Waste plastic pyrolysis plays a part in a variety of chemical recycling technologies. Typically, waste plastic pyrolysis facilities focus on producing recycled content pyrolysis oil (r-pyoil) that can be readily transported to an onsite or offsite facility for further use in making recycled content products.
In addition to r-pyoil, waste plastic pyrolysis produces heavy components (e.g., waxes, tar, and char) and recycled content pyrolysis gas (r-pygas). Although r-pygas produced by the waste plastic pyrolysis typically has 100 percent recycled content, it is common practice for the r-pygas to be burned as fuel to provide heat for the pyrolysis reaction. Although burning r-pygas as fuel for pyrolysis may be economically efficient, such practice runs counter to one of the main goals of chemical recycling, which is to transform as much of the waste plastic as possible in new products. Thus, a better use for r-pygas is needed.
In one aspect, the present technology concerns a process for producing a readily storable and transportable light hydrocarbon feedstock having recycled content from waste plastic, where the process comprises the following steps: (a) pyrolyzing waste plastic to thereby produce a recycled content pyrolysis gas (r-pygas); (b) liquifying at least a portion of the r-pygas to thereby provide a recycled content liquified pyrolysis gas (r-LPyG), wherein the liquifying is carried out using a method comprising compression, cooling, or compression and cooling of the r-pygas; and (c) maintaining at least a portion of the r-LPyG in a liquified state during storing, transporting, or storing and transporting of the r-LPyG.
In one aspect, the present technology concerns a process for producing liquified pyrolysis gas having recycled content (r-LPyG), where the process comprises the following steps: (a) pyrolyzing waste plastic to thereby produce a recycled content pyrolysis gas (r-pygas); (b) using at least a portion of the r-pygas gas as fuel for the pyrolyzing of step (a); (c) liquifying at least a portion of the r-pygas to thereby provide a recycled content liquified pyrolysis gas (r-LPyG); and (d) performing one or both of the following steps—(i) storing the r-LPyG in liquified state for a continuous storage period of at least 1 hour and/or (ii) loading the r-LPyG into a transportation apparatus configured to transport the r-LPyG in a liquified state for a distance of at least 1 mile.
In one aspect, the present technology concerns a process for producing liquified pyrolysis gas having recycled content (r-LPyG), where the process comprises the following steps: (a) pyrolyzing waste plastic to thereby produce a recycled content pyrolysis gas (r-pygas) and a recycled content pyrolysis oil (r-pyoil); (b) liquifying at least a portion of the r-pygas to thereby provide a recycled content liquified pyrolysis gas (r-LPyG); (c) loading at least a portion of the r-LPyG into a first transportation apparatus configured to transport the r-LPyG in a liquified state; and (d) loading at least a portion of the r-pyoil into a second transportation apparatus configured to transport the r-pyoil in a liquid state.
We have discovered new methods and systems for providing a readily storable and transportable feed material produced from a recycled content stream previously burned as fuel. More specifically, we have discovered that pyrolysis gas produced from the pyrolysis of waste plastic can be liquified for use as a storable and/or transportable feed to a chemical manufacturing facility.
As used herein, the term “r-pygas” refers to a composition obtained from waste plastic pyrolysis that is gaseous at 25° C. at 1 atm. As used herein, the terms “r-pyoil” refers to a composition obtained from waste plastic pyrolysis that is liquid at 25° C. and 1 atm. As used herein, the term “r-pyrolysis residue” refers to a composition obtained from waste plastic pyrolysis that is not r-pygas or r-pyoil and that comprises predominantly pyrolysis char and pyrolysis heavy waxes. As used herein, the term “pyrolysis char” refers to a carbon-containing composition obtained from pyrolysis that is solid at 200° C. and 1 atm. As used herein, the term “pyrolysis heavy waxes” refers to C20+ hydrocarbons obtained from pyrolysis that are not pyrolysis char, pyrolysis gas, or pyrolysis oil.
