Systems and methods for processing pyrolysis oil

Abstract

A method for removing paraffin wax from pyrolysis oil includes flowing the pyrolysis oil into a tank and reducing the temperature of the pyrolysis oil to a temperature that causes the paraffin wax in solution in the pyrolysis oil to precipitate, forming (1) the paraffin wax in solid form and (2) residual pyrolysis oil in liquid form. The method further includes pumping the residual pyrolysis oil from the tank to a first location. Next, the method includes heating the solid paraffin wax to form the liquid paraffin wax and pumping the liquid paraffin wax to a second location. In this way, the paraffin wax and the residual pyrolysis oil can be treated separately according to their respective properties.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority from European Patent Application No. 22203852.3, filed October 26, 2022, the contents of which are incorporated herein by reference in their entirety. [Technical Field]

[0002] The present invention relates generally to the processing of pyrolysis oil. Specifically, the present invention relates to removing wax from pyrolysis oil, cracking the residual pyrolysis oil to produce olefins, and / or cracking paraffinic wax to produce olefins. [Background technology]

[0003] Chemical recycling of mixed plastic waste produces materials that can be used as feedstock for olefin production. This chemical recycling involves pyrolysis of mixed plastic waste to produce a hydrocarbon liquid known as pyrolysis oil (pyrolysis oil). Pyrolysis oil typically has a relatively high cold filter plugging point (CFPP), which can be attributed to the presence of heavy paraffin compounds (wax) in the pyrolysis oil. Paraffinic wax consists of linear saturated hydrocarbons with carbon atoms ranging from C18 to C36. Paraffinic wax primarily contains normal paraffins (80–90 wt%), with additional branched paraffins (isoparaffins) and cycloparaffins (10–20 wt% total). The paraffinic wax in pyrolysis oil can be considered a heavy tail, which is known to be problematic for steam cracking furnaces. Therefore, there is a need to reduce the amount of paraffinic wax in the pyrolysis oil that is destined for cracking. Summary of the Invention

[0004] The inventors have discovered a system and method that solves at least some of the problems associated with pyrolysis oil processing. According to embodiments of the present invention, heavy paraffin compounds contained in pyrolysis oil tend to form solid waxes at low ambient temperatures. Therefore, according to embodiments of the present invention, the heavy paraffinic materials in the pyrolysis oil can be caused to form solids, which can then be separated from the lighter liquid portion of the pyrolysis oil. The lighter portion of the pyrolysis oil and the heavy paraffinic wax can then be processed separately.

[0005] An embodiment of the present invention includes a method for treating pyrolysis oil. The method includes flowing the pyrolysis oil into a tank and reducing the temperature of the pyrolysis oil to a temperature that causes the paraffinic wax in solution in the pyrolysis oil to precipitate, forming (1) the paraffinic wax in solid form and (2) residual pyrolysis oil in liquid form. The method further includes pumping the residual pyrolysis oil from the tank to a first location. Next, the method includes heating the paraffinic wax in solid form to form the paraffinic wax in liquid form and pumping the paraffinic wax in liquid form to a second location.

[0006] The following contains definitions of various terms and phrases used throughout this specification.

[0007] The terms "about" or "approximately" are defined as close to what would be understood by one of ordinary skill in the art. In one non-limiting embodiment, the term is defined as within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0008] For purposes of this disclosure, "X, Y, and / or Z" may be interpreted as X alone, Y alone, Z alone, or any combination of two or more items X, Y, Z (e.g., XYZ, XY, XZ, YZ).

[0009] The terms "wt %, "vol %", or "mole %" refer to the weight, volume, or mole % of a component based on the total weight, volume, or moles of the material containing the component, respectively. In a non-limiting example, 10 moles of a component in 100 moles of a material is 10 mole % of the component.

[0010] The term "substantially" and variations thereof are defined to include within 10%, within 5%, within 1%, or within 0.5%.

[0011] The terms "inhibiting," or "reducing," or "preventing," or "avoiding," or any variations of these terms, as used in the claims and / or specification, include any measurable decrease or complete inhibition to achieve a desired result.

