JP2023552612A - Process for steam decomposition of chlorine-containing raw materials - Google Patents

Abstract

A method of treating plastics and a method of treating pie oil derived from plastics. A numerical model of the correlation between chlorine content in one or more process streams of a steam cracking unit and a hydrocarbon to steam ratio in a feed stream of the steam cracking unit is constructed. A blend of pie oil and naphtha is mixed with steam at a hydrocarbon to steam ratio obtained from the model to produce the feedstream for the steam cracking unit. The feedstream is processed in the steam cracking unit to produce olefins.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority from U.S. Provisional Application No. 63/123,998, filed December 10, 2020, which is incorporated herein by reference in its entirety. .

TECHNICAL FIELD This invention relates generally to steam cracking processes. More specifically, the present invention relates to a method of processing plastic-derived pyrolysis oil ("pyoil") to produce a feedstream for a steam cracker.

Chemical recycling of mixed plastic waste has become a new route to produce certified circular polymers. The recycling process involves pyrolysis of waste plastics, which typically results in a pyoil stream containing high levels of contaminants, including organochlorine, organic nitrogen, and oxygenated additives. The presence of chlorine in the feedstock of the steam cracking unit leads to corrosion of the radiant coil of the furnace of the steam cracking unit. Furthermore, downstream of the olefin production plant, chlorine can lead to stress crack corrosion.

Conventional methods for reducing the chlorine content in plastic-derived pie oils include blending with naphtha and/or gas condensates. Naphtha or gas condensate typically contains 0.2 to 1.6 ppm organic chlorides. Pie oil contains 67 ppm to 521 ppm organic chlorides. Therefore, in order to reduce the effect of contaminants and make the pie oil safe for subsequent petrochemical units, the pie oil is blended with naphtha or gas condensate in a mass ratio of about 1:167 (pie oil: naphtha). . However, using naphtha with a high naphtha to pie oil blend ratio is costly, resulting in higher costs for producing olefins and other valuable chemicals from pie oil.

Overall, although systems and methods exist for reducing chlorine levels in pie oils derived from plastics, there remains a need for improvements in this field in light of at least the aforementioned drawbacks of the prior art methods.

SUMMARY OF THE INVENTION A solution has been found to at least the aforementioned problems associated with methods for reducing heteroatomic contaminant content. The solution resides in a method for processing pie oil that includes mixing pie oil with naphtha and steam. This can be beneficial in diluting the contaminants in the pie oil without using large amounts of naphtha, thereby reducing manufacturing costs compared to conventional methods. Furthermore, the disclosed method is optimal for minimizing the effect of the contaminants in the steam cracking unit while maintaining low manufacturing costs for the steam cracking of the pie oil compared to conventional methods. The method may further include building a numerical model for the correlation between the steam-to-hydrocarbon ratio and the chlorine content so as to determine the steam-to-hydrocarbon ratio. Therefore, the method of the present invention provides a technical solution to the problems associated with the conventional methods for reducing pollutants in pie oils derived from plastics.

Embodiments of the invention include a method of processing pie oil. The method includes mixing pie oil obtained by pyrolysis of plastics with naphtha to produce a hydrocarbon stream having a chlorine (elemental) content lower than the chlorine (elemental) content of the pie oil. . The method includes mixing the hydrocarbon stream with steam to form a feed stream. The method includes steam cracking the feedstream under reaction conditions sufficient to produce olefins.

Embodiments of the invention include a method of processing pie oil. The method includes mixing pie oil obtained by pyrolysis of plastics with naphtha to produce a hydrocarbon stream containing 1 to 3 ppm chlorine. The pie oil contains more than 60 ppm chlorine. The method includes mixing the hydrocarbon stream with steam at a steam to hydrocarbon mass ratio of greater than 0.35 to produce a feedstream having a chlorine (elemental) content lower than the chlorine content of the hydrocarbon stream. Including forming. The method includes steam cracking the feedstream under reaction conditions sufficient to produce olefins.

