Systems and methods for stabilizing, storing, and transporting oxygen-sensitive pyrolysis oil

Abstract

This document provides systems and methods for limiting or eliminating the formation of gum deposits in pyrolysis oils during storage and / or transportation within a containment container. One such method includes the steps of loading pyrolysis oil into the internal volume of a containment container and reducing the oxygen content within the internal volume of the containment container to inhibit the formation of gum deposits in the pyrolysis oil during storage and / or transportation. In some instances, reducing the oxygen content includes contacting the pyrolysis oil with solid carbon dioxide (CO2) before, during, or after loading the pyrolysis oil into the internal volume of the containment container. In some instances, reducing the oxygen content includes contacting the gaseous headspace within the internal volume with an oxygen-removing material before, during, or after loading the pyrolysis oil.

Description

Technical Field

[0001] This disclosure generally relates to systems and methods for the stabilization, storage, and transportation of pyrolysis oil. More specifically, this disclosure relates to systems and methods for limiting or eliminating gum formation in pyrolysis oil during storage and / or transportation by removing oxygen dissolved in and / or present in the storage or transportation container. Background Technology

[0002] 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 high temperatures (e.g., between 400°C and 500°C). Pyrolysis oil primarily contains small hydrocarbon molecules that may contain a variety of heteroatoms, such as oxygen, nitrogen, and halogen (e.g., chlorine, bromine, fluorine) atoms, depending on the composition of the MPW and the pyrolysis process. Atmospheric gases, including oxygen (O2), may dissolve in the pyrolysis oil, for example, during the transfer of the pyrolysis oil to a container for storage or transport. Furthermore, atmospheric O2 may be present in the container before the pyrolysis oil is loaded, and this O2 may gradually dissolve into the pyrolysis oil over time. It is currently accepted that the heteroatoms and dissolved oxygen content in pyrolysis oil contribute to the formation of undesirable gum deposits 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.

[0003] As pyrolysis oil is oxidized during storage or transportation, it begins to form gums, which are oxidized solid particles of pyrolysis oil that are insoluble in the remaining liquid pyrolysis oil. When the pyrolysis oil is removed from its container after storage or transportation, most of these gums remain as deposits on the inner surfaces of the storage or transportation containers, which typically require cleaning to remove the gum deposits before they can be used for other purposes. Cleaning containers used for storing or transporting pyrolysis oil takes approximately three times longer than cleaning containers used for other hydrocarbons, undesirably increasing operating costs and delays. Furthermore, after the pyrolysis oil is removed, large quantities of organic solvents (e.g., acetone) are typically used to dissolve and remove the gum deposits inside these containers, undesirably increasing operating costs associated with the procurement, application, and disposal of these organic solvents. In some cases, depending on the organic solvent used, certain protective, ventilation, and monitoring devices may also be used to limit and / or monitor exposure to organic solvents, further increasing operating costs. Therefore, efforts to limit the formation of gums inherent in pyrolysis oil during storage and transportation remain necessary. Summary of the Invention Invention Overview

[0005] Examples described herein include systems and methods for limiting or eliminating the formation of gum deposits in pyrolysis oil within a containment container during storage and / or transportation. One such method includes the steps of loading pyrolysis oil into the internal volume of a containment container and reducing the oxygen content within the internal volume of the containment container to inhibit the formation of gum deposits in the pyrolysis oil during storage and / or transportation. In some examples, reducing the oxygen content includes purging the gaseous headspace within the internal volume with an inert gas before, during, and after loading the pyrolysis oil. In some examples, reducing the oxygen content includes supplying an inert gas stream to the pyrolysis oil within the internal volume to purge dissolved oxygen, wherein the inert gas stream subsequently purges oxygen from the gaseous headspace within the internal volume. In some instances, the method includes placing solid carbon dioxide (CO2) in a container disposed outside and in fluid communication with the internal volume, wherein the container is configured to sublimate the solid CO2 to generate gaseous CO2 as an inert gas stream delivered to the internal volume, thereby purging oxygen dissolved in the pyrolysis oil and purging oxygen from the gaseous headspace within the internal volume. In some instances, reducing the oxygen content includes contacting the pyrolysis oil with solid CO2 before, during, or after loading the internal volume of the containing container, wherein the solid CO2 sublimates to generate gaseous CO2, which purges oxygen dissolved in the pyrolysis oil, purges oxygen from the gaseous headspace within the internal volume, or a combination thereof.

[0006] In some instances, reducing the oxygen content includes contacting the gaseous headspace within the internal volume with an oxygen-removing material before, during, or after loading the pyrolysis oil. In some instances, reducing the oxygen content includes placing an oxygen-removing material within the internal volume before, during, or after loading the pyrolysis oil, wherein the oxygen-removing material is configured to float on the surface of the pyrolysis oil after loading. In some instances, reducing the oxygen content includes contacting the gaseous headspace of the internal volume with an oxygen-removing material disposed outside the internal volume and in fluid communication with the gaseous headspace of the internal volume. In some instances, after reducing the oxygen content, the pyrolysis oil contains less than 0.3 parts by weight per million parts by weight (ppmw) of gum impurities after up to five weeks of storage and / or transportation. In some instances, the pyrolysis oil exhibits a 60% to 90% reduction in gum impurity content after storage and / or transportation compared to the same pyrolysis oil stored and / or transported in the same manner but without reducing the oxygen content within the internal volume.

[0007] One such system includes a containment container having an internal volume configured to hold pyrolysis oil for storage and / or transport. The system includes a vessel disposed outside the containment container and in fluid communication with the internal volume of the containment container, wherein the vessel is configured to receive and sublimate solid carbon dioxide (CO2) to generate a gaseous CO2 stream, which is delivered to the internal volume of the containment container before, during, or after the pyrolysis oil is loaded, to reduce the oxygen content in the internal volume. In some instances, the gaseous CO2 stream is configured to purge oxygen dissolved in the pyrolysis oil, purge oxygen from the atmosphere within the internal volume, or a combination thereof. In some instances, the containment container includes an oxygen-scavenging material in fluid communication with a gaseous topspace within the internal volume of the containment container, wherein the oxygen-scavenging material is configured to sequester oxygen from the gaseous topspace before, during, or after the pyrolysis oil is loaded into the internal volume of the containment container. In some instances, the oxygen-scavenging material is disposed within a removable cylinder, which is located within or outside the internal volume of the containment container. In some instances, the containment container includes anisotanks, or containment containers for tanker trucks, tanker barges, or railway tankers.

