cleaning water-dispersible colloidal deposits from the sealed container.

[0013] Figure 3A This is a schematic diagram of sealing the container before loading with pyrolysis oil, based on the example.

[0014] Figure 3B It is based on the example after loading with pyrolysis oil Figure 3A A schematic diagram of a sealed container.

[0015] Figure 3C This is based on the example after the pyrolysis oil is removed and water-dispersible colloidal deposits remain on the inner surface of the sealed container. Figure 3B A schematic diagram of a sealed container.

[0016] Figure 3D This is based on the example of using an aqueous fluid to disperse and remove water-dispersible colloidal deposits retained on the inner surface of a sealed container. Figure 3C A schematic diagram of a sealed container. Detailed Implementation

[0017] This disclosure describes various examples relating to systems and methods for limiting gum formation in pyrolysis oils and removing gum impurities from pyrolysis oils during storage and / or transportation, as well as improved techniques for removing gum deposits from the inner surfaces of sealed containers for storage and / or transportation. Descriptions may use the phrases “in some examples,” “in various examples,” “in one example,” or “in an example,” each of which may refer to one or more of the same or different examples. Furthermore, the terms “comprising,” “including,” “having,” etc., used in relation to examples of this disclosure are synonymous. The term “a plurality” as used herein refers to two or more items or components / components. The terms “about” or “approximately” are defined as close to as understood by one of ordinary skill in the art. In a non-limiting example, these terms are defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0018] When used in the claims and / or description, the terms “removal,” “reduced,” “reduced,” “decreased,” or any variation thereof include any measurable reduction of one or more components in a mixture to achieve a desired result. When used in the claims or description in conjunction with any of the terms “comprising,” “including,” “containing,” or “having,” the word “an” or “a” may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more.” The terms “weight%,” “volume%,” or “molar%” refer to the weight, volume, or molar percentage of a component, based on the total weight, volume, or moles of the material comprising that component. In a non-limiting example, 10 grams of component in 100 grams of material is 10% by weight of the component.

[0019] Examples include systems and methods for limiting gum formation in pyrolysis oil and removing gum impurities from pyrolysis oil during storage and / or transportation, as well as improved techniques for removing gum deposits from the inner surface of sealed containers during storage and / or transportation. One such method includes the step of loading a sealed container with a dispersant and pyrolysis oil, the dispersant being a polar surfactant immiscible with the pyrolysis oil. The step includes contacting the pyrolysis oil with the dispersant inside the sealed container to extract gum impurities from the pyrolysis oil, thereby producing a stabilized pyrolysis oil and forming water-dispersible gum deposits on the inner surface of the sealed container. In some examples, the step includes pumping or discharging the stabilized pyrolysis oil from the sealed container, wherein the water-dispersible gum deposits remain on the inner surface of the sealed container. In some examples, after removing the stabilized pyrolysis oil from the sealed container, the step includes applying an aqueous fluid to the inner surface of the sealed container to disperse and remove the water-dispersible gum deposits from the inner surface of the sealed container. For example, applying an aqueous fluid may include water jetting or pressure cleaning the inner surface of a sealed container to remove water-dispersible colloidal deposits. In some examples, the aqueous fluid does not contain acetone or other organic solvents.

[0020] In some examples, the pyrolysis oil is derived from the pyrolysis of mixed plastic waste. In some examples, the stabilized pyrolysis oil removed from sealed containers contains fewer than 1 wt% to 10 wt% heteroatoms relative to the pyrolysis oil, wherein heteroatoms include oxygen, nitrogen, or halogen atoms, or combinations thereof. In some examples, the stabilized pyrolysis oil contains less than 1 wt% gum impurities. In some examples, the dispersant contains a polyoxyolefin block copolymer having a hydrophilic-lipophilic balance (HLB) value greater than 10. In some examples, the dispersant contains a poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEO-PPO-PEO) block copolymer having an HLB value of 18 to 23.