In an embodiment or in combination with any embodiment mentioned herein, the r-pyoil can be the predominate product produced by the waste plastic pyrolysis step, with the r-pygas being a minor/coproduct of the pyrolysis step. For example, the amount by weight of r-pygas produced from pyrolyzing the waste plastic can be less than 75, or less than 50, or less than 40, or less than 30, or less than 20 weight percent of the amount of r-pyoil produced from pyrolyzing the waste plastic. Additionally, or alternatively, the pyrolyzing can convert 30 to 95, or 40 to 90, or 50 to 80, or 55 to 75 weight percent of the waste plastic feedstock into the r-pyoil and/or the pyrolyzing can convert 0.5 to 50, or 1 to 40, or 2 to 30, or 4 to 25 weight percent of the waste plastic feedstock into the r-pygas.
As shown in
The r-pygas produced by the process in
As shown in
As discussed in further detail below with reference to
In an embodiment or in combination with any embodiment mentioned herein, at least 20, or at least 30, or at least 40, or at least 50, or at least 75, or at least 90, or at least 95, or at least 99 weight percent of the ethane and lighter compounds present in the r-pygas produced from the pyrolysis step and introduced into the liquification process are not liquified in the liquification process and exit the liquification process with the non-condensable gas. The pyrolysis facility can produce the r-LPyG in an amount by weight that is at least 1.5, or at least 2, or at least 5, or at least 10 times greater than the amount of the non-condensable gas produced.
As depicted in
In an embodiment or in combination with any embodiment mentioned herein, there is provided a waste plastic pyrolysis facilities that (a) produces a pyrolysis effluent comprising r-pygas and a recycled content pyrolysis oil (r-pyoil), liquefying the r-pyas to produce r-LPyG, loading the r-LPyG to transportable container, and shipping the r-LPyG in the transportable container from the pyrolysis facility, wherein the r-LPyG is transported in a liquified state to a destination for at least 1, at least 10, at least 50, at least 100, at least 500, or at least 1000 miles. The container received at the destination may be the same container in which the r-LPyG was shipped from the pyrolysis facility, or may be a different container
In an embodiment or in combination with any embodiment mentioned herein, the r-LPyG storage and/or transportation step depicted in
In an embodiment or in combination with any embodiment mentioned herein, the apparatus in which the r-LPyG is stored and/or transported can be insulated, cooled, and/or pressurized. For example, the r-LPyG storage/transportation apparatus can be an insulated, cooled, and/or pressurized tank, conduit, and/or pipeline. The tank can be a stationary tank or a tank located on a rail car, truck, trailer, or ship. In one embodiment, after liquification, the r-LPyG is immediately loaded into a railcar tank that maintains the r-LPyG in a liquified state while it is transported via railway to the r-LPyG processing and/or end use site/facility. In another embodiment, the r-LPyG is immediately loaded into a relatively large stationary storage tank located at the pyrolysis facility, where the storage tank maintains the r-LPyG in a liquified state until one or more transportable tanks (e.g., on railcars, trucks, trailers, or ships) are ready to be loaded from the stationary storage tank. In yet another embodiment, the r-LPyG is immediately loaded into a stationary tank that maintains the r-LPyG in a liquified state until it is introduced into a pipeline or conduit for transport to the r-LPyG processing and/or end use site/facility.
In an embodiment or in combination with any embodiment mentioned herein, the r-LPyG processing and/or end use site/facility and the pyrolysis facility (including pyrolysis, separation, and/or liquification) can be co-located. When the facilities are co-located, the r-LPyG may not need to be maintained in a liquified state for as long or transported as far as when the facilities are located remotely from one another. However, even when the facilities are co-located, liquification of the r-pygas may be necessary to ensure, for example, that a consistent supply of r-LPyG is provided to the processing and/or end use facility. Such a consistent supply can be provided using an onsite storage tank(s) for maintaining relatively large volumes of the r-LPyG in a liquified state. These onsite storage tanks can ensure a consistent supply for r-LPyG, even if the rate of r-pygas produced by the pyrolysis facility fluctuates or has intermittent stoppages.
