Patent Application
20240117261
The present disclosure relates to methods of producing a fuel oil comprising pyrolysis products from waste plastics and an associated system. In particular, certain embodiments of the disclosure relate to methods producing a fuel oil by replacing high value components of typical fuel oil with the pyrolysis products from the waste plastics.
Conventional fuel oils are used in marine and shipping applications due to their relative abundance and affordability. Fuel oils are typically blends of various hydrocarbon streams including vacuum residue oil and significant volumes of less viscous kerosene, light gas oil, and fluid catalytic cracking cycle and decant oil (FCC decanted oil or cycle oils), visbroken residues, and delayed coking liquids. Vacuum residue oil is a viscous hydrocarbon stream that requires blending with other hydrocarbon streams to reduce viscosity and to meet other fuel oil specifications. However, fuel oils must comply with strict specifications to be marketable. The addition of kerosene and light gas oil currently provides refineries with a pathway to regulatory compliance by reducing the viscosity of the blend to meet standardized specifications and generate a marketable product. However, since the cutter stock, such as kerosene and light gas oil, is generally significantly more valuable than the resulting fuel oil blend their use is desirably minimized.
Tangentially, plastic is a synthetic or semisynthetic organic polymer composed of mainly carbon and hydrogen and is used abundantly throughout the World in the production of disposable or limited use items. However, plastics tend to be durable, with a slow rate of degradation, therefore they stay in the environment for a long time and are not prone to rapid breakdown upon disposal. This phenomenon results in vast quantities of waste plastics being generated on a worldwide basis annually.
Accordingly, there is a clear and long-standing need to both produce fuel oils in a more economic manner and to provide a useful application of the waste plastics continuously generated worldwide. The present disclosure provide a solution to utilize the pyrolysis products generated from the pyrolysis of waste plastics in place of high value cutter stock in the generation of fuel oils.
In accordance with one or more embodiments of the present disclosure, a method of producing a fuel oil comprising pyrolysis products from waste plastics is disclosed. The method includes (a) conducting pyrolysis of a plastic feedstock to produce a stream of plastic pyrolysis oil, the plastic feedstock comprising mixed waste plastics; (b) feeding the plastic pyrolysis oil to a first fractionator to separate the plastic pyrolysis oil at a first cut temperature, where the first cut temperature is in the range of 80° C. to 250° C. such that the plastic pyrolysis oil is split into a distillate fraction comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction comprising hydrocarbons boiling above the first cut temperature; and (c) feeding the topped pyrolysis product fraction along with one or more streams selected from the group consisting of a kerosene stream, a light gas oil stream, a vacuum residue stream, a FCC clarified oil stream, and an aromatic bottoms stream to a fuel oil blending unit to generate a fuel oil product stream, wherein the kerosene stream comprises hydrocarbons boiling in the range of 150 to 240° C., the light gas oil comprises hydrocarbons boiling in the range of 240 to 320° C., the vacuum residue comprises hydrocarbons boiling above 480° C., the FCC clarified oil stream comprises hydrocarbons from a fluid catalytic cracking unit boiling above 480° C., and the aromatic bottoms stream comprises aromatics with carbon number of 9 and greater.
In accordance with one or more embodiments of the present disclosure, a system for preparing a fuel oil comprising pyrolysis products from waste plastics is disclosed. The system includes an inlet stream comprising mixed plastics; a plastic pyrolysis unit, the plastic pyrolysis unit in fluid communication with the inlet stream, and operable to generate a stream of plastic pyrolysis oil from the inlet stream; a first fractionator, the first fractionator in fluid communication with the plastic pyrolysis unit and operable to separate the stream of plastic pyrolysis oil at a first cut temperature, where the first cut temperature is in the range of 80° C. to 250° C. such that the plastic pyrolysis oil is split into a distillate fraction comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction comprising hydrocarbons boiling above the first cut temperature; and a fuel oil blending unit, the fuel oil blending unit in fluid communication with the first fractionator to blend the topped pyrolysis product fraction with one or more streams selected from the group consisting of a kerosene stream, a light gas oil stream, a vacuum residue stream, a FCC clarified oil stream, and an aromatic bottoms stream to generate a fuel oil product stream, wherein the kerosene stream comprises hydrocarbons boiling in the range of 150 to 240° C., the light gas oil comprises hydrocarbons boiling in the range of 240 to 320° C., the vacuum residue comprises hydrocarbons boiling above 480° C., the FCC clarified oil stream comprises hydrocarbons from a fluid catalytic cracking unit boiling above 480° C., and the aromatic bottoms stream comprises aromatics with carbon number of 9 and greater.