[0012] The term "effective," as that term is used in the specification and / or claims, means sufficient to accomplish a desired, expected, or intended result.

[0013] In the claims or specification, the use of the terms "a" or "an" when used in conjunction with the terms "comprising," "including," "containing," or "having" can mean "one," but is also consistent with the meanings of "one or more," "at least one," and "one or more."

[0014] The words "comprising" (and any form of "comprising", such as "comprise" and "comprises"), "having" (and any form of "having", such as "have" and "has"), "including" (and any form of "including", such as "includes" and "include"), or "containing" (and any form of "containing", such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0015] The processes of the present invention may "comprise," "consist essentially of," or "consist of" certain ingredients, components, compositions, etc., disclosed throughout this specification.

[0016] The term "primarily," as used herein and / or in the claims, means greater than any of 50 wt%, 50 mol%, and 50 vol%. For example, "primarily" includes 50.1 wt% to 100 wt%, 50.1 mol.% to 100 mol.% and all values ​​and ranges therebetween, or 50.1 vol.% to 100 vol.% and all values ​​and ranges therebetween.

[0017] Other objects, features, and advantages of the present invention will become apparent from the following drawings, detailed description, and examples. It should be understood, however, that the drawings, detailed description, and examples, while indicating specific embodiments of the present invention, are given by way of illustration only and are not meant to be limiting. Moreover, it is contemplated that various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from a particular embodiment can be combined with features from other embodiments. For example, features from one embodiment can be combined with features from any of the other embodiments. In further embodiments, additional features can be added to the specific embodiments described herein. [Brief explanation of the drawings]

[0018] For a more thorough understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0019] [Figure 1] 1 illustrates a system for treating pyrolysis oil according to an embodiment of the present invention. [Figure 2] FIG. 1 illustrates a method for treating pyrolysis oil according to an embodiment of the present invention. [Figure 3] Changes in normal paraffin distribution due to freezing experiments [Figure 4] Changes in isoparaffin distribution due to freezing experiments [Figure 5] Changes in normal naphthene distribution due to freezing experiments [Figure 6] Changes in isonaphthene distribution due to freezing experiments [Figure 7] Changes in aromatic compound distribution due to freezing experiments [Figure 8] Changes in total carbon distribution due to freezing experiments DETAILED DESCRIPTION OF THE INVENTION

[0020] As described herein, embodiments of the present invention include a process for removing paraffinic wax from pyrolysis oil. Removal of paraffinic wax is advantageous because it reduces the weight of the pyrolysis oil, making it more suitable as a feedstock for steam cracking. This paraffinic wax can be considered a heavy tail, which is known to be problematic for steam cracking furnaces. Removing the paraffinic wax in accordance with embodiments of the present invention allows for optimized processing of the pyrolysis oil components. In accordance with embodiments of the present invention, the removed paraffinic wax and the residual pyrolysis oil can be processed in different ways, each according to the most effective process for that particular component. For example, the paraffinic wax and the residual pyrolysis oil can be processed in two different furnaces with different severity levels. Processing the paraffinic wax and the residual pyrolysis oil allows for greater flexibility in controlling the product slate. For example, each steam cracker can be tailored to market demands to optimize steam cracking margins.

[0021] Figure 1 illustrates a system 10 for processing pyrolysis oil according to an embodiment of the present invention. Figure 2 illustrates a method 20 for processing pyrolysis oil according to an embodiment of the present invention. In an embodiment of the present invention, method 20 is implemented using system 10.