[0008] This document discusses in detail the aspects and advantages of these exemplary examples and other examples. Furthermore, it should be understood that the above 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 purposes, together with the advantages and features of this disclosure, 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

[0009] The accompanying drawings, which are intended to provide a further understanding of examples of this disclosure and form part of this specification, illustrate examples of this disclosure and, together with the detailed description, serve to explain the principles of the examples discussed herein. No structural details of this disclosure are attempted to be shown; only what is necessary for understanding the examples discussed herein and their various embodiments is presented. By convention, the various features in the drawings discussed below are not necessarily drawn to scale. The dimensions of various features and elements in the drawings may be enlarged or reduced to more clearly illustrate the examples of this disclosure.

[0010] Figure 1 This is a schematic diagram illustrating a method for stabilizing pyrolysis oil before, during, or after it is loaded into a container for transport and / or storage, based on an example.

[0011] Figure 2 This is a schematic diagram of a method for stabilizing pyrolysis oil for transport and / or storage, based on an example, by degassing O2 from the gaseous headspace of the pyrolysis oil and / or containing container.

[0012] Figure 3 This is a schematic diagram of a system for degassing a container before, during, and / or after it is loaded with pyrolysis oil, based on an example.

[0013] Figure 4 This is a schematic diagram of a system for degassing a container before, during, and / or after it is loaded with pyrolysis oil, based on an example.

[0014] Figure 4 This is a schematic diagram of a system for degassing pyrolysis oil during loading into a containment container, based on an example.

[0015] Figure 6 This is a schematic diagram of a method for capturing and sealing O2 from the gaseous headspace of a container to stabilize pyrolysis oil during transport and / or storage, based on an example.

[0016] Figure 7 This is a schematic diagram of a system for removing O2 from a container before, during, and / or after the container is loaded with pyrolysis oil, based on an example.

[0017] Figure 8 This is a schematic diagram of another system for removing O2 from a container before, during, and / or after the container is loaded with pyrolysis oil, based on one example.

[0018] Figure 9 This is a schematic diagram of another system for removing O2 from a container before, during, and / or after the container is loaded with pyrolysis oil, based on one example.

[0019] Figure 10 This is a schematic diagram of a method for stabilizing pyrolysis oil during storage and / or transportation, based on an example, in which a controller conditionally activates the deoxygenation system of a containment container to remove and seal O2 from inside the containment container.

[0020] Figure 11 This is a schematic diagram of a system for removing O2 from a container before, during, and / or after the container is loaded with pyrolysis oil, based on an example.

[0021] Figure 12 It is a graph showing the change of dry gel content of a sample over time, based on an example. Invention Details

[0023] This disclosure describes various examples of systems and methods relating to limiting gum formation and removing gum impurities during the storage and / or transportation of pyrolysis oils, as well as improved techniques for removing gum deposits from the inner surfaces of storage and / or transportation containers. This specification may use phrases such as "in some instances," "in various instances," "in one instance," or "in an instance," each of which may refer to one or more of the same or different instances. Furthermore, for the purposes of this disclosure, the terms "comprising," "including," "having," and similar terms are synonymous. The term "a plurality" as used herein refers to two or more items or components. The terms "about" or "approximately" are defined as a close approximation 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%.

[0024] When used in the claims and / or description, the terms "removed," "reduced," "reduced," "reduced," or any variation thereof include any measurable reduction of one or more components in a mixture to achieve the desired result. In the claims or description, when the word "an" or "a" is used with any of the terms "comprising," "including," "containing," or "having," it may mean "an," but also corresponds to the meaning of "one or more," "at least one," and "more than one." The terms "weight%," "volume%," or "molar%" refer to the weight, volume, or molar percentage of a component, based on the total weight, total volume, or total number of moles containing said component. In a non-limiting example, 10 grams of component in 100 grams of material constitutes 10% by weight of said component.

[0025] Examples described herein include systems and methods for limiting or eliminating the formation of gum deposits in pyrolysis oil within a containment container during storage and / or transportation. One such method includes the steps of loading pyrolysis oil into the internal volume of a containment container and reducing the oxygen content within the internal volume of the containment container to inhibit the formation of gum deposits in the pyrolysis oil during storage and / or transportation. In some instances, reducing the oxygen content includes purging the gaseous headspace within the internal volume with an inert gas before, during, or after loading the pyrolysis oil. In some instances, reducing the oxygen content includes supplying an inert gas stream to the pyrolysis oil within the internal volume to purge dissolved oxygen from the pyrolysis oil, wherein the inert gas stream subsequently purges oxygen from the gaseous headspace within the internal volume. In some instances, the method includes placing solid carbon dioxide (CO2) in a container located outside and in fluid communication with the internal volume, wherein the container is configured to sublimate the solid CO2 to generate gaseous CO2 as an inert gas stream delivered to the internal volume, thereby purging oxygen dissolved in the pyrolysis oil and purging oxygen from the gaseous headspace within the internal volume. In some instances, reducing the oxygen content includes contacting the pyrolysis oil with solid CO2 before, during, or after loading the internal volume of the containing container, wherein the solid CO2 sublimates to generate gaseous CO2, which purges oxygen dissolved in the pyrolysis oil, purges oxygen from the gaseous headspace within the internal volume, or a combination thereof.