Additional features and advantages of the described embodiments will be set forth in the detailed description that follows. The additional features and advantages of the described embodiments will be, in part, readily apparent to those skilled in the art from that description or recognized by practicing the described embodiments, including the detailed description that follows as well as the drawings and the claims.
The following detailed description of specific embodiments of the present disclosure can be best understood when read in conjunction with the following drawings in which:
For the purpose of describing the simplified schematic illustrations and descriptions of
It should further be noted that arrows in the drawings refer to process streams. However, the arrows may equivalently refer to transfer lines that may serve to transfer process streams between two or more system components. Additionally, arrows that connect to system components define inlets or outlets in each given system component. The arrow direction corresponds generally with the major direction of movement of the materials of the stream contained within the physical transfer line signified by the arrow. Furthermore, arrows that do not connect two or more system components signify a product stream which exits the depicted system or a system inlet stream which enters the depicted system. Product streams may be further processed in accompanying chemical processing systems or may be commercialized as end products. System inlet streams may be streams transferred from accompanying chemical processing systems or may be non-processed feedstock streams. Some arrows may represent recycle streams, which are effluent streams of system components that are recycled back into the system. However, it should be understood that any represented recycle stream, in some embodiments, may be replaced by a system inlet stream of the same material, and that a portion of a recycle stream may exit the system as a system product.
Additionally, arrows in the drawings may schematically depict process steps of transporting a stream from one system component to another system component. For example, an arrow from one system component pointing to another system component may represent “passing” a system component effluent to another system component, which may include the contents of a process stream “exiting” or being “removed” from one system component and “introducing” the contents of that product stream to another system component.
It should be understood that two or more process streams are “mixed” or “combined” when two or more lines intersect in the schematic flow diagrams, such as in
Reference will now be made in greater detail to various embodiments, some embodiments of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or similar units.
Embodiments of methods of producing a fuel oil comprising pyrolysis products from waste plastics and associated systems are provided in the present disclosure.
In accordance with the present disclosure, plastic pyrolysis oil generated from the pyrolysis of waste plastics is directly provided as a fuel oil blending component. The ultimately generated fuel oil comprises the aforementioned plastic pyrolysis oil as well as traditional components of fuel oils including kerosene, light gas oil (LGO), fluidized catalytic cracking (FCC) decanted oil or cycle oils, and vacuum residue. As previously indicated, vacuum residue traditionally must be blended with other streams having lower viscosity to allow for effective transportation. Blending streams into the vacuum residue used for this purpose are traditionally kerosene, LGO and FCC decanted oil or cycle oils. However, blending these higher-value streams comes at the cost of a lower production of kerosene and diesel as the kerosene and other high value streams are utilized in the fuel oil blending instead of separated collected and utilized in an alternative process. Therefore, the lower-value aforementioned plastic pyrolysis oil streams can be used as a fuel oil blending component that can help the circular economy. Blending plastic pyrolysis oil recycles the waste plastic back to origin and removes the same from disposal in a landfill or the environment. At the same time, with plastic pyrolysis oil streams being able to substitute kerosene, LGO and FCC decanted oil or cycle oils, the production of kerosene, LGO and FCC decanted oil or cycle oils increases and provides an economic benefit to the refinery.
A method of producing a fuel oil comprising pyrolysis products from waste plastics includes conducting pyrolysis of a plastic feedstock to produce a stream of plastic pyrolysis oil, feeding the plastic pyrolysis oil to a first fractionator to separate the plastic pyrolysis oil at a first cut temperature such that the plastic pyrolysis oil is split into a distillate fraction and a topped pyrolysis product fraction, and feeding the topped pyrolysis product fraction along with one or more streams selected from the group consisting of a kerosene stream, a light gas oil stream, a vacuum residue stream, a FCC clarified oil stream, and an aromatic bottoms stream to a fuel oil blending unit to generate a fuel oil product stream. The plastic feedstock pyrolyzed to generate the stream of plastic pyrolysis oil comprises mixed waste plastics. Further, the first cut temperature in the first fractionator may be in the range of 80° C. to 250° C. such that the plastic pyrolysis oil is split into a distillate fraction comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction comprising hydrocarbons boiling above the first cut temperature.