[0022] As shown in FIG. 1 , a system 10 according to an embodiment of the present invention includes pyrolysis oil 100 stored in a tank 101. In embodiments of the present invention, the tank 101 may be a fixed tank or a mobile tank located in a bulk transport container or vehicle. In embodiments of the present invention, the tank 101 is adapted to cool and / or heat the material stored in the tank 101. For example, in embodiments of the present invention, the tank 101 includes a circulating coolant that cools (a) the tank and / or (b) coils within the tank, thereby cooling the pyrolysis oil 100. Alternatively, or additionally, in embodiments of the present invention, the tank 101 may include a heating device for heating paraffinic wax that may be deposited in the tank 101. According to an embodiment of the present invention, the tank 101 is fluidly connected to (1) the residual pyrolysis oil tank 102, so that the residual pyrolysis oil 104 can flow from the tank 101 to the residual pyrolysis oil tank 102, and (2) the paraffinic wax tank 103, so that the paraffinic wax 105 can flow from the tank 101 to the paraffinic wax tank 103. In an embodiment of the present invention, the paraffinic wax tank 103 is a heating tank. In an embodiment of the present invention, the residual pyrolysis oil tank 102 is fluidly connected to a cracking unit having a low cracking operating temperature (COT), i.e., a low COT cracking unit 106, so that the residual pyrolysis oil 104 can flow from the residual pyrolysis oil tank 102 to the low COT cracking unit 106. In an embodiment of the present invention, the paraffinic wax tank 103 is fluidly connected to a high COT cracking unit 107, so that the paraffinic wax 105 can flow from the paraffinic wax tank 103 to the high COT cracking unit 107. According to an embodiment of the present invention, the low COT decomposition unit 106 and the high COT decomposition unit 107 have different decomposition operating temperatures.For example, according to an embodiment of the present invention, the low COT cracking unit 106 has a COT in the range of 775 to 825°C, including any of the ranges of 775 to 780°C, 780 to 785°C, 785 to 790°C, 790 to 795°C, 795 to 800°C, 800 to 805°C, 805 to 810°C, 810 to 815°C, 815 to 820°C, and 820 to 825°C, and the high COT cracking unit 107 has a COT in the range of 826 to 875°C, including any of the ranges of 826 to 830°C, 830 to 835°C, 835 to 840°C, 840 to 845°C, 845 to 850°C, 850 to 855°C, 855 to 860°C, 860 to 865°C, 865 to 870°C, and 870 to 875°C.

[0023] 2, in an embodiment of the present invention, the method 20 includes, in block 200, flowing the pyrolysis oil 100 into a tank 101. The method 20 further includes, in block 201, lowering the temperature of the pyrolysis oil 100 to a temperature that causes the paraffinic wax 105 in solution in the pyrolysis oil 100 to precipitate, forming (1) the paraffinic wax 105 in solid form and (2) the residual pyrolysis oil 104 in liquid form. In an embodiment of the present invention, the pyrolysis oil 100 is lowered to a temperature of -10°C to 2°C, including any of the ranges of -10°C to -8°C, -8°C to -6°C, -6°C to -4°C, -4°C to -2°C, -2°C to 0°C, and 0°C to 2°C, to precipitate the paraffinic wax 105. According to an embodiment of the present invention, reducing the temperature of the pyrolysis oil 100 includes using a circulating coolant to cool (1) the tank and / or (2) the coils in the tank, thereby cooling the pyrolysis oil 100. According to an embodiment of the present invention, the method 20 includes, in block 202, pumping the residual pyrolysis oil 104 from the tank 101 to a first location, which is the residual pyrolysis tank 102 (a feed tank for the low COT cracking unit 106). According to an embodiment of the present invention, for separation of the paraffinic wax 105 from the pyrolysis oil 100, the residual pyrolysis oil 104 can have a cold filter plugging point (CFPP) of -5 to 5°C, including any of the following ranges: -5 to -4°C, -4 to -3°C, -3 to -2°C, -2 to -1°C, -1 to 0°C, 0 to 1°C, 1 to 2°C, 2 to 3°C, 3 to 4°C, and 4 to 5°C. In an embodiment of the invention, the pumping of the residual pyrolysis oil 104 in block 202 is from a height greater than 1 to 10 inches above the bottom of the tank 101. In block 203, the method 20 further includes heating the paraffinic wax 105 in solid form in the tank 101 to form the paraffinic wax 105 in liquid form. According to an embodiment of the invention, the paraffinic wax 105 comprises straight-chain saturated hydrocarbons having carbon atoms in the range of C18 to C36, and / or the paraffinic wax 105 comprises 80 to 90 wt% normal paraffin content and 10 to 20 wt% branched paraffins (isoparaffins) and cycloparaffins.The method 20 includes, at block 204, pumping the paraffinic wax 105 in liquid form to a second location, which is the paraffinic wax tank 103 (a supply tank for the high COT cracking unit 107).