[0026] In some instances, reducing the oxygen content includes contacting the gaseous headspace within the internal volume with an oxygen-removing material before, during, or after loading the pyrolysis oil. In some instances, reducing the oxygen content includes placing an oxygen-removing material within the internal volume before, during, or after loading the pyrolysis oil, wherein the oxygen-removing material is configured to float on the surface of the pyrolysis oil after loading. In some instances, reducing the oxygen content includes contacting the gaseous headspace of the internal volume with an oxygen-removing material disposed outside the internal volume and in fluid communication with the gaseous headspace of the internal volume. In some instances, after reducing the oxygen content, the pyrolysis oil contains less than 0.3 parts by weight per million parts by weight (ppmw) of gum impurities after up to five weeks of storage and / or transportation. In some instances, the pyrolysis oil exhibits a 60% to 90% reduction in gum impurity content after storage and / or transportation compared to the same pyrolysis oil stored and / or transported in the same manner but without reducing the oxygen content within the internal volume.

[0027] One such system includes a containment container having an internal volume configured to hold pyrolysis oil for storage and / or transport. The system includes a vessel disposed outside the containment container and in fluid communication with the internal volume of the containment container, wherein the vessel is configured to receive and sublimate solid carbon dioxide (CO2) to generate a gaseous CO2 stream, which is delivered to the internal volume of the containment container to reduce the oxygen content in the internal volume before, during, or after the pyrolysis oil is loaded into the internal volume of the containment container. In some instances, the gaseous CO2 stream is configured to purge oxygen dissolved in the pyrolysis oil, purge oxygen from the atmosphere within the internal volume, or a combination thereof. In some instances, the containment container includes an oxygen-scavenging material in fluid communication with a gaseous topspace within the internal volume of the containment container, wherein the oxygen-scavenging material is configured to trap oxygen from the gaseous topspace before, during, or after the pyrolysis oil is loaded into the internal volume of the containment container. In some instances, the oxygen-scavenging material is disposed within a removable cylinder, which is located within or outside the internal volume of the containment container. In some instances, the containment container includes tank containers, or containment containers for tank trucks, tank barges, or railcars.

[0028] Figure 1 This is a schematic diagram of an embodiment of a method 100 for stabilizing pyrolysis oil placed in a container for transport and / or storage. For the example shown, method 100 begins at step 102, which involves pyrolyzing mixed plastic waste (MPW) to produce pyrolysis oil. For example, MPW can be heated under anaerobic conditions to a temperature of 400°C to 500°C to produce pyrolysis oil. As noted, while pyrolysis oil primarily contains small hydrocarbon molecules, depending on the composition of the MPW and the pyrolysis process, at least some of these molecules may also contain heteroatoms, such as oxygen, nitrogen, and halogen (e.g., chlorine, bromine, fluorine) atoms. Furthermore, when the pyrolysis oil is exposed to the atmosphere after production, atmospheric O2 dissolves in it. It is currently recognized that the dissolved oxygen content in the pyrolysis oil contributes to undesirable gum formation during storage and / or transport. It is also currently recognized that once gum formation begins in a fresh batch of pyrolysis oil, the initially formed insoluble gum particles act as seed crystals, promoting further gum formation on their surface.

[0029] For the illustrated example, method 100 proceeds to step 104, which involves loading (e.g., pumping, discharging) the pyrolysis oil into a containment container. Furthermore, method 100 includes step 106, which involves removing O2 dissolved in the pyrolysis oil and / or present in the gaseous headspace of the containment container using an inert gas or deoxygenating material before, during, and / or after loading the pyrolysis oil into the containment container, to produce stabilized pyrolysis oil. As used herein, the term "gaseous headspace" refers to the internal volume of the containment container not occupied by the pyrolysis oil. For a containment container not loaded with pyrolysis oil, the entire internal volume of the containment container constitutes the gaseous headspace. For a containment container loaded with pyrolysis oil, the gaseous headspace refers to the volume of gas (e.g., air, atmospheric O2, carbon dioxide (CO2), volatile organic compounds) above the pyrolysis oil within the internal volume of the containment container. As described herein, in some embodiments, O2 dissolved in the pyrolysis oil and / or present in the gaseous headspace of the containment container can be displaced and removed from the internal volume of the containment container by degassing using an inert gas. As used herein, "inert gas" refers to a gas that does not undergo substantial chemical reaction with the pyrolysis oil (e.g., CO2, nitrogen (N2), argon (Ar), helium (He)). As described herein, in some embodiments, deoxygenating materials are used to capture and seal O2 present in the gaseous headspace of the containment container (e.g., atmospheric O2 present in the containment container before loading the pyrolysis oil, which is gradually released into the gaseous headspace dissolved in the pyrolysis oil over time). Although discussed separately in different examples below, in some embodiments, the degassing and deoxygenation techniques described herein may be used synergistically to further reduce the O2 content within the containment container volume during pyrolysis oil storage and / or transportation.

[0030] For the illustrated example, method 100 proceeds to step 108, which involves removing the stabilized pyrolysis oil from the container after storage and / or transportation. For example, the stabilized pyrolysis oil may be pumped out or discharged from the container. Compared to pyrolysis oil stored and / or transported in the same manner but without the aforementioned O2 removal technology (e.g., the pyrolysis oil formed in step 102), the stabilized pyrolysis oil contains significantly less dissolved O2 and significantly fewer colloidal impurities (e.g., a reduction of approximately 60% to approximately 90% by weight in colloidal impurities). By reducing or eliminating colloidal formation during the storage and / or transportation of the stabilized pyrolysis oil, the present invention facilitates easier cleaning of the container between multiple uses and may reduce the use of organic solvents (e.g., acetone) during cleaning, which hopefully reduces the time, operating costs, and complexity associated with cleaning the container after storage and / or transportation of the pyrolysis oil. For example, in some cases, the cleaning process implemented by the technology of this invention is similar to the cleaning process of containers after storing and / or transporting other hydrocarbon feedstocks (e.g., petroleum feedstocks), without requiring the intensive cleaning typically required for cleaning gum deposits in containers previously used for storing and / or transporting pyrolysis oil without using the O2 removal technology described herein. Furthermore, by reducing or eliminating gum formation during storage and / or transport, stabilized pyrolysis oil is easier and cleaner to handle, thus reducing the likelihood of adverse effects on processing equipment (e.g., pumps, pre-processors, fractionators, crackers) used for post-storage and / or transport of stabilized pyrolysis oil.