In an embodiment or in combination with any embodiment mentioned herein, the pyrolysis facility/process is a commercial scale facility/process receiving the waste plastic feedstock at an average annual feed rate of at least 100, or at least 500, or at least 1,000, or at least 2,000 pounds per hour, averaged over one year. Further, the pyrolysis facility can produce the r-oil and r-pygas in combination at an average annual rate of at least 100, or at least 1,000, or at least 5,000, at least 10,000, at least 50,000, or at least 75,0000 pounds per hour, averaged over one year.
In an embodiment or in combination with any embodiment mentioned herein, the r-LPyG processing and/or end use site/facility can be located remotely from the r-pyoil processing and/or end use site facility. In that case, the producer of the r-pyoil and the r-LPyG transports the r-pyoil and/or r-LPyG to different locations and/or different entities by different transportation routes.
Alternatively, the r-LPyG processing and/or end use site/facility can be co-located and/or co-owned with the r-pyoil processing and/or end use site/facility. In that case, the producer of the r-pyoil and the r-LPyG can transport the r-pyoil and/or r-LPyG to the same site/facility, possibly even using the same transportation mode. For example, both r-pyoil and r-LPyG could be transported using a single train, with certain railcars carrying tanks of r-pyoil and other railcars carrying tanks of r-LPyG.
As discussed in more detail below with reference to
The pyrolysis reactor depicted in
The pyrolysis reaction can involve heating and converting the waste plastic feedstock in an atmosphere that is substantially free of oxygen or in an atmosphere that contains less oxygen relative to ambient air. For example, the atmosphere within the pyrolysis reactor may comprise not more than 5, not more than 4, not more than 3, not more than 2, not more than 1, or not more than 0.5 weight percent of oxygen.
The temperature in the pyrolysis reactor can be adjusted so as to facilitate the production of certain end products. In an embodiment or in combination with any embodiment mentioned herein, the peak pyrolysis temperature in the pyrolysis reactor can be at least 325° C., or at least 350° C., or at least 375° C., or at least 400° C. Additionally or alternatively, the peak pyrolysis temperature in the pyrolysis reactor can be not more than 800° C., not more than 700° C., or not more than 650° C., or not more than 600° C., or not more than 550° C., or not more than 525° C., or not more than 500° C., or not more than 475° C., or not more than 450° C., or not more than 425° C., or not more than 400° C. More particularly, the peak pyrolysis temperature in the pyrolysis reactor can range from 325 to 800° C., or 350 to 600° C., or 375 to 500° C., or 390 to 450° C., or 400 to 500° C.
The residence time of the feedstock within the pyrolysis reactor can be at least 1, or at least 5, or at least 10, or at least 20, or at least 30, or at least 60, or at least 180 seconds. Additionally, or alternatively, the residence time of the feedstock within the pyrolysis reactor can be less than 2, or less than 1, or less than 0.5, or less than 0.25, or less than 0.1 hours. More particularly, the residence time of the feedstock within the pyrolysis reactor can range from 1 second to 1 hour, or 10 seconds to 30 minutes, or 30 seconds to 10 minutes.
The pyrolysis reactor can be maintained at a pressure of at least 0.1, or at least 0.2, or at least 0.3 barg and/or not more than 60, or not more than 50, or not more than 40, or not more than 30, or not more than 20, or not more than 10, or not more than 8, or not more than 5, or not more than 2, or not more than 1.5, or not more than 1.1 barg. The pressure within the pyrolysis reactor can be maintained at atmospheric pressure or within the range of 0.1 to 60, or 0.2 to 10, or 0.3 to 1.5 barg.
The pyrolysis reaction in the reactor can be thermal pyrolysis, which is carried out in the absence of a catalyst, or catalytic pyrolysis, which is carried out in the presence of a catalyst. When a catalyst is used, the catalyst can be homogenous or heterogeneous and may include, for example, certain types of zeolites and other mesostructured catalysts.
In the embodiment depicted in
In an embodiment or in combination with any embodiment mentioned herein, the r-pygas exiting the top of separator S5 can have the composition shown below in Table 1.