[0024] According to an embodiment of the present invention, the method 20 includes, at block 205, flowing the residual pyrolysis oil 104 from the residual pyrolysis oil tank 102 to a low COT cracking unit 106 adapted to crack the pyrolysis oil. In an embodiment of the present invention, at block 206, the method 20 includes cracking the residual pyrolysis oil 104 at a COT of 775-825°C to form one or more olefins. According to an embodiment of the present invention, the one or more olefins formed in block 206 can include ethylene and / or propylene.

[0025] According to an embodiment of the present invention, the method 20 includes, at block 207, flowing the paraffinic wax 105 from the paraffinic wax tank 103 to a high COT cracking unit 107 adapted to crack the paraffinic wax. According to an embodiment of the present invention, at block 208, the method 20 includes cracking the paraffinic wax 105 at a COT of 826-875°C to form one or more olefins. According to an embodiment of the present invention, the one or more olefins formed in block 208 can include ethylene and / or propylene.

[0026] Although embodiments of the present invention have been described with reference to the blocks of Figure 2, it should be understood that the operation of the present invention is not limited to the specific blocks and / or the specific order of blocks shown in Figure 2. Thus, embodiments of the present invention may use various blocks in a different order than in Figure 2 to provide functionality as described herein.

[0027] The systems and processes described herein may further include various equipment not shown but known to those skilled in the art of chemical processing, such as some controllers, piping, computers, valves, pumps, heaters, thermocouples, pressure indicators, mixers, heat exchangers, etc.

[0028] As part of the disclosure of the present invention, the following specific examples are provided. The examples are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art will readily recognize parameters that can be changed or modified to yield essentially the same results. [Example]

[0029] (Freezing experiment) The pie oil was placed in a refrigerator at 2°C for 24 hours, allowing the formation of a crystalline phase at the bottom and a supernatant liquid phase. Both were analyzed by group typing (GC x GC). This analysis revealed that the crystalline / waxy layer contained more of the heavy component C21+, based on Figures 3 to 8.

[0030] In the context of the present invention, at least the following eleven embodiments are described. Embodiment 1 is a method for treating pyrolysis oil. The method includes flowing the pyrolysis oil into a tank. The method further includes reducing the temperature of the pyrolysis oil to a temperature at which the paraffinic wax in solution in the pyrolysis oil precipitates to form (1) the paraffinic wax in solid form and (2) a residual pyrolysis oil in liquid form. The method further includes pumping the residual pyrolysis oil from the tank to a first location. In addition, the method includes heating the paraffinic wax in solid form to form the paraffinic wax in liquid form, and pumping the paraffinic wax in liquid form to a second location. Embodiment 2 is the method described in embodiment 1, wherein the pyrolysis oil is cooled to a temperature of -10°C to 2°C to precipitate the paraffinic wax. Embodiment 3 is the method described in either embodiment 1 or 2, wherein the residual pyrolysis oil is pumped from a height of more than 1 to 10 inches above the bottom of the tank. Embodiment 4 is the method of any one of embodiments 1 to 3, wherein lowering the temperature of the pyrolysis oil comprises using a circulating coolant to cool (1) the tank and / or (2) the coils in the tank, thereby cooling the pyrolysis oil. Embodiment 5 is the method of any one of embodiments 1 to 4, wherein the cold filter plugging point (CFPP) of the residual pyrolysis oil is between -5°C and 5°C. Embodiment 6 is the method of any one of embodiments 1 to 5, wherein the paraffinic wax comprises straight-chain saturated hydrocarbons having carbon atoms ranging from C18 to C36. Embodiment 7 is the method of any one of embodiments 1 to 6, wherein the paraffinic wax has a normal paraffin content of 80 to 90 wt% and branched paraffins (isoparaffins) and cycloparaffins of 10 to 20 wt%. Embodiment 8 is the method of any one of embodiments 1 to 7, wherein the tank is located in a bulk transport container or vehicle. Embodiment 9 is the method of any one of embodiments 1 to 8, wherein the first location is a feed tank for the first cracking unit; and the method further comprises cracking the residual pyrolysis oil to form olefins at a COT in the range of 775 to 825°C; and cracking the residual pyrolysis oil to form one or more olefins.Embodiment 10 is the method of any one of embodiments 1 to 9, wherein the second location is a feed tank for a second cracking unit, and the method further comprises cracking the paraffinic wax in liquid form to form one or more olefins at a COT in the range of 826 to 875° C. Embodiment 11 is the method of any one of embodiments 1 to 10, wherein the olefins comprise one or more of ethylene and propylene.