The associated system for preparing a fuel oil comprising pyrolysis products from waste plastics includes an inlet stream comprising mixed plastics, a plastic pyrolysis unit, a first fractionator, and a fuel oil blending unit. The plastic pyrolysis unit is in fluid communication with the inlet stream, and operable to generate a stream of plastic pyrolysis oil from the inlet stream. The first fractionator is in fluid communication with the plastic pyrolysis unit and operable to separate the stream of plastic pyrolysis oil at a first cut temperature. The first cut temperature is in the range of 80° C. to 250° C. such that the plastic pyrolysis oil is split into a distillate fraction comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction comprising hydrocarbons boiling above the first cut temperature. The fuel oil blending unit is in fluid communication with the first fractionator and blends the topped pyrolysis product fraction with one or more streams selected from the group consisting of a kerosene stream, a light gas oil stream, a vacuum residue stream, a FCC clarified oil stream, and an aromatic bottoms stream to generate a fuel oil product stream.
Having generally described the methods and associated of producing a fuel oil comprising pyrolysis products from waste plastics, embodiments of the same are described in further detail and with reference to the various Figures.
Referring first to
Plastic Feedstock
In one or more embodiments, the inlet stream 101 comprises a plastic feedstock including mixed plastics of differing compositions. The plastic feedstock provided to the plastic pyrolysis unit 151 may be a mixture of plastics from various polymer families. In various embodiments, the plastic feedstock may comprise plastics representative of one or more of the polymer families disclosed in Table 1. Specifically, the plastic feedstock may comprise plastics representative of one or more of olefins, carbonates, aromatic polymers, sulfones, fluorinated hydrocarbon polymers, chlorinated hydrocarbon polymers, and acrylonitriles. Further, the plastic feedstock provided to the plastic pyrolysis unit 151 may be a mixture of high density polyethylene (HDPE, for example, a density of about 0.93 to 0.97 grams per cubic centimeter (g/cm3), low density polyethylene (LDPE, for example, about 0.910 g/cm3 to 0.940 g/cm3), polypropylene (PP), linear low density polyethylene (LLDPE), polystyrene (PS), polyethylene terephthalate (PET). It will be appreciated that utilization of the mixed plastics feedstock allows for recycling of plastics without necessitating fine sorting of the plastics.
The plastics of the inlet stream 101 may be provided in a variety of different forms. The plastics may be in the form of a powder in smaller scale operations. The plastics may be in the form of pellets, such as those with a particle size of from 1 to 5 millimeter (mm) for larger scale operations. In further embodiments, the plastics may be provided as a chopped or ground product. Further, the plastics of the inlet stream 101 may be natural, synthetic or semi-synthetic polymers. In various embodiments, the plastics of the inlet stream 101 may comprise waste plastic, manufacturing off-spec product, new plastic products, unused plastic products, as well as their combinations.
Plastic Pyrolysis
The plastic pyrolysis unit 151 converts the inlet stream 101 of plastics to gaseous and liquid products. The liquid products are provided as an effluent from the plastic pyrolysis unit 151 as the stream of plastic pyrolysis oil 102. The stream of gaseous products are generically shown in
The specific reactor used as the plastic pyrolysis unit 151 can be of different types and are not limited for the purposes of the present disclosure. One skilled in the art will appreciate that typical reactor types that can be used to serve the function of the plastic pyrolysis unit 151 are tank reactors, rotary kilns, packed beds, bubbling and circulating fluidized bed, ebullated-bed, and others appreciated by those skilled in the art. In one or more embodiments, the pyrolysis of the plastic feedstock in the inlet stream 101 is performed in the presence or absence of a catalyst at a temperature of 300 to 1000° C. In various further embodiments, the plastic pyrolysis unit 151 may operate at a low severity at a temperature less than or equal to 450° C., at a high severity at a temperature greater than 450° C., at a temperature of 300 to 450° C., at a temperature of 450 to 1000° C., at a temperature of 450 to 750° C., at a temperature of 600 to 1000° C., or at a temperature of 750 to 1000° C. In various embodiments, the plastic pyrolysis unit 151 may operate at a pressure in the range of 1 to 100 bars, 1 to 50 bars, 1 to 25 bars, or 1 to 10 bars. Further, in various embodiments, the residence time of the plastic feedstock in the plastic pyrolysis unit 151 may be 1 to 3600 seconds, 60 to 1800 seconds, or 60 to 900 seconds.
Plastic Pyrolysis Oil
In one or more embodiments, the plastic pyrolysis oil 102 comprises up to 90 weight percent paraffins, up to 90 weight percent olefins and olefins, up to 45 weight percent naphtenes, and up to 10 weight percent aromatics. In further, embodiments, the plastic pyrolysis oil 102 comprises up to 50 weight percent paraffins, up to 50 weight percent olefins and olefins, up to 45 weight percent naphtenes, and up to 10 weight percent aromatics.