25-99
10-80
As used herein, the term “Cx” or “Cx hydrocarbon,” refers to a hydrocarbon compound including “x” total carbons per molecule, and encompasses all olefins, paraffins, aromatics, heterocyclic, and isomers having that number of carbon atoms. For example, each of normal, iso, and tert-butane and butene and butadiene molecules would fall under the general description “C4.”
It should be noted that the separation scheme (i.e., the fractionation column and separator S5) depicted in
As shown in
Although
In an embodiment or in combination with any embodiment mentioned herein, the inlet pressure to compressor stage CS1 can be 1 to 4, or 1.1 to 2.5, or 1.2 to 1.8 barg; the outlet pressure of compressor stage CS1 and the inlet pressure to CS2 can be 2.0 to 6.0, or 3.0 to 4.0, or 3.2 to 3.8 barg; the outlet pressure of compressor stage CS2 and the inlet pressure to CS3 can be 6 to 12, or 7 to 11, or 8 to 10 barg; and the outlet pressure from compressor stage CS3 can be 15 to 35, 18 to 28, or 20 to 25 barg.
The cooling carried out after each compression stage can be sufficient to cause at least a portion of the effluent from the preceding compression stage to condense. Such cooling can be carried out using indirect heat exchange with a cooling fluid (such as cooling water) in heat exchangers C1, C2, and C3.
As shown in
The initial steps of the system depicted in
The rich oil stream exiting the bottom of the absorber is pumped by pump P4 to an expander E1, where its pressure is let down to cause cooling of the rich oil stream. From expander E1, the cooled rich oil stream is fed to a pyoil recovery column, which separates the cooled rich oil stream from expander E1 into a liquid light pyoil stream and an overhead vapor stream. The liquid light pyoil stream exits a bottom outlet of the pyoil recovery column and is then pumped via a pump P5 to the upper inlet of the absorber for use as the absorption liquid. In certain embodiments, all or part of the naphtha and light pyoil streams produced by the separation system (e.g., fractionation column and separator S5) immediately downstream of the pyrolysis reactor can be used as all or part of the absorption liquid fed to the upper inlet of the absorption column.
The overhead vapor stream exiting the pyoil recovery column is sequentially cooled in heat exchangers C4 (via cooling water), C5 (via expanded non-condensable gas), and C6 (via expanded r-LPyG) to thereby cause condensing of at least a portion of the overhead stream. The resulting cooled stream is supplied to a separator S4 for separation into a dry gas stream and a liquid stream comprising C2-C5 components. The liquid stream exiting the separator S4 then passes to a pump P6. The pump P6 pumps a first portion of the liquid stream to the r-LPyG storage and/or transportation apparatus (e.g., tank or pipeline). A second portion of the liquid stream exiting the pump P6 can be passed through an expander E4, where its pressure is let down and it is cooled. The cooled stream from expander E4 is then used in heat exchanger C6 to cool the overhead stream from the pyoil recovery column.
The non-condensable dry gas exiting the upper outlet of the absorber is passed through an expander E2, where its pressure is reduced to cause cooling of the non-condensable gas stream. The cooled non-condensable gas from expander E2 is then passed through the heat exchanger C5 and used to cool the vapor stream exiting the overhead of the pyoil recovery column. After being warmed in the heat exchanger C5, the non-condensable (“NC Gas in
In an embodiment or in combination with any embodiment mentioned herein, the systems depicted in
25-99
97-99.5
10-80
The cracking facility depicted in
As illustrated in
Feeding the r-LPyG to the cracker facility allows for recycled content from the r-LPyG to be supplied to the various products of the cracking facility, such as r-ethylene, r-propylene, and r-C5+ compounds. In addition, the r-propane, and optionally the r-C4, present in the r-LPyG can be separated in the separation section combined with the main feed to the cracker furnace, thereby providing recycled content to the cracker feed.
In this example, computer modeling is used to simulate a process and system for liquifying recycled content pyrolysis gas (r-pygas).