Embodiments of the invention include methods of processing plastics. The method includes (a) treating the plastic under sufficient pyrolysis conditions to produce a pie oil containing hydrocarbons and greater than 60 ppm chlorine. The method includes (b) mixing the pie oil with naphtha to produce a hydrocarbon stream containing 1 to 3 ppm chlorine. The method includes (c) mixing the hydrocarbon stream with steam at a first steam to hydrocarbon ratio to produce a first feedstream. The method includes (d) steam cracking the feedstream in a steam cracker under reaction conditions sufficient to produce a waste stream comprising olefins, aromatics, and steam. The method includes (e) separating the waste stream in a separation unit to produce one or more product streams including an ethylene stream, a propylene stream, a _C4 stream, and a pyrolysis gas stream. The method includes (f) determining the chlorine content of one or more process streams produced in steps (d) and (e). (g) repeating steps (c)-(f), but in step (c) using a second steam-to-hydrocarbon ratio to determine the steam-to-hydrocarbon ratio of the one or more process streams; Including obtaining data on chlorine content. The method includes (h) building a numerical model of the correlation between steam-to-hydrocarbon ratio and chlorine content of the one or more process streams. The method includes (i) determining a final steam-to-hydrocarbon ratio using the numerical model such that the chlorine content of the one or more process streams is each less than 3 ppm. The method includes (j) operating the steam cracker using the final steam to hydrocarbon ratio to treat the hydrocarbon stream.

Below are definitions of various terms used throughout this specification.

The terms "about" or "approximately" are defined as approximations, as understood by those skilled 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%.

The terms "wt.%," "vol.%," or "mol.%" refer to a weight or volume percentage of an ingredient, respectively, based on the total weight, volume, or total molar amount of the material containing the ingredient. , or mole percentage. In a non-limiting example, 10 moles of the component in 100 moles of the material is 10 mol. % component.

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

When used in the claims and/or the foregoing specification, the terms "inhibit" or "reduce" or "prevent" or "avoid" or any variations of these terms may be used in the claims and/or in the foregoing specification. including any measurable reduction or complete inhibition of achieving the result.

As used in the specification and/or claims, the term "effective" means suitable for achieving a desired, expected, or intended result.

The term "cyclic polymer" as used in the specification and/or claims refers to a polymer made from ethylene or propylene produced by steam cracking of pyrolysis oil.

The term "chlorine content" as used in the specification and/or claims refers to the concentration of elemental chlorine. The chlorine element is present in the molecular structure of the chlorinated compound.

The use of the word "a" or "an" in the claims or the specification refers to "comprising," "including," "containing," or "having." When used in conjunction with the above term ``having'', it may mean ``one'', but the above meanings of ``one or more,'' ``at least one,'' and ``one or more.'' It also matches.

"comprising" (and all forms of comprising such as "comprise" and "comprises"), "having" (and all forms of having such as "have" and "has"), "including" The words "including" (and all forms of including, such as "includes" and "include") or "containing" (and all forms of containing, such as "contains" and "contain") are inclusive or without limitation, and does not exclude additional unlisted elements or method steps.

The process of the present invention "comprises," "consists essentially of," or specifies the particular components, ingredients, compositions, etc. disclosed throughout the specification. It may "consist of" constituent elements, ingredients, compositions, etc.

As used in the specification and/or claims, the term "predominantly" means 50 wt. %, 50 mol. %, and 50vol. It means more than either %. For example, "mainly" may include 50.1wt. %~100wt. % and all values and ranges therebetween, 50.1 mol. %~100mol. % and all values and ranges therebetween, or 50.1 vol. %~100vol. % and all values and ranges therebetween.

Other objects, features and advantages of the invention will become apparent from the following figures, detailed description and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating particular embodiments of the invention, are presented by way of illustration only and are not meant to be limiting. Additionally, changes and modifications within the spirit and scope of the invention are intended to become apparent to those skilled in the art from this detailed description. In further embodiments, features from particular embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein.

For a more complete understanding, reference is made to the following description in conjunction with the accompanying drawings.