[0021] One such system or apparatus is a sealed container for storing or transporting pyrolysis oil, wherein the sealed container contains pyrolysis oil and a dispersant, the dispersant being a polar surfactant immiscible with the pyrolysis oil. In some examples, the inner surface of the sealed container is coated with a dispersant before the sealed container is loaded with pyrolysis oil for storage or transport. In some examples, the inner surface of the sealed container contains water-dispersible colloidal deposits formed when colloidal impurities of the pyrolysis oil come into contact with the dispersant. In some examples, the dispersant is a polyoxyolefin block copolymer having a hydrophilic-lipophilic balance (HLB) value of 18 to 23. In some examples, the sealed container is a road tanker, rail tanker, or marine tanker.

[0022] Figure 1This is a schematic diagram of an example of a method 100 for stabilizing pyrolysis oil stored in a sealed container and subsequently cleaning water-dispersible gum deposits from the sealed container. For the example shown, method 100 begins with step 102 of pyrolyzing mixed plastic waste (MPW) to produce pyrolysis oil. For example, the MPW can be heated to a temperature of 400°C to 500°C under anaerobic conditions to produce pyrolysis oil. As described, although pyrolysis oil primarily contains small hydrocarbon molecules, at least some of these molecules may also contain heteroatoms, such as oxygen, nitrogen, and halogen (e.g., chlorine, bromine, fluorine) atoms, depending on the composition of the MPW and the pyrolysis process. Additionally, atmospheric O2 can dissolve in the pyrolysis oil in certain circumstances. It is recognized that the heteroatom and / or dissolved oxygen content of the pyrolysis oil can lead to undesirable gum formation within the pyrolysis oil during storage and / or transportation.

[0023] For the example shown, method 100 proceeds to step 104, which involves combining the pyrolysis oil with the dispersant. More specifically, the dispersant is a polar surfactant that is immiscible with the pyrolysis oil (i.e., not miscible with the pyrolysis oil). As described below, the dispersant is also an emulsifier capable of forming and / or stabilizing an oil-in-water emulsion in the presence of an aqueous fluid. The dispersant typically has a hydrophilic-lipophilic balance (HLB) value greater than 10, for example, 10 to 30, 15 to 25, or 18 to 23 in some examples (calculated according to Davies' method). In some examples, the dispersant is a polyoxyolefin block copolymer. For example, the dispersant may be a poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEO-PPO-PEO) block copolymer. In some examples, the dispersant is Synperonic PeP105 (e.g., Chemical Abstracts Service (CAS) number 9003-11-6), which has an approximate molecular weight of 6500 g / mol, wherein approximately half of the dispersant by weight is PEO. In some examples, the dispersant is in paste form and can be dissolved in a small amount of organic solvent (e.g., toluene) for easy handling and mixing of the dispersant with the pyrolysis oil.

[0024] For the example shown, method 100 proceeds to step 106, which involves placing the pyrolysis oil and dispersant into a sealed container. In some examples, the dispersant and pyrolysis oil are combined before being loaded into the sealed container, while in other examples, they are combined within the sealed container itself. The dispersant combines with and separates colloidal impurities in the pyrolysis oil, resulting in a stabilized pyrolysis oil that typically has a lower colloidal content and a lower heteroatom content. More specifically, the combination of colloidal impurities and the dispersant forms a water-dispersible colloidal deposit on the inner surface of the sealed container, thereby isolating the colloidal impurities from the stabilized pyrolysis oil. In some examples, after exposure to the dispersant for at least 24 hours, the stabilized pyrolysis oil contains 1 wt% to 10 wt% fewer heteroatoms (e.g., nitrogen, oxygen, and / or halogen atoms) compared to the pyrolysis oil initially formed in step 102. In some examples, after exposure to the dispersant for at least 24 hours, the stabilized pyrolysis oil contains less than 1 wt% of colloidal impurities (e.g., less than 5 wt%, less than 3 wt%, less than 2 wt%, or less than 1 wt% of colloidal impurities). In some examples, the stabilized pyrolysis oil is lighter in color and / or exhibits higher optical transmittance compared to the pyrolysis oil formed in step 102 or stored or transported in a sealed container without the dispersant. Furthermore, this reduced level of colloidal impurities can be maintained indefinitely as long as the pyrolysis oil remains in contact with a sufficient amount of dispersant.