The below table provides property and composition details for each of the liquid streams (L1-L4) and vapor streams (V1-V4) shown in
Table 3 shows, for example, that the system depicted in
It should be understood that the following is not intended to be an exclusive list of defined terms. Other definitions may be provided in the foregoing description, such as, for example, when accompanying the use of a defined term in context.
As used herein, the terms “a,” “an,” and “the” mean one or more.
As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.
As used herein, the phrase “at least a portion” includes at least a portion and up to and including the entire amount or time period.
As used herein, the term “chemical pathway” refers to the chemical processing step or steps (e.g., chemical reactions, physical separations, etc.) between an input material and a product material, where the input material is used to make the product material.
As used herein, the term “chemical recycling” refers to a waste plastic recycling process that includes a step of chemically converting waste plastic polymers into lower molecular weight polymers, oligomers, monomers, and/or non-polymeric molecules (e.g., hydrogen, carbon monoxide, methane, ethane, propane, ethylene, and propylene) that are useful by themselves and/or are useful as feedstocks to another chemical production process(es).
As used herein, the term “co-located” refers to the characteristic of at least two objects being situated on a common physical site, and/or within one mile of each other.
As used herein, the term “commercial scale facility” refers to a facility having an average annual feed rate of at least 500 pounds per hour, averaged over one year.
As used herein, the terms “comprising,” “comprises,” and “comprise” are open-ended transition terms used to transition from a subject recited before the term to one or more elements recited after the term, where the element or elements listed after the transition term are not necessarily the only elements that make up the subject.
As used herein, the term “cracking” refers to breaking down complex organic molecules into simpler molecules by the breaking of carbon-carbon bonds.
As used herein, the terms “credit-based recycled content,” “non-physical recycled content,” and “indirect recycled content” all refer to matter that is not physically traceable back to a waste material, but to which a recycled content credit has been attributed.
As used herein, the term “directly derived” refers to having at least one physical component originating from waste material.
As used herein, the terms “including,” “include,” and “included” have the same open-ended meaning as “comprising,” “comprises,” and “comprise” provided above.
As used herein, the term “indirectly derived” refers to having an applied recycled content (i) that is attributable to waste material, but (ii) that is not based on having a physical component originating from waste material.
As used herein, the term “located remotely” refers to a distance of at least 0.1, 0.5, 1, 5, 10, 50, 100, 500, or 1000 miles between two facilities, sites, or reactors.
As used herein, the term “mass balance” refers to a method of tracking recycled content based on the mass of the recycled content in various materials.
As used herein, the terms “physical recycled content” and “direct recycled content” both refer to matter that is physically traceable back to a waste material.
As used herein, the term “predominantly” means more than 50 percent by weight. For example, a predominantly propane stream, composition, feedstock, or product is a stream, composition, feedstock, or product that contains more than 50 weight percent propane.
As used herein, the term “pyrolysis” refers to thermal decomposition of one or more organic materials at elevated temperatures in an inert (i.e., substantially oxygen free) atmosphere.
As used herein, the terms “pyrolysis gas” and “pygas” refer to a composition obtained from pyrolysis that is gaseous at 25° C.
As used herein, the terms “pyrolysis oil” or “pyoil” refers to a composition obtained from pyrolysis that is liquid at 25° C. and 1 atm.
As used herein, the term “pyrolysis residue” refers to a composition obtained from pyrolysis that is not pyrolysis gas or pyrolysis oil and that comprises predominantly pyrolysis char and pyrolysis heavy waxes.
As used herein, the term “recycled content” refers to being or comprising a composition that is directly and/or indirectly derived from recycled material. Recycled content is used generically to refer to both physical recycled content and credit-based recycled content. Recycled content is also used as an adjective to describe material having physical recycled content and/or credit-based recycled content.
As used herein, the term “recycled content credit” refers to a non-physical measure of physical recycled content that can be directly or indirectly (i.e., via a digital inventory) attributed from a first material having physical recycled content to a second material having less than 100 percent physical recycled content.
As used herein, the term “total recycled content” refers to the cumulative amount of physical recycled content and credit-based recycled content from all sources.
As used herein, the term “waste material” refers to used, scrap, and/or discarded material.