In one or more embodiments, the plastic pyrolysis oil 102 comprises less than 10,000 parts per million (ppm) by weight (ppmw) sulfur. In various further embodiments, the plastic pyrolysis oil 102 comprises less than 1,000 ppmw sulfur, less than 500 ppmw sulfur, less than 200 ppmw sulfur, less than 100 ppmw sulfur, or less than 50 ppmw sulfur. In further embodiments, and with reference to
First Fractionator
The first fractionator 152 may comprise any unit operation or system known to those skilled in the art for separating a hydrocarbon stream by vapor pressure. An example fractionation unit is an atmospheric distillation unit. An atmospheric distillation unit utilizes fractional distillation by heating the feed to a temperature at which one or more fractions of the mixture will vaporize while leaving other fractions as liquid to separate the feed stream. Further, in various embodiments, the first fractionator 152 may be a simple flash column or true boiling point distillation with at least 15 theoretical plates. In one or more embodiments, the first fractionator 152 separates the stream of plastic pyrolysis oil 102 at a first cut temperature to generate the distillate fraction comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction comprising hydrocarbons boiling above the first cut temperature.
In one or more embodiments, the first cut temperature where the stream of plastic pyrolysis oil 102 is split to generate the distillate fraction and the topped pyrolysis product fraction is in the range of 80° C. to 250° C. In various embodiments, the first cut temperature may be in the range of 160° C. to 250° C., 180° C. to 250° C., 80° C. to 200° C., 80° C. to 180° C., 80° C. to 160° C., or 160° C. to 250° C. For example, in one or more embodiments the first cut temperature may be 80° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 80° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 80° C. In one or more further embodiments the first cut temperature may be 160° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 160° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 160° C. In one or more further embodiments the first cut temperature may be 180° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 180° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 180° C. In one or more further embodiments the first cut temperature may be 240° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 240° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 240° C.
It is noted that when the plastic feedstock includes polymers that contain sulfur, chlorine, or fluorine, treatment of the plastic pyrolysis oil 102 may be desirable before further processing. The pretreatment may be completed before or after the first fractionator 152.
Fuel Oil Blending Unit
The fuel oil blending unit 153 is in fluid communication with the first fractionator 152 to blend the topped pyrolysis product fraction 104 with one or more other hydrocarbon stream to generate the fuel oil product stream 110. In one or more embodiments, the topped pyrolysis product fraction 104 is blended with one or more streams selected from the group consisting of the kerosene stream 202, the light gas oil stream 204, the vacuum residue stream 206, the FCC clarified oil stream 208, and the aromatic bottoms stream 210 in the fuel oil blending unit 153 to generate the fuel oil product stream 110.
It will be appreciated that addition of the topped pyrolysis product fraction 104 as a process stream input to the fuel oil blending unit 153 allows for a reduction in input from one or more of the other hydrocarbon streams to generate a positive economic impact. For example, input of high value stream such as the kerosene stream 202, the light gas oil stream 204, or both may be reduced preserving such high value streams for direct sale or alternate implementation within the refining complex. As such, in accordance with the various embodiments, the topped pyrolysis product fraction 104 is used as a fuel oil blending component where the topped pyrolysis product fraction 104 substitutes higher value cutter stock or stocks to maintain fuel oil product specifications while increasing profit margins.
In one or more embodiments and with reference to
In one or more embodiments and with reference to
As previously indicated, the kerosene stream 202, the light gas oil stream 204, the vacuum residue stream 206, the FCC clarified oil stream 208, and the aromatic bottoms stream 210 as well as the topped pyrolysis oil fraction 104 are provided to the fuel oil blending unit 153 to generate the fuel oil product 110. For purposed of the present disclosure, the kerosene stream 202 comprises hydrocarbons boiling in the range of 150 to 240° C., the light gas oil 204 comprises hydrocarbons boiling in the range of 240 to 320° C., the vacuum residue 206 comprises hydrocarbons boiling above 480° C., the FCC clarified oil stream 208 comprises hydrocarbons from a fluid catalytic cracking unit boiling above 480° C., and the aromatic bottoms stream 210 comprises aromatics with carbon number of 9 and greater. The aromatic bottoms stream 210 additionally is generally provided from an aromatic recovery complex. The aromatic bottoms stream 210 contains mono-aromatics in major proportion and di-aromatics and greater in minor proportion with it noted that di-aromatics are provided in greater proportion than the tri- and greater aromatics.