1 is a flowchart outlining a method for processing plastics according to an embodiment of the invention. FIG. 2 is a schematic diagram of a disassembly unit according to an embodiment of the invention. 1 is a flowchart outlining a method of processing pie oil according to an embodiment of the invention. FIG. 3 shows a comparison of measured chlorine levels in process water of a steam cracking unit and model predicted chlorine levels. FIG. 3 shows a comparison of measured chlorine levels in the steam/liquid water separator bottom stream of a steam cracking unit with model predicted chlorine levels. FIG. 2 shows the expected chlorine concentration in process water as a function of steam to oil (hydrocarbon) ratio.

Currently, plastic-derived pie oils containing high levels of heteroatomic contaminants, including chlorine, are processed by blending the pie oils with large amounts of naphtha at pie oil to naphtha mass ratios up to 1:167. This can be costly due to the high cost of naphtha, making the overall process less economically viable. The present invention provides a solution to this problem. Said solution presupposes a method of processing pie oil. The disclosed method of pie oil processing includes blending the pie oil with naphtha to form a hydrocarbon stream and further diluting the hydrocarbon stream with steam to produce a steam cracker having a chlorine level safe for the steam cracking unit. Including generating a feedstream for the device. This can significantly reduce the amount of naphtha required to blend with pie oil, thereby reducing the overall cost of reducing chlorine levels in pie oil. The disclosed method may include building a numerical model that correlates the hydrocarbon stream to steam mass ratio and chlorine content of one or more process streams in a steam cracking unit. Using the numerical model, an optimized hydrocarbon to steam mass ratio can be obtained that can ensure production efficiency and low chlorine levels in the steam cracking unit, resulting in improved production efficiency from pie oil, The safety level of pie oil processing is increased. These and other non-limiting aspects of the invention are discussed in further detail in the following sections.

A. How to dispose of plastic

In an embodiment of the invention, the method for treating plastics includes building a numerical model that correlates hydrocarbon to steam ratio and chlorine level in a process stream in a steam cracking unit. Referring to FIG. 1, a flowchart of a method 100 for processing plastics is shown.

According to an embodiment of the invention, as shown at block 101, method 100 includes processing a plastic under sufficient pyrolysis conditions to produce pie oil containing hydrocarbons and greater than 60 ppm chlorine. In embodiments of the invention, the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS), or combinations thereof. The thermal decomposition conditions are 300 to 700°C, 300 to 350°C, 350 to 400°C, 400 to 450°C, 450 to 500°C, 500 to 550°C, 550 to 600°C, 600 to 650°C, and 650 to 700°C. Including the pyrolysis temperature range of °C and all ranges and values therebetween. The pyrolysis conditions further include a pyrolysis pressure of 1 to 5 bar. In an embodiment of the invention, the pie oil contains 60-600 ppm chlorine; Including and including all ranges and values between 540 and 600 ppm.

According to an embodiment of the invention, as shown at block 102, method 100 includes mixing the pie oil with naphtha to produce a hydrocarbon stream. The hydrocarbon stream contains 1-3 ppm chlorine, as well as 0.1-0.3 ppm, 0.3-0.6 ppm, 0.6-0.9 ppm, 0.9-1.2 ppm, 1.2-1 Everything in between, including the ranges .5ppm, 1.5-1.8ppm, 1.8-2.1ppm, 2.1-2.4ppm, 2.4-2.7ppm and 2.7-3.0ppm. may include ranges and values. In an embodiment of the invention, the pie oil and the naphtha are mixed at a pie oil to naphtha mass ratio of 1:400 to 1:60 and all ranges and values therebetween. In an embodiment of the invention, the naphtha includes light virgin naphtha and/or full range naphtha. In embodiments of the invention, naphtha may include C ₄ to C ₁₀ hydrocarbons.

According to an embodiment of the invention, as shown at block 103, method 100 includes mixing the hydrocarbon stream with steam at a first steam-to-hydrocarbon ratio to produce a first feedstream. In the embodiment of the present invention, the steam is at a temperature of 180-300°C. The first steam to hydrocarbon ratio is within the range of 0.35 to 1.0, and 0.35 to 0.40, 0.40 to 0.45, 0.45 to 0.50, 0.50 to 0.55, 0.55-0.60, 0.60-0.65, 0.65-0.70, 0.70-0.75, 0.75-0.80, 0.80-0. 85, 0.85 to 0.90, 0.90 to 0.95, 0.90 to 0.95, and all ranges and values therebetween, including the ranges 0.95 to 1.0.