[0025] Because the dispersant is immiscible with the pyrolysis oil, it exists as a separate phase when combined with the pyrolysis oil. For example, the dispersant can form a higher-density layer or phase below the pyrolysis oil within a sealed container, such as between the pyrolysis oil and the inner surface of the sealed container. Furthermore, the polarity of the dispersant is sufficient to remove polar colloidal impurities formed in the pyrolysis oil by dissolving in the separate phase. It is now recognized that, in the absence of the disclosed dispersant, once colloid formation begins in a fresh batch of pyrolysis oil, the initially insoluble colloidal particles formed act as seeds promoting further colloid formation on their surfaces. By providing a separate layer or phase that captures and separates the initially formed colloidal particles, the disclosed dispersant purifies and stabilizes the pyrolysis oil while limiting further colloid formation or reducing the rate of colloid formation in the pyrolysis oil. Furthermore, it is recognized that the inner surface of a sealed container (e.g., a metal or glass sealed container) can also act as a surface promoting colloid formation within the pyrolysis oil. Therefore, since in some examples the dispersant can provide a separate layer or phase that isolates the pyrolysis oil from the inner surface of the sealed container, it is believed that the dispersant can further limit gum formation within the pyrolysis oil or reduce the gum formation rate within the pyrolysis oil. Moreover, it is now recognized that the aforementioned effects of the dispersant are surprising and unexpected, as those skilled in the art would not typically tend to combine pyrolysis oil with an immiscible dispersant and expect beneficial results.

[0026] For the example shown, method 100 proceeds to step 108, which involves removing the stabilized pyrolysis oil from the sealed container. For example, the stabilized pyrolysis oil can be pumped or drained from the sealed container. Once the pyrolysis oil is removed, a water-dispersible colloidal deposit formed from a mixture of colloidal impurities and a dispersant remains attached to the inner surface of the sealed container. Unlike colloidal deposits formed solely from pyrolysis oil that require removal with organic solvents (e.g., acetone), the water-dispersible colloidal deposit readily disperses in an aqueous fluid as an oil-in-water emulsion due to the presence of the dispersant.

[0027] For the example shown, method 100 concludes with the step of applying an aqueous fluid to the inner surface of a sealed container to disperse and remove water-dispersible colloidal deposits from the inner surface of the sealed container. In some examples, the aqueous fluid may include a detergent or an additional surfactant. However, in most examples, water alone is sufficient to remove water-dispersible colloidal deposits, which advantageously reduces operating costs and complexity. In some examples, water jetting or pressure cleaning may be used to apply the aqueous fluid to the inner surface of the sealed container to enhance the removal of water-dispersible colloidal deposits, which can desirably reduce the total volume of aqueous fluid consumed and / or cleaning time for cleaning the sealed container. In some examples, the aqueous fluid may be heated to 60°C to 95°C to promote the removal of water-dispersible colloidal deposits, while in other examples, the aqueous fluid is maintained at ambient temperature to desirably reduce power consumption. The resulting cleaning fluid includes colloidal impurities separated from stabilized pyrolytic oil, wherein these colloidal impurities are dispersed in oil droplets emulsified within the aqueous fluid by a dispersant. The cleaning fluid is removed from the sealed container (e.g., pumped or discharged) to obtain a sealed container with no gum deposits on its inner surface. In some examples, the cleaning fluid is directed to a water treatment system that purifies the cleaning fluid by removing emulsified oil droplets. In some examples, the water treatment system also recovers water from the cleaning fluid for recycling for cleaning the sealed container or other industrial processes.