[0031] Figure 2 This is a schematic diagram of an embodiment of method 200 for stabilizing pyrolysis oil for transport and / or storage by degassing O2 from the gaseous headspace of the pyrolysis oil and / or containing container. Method 200 begins with step 202, which involves pyrolyzing MPW to produce pyrolysis oil; and step 204, which involves loading the pyrolysis oil into the containing container, these steps being as described above for... Figure 1 The discussion proceeds. Method 200 includes step 206, which involves degassing the pyrolysis oil and / or the gaseous headspace of the containment container with an inert gas that displaces O2 from the pyrolysis oil and / or the containment container to produce stabilized pyrolysis oil. As described below, the degassing in step 206 can be performed in a variety of different ways using different inert gas sources. In some embodiments, the inert gas is gaseous CO2, and in some embodiments, the gaseous CO2 is produced via the sublimation of solid CO2 (also referred to herein as dry ice). For example, in some embodiments, step 206 of method 200 includes placing dry ice in the pyrolysis oil, the containment container, and / or a chamber in fluid communication with the containment container before, during, or after loading the pyrolysis oil into the containment container, such that as the dry ice sublimates, the gaseous CO2 removes and displaces O2 from the pyrolysis oil and / or the containment container's gaseous headspace. Figure 2 In the illustrated embodiment, method 200 ends at step 208, which involves removing the stabilized pyrolysis oil from the container after storage and / or transportation. This stabilized pyrolysis oil contains significantly less dissolved O2 and significantly fewer colloidal impurities compared to pyrolysis oil stored and / or transported without undergoing the O2 removal step 206 (e.g., the pyrolysis oil formed in step 202).

[0032] Figure 3 It is based on Figure 2 A schematic diagram of an embodiment of a system 300 for degassing the containment container 302 before, during, and / or after loading the containment container 302 with the pyrolysis oil 304, step 206 of method 200. More specifically, the illustrated example of the containment container 302 is a transport containment container (e.g., a road tanker) attached to a truck 306 for transport; in other examples, the containment container 302 may be associated with a railway car or ocean-going freighter for transport, or it may be a stationary storage tank for storage. System 300 includes an inert gas source 308 that provides a supply or flow of inert gas 310. In some embodiments, the inert gas source 308 is a gas cylinder that stores inert gas 310 in a compressed state, and the inert gas may be liquid under pressure within the cylinder. For example, the gas cylinder may store CO2, N2, Ar, He, oxygen-free air, or combinations thereof as inert gas 310. In other embodiments, the inert gas source 308 may be a sealable container (e.g., in fluid communication with the interior of the containment container 302, specifically with the pyrolysis oil 304 inside the containment container 302) filled with dry ice before sealing. As the sealable container absorbs heat from the surrounding environment, the dry ice sublimates to produce gaseous CO2 as the inert gas 310. In some embodiments, the inert gas source 308 is connected to the containment container 302 or the truck 306 to degas the pyrolysis oil 304 during or throughout transport; in other embodiments, the inert gas source 308 is temporarily fluid-coupled to the interior of the containment container 302 before the truck 306 begins its journey to its delivery destination to degas the interior of the containment container.

[0033] for Figure 3In one embodiment of the system 300 shown, an inert gas 310 stream is delivered into the containment container 302. More specifically, when the containment container 302 is filled with pyrolysis oil 304, the inert gas 310 stream is delivered into the pyrolysis oil 304, and preferably, the inert gas 310 stream is delivered at or near the bottom of the containment container 302 (e.g., within 5% to 10% of the lower vertical height). In some embodiments, the inert gas 310 stream passes through a dedicated conduit installed in the containment container 302, which delivers the inert gas 310 stream to or near the bottom of the containment container 302; while in other embodiments, the conduit may be temporarily introduced through an access port of the containment container and (when the pyrolysis oil 304 is present) temporarily immersed in the pyrolysis oil 304 for a degassing process. Inert gas 310 flows through pyrolysis oil 304 and bubblees upwards, displacing O2 dissolved in pyrolysis oil 304. The displaced O2 enters the gaseous top space 312 of the container 302. At this time, the gaseous top space 312 of the container 302 may contain the inert gas that has passed through pyrolysis oil 304, O2 previously dissolved in pyrolysis oil 304, and air that may have been present in the container 302 before the pyrolysis oil 304 was loaded. As inert gas 310 flows into the container 302, a portion 314 of the gaseous top space 312 containing the purged O2 and inert gas leaves the container 302, which over time reduces the amount of O2 present inside the container 302 (e.g., dissolved in pyrolysis oil 304 and / or present in the gaseous top space 312). In some embodiments, the purge flow of O2 and inert gas 314 passes through an installed dedicated conduit (e.g., a purge line) of the containment container 302, which fluidly connects the gaseous top space 312 to the outside of the containment container 302; in other embodiments, the conduit may be temporarily introduced through an access port or hatch of the containment container and temporarily positioned within the gaseous top space 312 for the degassing process. It is understood that regardless of how the inert gas 310 flow is introduced into the containment container 302, and how the purge flow of O2 and inert gas 314 exits the containment container 302, it is generally desirable that the interior of the containment container 302 remain substantially sealed during and after the degassing process to prevent the pyrolysis oil 304 or the gaseous top space 312 from contacting additional atmospheric O2. In some implementations, this may involve using a bubbler or another suitable device to achieve a unidirectional flow of the purged O2 and inert gas 314 from the gaseous top space 312 of the containment container 302 to the atmosphere, while preventing or blocking the backflow of atmospheric gas into the containment container 302.