According to an embodiment of the present invention, as shown at block 104, the method 200 includes, in a steam cracker, the first feedstream sufficient to produce a waste stream comprising olefins, aromatics, and steam. It involves steam decomposition under reaction conditions. In embodiments of the invention, at block 104, the reaction conditions may include a decomposition temperature of 780-870° C. and a residence time in the steam cracker of 10-700 ms.

According to an embodiment of the invention, as shown in block 105, the method 100 separates the waste stream in a separation unit into an ethylene stream containing primarily ethylene, a propylene stream containing primarily propylene, and a propylene stream containing primarily propylene. producing one or more product streams including a _C4 stream comprising _C4 hydrocarbons and a pyrolysis gas stream comprising pyrolysis gas.

In an embodiment of the invention, the steam cracking at block 104 and the separation at block 105 are performed in a steam cracking unit 200, as shown in FIG. A cracking unit 200 receives the feedstream 11 obtained in block 103 and includes a steam cracker 201 configured to crack the feedstream 11 to produce a waste stream 12 comprising olefins, aromatics, and steam. may include. The cracking unit 200 separates the waste stream 12 into a first upper stream 13 containing olefins, aromatics, and steam, a carbon black oil stream 14 containing primarily carbon black oil, and a cracking stream 14 containing primarily naphthalene. It may primarily include a rectification column 202 configured to form a distillate stream 15. The cracking unit 200 quenches the first upper stream 13 to produce a quench water stream 16 containing primarily water and 0.1-20 ppm chlorine and a quench waste stream 18 containing primarily C ₁ -C ₅ hydrocarbons. and a pygas stream 17 comprising _C5 + pyrolysis gasoline. In embodiments of the invention, the outlet of water quench column 203 is in fluid communication with the inlet of water vapor/liquid water separator 220 such that quenched water stream 16 flows from water quench column 203 to water vapor/liquid water separator 220. . Vapor liquid water separator 220 is configured to separate quench water stream 16 to produce (1) a purge stream 42 containing water and chlorine-containing contaminants, and (2) a recycle stream 41 containing vapor. can do. Recycle stream 41 may be routed back to steam cracker 201 .

Decomposition unit 200 may include a compressor 204 configured to compress quenched waste stream 18 to produce compressed waste stream 19 and additional pygas stream 20 . Additional pygas stream 20 may include a liquid fraction of quenched waste stream 18 . In embodiments of the invention, the pygas stream 17 and the further pygas stream 20 may form a composite pygas stream 38. In embodiments of the invention, composite pygas stream 38 includes 0.1 to 1 ppm elemental chlorine. According to an embodiment of the invention, the decomposition unit 200 is an acid removal device configured to remove acid from the compressed waste stream 19 to produce an acid stream 21 containing one or more acids and an acid-free waste stream 22. unit 205. The acid-free waste stream 22 is compressed in a second compressor 206 and then cooled in a cold box 207 to form a light stream 23 containing primarily methane and hydrogen together and a demethanizer feedstream 24. can. Cracking unit 200 may further include a demethanizer 208 configured to remove methane from demethanizer feedstream 24 to form methane stream 25 and deethanizer feedstream 26 . In an embodiment of the invention, methane stream 25 is recycled to cold box 207. Deethanizer feedstream 26 may be further processed in deethanizer 209 to produce a C ₂ stream 27 containing primarily C ₂ hydrocarbons and a depropanizer feedstream 28 . The _C2 stream 27 is further processed in an acetylene extraction unit 210 to remove an acetylene stream 29 containing primarily acetylene, and then further processed in a _C2 splitter 211 to separate an ethylene stream 30 containing mainly ethylene. An ethane stream 31 containing ethane can be generated.