As used herein, the terms “waste plastic” and “plastic waste” refer to used, scrap, and/or discarded plastic materials.
In a first embodiment of the present technology there is provided a process producing a readily storable and transportable light hydrocarbon feedstock having recycled content from waste plastic, where the process comprises the following steps: (a) pyrolyzing waste plastic to thereby produce a recycled content pyrolysis gas (r-pygas); (b) liquifying at least a portion of the r-pygas to thereby provide a recycled content liquified pyrolysis gas (r-LPyG), wherein the liquifying is carried out using a method comprising compression, cooling, or compression and cooling of the r-pygas; and (c) maintaining at least a portion of the r-LPyG in a liquified state during storing, transporting, or storing and transporting of the r-LPyG.
The first embodiment described in the preceding paragraph can also include one or more of the additional aspects/features listed in the following bullet pointed paragraphs. Each of the below additional features of the first embodiment can be standalone features or can be combined with one or more of the other additional features to the extent consistent. Additionally, the following bullet pointed paragraphs can be viewed as dependent claim features having levels of dependency indicated by the degree of indention in the bulleted list (i.e., a feature indented further than the feature(s) listed above it is considered dependent on the feature(s) listed above it).
In a second embodiment of the present technology there is provided a process for producing liquified pyrolysis gas having recycled content (r-LPyG), where the process comprises the following steps: (a) pyrolyzing waste plastic to thereby produce a recycled content pyrolysis gas (r-pygas); (b) using at least a portion of the r-pygas gas as fuel for the pyrolyzing of step (a); (c) liquifying at least a portion of the r-pygas to thereby provide a recycled content liquified pyrolysis gas (r-LPyG); and (d) performing one or both of the following steps—(i) storing the r-LPyG in liquified state for a continuous storage period of at least 1, 2, 4, 8, 12, 24, or 36 hours and/or (ii) loading the r-LPyG into a transportation apparatus configured to transport the r-LPyG in a liquified state for a distance of at least 1 mile.
The second embodiment described in the preceding paragraph can also include one or more of the additional aspects/features listed in the following bullet pointed paragraphs. Each of the below additional features of the second embodiment can be standalone features or can be combined with one or more of the other additional features to the extent consistent. Additionally, the following bullet pointed paragraphs can be viewed as dependent claim features having levels of dependency indicated by the degree of indention in the bulleted list (i.e., a feature indented further than the feature(s) listed above it is considered dependent on the feature(s) listed above it).
In a third embodiment of the present technology there is provided a process for producing liquified pyrolysis gas having recycled content (r-LPyG), where the process comprises the following steps: (a) pyrolyzing waste plastic to thereby produce a recycled content pyrolysis gas (r-pygas) and a recycled content pyrolysis oil (r-pyoil); (b) liquifying at least a portion of the r-pygas to thereby provide a recycled content liquified pyrolysis gas (r-LPyG); (c) loading at least a portion of the r-LPyG into a first transportation apparatus configured to transport the r-LPyG in a liquified state; and (d) loading at least a portion of the r-pyoil into a second transportation apparatus configured to transport the r-pyoil in a liquid state.
The third embodiment described in the preceding paragraph can also include one or more of the additional aspects/features listed in the following bullet pointed paragraphs. Each of the below additional features of the third embodiment can be standalone features or can be combined with one or more of the other additional features to the extent consistent. Additionally, the following bullet pointed paragraphs can be viewed as dependent claim features having levels of dependency indicated by the degree of indention in the bulleted list (i.e., a feature indented further than the feature(s) listed above it is considered dependent on the feature(s) listed above it).
The preferred forms of the invention described above are to be used as illustration only and should not be used in a limiting sense to interpret the scope of the present invention. Modifications to the exemplary embodiments, set forth above, could be readily made by those skilled in the art without departing from the spirit of the present invention.
The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as it pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.
Filing Document | Filing Date | Country | Kind |
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PCT/US2022/026679 | 4/28/2022 | WO |
Number | Date | Country | |
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63202128 | May 2021 | US |