[0034] Figure 4 It is based on Figure 2Step 206 of method 200 is a schematic diagram of an embodiment of a system 400 for degassing the containment container 402 before, during, and / or after loading the containment container 402 with pyrolysis oil 404. More specifically, the illustrated example of the containment container 402 is a transport containment container (e.g., a road tanker) connected to a truck 406 for transport; in other examples, the containment container 402 may be associated with a railcar or ocean-going freighter for transport, or it may be a stationary storage tank for storage. In the illustrated embodiment, dry ice 408 is deposited inside the containment container 402 before, during, or after the pyrolysis oil 404 is loaded into the containment container. For example, the dry ice 408 may be introduced into the containment container 402 via an access port or hatch of the containment container and dispersed within the pyrolysis oil 404 (if present). In some implementations, dry ice 408 is in the form of small particles (e.g., with a diameter in the millimeter to centimeter range) to increase the contact surface area between dry ice 408 and pyrolysis oil 404.

[0035] for Figure 4In the embodiment of system 400 shown, when dry ice 408 absorbs heat from the surrounding environment (e.g., from pyrolysis oil 404) within the containment container 402, it sublimates to form gaseous CO2. When the containment container 402 is filled with pyrolysis oil 404, the gaseous CO2 bubbles upwards through the pyrolysis oil 404, displacing the O2 dissolved in the pyrolysis oil, and the displaced O2 enters the gaseous top space 412 of the containment container 402. At this time, the gaseous top space 412 of the containment container 402 may contain the gaseous CO2 that has passed through the pyrolysis oil 404, the O2 previously dissolved in the pyrolysis oil 404, and air that may have been present in the containment container 402 before the pyrolysis oil 404 was loaded or entered the containment container 402 when the dry ice 408 was introduced. As the dry ice 408 sublimates and increases the pressure inside the containment container 402, a portion 414 of the gaseous topspace 412, containing the purged O2 and gaseous CO2, leaves the containment container 402. This reduces the amount of O2 present inside the containment container 402 over time (e.g., dissolved in the pyrolysis oil 404 and / or present in the gaseous topspace 412). In some embodiments, the purge flow of O2 and CO2 gas 414 passes through an installed dedicated conduit (e.g., a purge line) connecting the gaseous topspace 412 to the outside of the containment container 402; in other embodiments, the conduit may be temporarily introduced through an access port or hatch of the containment container and temporarily positioned within the gaseous topspace 412 for the degassing process. Understandably, regardless of how the purged O2 and CO2 gas 414 flows out of the interior of the containment container 402, it is generally desirable to seal the interior of the containment container 402 during and after the degassing process to prevent the pyrolysis oil 404 or the gaseous headspace 412 from contacting additional atmospheric O2. In some embodiments, this may involve using a bubbler or another suitable device to achieve a unidirectional flow of the purged O2 and CO2 gas 414 from the gaseous headspace 412 of the containment container 402 to the atmosphere, while preventing or blocking the backflow of atmospheric gas into the containment container 402.

[0036] Figure 5 It is based on Figure 2 Step 206 of method 200 is a schematic diagram of an embodiment of a system 500 for degassing pyrolysis oil 504 during loading into container 502. More specifically, the illustrated example of container 502 is a transport container (e.g., a road tanker) connected to truck 506 for transport; in other instances, container 502 may be associated with a railway car or ocean-going vessel for transport, or it may be a stationary storage tank for storage. Figure 5 The illustrated system implementation includes an inert gas source 508 that provides the supply or flow of inert gas 510, as described above. Figure 3 The discussion. Figure 5 An embodiment of the system shown includes a mixing chamber 512 (also referred to herein as a degassing chamber) that receives a flow of inert gas 510 and a supply or flow of pyrolysis oil 504. The flow of inert gas 510 is introduced at or near the bottom of the mixing chamber 512 and bubbled upwards through the pyrolysis oil 504 to displace dissolved O2 therein, subsequently purging the mixture of O2 and inert gas 514 from the mixing chamber 512. After exiting the mixing chamber 512, the stabilized pyrolysis oil 516 is loaded (e.g., pumped, discharged) into the internal volume of a containing container 502 for storage and / or transport. In some embodiments, prior to loading the stabilized pyrolysis oil 516, atmospheric O2 present in the gaseous headspace 518 of the containment container 502 may be removed (e.g., by degassing using an inert gas stream 510, or by sealing with an oxygen-removing material as described below) to ensure that atmospheric O2 present in the gaseous headspace 518 has no opportunity to dissolve into the stabilized pyrolysis oil 516 and promote gum formation. In some embodiments, a bubbler or other suitable device may be used to achieve unidirectional flow of atmospheric gas from the internal volume of the containment container 502 to the atmosphere during loading of the stabilized pyrolysis oil to balance pressure, while preventing or blocking the backflow of atmospheric gas into the containment container 502.

[0037] Figure 6 This is a schematic diagram of an example of a method 600 for capturing and sealing O2 from the gaseous headspace of a containment container to stabilize pyrolysis oil during transport and / or storage. Method 600 begins with step 602, which involves pyrolyzing MPW to produce pyrolysis oil; and step 604, which involves loading the pyrolysis oil into a containment container, as described above for... Figure 1 The process is carried out as discussed. Method 600 includes step 606, which involves contacting the gaseous headspace of the containment container with an oxygen-removing material before, during, and / or after loading the pyrolysis oil to reduce the oxygen content in the gaseous headspace, thereby producing stabilized pyrolysis oil. Method 600 ends at step 608, which involves removing the stabilized pyrolysis oil from the containment container after storage and / or transportation, wherein the stabilized pyrolysis oil has significantly less dissolved O2 and significantly fewer colloidal impurities compared to pyrolysis oil stored and / or transported without undergoing the O2 removal step 606 (e.g., the pyrolysis oil formed in step 602).