The cracking unit 200 is configured to separate the depropanizer feedstream 28 to form a _C3 stream 32 containing primarily _C3 hydrocarbons and a debutanizer feedstream 33. Apparatus 212 may further be included. C ₃ stream 32 may be further processed in MAPD reactor 213 and C ₃ splitter 214 to produce a propylene stream 34 containing primarily propylene and a propane stream 35 containing propane. MAPD reactor 213 can be configured to remove methylacetylene and propadiene (MAPD) before entering the _C3 splitter. In an embodiment of the invention, the cracking unit 200 separates the debutanizer feedstream 33 into a _C4 stream 36 containing _C4 hydrocarbons and a _C5 + stream 37 containing primarily _C5 + hydrocarbons. A debutanizer 215 configured to produce a debutanizer 215 may further be included. In embodiments of the invention, composite pygas stream 38 may be combined with C ₅ + stream 37 to form final pygas stream 39 . In embodiments of the invention, each of demethanizer 208, deethanizer 209, _C2 splitter 211, depropanizer 212, _C3 splitter 214, and debutanizer 215 includes a distillation column.

According to an embodiment of the invention, as shown at block 106, method 100 includes determining the chlorine content of one or more process streams produced at blocks 104 and 105. In the embodiment of the present invention, the process streams at block 106 include cracked distillate stream 15, feed stream 11, quench water stream 16, acid stream 21, combined pygas stream 38, debutanizer feed stream 33. , final pygas stream 39 or a combination thereof. In an embodiment of the invention, said determination of chlorine content in block 106 is performed by sampling at the inlet and downstream of said plant according to a Cl mass balance. In an embodiment of the invention, about 80% of the chlorine uptake is in the process water (quench water stream 16).

According to an embodiment of the invention, as shown in block 107, method 100 repeats blocks 103 through 106, but in block 103 using a second steam to hydrocarbon ratio to including obtaining steam-to-hydrocarbon ratio and chlorine content data for the process stream. In embodiments of the invention, the steam to hydrocarbon ratio ranges from 0.35 to 1.0; 0.50-0.55, 0.55-0.60, 0.60-0.65, 0.65-0.70, 0.70-0.75, 0.75-0.80, 0. All ranges and values in between, including the ranges 80 to 0.85, 0.85 to 0.90, 0.90 to 0.95, 0.90 to 0.95, and 0.95 to 1.0. controlled.

According to an embodiment of the invention, as shown at block 108, method 100 includes building a numerical model of the correlation between steam-to-hydrocarbon ratio and chlorine content of the one or more process streams. include. In an embodiment of the invention, the numerical model is constructed using inlet and downstream sampling of the plant according to the Cl mass balance. In an embodiment of the invention, a conversion of 88% for Cl in the feed stream that ultimately reaches the process water (quench water stream 16) was obtained. In an embodiment of the invention, the numerical model is configured to predict the chlorine content in the one or more process streams of the cracking unit 200 using the steam to hydrocarbon ratio as an input.

According to embodiments of the present invention, as shown in block 109, method 100 includes blocking such that the chlorine content of the one or more process streams of cracking unit 200 is each lower than a predetermined level. using the numerical model constructed at 108 to determine a final steam to hydrocarbon ratio. The predetermined level is configured to minimize the corrosion rate in the decomposition unit 200. The predetermined level may be 3 ppm. In an embodiment of the invention, said determination substitutes a target chlorine level by using a calculated conversion rate (e.g., 88%) of Cl from feed stream 11 to said process water (quench water stream 16). including doing. In an embodiment of the invention, the target chlorine level is obtained at block 108. According to an embodiment of the invention, as shown in block 110, the method 100 uses the final steam-to-hydrocarbon ratio obtained in block 109 to generate the steam cracker (steam cracker 201 of cracker unit 200). and processing the hydrocarbon stream.

B. How to process pie oil

As shown in FIG. 3, embodiments of the invention include a method 300 of processing pie oil. According to an embodiment of the present invention, as shown in block 301, the method 300 includes mixing pie oil obtained by pyrolysis of plastics with naphtha to reduce the chlorine (elemental) content of said pie oil. ) producing a hydrocarbon stream having a hydrocarbon content. In embodiments of the invention, the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS), or combinations thereof.