It will be appreciated that each of the kerosene stream 202, the light gas oil stream 204, the vacuum residue stream 206, the FCC clarified oil stream 208, and the aromatic bottoms stream 210 represent a multitude of individual components each with individual boiling points such that the totality of the kerosene stream 202, the light gas oil stream 204, the vacuum residue stream 206, the FCC clarified oil stream 208, the aromatic bottoms stream 210, and the topped pyrolysis oil fraction 104 when combined at specific ratios generate the fuel oil product 110 within specification. Merely combining a stream generated from pyrolysis of waste plastics and one or more hydrocarbon streams will not unavoidably generate a fuel oil product stream 110 within specification, but instead the formulation must be determined based on the individual composition of each feed stream.
In one or more embodiments, the fuel oil product stream 110 comprises 0.5 to 20 volume percent (vol. %) of the topped pyrolysis product fraction 104. It will be appreciated that inclusion of the topped pyrolysis product fraction 104 within the fuel oil product stream 110 represents a commensurate reduction in higher value input streams, such as the kerosene stream 202 or the light gas oil stream 204. Even at 0.5 volume percent, inclusion of the topped pyrolysis product fraction 104 represents a substantial economic benefit through reduction in flow of higher value streams as inputs to the fuel oil blending unit 153. Further, environmental benefits are provided by providing useful utilization of waste plastics. In various further embodiments, the fuel oil product stream 110 comprises 0.5 to 15 vol. %, 0.5 to 10 vol. %, 1 to 20 vol. %, 1 to 15 vol. %, 1 to 10 vol. %, 1 to 5 vol. %, or 5 to 10 vol. % of the topped pyrolysis product fraction 104.
Blending ratios of the various stream within the fuel oil blending unit 153 are dependent on the market value of the individual blending components, the specifications of the desired fuel oil, and present availability of blending components at the refinery. Blending ratios may be adjusted to maximize profit of the refinery with the components having the highest market value substituted with the topped pyrolysis product fraction 104. It will be appreciated that the blending ratios can be modelled or monitored in real time to provide maximum profitability in real time.
Fuel Oil Product
In one or more embodiments, the fuel oil product stream 110 consists of fuel oil conforming with International Maritime Organization (IMO) specifications. In one or more embodiments, the fuel oil product stream 110 consists of fuel oil conforming with International Organization for Standardization (ISO) 8271 specifications. In one or more specific embodiments, the fuel oil product stream 110 comprises a specific gravity (15/15° C.) of 1.010 or less, a sulfur content of 3.7 weight percent or less, a kinematic viscosity (at 50° C.) of 700 cSt or less, a flash point of 60.0° C. or greater, and a carbon residue of 20.0 weight percent or less. In one or more specific embodiments, the fuel oil product stream 110 comprises a specific gravity (15/15° C.) of 0.979 or less, a sulfur content of 3.7 weight percent or less, a kinematic viscosity (at 50° C.) of 380 cSt or less, a flash point of 65.5° C. or greater, and a carbon residue of 20.0 weight percent or less.
Pretreater
With reference to
In one or more embodiments and as illustrated in
Removal of contaminants is desirable as nitrogen can poison the streams for downstream processing, chlorine causes metallurgical issues such as corrosion and therefore must meet the design specification of the any processing units, and sulfur removal is desirable to meet final fuel specifications.
Demetallization Operation
In one or more embodiments and with reference to
In one or more embodiments, the demetallization operation 154 may be catalytic hydrodemetallization. U.S. Pat. No. 8,491,779, incorporated by reference, teaches the integration of catalytic hydrodemetallization (HDM) into a refinery process. The HDM step is carried out in the presence of a catalyst and hydrogen. Further, in one or more embodiments, the hydrogen that is used can come from the further processing unit 300 or another unit operation within the general refining complex. The HDM is generally carried out at 370 to 415° C. and pressure of 30 to 200 bars. Also, see U.S. Pat. No. 5,417,846, incorporated by reference, teaching HDM, as well as U.S. Pat. Nos. 4,976,848; 4,657,664; 4,166,026; and 3,891,541, all of which are incorporated by reference.
In one or more embodiments, the demetallization operation 154 may be solvent deasphalting. The process of solvent deasphalting results in the metal containing hydrocarbons of the topped pyrolysis product fraction 104 ending up in an asphaltenes stream of a solvent deasphalting unit. U.S. Pat. No. 7,566,394, incorporated by reference, teaches details of a solvent deasphalting process.