[0038] Figure 7 It is based on Figure 6A schematic diagram of an embodiment of a system 700 for removing O2 from a container 702 before, during, and / or after loading pyrolysis oil 704 into the container 702, is shown in step 606 of method 600. More specifically, the illustrated example of the container 702 is a transport container (e.g., a road tanker) attached to a truck 706 for transport; in other examples, the container 702 may be associated with a railway car or ocean-going freighter for transport, or it may be a stationary storage tank for storage. Figure 7 In the illustrated embodiment, the containment container 702 includes a holder 708 (e.g., 708A, 708B) located within the gaseous top space 712 of the containment container 702, above the liquid level of the pyrolysis oil 704. The holder 708 is designed to receive a removable cartridge 710 (e.g., 710A, 710B) containing O2 scavenging material and includes suitable openings to allow the gaseous top space 712 to contact the removable cartridge 710. Although Figure 7 The embodiment shown depicts two reservoirs 708 and two cylinders 710. However, in other embodiments, depending on the size of the containment container, the duration for which the pyrolysis oil 704 will be stored and / or transported in the containment container, the dissolved O2 content in the pyrolysis oil, the amount of O2 that each cylinder can seal, and other factors, the containment container 702 may include any suitable number of reservoirs 708 and cylinders 710 (e.g., 1, 2, 3, 4, 5, 6, or more). An O2 scavenging material in the removable cylinder 710 interacts with the O2 present in the gaseous headspace 712 of the containment container 702 (e.g., through chemical reaction, adsorption, absorption, or otherwise sealing), thereby reducing the O2 content in the gaseous headspace 712 over time. Furthermore, because the pyrolysis oil 704 exchanges dissolved gases with the gaseous headspace 712 over time, the dissolved O2 content in the pyrolysis oil 704 also decreases over time, thereby stabilizing the pyrolysis oil 704 and limiting or eliminating gum formation during storage and / or transport.

[0039] for Figure 7In one embodiment of the system 700 shown, the drum seat 708 is installed via an access hatch 714 (e.g., 714A, 714B) located on or near the top of the containment container 702 (e.g., within 5% to 15% of the vertical height). The access hatch 714 allows an operator to access the drum seat 708 to remove and replace the drum 710 before resealing the internal volume of the containment container 702. For example, in some embodiments, the operator may install a fresh drum 710 into the containment container 702 at a predetermined time (e.g., 1 hour, 6 hours, 12 hours, 1 day) before loading the pyrolysis oil 704, allowing sufficient time for the drum 710 to significantly reduce the O2 content in the gaseous headspace 712 before loading. In other cases, the operator may install a fresh drum 710 into the containment container 702 during loading the pyrolysis oil 704 and / or during the storage and / or transport of the pyrolysis oil 704. In some embodiments, the waste cartridge 710 removed from the receiving container 702 can be renewed or regenerated, for example by treating the waste cartridge with one or more chemical reagents (e.g., acid or alkali) and / or by one or more physical processes (e.g., heating and / or placing it under vacuum).

[0040] Figure 8 It is based on Figure 6 Step 606 of method 600 is a schematic diagram of an embodiment of a system 800 for removing O2 from the container 802 before, during, and / or after loading the pyrolysis oil 704 into the container 802. More specifically, the illustrated example of the container 802 is a transport container (e.g., a road tanker) attached to a truck 806 for transport; in other examples, the container 802 may be associated with a railway car or ocean-going freighter for transport, or it may be a stationary storage tank for storage. Figure 8 The embodiment shown includes a container 802 comprising a float 808 containing, as described above, a float 808. Figure 7 The removable cylinder 810 is equipped with an O2 scavenging material. More specifically, a floating cylinder seat 808 is located within the gaseous headspace 812 of the containing container 802, floating on or near the pyrolysis oil 804. The O2 scavenging material of the removable cylinder 810 interacts with the O2 present in the gaseous headspace 812 of the containing container 802 (e.g., through chemical reaction, adsorption, absorption, or other means of sealing), thereby gradually reducing the O2 content in the gaseous headspace 812 over time. Furthermore, because the pyrolysis oil 804 exchanges dissolved gases with the gaseous headspace 812 over time, the dissolved O2 content in the pyrolysis oil 804 also decreases over time, thereby stabilizing the pyrolysis oil 804 and limiting or eliminating the formation of gums during storage and / or transportation.

[0041] for Figure 8In one embodiment of the system 800 shown, the floating drum holder 808 comprises three removable drums 810. In other embodiments, the floating drum holder 808 may be designed to contain any suitable number of removable drums 810 (e.g., 1, 2, 3, 4, 5, 6 or more), depending on factors such as the size of the containment container, the duration for which the pyrolysis oil 804 will be stored and / or transported in the containment container, the dissolved O2 content of the pyrolysis oil, and the amount of O2 that each drum can seal. In some embodiments, the floating drum holder 808 may be loaded with fresh removable drums 810 and placed in the internal volume of the containment container 802 at a predetermined time (e.g., 1 hour, 6 hours, 12 hours, 1 day) before loading the pyrolysis oil 804, allowing sufficient time for the drums 810 to significantly reduce the O2 content in the gaseous headspace 812 before loading. Once pyrolysis oil 804 is loaded, the floating cylinder seat 808 floats on top of the pyrolysis oil 804 to reduce the O2 content in the gaseous headspace 812 throughout the storage and / or transportation of the pyrolysis oil 804. In some embodiments, the floating cylinder seat 808 and / or removable cylinder 810 are removed from the internal volume of the receiving container 802 after the pyrolysis oil 804 has been unloaded. In some embodiments, the used cylinder 810 removed from the receiving container 802 can be renewed or regenerated, for example, by treating the used cylinder 810 with one or more chemical reagents (e.g., acids or alkalis) and / or by employing one or more physical processes (e.g., heating and / or placing it under vacuum).