[0028] Figure 2This is a schematic diagram of an example of a method 200 for stabilizing pyrolysis oil in a sealed container during transport and subsequently cleaning water-dispersible colloidal deposits from the sealed container. For the example shown, method 200 begins at step 202, which involves pyrolyzing mixed plastic waste (MPW) to produce pyrolysis oil, as described above. Method 200 continues to step 204, which involves loading the sealed container of the vehicle with a dispersant and the pyrolysis oil prior to transport. In some examples, the sealed container is a road tanker, rail tanker, or ocean tanker. As described, the dispersant is a polar surfactant and is immiscible with the pyrolysis oil. In some examples, the dispersant is applied to the inner surface of the sealed container before the pyrolysis oil is added. For example, the dispersant may be in the form of a paste, and the paste may be brushed or rolled onto the inner surface of the sealed container to form a waxy layer that isolates the pyrolysis oil to prevent direct contact with the inner surface of the sealed container. In some examples, the dispersant is dissolved in at least a minimum amount of organic solvent and sprayed onto the inner surface of a sealed container, and after the organic solvent evaporates, the dispersant forms a waxy layer that prevents or inhibits direct contact of the pyrolysis oil with the inner surface of the sealed container. In some examples, the dispersant and the pyrolysis oil are combined before, during, or after the pyrolysis oil is loaded into the sealed container.

[0029] For the example shown, method 200 proceeds to step 206, which involves transporting the sealed container from the first location to the second location using a vehicle. For example, the sealed container can be transported by road, rail, or waterway, allowing the pyrolysis oil to come into contact with the dispersant for at least 24 hours. In some examples, motion associated with transporting the sealed container (e.g., acceleration, vibration, oscillation) promotes enhanced contact between the pyrolysis oil and the dispersant. During contact in the pyrolysis oil during transport, the dispersant combines with the colloidal impurities of the pyrolysis oil to form a water-dispersible colloidal deposit on the inner surface of the sealed container, producing stabilized pyrolysis oil as described above.

[0030] For the example shown, after reaching the second position, method 200 proceeds to step 208, unloading the vehicle's sealed container by pumping or draining the stabilized pyrolysis oil from the sealed container. As described above, after removing the stabilized pyrolysis oil, water-dispersible colloidal deposits remain on the inner surface of the sealed container. Method 200 concludes with step 210, applying an aqueous fluid to the inner surface of the sealed container to disperse and remove the water-dispersible colloidal deposits from the inner surface of the sealed container. As described, in some examples, water jetting or pressure cleaning can be used to apply the aqueous fluid to the inner surface of the sealed container to enhance the removal of the water-dispersible colloidal deposits, which can hopefully reduce the total volume of aqueous fluid consumed and / or cleaning time for cleaning the sealed container. As described, in some examples, after applying the aqueous fluid, the resulting cleaning fluid is directed to a water treatment system that purifies the cleaning fluid by removing emulsified oil droplets and recycles the water for reuse. In some examples, when the properties of the dispersant are favorable for surface application, the inner surface of the cleaned sealed container is then coated with the dispersant to prepare the sealed container for receiving another batch of pyrolysis oil for transport.

[0031] Figure 3A This is a schematic diagram of an example of a sealed container 300 before being loaded with pyrolysis oil. More specifically, the illustrated example of sealed container 300 is a transport sealed container (e.g., a road tanker truck) coupled to a truck 302 for transport, while in other examples, sealed container 300 may be coupled to a railcar or an ocean liner for transport. For in Figure 3A In the example shown, the inner surface of the sealed container 300 has been coated with dispersant 304. For example, as noted, in some examples, the dispersant is applied to the inner surface using a brush, roller, spray, or any other suitable application technique to form a waxy layer on the inner surface of the sealed container 300. Although for... Figure 3A In the example shown, dispersant 304 is shown to cover all the inner surfaces of the sealed container 300, but in other examples, only a portion of the inner surfaces of the sealed container 300 (e.g., only a portion that will come into contact with the pyrolysis oil during transport) is coated with the dispersant.