Further Processing
The distillate fraction 103 may undergo further processing in a further processing unit 300 to generate useful products. While not the main focus of the present disclosure, it will be appreciated that the distillate fraction 103 may be provided to a further processing unit 300 to generate value added products.
In one or more embodiments, the distillate fraction 103 may be provided to hydrotreating units to remove di-olefins and mono-olefins to generate a feedstream for yet further processing. An example of such further processing unit 300 and method to remove di-olefins and mono-olefins to generate a feedstream for yet further processing is provided in U.S. patent Ser. No. 17/355,718, incorporated by reference.
In one or more embodiments, the distillate fraction 103 may be provided to an oligomerization operation to generate long chain olefins for yet further processing. An example of such further processing unit 300 and method to complete an oligomerization operation to generate long chain olefins for yet further processing is provided in U.S. patent Ser. No. 17/668,478, incorporated by reference.
In one or more embodiments, the distillate fraction 103 may be directly provided or provided after initial processing to a hydrotreating or steam cracking unit to produce useful and value added products such as ethylene.
While examples of further processing units 300 are provided it will be appreciated that the distillate fraction 103 could be treated in any manner known to one skilled in the art. However, the benefit of utilizing all the components of the plastic pyrolysis oil 102 is consistent regardless of what further processing unit 300 is implemented such that the inlet stream 101 of waste plastics is fully integrated back into useful products. A full circular economy is produced where traditional waste or scrap plastics are converted into value added products or able to be utilized as a feedstream in further processes such that waste plastics are removed from landfills, roads, forests, and oceans.
Having described the system for preparing a fuel oil comprising pyrolysis products from waste plastics, it is expressly indicated that the associated method of preparing a fuel oil comprising pyrolysis products from waste plastics using the same is also envisioned and disclosed in conjunction with the system. However, in the interest of absolute clarity the method of preparing a fuel oil comprising pyrolysis products from waste plastics is additionally expressly presented. The method includes conducting pyrolysis of a plastic feedstock to produce a stream of plastic pyrolysis oil 102, feeding the plastic pyrolysis oil 102 to a first fractionator 152 to separate the plastic pyrolysis oil 102 into at a first cut temperature, where the first cut temperature is in the range of 80° C. to 250° C. such that the plastic pyrolysis oil 102 is split into a distillate fraction 103 comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction 104 comprising hydrocarbons boiling above the first cut temperature, and feeding the topped pyrolysis product fraction 104 along with one or more streams selected from the group consisting of a kerosene stream 202, a light gas oil stream 204, a vacuum residue stream 206, a FCC clarified oil stream 208, and an aromatic bottoms stream 210 to a fuel oil blending unit 153 to generate a fuel oil product stream 110. The two step oligomerization operation includes feeding the distillate fraction 103 to the first hydrotreating unit 154 configured and operated to remove di-olefins by hydrogenation from the distillate fraction 103 to produce the first product stream 106 of dediolefinized plastic pyrolysis distillate and feeding the first product stream 106 to the olefin oligomerization reactor 156 configured and operated to react and combine mono-olefins in the first product stream 106 to form longer chain olefins and produce the second product stream 108 of oligomerized plastic pyrolysis distillate.
The following examples illustrate features of the present disclosure but are not intended to limit the scope of the disclosure.
To demonstrate the utility of the methods of producing a fuel oil comprising pyrolysis products from waste plastics in accordance with the present disclosure representative testing models were completed. Specifically, a variety of fuel oil product streams 110 were generated in accordance with embodiments of the present disclosure.
A plastic feed comprising a mixture of HDPE, LDPE, PP, LLDPE, PS, and PET was provided to a plastic pyrolysis unit 151 and processed to generate a stream of plastic pyrolysis oil 102. The properties and composition of the plastic pyrolysis oil 102 are shown in Table 2.
Further, the plastic pyrolysis oil 102 was provided to a first fractionator 152 in accordance with the present disclosure and separated into a distillate fraction 103 boiling in the range of 36 to 180° C., and a topped pyrolysis product fraction 104 including hydrocarbons boiling at 180° C. or greater. Specifically, light fractions boiling at less than 180° C. were removed from the plastic pyrolysis oil 102 as the distillate fraction 103 by a TBP distillation with a column having 15 theoretical plates. The breakdown of the distillate fraction 103 and the topped pyrolysis product fraction 104 are provided in Table 3.