[0042] Figure 9 It is based on Figure 6 A schematic diagram of an embodiment of a system 900 for removing O2 from a container 902 before, during, and / or after loading pyrolysis oil 904 into the container 902, is shown in step 606 of method 600. More specifically, the illustrated example of the container 902 is a transport container (e.g., a road tanker) connected to a truck 906 for transport; in other examples, the container 902 may be associated with a railway car or ocean-going freighter for transport, or it may be a stationary storage tank for storage. Figure 9 The embodiment shown includes a receiving container 902 comprising an outer cylindrical base 908 containing, as described above, for... Figure 7 The removable cylinder 910 with O2 scavenging material is described. The system 900 shown functions similarly to systems 800 and 700 described above, except that the outer cylinder base 908 and the removable cylinder 910 are positioned outside the internal volume of the receiving container 902. For Figure 8In the illustrated embodiment, the removable cylinder 910 is in fluid communication with the gaseous headspace 912 of the containing container 902 via at least two flow paths or conduits, allowing the gaseous headspace 912 to passively circulate through the removable cylinder 910. This reduces the O2 content of the gaseous headspace 912 over time and stabilizes the pyrolysis oil 904 throughout storage and / or transport. It is understood that the external cylinder seat 908 provides a more convenient route for the operator to replace the cylinder 910 compared to other embodiments. In some embodiments, the system 900 includes isolation valves 914 (e.g., 914A, 914B) that allow the operator to fluidly isolate the external cylinder seat 908 from the internal volume of the containing container 902, thereby limiting the exposure of the internal volume of atmospheric O2 of the containing container to the operator when accessing and replacing the cylinder 910.

[0043] Figure 10 This is a schematic diagram of an embodiment of method 1000, wherein a controller conditionally activates the deoxygenation system of the containment container to remove and seal O2 from the interior of the containment container, thereby stabilizing the pyrolysis oil during storage and / or transportation. Method 1000 includes step 1002, wherein the controller determines that the O2 content in the gaseous headspace of the containment container containing the pyrolysis oil is greater than a preset threshold, or determines that a preset time has elapsed since the last activation of the pump or fan of the deoxygenation system. Method 1000 includes step 1004, wherein in response to satisfying one or more conditions of step 1002, the controller provides a suitable control signal to activate the pump or fan of the deoxygenation system, thereby drawing airflow from the headspace of the containment container, directing the airflow to a deoxygenating material to generate an oxygen-deficient flow, and directing the oxygen-deficient flow into the containment container to displace oxygen dissolved in the pyrolysis oil and / or present in the gaseous headspace of the containment container.

[0044] for Figure 10 In the illustrated implementation, method 1000 includes step 1006, wherein in response to determining that the O2 content in the gaseous headspace of the containment container is less than or equal to a preset threshold, or determining that a second preset time has elapsed since the deoxygenation system was started, the controller provides an appropriate control signal to deactivate the pump or fan of the deoxygenation system. As indicated by arrow 1008, the controller then returns to step 1002 and monitors the O2 content in the gaseous headspace and / or the time elapsed since the most recent start of the pump or fan of the deoxygenation system to determine when the pump or fan of the deoxygenation system will be started again.

[0045] Figure 11 It is based on Figure 10Method 1000 is a schematic diagram of an embodiment of a system 1100 for removing O2 from a container 1102 before, during, and / or after loading pyrolysis oil 1104 into the container 1102. More specifically, the illustrated example of the container 1102 is a transport container (e.g., a road tanker) attached to a truck 1106 for transport; in other examples, the container 1102 may be associated with a railway car or ocean-going freighter for transport, or it may be a stationary storage tank for storage. Figure 11 The illustrated embodiment includes a pump or fan 1108, an O2 sensor 1110 located within the gaseous top space 1112 of the containment container 1102, an outer housing 1114 having one or more cylinders 1116 containing O2 removal material, and a controller 1118.

[0046] for Figure 11 In the embodiment of system 1100 shown, controller 1118 includes memory 1120 (e.g., random access memory (RAM), read-only memory (ROM), solid-state drive (SSD) or other suitable memory or storage device), the storage of which is used to implement Figure 10 Method 1000 has processor-executable instructions. The controller 1118 includes a processor 1122 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), or one or more coprocessor units) that executes instructions stored in memory 1120 to perform... Figure 10 Method 1000. Controller 1118 also includes a clock 1124, which enables the controller to determine the elapsed time between different control actions. For the illustrated embodiment, controller 1118 is communicatively connected to O2 sensor 1110 to receive measurements of the O2 content in the gaseous headspace 1112 of containment container 1102, and communicatively connected to pump or fan 1108 to provide start and stop control signals during operation.

[0047] for Figure 11In one embodiment of the system 1100 shown, the controller 1118 is configured to monitor the O2 content in the gaseous headspace 1112 of the containment container 1102 before, during, and / or after loading the pyrolysis oil 1104, and conditionally provide a control signal to start the pump or fan 1108 when the O2 content exceeds a preset threshold or when a predetermined amount of time has elapsed since the most recent start-up of the pump or fan 1108. Upon start-up, the pump or fan 1108 draws in a portion of the gaseous headspace 1112 and drives it through the removable cylinder 1116 of the spool 1114 to reduce or eliminate the O2 content, and then directs the resulting O2-lean gas flow to the lower part of the containment container 1102 (e.g., to its bottom or vicinity when the pyrolysis oil 1104 is present). When container 1102 is loaded, a lean O2 gas stream can be bubbled through pyrolysis oil 1104 and degassed, displacing the O2 dissolved in the pyrolysis oil into the gaseous headspace 1112 and stabilizing the pyrolysis oil during storage and / or transport. System 1100 can also be started before loading pyrolysis oil 1104 to achieve a desired preset O2 content in the gaseous headspace 1112. Once controller 1118 determines that the O2 content in the gaseous headspace 1112 is below a preset threshold, or that a preset amount of time has elapsed since pump or fan 1108 was started, controller 1118 can provide a control signal to shut down pump or fan 1108 as described above.

[0048] Example

[0049] Example 1: In the first experimental example, four sample vials were filled with fresh pyrolysis oil. Dry ice was added to three of the sample vials, while no dry ice was added to the control sample vial. After the dry ice sublimated, the sample vials were sealed all four times. At the end of the four-week period, the three sample vials with added dry ice showed high transmittance, indicating less gum formation and no gum visible at the bottom of the vials. In contrast, the control samples without dry ice showed lower transmittance, and gum was clearly visible at the bottom of the control sample vials.