The pie oil may contain greater than 60 ppm elemental chlorine. In an embodiment of the invention, in block 301 naphtha and pie oil are mixed in a mass ratio of up to 167:1, preferably 50:1. In an embodiment of the invention, the naphtha comprises a hydrocarbon having a boiling point range of 35-200°C. The pie oil contains hydrocarbons having a boiling point range of 35-390°C. The pie oil contains more than 60 ppm elemental chlorine, preferably 60-600 ppm chlorine and 60-120 ppm, 120-180 ppm, 180-240 ppm, 240-300 ppm, 300-360 ppm, 360-420 ppm, 420-480 ppm, 480-540 ppm and all ranges and values therebetween, including the range 540-600 ppm. The hydrocarbon stream contains 1-3 ppm elemental chlorine as well as 1-1.2 ppm, 1.2-1.4 ppm, 1.4-1.6 ppm, 1.6-1.8 ppm, 1.8-2.0 ppm. , 2.0-2.2ppm, 2.2-2.4ppm, 2.4-2.6ppm, 2.6-2.8ppm and 2.8-3ppm, and all ranges and values therebetween. including.

According to an embodiment of the invention, as shown at block 302, method 300 includes mixing the hydrocarbon stream with steam to form a feed stream. In an embodiment of the invention, in block 302, the hydrocarbon stream is added to a ～0.50, 0.50～0.55, 0.55～0.60, 0.60～0.65, 0.65～0.70, 0.70～0.75, 0.75～0 Steam to hydrocarbon mass for all ranges and values therebetween, including the ranges .80, 0.80 to 0.85, 0.85 to 0.90, 0.90 to 0.95, and 0.95 to 1. Mix with steam at the ratio. In an embodiment of the invention, said feedstream comprises 0.2-1.6 ppm chlorine (elemental), preferably 0.2-0.8 ppm and 0.2-0.3 ppm, 0.3-0. 4ppm, 0.4-0.5ppm, 0.5-0.6ppm, 0.6-0.7ppm and 0.7-0.8ppm, including all ranges and values therebetween. In an embodiment of the invention, in block 302, the steam is heated at 180-300°C; , 240-250°C, 250-260°C, 260-270°C, 270-280°C, 280-290°C and 290-300°C, and all ranges and values therebetween.

According to an embodiment of the invention, as shown at block 303, method 300 includes steam cracking the feedstream under reaction conditions sufficient to produce olefins. In an embodiment of the invention, said steam cracking at block 303 is performed in cracking unit 200. The olefins produced in block 303 include ethylene, propylene, _C4 olefins, or combinations thereof. Steam decomposition in block 303 is carried out at temperatures of 780-870°C, All ranges and values of decomposition temperatures therebetween can be carried out, including the ranges ˜860° C. and 860-870° C. The steam decomposition in block 303 is in the range 10-700ms, as well as 10-50ms, 50-100ms, 100-150ms, 150-200ms, 200-250ms, 250-300ms, 300-350ms, 350-400ms, 400-450ms. .

Although embodiments of the present invention have been described with reference to the blocks of FIGS. 1 and 3, operations of the present invention may include the specific blocks shown in FIGS. It should be understood that the order is not limited. Accordingly, embodiments of the invention may use various blocks in different sequences than those of FIGS. 1 and 3 to provide functionality as described herein.

The systems and processes described herein may also include various equipment not shown but known to those skilled in the art of chemical processing. For example, some controllers, pipes, computers, valves, pumps, heaters, thermocouples, pressure indicators, mixers, heat exchangers, etc. may not be shown.

As part of the above disclosure of the present invention, specific examples are given below. 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 varied or modified to achieve essentially the same results.

(Chlorine content of process water stream in steam cracking unit)
Pie oil containing 50-226 ppm chlorine is blended with naphtha to reduce the chlorine concentration in the blend to 1-3 ppm. Common steam cracker feedstocks such as gas condensate and naphtha contain chlorine at levels of 0.1 to less than 1.0 ppm. By measuring the chlorine at the inlet, it is therefore possible to calculate the chlorine uptake of the plant in kg/hr. Assuming that 88% of the chlorine uptake ends up in the process water (quench water stream 16 in Figure 2), it is possible to predict the chlorine concentration in the downstream process water. The results are shown in FIGS. 4 and 5. As shown in Figures 4 and 5, the chlorine concentration measured in the process water (quench water stream 16 in Figure 2) by performing sampling and the predicted value (estimated based on the chlorine inlet) are acceptable. matches.