After pyrolysis and separation, the topped pyrolysis product fraction 104 was blended with a typical refinery fuel oil blend to generate fuel oil product stream 110 in accordance with the present disclosure. The typical refinery fuel oil blend is characterized in Table 4 and represents Comparative Example 1. For each of the inventive examples kerosene was omitted from the typical refinery fuel oil blend and substituted with the topped pyrolysis product fraction 104. Inventive Example 2 represents substitution of topped pyrolysis product fraction 104 for a portion of the kerosene in the typical refinery fuel oil blend such that the generated fuel oil product stream comprises 1 volume percent topped pyrolysis product fraction 104. Inventive Example 3 represents substitution of topped pyrolysis product fraction 104 for a portion of the kerosene in the typical refinery fuel oil blend such that the generated fuel oil product stream comprises 5 volume percent topped pyrolysis product fraction 104. Inventive Example 3 represents substitution of topped pyrolysis product fraction 104 for a portion of the kerosene in the typical refinery fuel oil blend such that the generated fuel oil product stream comprises 10 volume percent topped pyrolysis product fraction 104.
Characterization of the fuel oils of Comparative Example 1, Inventive Example 2, Inventive Example 3, and Inventive Example 4 demonstrate that fuel oil specifications may still be met when replacing high value fuel oil components with the topped plastic pyrolysis oil fraction 104. Specifically, sulfur content, specific gravity, viscosity kinematic, flash point, microcarbon residue, pour point, and chlorine specifications were all met with as great as 10 volume percent of the fuel oil product stream 110 comprising the topped plastic pyrolysis oil fraction 104. The performance of each individual example is presented in Table 5.
It should now be understood the various aspects of the method of producing a fuel oil comprising pyrolysis products from waste plastics and associated system for preparing a fuel oil comprising pyrolysis products from waste plastics are described and such aspects may be utilized in conjunction with various other aspects.
According to a first aspect, a method of producing a fuel oil comprising pyrolysis products from waste plastics, the method includes (a) conducting pyrolysis of a plastic feedstock to produce a stream of plastic pyrolysis oil, the plastic feedstock comprising mixed waste plastics; (b) feeding the plastic pyrolysis oil to a first fractionator to separate the plastic pyrolysis oil at a first cut temperature, where the first cut temperature is in the range of 80° C. to 250° C. such that the plastic pyrolysis oil is split into a distillate fraction comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction comprising hydrocarbons boiling above the first cut temperature; and (c) feeding the topped pyrolysis product fraction along with one or more streams selected from the group consisting of a kerosene stream, a light gas oil stream, a vacuum residue stream, a FCC clarified oil stream, and an aromatic bottoms stream to a fuel oil blending unit to generate a fuel oil product stream, wherein the kerosene stream comprises hydrocarbons boiling in the range of 150 to 240° C., the light gas oil comprises hydrocarbons boiling in the range of 240 to 320° C., the vacuum residue comprises hydrocarbons boiling above 480° C., the FCC clarified oil stream comprises hydrocarbons from a fluid catalytic cracking unit boiling above 480° C., and the aromatic bottoms stream comprises aromatics with carbon number of 9 and greater.
A second aspect includes the method of the first aspect in which the plastic pyrolysis oil comprises up to 90 weight percent of paraffins, up to 90 weight percent olefins, up to 45 weight percent naphtenes, and up to 10 weight percent aromatics.
A third aspect includes the method of the first or second aspect in which the fuel oil product stream comprises a specific gravity (15/15° C.) of 1.010 or less, a sulfur content of 3.7 weight percent or less, a kinematic viscosity (at 50° C.) of 700 cSt or less, a flash point of 60.0° C. or greater, and a carbon residue of 20.0 weight percent or less.
A fourth aspect includes the method of any of the first through third aspect in which the plastic feedstock comprises mixed plastics of differing compositions.
A fifth aspect includes the method of any of the first through fourth aspects in which the pyrolysis of the plastic feedstock is performed in the presence of a catalyst at a temperature of 300° C. to 1000° C.
A sixth aspect includes the method of any of the first through fifth aspects in which the first cut temperature is 80° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 80° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 80° C.
A seventh aspect includes the method of any of the first through fifth aspects in which the first cut temperature is 160° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 160° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 160° C.
An eighth aspect includes the method of any of the first through fifth aspects in which the first cut temperature is 180° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 180° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 180° C.
A ninth aspect includes the method of any of the first through fifth aspects in which the first cut temperature is 240° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 240° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 240° C.
A tenth aspect includes the method of any of the first through ninth aspects in which the fuel oil product stream comprises 0.5 to 20 volume percent of the topped pyrolysis product fraction.