[0031] The systems and processes described herein may further include various equipment not shown but known to those skilled in the art of chemical processing. For example, some controllers, piping, computers, valves, pumps, heaters, thermocouples, pressure indicators, mixers, heat exchangers, etc. may not be shown. Unless expressly excluded, all embodiments described above and herein may be combined in any manner.

[0032] Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope of the embodiments, as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the processes, machines, manufacture, compositions of matter, means, methods, and steps described herein. As will be readily apparent from the above disclosure, one skilled in the art may utilize currently existing or later-developed processes, machines, manufacture, compositions of matter, means, methods, or steps that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. 1. A method for treating pyrolysis oil, the method comprising: pouring the pyrolysis oil into a tank; reducing the temperature of the pyrolysis oil to a temperature that causes the paraffinic wax in solution in the pyrolysis oil to precipitate to form (1) paraffinic wax in solid form and (2) residual pyrolysis oil in liquid form; pumping the residual pyrolysis oil from the tank to a first location; heating said paraffin wax in solid form to form a paraffin wax in liquid form; and pumping the paraffinic wax in liquid form to a second location.

2. 10. The method of claim 1, wherein the pyrolysis oil is cooled to a temperature of between -10°C and 2°C to precipitate the paraffinic wax.

3. 3. The method of claim 1, wherein the pumping of the residual pyrolysis oil is from a height greater than 1 to 10 inches above the bottom of the tank.

4. 3. The method of claim 1, wherein the reduction in the temperature of the pyrolysis oil comprises cooling (1) the tank and / or (2) a coil within the tank with a circulating coolant, thereby cooling the pyrolysis oil.

5. 3. The method according to any one of claims 1 to 2, wherein the residual pyrolysis oil has a cold filter plugging point (CFPP) of -5°C to 5°C.

6. 3. The method of any one of claims 1 to 2, wherein the paraffinic wax comprises straight chain saturated hydrocarbons having carbon atoms in the range of C18 to C36.

7. The method according to any one of claims 1 to 2, wherein the paraffinic wax has a normal paraffin content of 80 to 90 wt% and branched paraffins (isoparaffins) and cycloparaffins of 10 to 20 wt%.

8. 3. The method of claim 1, wherein the tank is located in a bulk shipping container or a vehicle.

9. The first location is a supply tank for a first decomposition unit, and the method further comprises:

3. The method according to any one of claims 1 to 2, wherein the residual pyrolysis oil is cracked to form olefins at a COT in the range of 775 to 825°C, and the residual pyrolysis oil is cracked to form one or more olefins.

10. The second location is a supply tank for a second decomposition unit, and the method further comprises:

3. The process according to any one of claims 1 to 2, wherein the paraffinic wax in liquid form is cracked to form one or more olefins at a COT in the range of 826 to 875°C.

11. 10. The method of claim 9, wherein the olefin comprises one or more of ethylene and propylene.

12. 11. The method of claim 10, wherein the olefin comprises one or more of ethylene and propylene.

13. The second location is a supply tank for a second decomposition unit, and the method further comprises:

4. The method of claim 3, wherein the paraffinic wax in liquid form is cracked to form one or more olefins at a COT in the range of 826 to 875°C.

14. The second location is a supply tank for a second decomposition unit, and the method further comprises:

5. The method of claim 4, wherein the paraffinic wax in liquid form is cracked to form one or more olefins at a COT in the range of 826 to 875°C.

15. The second location is a supply tank for a second decomposition unit, and the method further comprises:

6. The method of claim 5, wherein the paraffinic wax in liquid form is cracked to form one or more olefins at a COT in the range of 826 to 875°C.

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