FIG. 6 shows the predicted chlorine concentration in the process water as a function of steam-to-oil ratio. In constructing the graph, it is assumed that all the furnaces process feedstocks with a maximum chlorine content of 3 ppm. With the same approach it will be possible to determine the maximum chlorine in the feedstock (naphtha/pyoil blend) and the remaining maximum chlorine of the conventional gas condensate processed in two furnaces.

In connection with the present invention, at least the following 12 embodiments are disclosed. Embodiment 1 is a method of treating pie oil. The method includes mixing pie oil obtained by pyrolysis of plastics with naphtha to produce a hydrocarbon stream having a chlorine content lower than the chlorine content of the pie oil. The method further includes mixing the hydrocarbon stream with steam to form a feedstream. The method further includes steam cracking the feedstream under reaction conditions sufficient to produce olefins. Embodiment 2 is the method of Embodiment 1, wherein the pie oil contains greater than 60 ppm chlorine. Embodiment 3 is the method of any of embodiments 1 and 2, wherein the hydrocarbon stream comprises 1-3 ppm elemental chlorine. Embodiment 4 is the method of any of embodiments 1-3, wherein the feedstream has a chlorine content that is less than the chlorine content of the hydrocarbon stream. Embodiment 5 is the method of any of embodiments 1-4, wherein the hydrocarbon stream is mixed with steam at a mass ratio of greater than 0.35. Embodiment 6 is an embodiment in which the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS), or combinations thereof. This is the method according to any one of 1 to 5. Embodiment 7 is a method according to any of embodiments 1 to 6, wherein said naphtha and said pie oil are mixed in a mass ratio of up to 167:1, preferably 50:1.

Embodiment 8 is a method of treating plastic. The method includes: (a) treating a plastic under sufficient pyrolysis conditions to produce a pie oil containing hydrocarbons and greater than 60 ppm chlorine; (b) mixing the pie oil with naphtha to produce a pie oil containing 1 to 3 ppm chlorine; (c) mixing said hydrocarbon stream with steam at a first steam-to-hydrocarbon ratio to produce a first feedstream; (d) in a steam cracker, producing an olefin containing hydrocarbon stream; (e) separating the waste stream in a separation unit to produce an ethylene stream and a propylene stream; and a _C4 stream and a pyrolysis gas stream; (f) determining the chlorine content of the one or more process streams produced in steps (d) and (e); (g) repeating steps (c)-(f), but in step (c) using a second steam-to-hydrocarbon ratio to determine the steam-to-hydrocarbon ratio and chlorine content of the one or more process streams; (h) constructing a numerical model of the correlation between steam-to-hydrocarbon ratio and chlorine content of the one or more process streams; (i) obtaining the data of the one or more process streams; determining a final steam-to-hydrocarbon ratio using the numerical model such that the chlorine content is lower than 3 ppm, respectively; (j) operating the steam cracker using the final steam-to-hydrocarbon ratio; , processing the hydrocarbon stream. Embodiment 9 provides that the separation in step (e) separates the waste stream from the steam cracker into an upper stream comprising C ₁ -C ₈ hydrocarbons and steam and a C ₉ -C ₁₂ carbonized 9. The method of embodiment 8, which may include producing a cracked distillate containing hydrogen and a carbon black oil containing _C12 + hydrocarbons. Embodiment 10 provides that step (e) quenches the upper stream to include a quench water stream containing 0.1 to 20 ppm chlorine, ethylene, propylene, _C4 hydrocarbons, and _C5 + hydrocarbons. 10. The method of any of embodiments 8 and 9, further comprising producing a quench waste stream and a pygas stream comprising _C5 + hydrocarbons. Embodiment 11 is the method of any of embodiments 8-9, wherein the pygas stream is combined with a compressed liquid fraction of the quenched waste stream to form a composite pyrolysis gas stream. Embodiment 12 is the method of any of embodiments 8-10, wherein the composite pyrolysis gas stream comprises 0.1 to 1 ppm chlorine. All embodiments described above and herein may be combined in any way unless expressly excluded.