[0050] Example 2: In the second experimental example, four Schott flasks were each filled with 400 ml of fresh pyrolysis oil, with atmospheric air above the oil in the gaseous headspace. One or more bags containing O2 scavenging material were added to three of the sample flasks and the flasks were sealed, while the control flasks were sealed without the O2 scavenging material. After three weeks, the sample flasks containing the O2 scavenging material showed no visible residue at the bottom, while the control flasks had a black bottom due to the formation of a large amount of residue.

[0051] Example 3: In the third experimental example, pyrolysis oil was added to two sample vials. One or more bags containing O2 scavenging material were added to one sample vial and the vial was sealed, while the control sample vial was sealed without O2 scavenging material. The dry gum content of the sample and control sample vials was then measured at half-week intervals over five weeks. The results are as follows: Figure 12 As shown. Figure 12 This is a graph showing the dry gel content (parts by weight / parts per million weight (ppmw)) of these samples as a function of time. Line 1202 corresponds to the control sample vial, while line 1204 corresponds to the sample vial containing O2 scavenging material. As shown in the figure, the sample vials containing O2 scavenging material exhibit significantly less gel formation compared to the control sample vials.

[0052] Other objects, features, and advantages of this disclosure will become apparent from the foregoing drawings, detailed description, and embodiments. However, it should be understood that while the drawings, detailed description, and embodiments illustrate specific examples of this disclosure, they are for illustrative purposes only and are not intended to be limiting. Furthermore, those skilled in the art will be able to anticipate variations and modifications within the spirit and scope of this disclosure based on the detailed description. In further examples, features of a particular embodiment may be combined with features of other embodiments. For example, a feature of one embodiment may be combined with features of any other embodiment. In further examples, additional features may be added to the particular embodiment described herein.

Claims

1. Methods, including: The pyrolysis oil is loaded into the internal volume of the container; and Reducing the oxygen content within the internal volume of the containment container to suppress the formation of colloidal impurities in the pyrolysis oil during storage and / or transportation, wherein reducing the oxygen content includes contacting the pyrolysis oil with gaseous carbon dioxide (CO2) before, during, or after loading the pyrolysis oil into the internal volume of the containment container to purge oxygen dissolved in the pyrolysis oil, or purging oxygen from the gaseous top space within the internal volume, or a combination thereof, wherein the gaseous CO2 is formed via the sublimation of solid CO2.

2. The method of claim 1, wherein reducing the oxygen content comprises purging the gaseous top space within the internal volume with the gaseous CO2 before, during, and after loading the pyrolysis oil.

3. The method of claim 1, wherein reducing the oxygen content comprises delivering the gaseous CO2 into the pyrolysis oil within the internal volume to purge oxygen dissolved in the pyrolysis oil, wherein the gaseous CO2 subsequently purges oxygen from the gaseous top space within the internal volume.

4. The method of claim 3, comprising: The solid CO2 is placed in a container outside the internal volume and in fluid communication with the internal volume, wherein the container is configured to sublimate the solid CO2 to generate gaseous CO2 as an inert gas stream delivered to the internal volume, thereby purging oxygen dissolved in the pyrolysis oil and purging oxygen from the gaseous top space within the internal volume.

5. The method of claim 1, wherein reducing the oxygen content comprises contacting the pyrolysis oil with the solid CO2 before, during, or after loading the pyrolysis oil into the internal volume of the containment container, wherein the solid CO2 sublimates to produce the gaseous CO2, which purges oxygen dissolved in the pyrolysis oil, purges oxygen from the gaseous top space within the internal volume, or a combination thereof.

6. The method of claim 1, wherein reducing the oxygen content includes contacting the gaseous top space within the internal volume with an oxygen-removing material before, during, or after loading the pyrolysis oil.

7. The method of claim 1, wherein reducing the oxygen content comprises placing an oxygen-removing material within the internal volume before, during, or after loading the pyrolysis oil, wherein the oxygen-removing material is configured to float on top of the pyrolysis oil after loading.

8. The method of claim 1, wherein reducing the oxygen content comprises contacting the gaseous top space of the internal volume with an oxygen-removing material placed outside the internal volume and in fluid communication with the gaseous top space of the internal volume.

9. The method of claim 1, wherein, After reducing the oxygen content, the pyrolysis oil contains less than 0.3 parts by weight per million parts by weight (ppmw) of gum impurities after storage and / or transportation for up to five weeks.

10. The method of claim 1, wherein the content of colloidal impurities in the pyrolysis oil is reduced by 60% to 90% by weight after storage and / or transportation of the same pyrolysis oil compared to the same pyrolysis oil stored and / or transported in the same manner but without reducing the oxygen content in the internal volume.

11. The system, including: A container having an internal volume configured to hold pyrolysis oil for storage and / or transport, wherein the container includes a tank container, or a container for tank trucks, tank barges, or railcars; and A container disposed outside the containment container and in fluid communication with the internal volume of the containment container, wherein the container is configured to receive and sublimate solid carbon dioxide (CO2) to generate a gaseous CO2 stream, which is delivered to the internal volume of the containment container to reduce the oxygen content in the internal volume before, during or after the pyrolysis oil is loaded into the internal volume of the containment container.

12. The system of claim 11, wherein the gaseous CO2 stream is configured to purge oxygen dissolved in the pyrolysis oil, purge oxygen from the atmosphere within the internal volume, or a combination thereof.

13. The system of claim 11, wherein the containment container includes an oxygen-removing material in fluid communication with a gaseous headspace within the internal volume of the containment container, wherein the oxygen-removing material is configured to trap oxygen from the gaseous headspace before, during, or after the pyrolysis oil is loaded into the internal volume of the containment container.

14. The system of claim 13, wherein the deoxygenating material is disposed within a removable cylinder, the cylinder being disposed within a cylinder seat located inside or outside the internal volume of the receiving container.

15. The system of claim 13, wherein the cylinder is configured to be loaded into the containment container prior to loading the pyrolysis oil, and configured to float on top of the pyrolysis oil after loading, such that the removable cylinder can contact the gaseous top space within the internal volume of the containment container.

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