[0032] Figure 3B It was after being loaded with pyrolysis oil 306. Figure 3AA schematic diagram of an example of a sealed container 300. In the example shown, the lack of miscibility between the pyrolysis oil 306 and the dispersant 304 causes the dispersant to remain close to the inner surface of the sealed container 300. Therefore, in the example shown, the dispersant typically isolates the pyrolysis oil 306 to prevent direct contact with the inner surface of the sealed container 300. In other examples where the dispersant is mixed with the pyrolysis oil before or during loading into the sealed container 300, the dispersant similarly separates into a separate layer or phase, which isolates the pyrolysis oil to prevent contact with at least a portion of the inner surface of the sealed container 300. In either case, once the pyrolysis oil 306 and the dispersant 304 come into contact with each other within the sealed container 300, the dispersant 304 binds with the colloidal impurities of the pyrolysis oil 306 and separates them as a water-dispersible colloidal deposit on the inner surface of the sealed container 300 throughout transport. As noted, this reduces the amount of colloidal impurities and / or heteroatoms in the pyrolysis oil, thereby resulting in the stabilization and / or purification of the pyrolysis oil 306 during storage and transport.

[0033] Figure 3C This is after the pyrolysis oil 306 has been removed. Figure 3B A schematic diagram of an example of a sealed container 300. For example, as noted, pyrolysis oil 306, stable during transport, can be pumped or discharged from the sealed container 300. Once removed, in some cases, the sealed container 300 may still contain some dispersant 304 that has not come into contact with or merged with the colloidal impurities of the pyrolysis oil 306. The dispersant 304 that merges with the colloidal impurities of the pyrolysis oil 306 forms a water-dispersible colloidal deposit 308, which remains on the inner surface of the sealed container 300. As noted, since the presence of colloidal impurities promotes further colloidal formation within the pyrolysis oil, it is now recognized that the inner surface of the sealed container 300 should be cleaned to remove any colloidal deposits before the sealed container 300 is used to transport additional pyrolysis oil or other hydrocarbon fluids.

[0034] Figure 3D This is when an aqueous fluid 310 is used to disperse and remove water-dispersible colloidal deposits retained on the inner surface of a sealed container 300. Figure 3C A schematic diagram of an example of a sealed container 300. For in Figure 3DIn the example shown, the aqueous fluid is primarily water (or consists entirely of water) and is delivered into the interior of the sealed container 300 using a water jet system 312. The water jet system 312 allows the aqueous fluid to be guided manually or robotically to the inner surface of the sealed container 300 to remove water-dispersible colloidal deposits 308 and disperse them into emulsified oil droplets 314 suspended within the cleaning fluid 316. Additionally, any residual dispersant 304 retained within the sealed container 300 is also removed by the aqueous fluid 310 and contributes to the emulsification of the oil droplets 314. The cleaning fluid 316 is then drained or pumped from the cleaned sealed container 300. In the example shown, the cleaning fluid 316 is delivered to a water treatment system 318, which processes the cleaning fluid 316 to remove the emulsified oil droplets 314 from the cleaning fluid 316. In some examples, the water treatment system 318 recovers at least a portion of the water 320 from the cleaning fluid 316, and the recovered water can be used to form at least a portion of the aqueous fluid 310 used to remove water-dispersible colloidal deposits during the cleaning of another sealed container.

[0035] Example

[0036] A series of experiments were performed to simulate the ability of the dispersant to stabilize pyrolysis oil and form a water-dispersible colloidal deposit on the inner surface of a sealed container. For these experiments, various concentrations of the dispersant (Synperonic PeP105) were combined with 50 mL of fresh pyrolysis oil in sealed glass containers. The dispersant was first dissolved in toluene before being combined with the pyrolysis oil, resulting in a concentration ranging from 50 parts per million (ppmw) to 5000 ppmw. After combining the dispersant and pyrolysis oil, each sealed container was exposed to air for the same period of time (e.g., 10 minutes) before sealing. The performance of the dispersant in the pyrolysis oil was evaluated over a two-week period relative to a control sample lacking the dispersant. At the end of both cycles, the stabilized pyrolysis oil was removed from the sealed container (e.g., drained, poured out), leaving a water-dispersible colloidal deposit along the inner surface of the sealed container. Dispersant concentrations as low as 50 ppmw were observed to be effective in forming water-dispersible colloidal deposits, and it was believed that even lower concentrations (e.g., 5 ppmw) could be effective depending on the composition of the pyrolysis oil in some embodiments. Dispersant concentrations above 200 ppmw were also observed to be extremely effective in forming water-dispersible colloidal deposits, and these deposits were easily removed and dispersed when the sealed container was washed with water alone.