Although embodiments of the present application and their advantages have been described in detail, various changes, substitutions, and modifications may be made herein without departing from the spirit and scope of the embodiments as defined by the appended claims. Please understand that you can do this in the book. Furthermore, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As those skilled in the art will readily appreciate from the foregoing disclosure, currently existing embodiments that perform substantially the same function or achieve substantially the same results as the foregoing corresponding embodiments described herein. Any process, machine, manufacture, composition of matter, means, method, or step that is currently or later developed may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims (20)

A method of processing pie oil, the method comprising:
mixing pie oil obtained by pyrolysis of plastics with naphtha to produce a hydrocarbon stream having a chlorine content lower than the chlorine content of said pie oil;
A method comprising: mixing the hydrocarbon stream with steam to form a feedstream; and steam cracking the feedstream under reaction conditions sufficient to produce olefins. 2. The method of claim 1, wherein the pie oil contains greater than 60 ppm chlorine. A process according to claim 1 or 2, wherein the hydrocarbon stream contains 1 to 3 ppm elemental chlorine. 3. A method according to claim 1 or 2, wherein the feedstream has a chlorine content that is less than the chlorine content of the hydrocarbon stream. 3. A method according to claim 1 or 2, wherein the hydrocarbon stream is mixed with steam in a mass ratio of greater than 0.35. 3. The plastic according to claim 1 or 2, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. Method. 3. A method according to claim 1 or 2, wherein the naphtha and the pie oil are mixed in a mass ratio of at most 167:1, preferably 50:1. A method of processing plastic, the method comprising:
(a) treating the plastic under sufficient pyrolysis conditions to produce a pie oil containing hydrocarbons and greater than 60 ppm chlorine;
(b) mixing the pie oil with naphtha to produce a hydrocarbon stream containing 1 to 3 ppm chlorine;
(c) mixing the hydrocarbon stream with steam at a first steam to hydrocarbon ratio to produce a first feedstream;
(d) in a steam cracker, steam cracking the first feedstream under reaction conditions sufficient to produce a waste stream comprising olefins, aromatics, and steam;
(e) separating the waste stream in a separation unit to produce one or more product streams including an ethylene stream, a propylene stream, a _C4 stream, and a pyrolysis gas stream;
(f) determining the chlorine content of the one or more process streams produced in steps (d) and (e);
(g) repeat steps (c)-(f), but in step (c) use the second steam-to-hydrocarbon ratio to determine the steam-to-hydrocarbon ratio and chlorine content of the one or more process streams; Get data;
(h) constructing a numerical model of the correlation between steam-to-hydrocarbon ratio and chlorine content of the one or more process streams;
(i) determining a final steam to hydrocarbon ratio using the numerical model such that the chlorine content of each of the one or more process streams is less than 3 ppm; and (j) determining the final steam to hydrocarbon ratio of the one or more process streams; operating the steam cracker using a ratio to treat the hydrocarbon stream. The separation in step (e) separates the waste stream from the steam cracker into an upper stream comprising C ₁ -C ₈ hydrocarbons and steam and a cracked distillate comprising C ₉ -C ₁₂ hydrocarbons. 9. The method of claim 8, which may include producing a feed oil and a carbon black oil comprising _C12 + hydrocarbons. Step (e) quenching the upper stream to produce a quench water stream containing 0.1 to 20 ppm chlorine, a quench wastewater stream containing ethylene, propylene, _C4 hydrocarbons, and _C5 + hydrocarbons; 9. The method of claim 8, further comprising producing a pygas stream comprising ₅ + hydrocarbons. 11. The method of claim 10, wherein the pygas stream is combined with a compressed liquid fraction of a quenched waste stream to form a composite pyrolysis gas stream. 12. The method of claim 11, wherein the composite pyrolysis gas stream contains 0.1 to 1 ppm chlorine. 4. The method of claim 3, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. 5. The method of claim 4, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. 6. The method of claim 5, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. 8. The method of claim 7, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. 9. The method of claim 8, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. 10. The method of claim 9, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. 11. The method of claim 10, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof. 12. The method of claim 11, wherein the plastic comprises polyolefin, polyethylene terephthalate (PET), polyamide (PA) and polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS) or combinations thereof.

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