[0037] Other objects, features, and advantages of this disclosure will become apparent from the foregoing drawings, detailed descriptions, and embodiments. However, it should be understood that while the drawings, detailed descriptions, and embodiments illustrate specific examples of this disclosure, they are given for illustrative purposes only and are not intended to be limiting. Furthermore, it will be apparent to those skilled in the art that changes and modifications within the spirit and scope of this disclosure will become apparent from the detailed descriptions. In other examples, features from specific examples may be combined with features from other examples. For example, a feature from one example may be combined with features from any other example. In other examples, additional features may be added to the specific examples described herein.

Claims

1. Methods, including: A sealed container is loaded with a dispersant and pyrolysis oil, wherein the dispersant is a polar surfactant that is immiscible with the pyrolysis oil; and The pyrolysis oil is brought into contact with the dispersant inside the sealed container to extract colloidal impurities from the pyrolysis oil, thereby producing a stabilized pyrolysis oil and forming a water-dispersible colloidal deposit on the inner surface of the sealed container.

2. The method according to claim 1, wherein the pyrolysis oil is derived from the pyrolysis of mixed plastic waste.

3. The method according to claim 1 or 2, comprising: The stabilized pyrolysis oil is pumped or discharged from the sealed container, wherein the water-dispersible colloidal deposits are retained on the inner surface of the sealed container.

4. The method according to claim 3, comprising: After the stabilized pyrolysis oil is removed from the sealed container, an aqueous fluid is applied to the inner surface of the sealed container to disperse and remove the water-dispersible colloidal deposits from the inner surface of the sealed container.

5. The method of claim 4, wherein applying the aqueous fluid includes water jetting or pressure cleaning the inner surface of the sealed container to remove the water-dispersible colloidal deposits.

6. The method of claim 4, wherein the aqueous fluid does not contain acetone or other organic solvents.

7. The method according to any one of claims 1 to 6, wherein the stabilized pyrolysis oil contains less heteroatoms relative to the pyrolysis oil, from 1% to 10 wt%, wherein the heteroatoms include oxygen atoms, nitrogen atoms, or halogen atoms, or combinations thereof.

8. The method according to any one of claims 1 to 6, wherein the stabilized pyrolysis oil contains less than 1 wt% gum impurities.

9. The method according to any one of claims 1 to 6, wherein the dispersant comprises a polyoxyolefin block copolymer having a hydrophilic-lipophilic balance (HLB) value greater than 10.

10. The method according to any one of claims 1 to 6, wherein the dispersant comprises a poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) (PEO-PPO-PEO) block copolymer having an HLB of 18 to 23.

11. A sealed container for storing or transporting pyrolysis oil, wherein the sealed container contains pyrolysis oil and a dispersant, the dispersant being a polar surfactant immiscible with the pyrolysis oil.

12. The sealed container of claim 11, wherein the inner surface of the sealed container is coated with the dispersant before the sealed container is loaded with the pyrolysis oil for storage or transport.

13. The sealed container according to claim 11 or 12, wherein the inner surface of the sealed container contains water-dispersible colloidal deposits formed when the colloidal impurities of the pyrolysis oil come into contact with the dispersant.

14. The sealed container according to any one of claims 11 to 13, wherein the dispersant is a polyoxyolefin block copolymer having a hydrophilic-lipophilic balance (HLB) value of 18 to 23.

15. The sealed container according to any one of claims 11 to 14, wherein the sealed container is a road tanker, a rail tanker, or an ocean tanker.

Images