An eleventh aspect includes the method of any of the first through tenth aspects in which where the plastic pyrolysis oil comprises less than 10,000 ppm by weight sulfur.
A twelfth aspect includes the method of any of the first through eleventh aspects in which the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream, as present, are provided as separate streams to the fuel oil blending unit with each of the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream individually flow controlled.
A thirteenth aspect includes the method of any of the first through eleventh aspects in which the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream, as present, are provided as a single bulk fuel oil stream to the fuel oil blending unit, wherein each of the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream individually flow controlled to form the bulk fuel oil stream.
According to a fourteenth aspect a system for preparing a fuel oil comprising pyrolysis products from waste plastics includes an inlet stream comprising mixed plastics; a plastic pyrolysis unit, the plastic pyrolysis unit in fluid communication with the inlet stream, and operable to generate a stream of plastic pyrolysis oil from the inlet stream; a first fractionator, the first fractionator in fluid communication with the plastic pyrolysis unit and operable to separate the stream of plastic pyrolysis oil at a first cut temperature, where the first cut temperature is in the range of 80° C. to 250° C. such that the plastic pyrolysis oil is split into a distillate fraction comprising hydrocarbons boiling in the range of 36° C. to the first cut temperature and a topped pyrolysis product fraction comprising hydrocarbons boiling above the first cut temperature; and a fuel oil blending unit, the fuel oil blending unit in fluid communication with the first fractionator to blend the topped pyrolysis product fraction with one or more streams selected from the group consisting of a kerosene stream, a light gas oil stream, a vacuum residue stream, a FCC clarified oil stream, and an aromatic bottoms stream to generate a fuel oil product stream, wherein the kerosene stream comprises hydrocarbons boiling in the range of 150 to 240° C., the light gas oil comprises hydrocarbons boiling in the range of 240 to 320° C., the vacuum residue comprises hydrocarbons boiling above 480° C., the FCC clarified oil stream comprises hydrocarbons from a fluid catalytic cracking unit boiling above 480° C., and the aromatic bottoms stream comprises aromatics with carbon number of 9 and greater.
A fifteenth aspect includes the system of the fourteenth aspect in which the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream, as present, are provided as separate streams to the fuel oil blending unit with each of the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream individually flow controlled.
A sixteenth aspect includes the system of the fourteenth aspect in which the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream, as present, are provided as a single bulk fuel oil stream to the fuel oil blending unit, wherein each of the kerosene stream, the light gas oil stream, the vacuum residue stream, the FCC clarified oil stream, and the aromatic bottoms stream individually flow controlled to form the bulk fuel oil stream.
A seventeenth aspect includes the system of any of the fourteenth through sixteenth aspects in which the plastic pyrolysis oil comprises up to 90 weight percent of paraffins, up to 90 weight percent olefins, up to 45 weight percent naphtenes, and up to 10 weight percent aromatics
An eighteenth aspect includes the system of any of the fourteenth through seventeenth aspects in which the plastic feedstock comprises mixed plastics of differing compositions.
A nineteenth aspect includes the system of any of the fourteenth through eighteenth aspects in which the first cut temperature is 80° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 80° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 80° C.
A twentieth aspect includes the system of any of the fourteenth through eighteenth aspects in which the first cut temperature is 160° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 160° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 160° C.
A twenty-first aspect includes the system of any of the fourteenth through eighteenth aspects in which the first cut temperature is 180° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 180° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 180° C.
A twenty-second aspect includes the system of any of the fourteenth through eighteenth aspects in which the first cut temperature is 240° C. such that the distillate fraction comprises hydrocarbons boiling in the range of 36 to 240° C. and the topped pyrolysis product fraction comprises hydrocarbons boiling above 240° C.
A twenty-third aspect includes the system of any of the fourteenth through twenty-second aspects in which the fuel oil product stream comprises 0.5 to 20 volume percent of the topped pyrolysis product fraction.
It should be apparent to those skilled in the art that various modifications and variations can be made to the described embodiments without departing from the spirit and scope of the claimed subject matter. Thus, it is intended that the specification cover the modifications and variations of the various described embodiments provided such modifications and variations come within the scope of the appended claims and their equivalents.
The verb “comprises” and its conjugated forms should be interpreted as referring to elements, components or steps in a non-exclusive manner. The referenced elements, components or steps may be present, utilized or combined with other elements, components or steps not expressly referenced. For the purposes of defining the present technology, the transitional phrase “consisting of” may be introduced in the claims as a closed preamble term limiting the scope of the claims to the recited components or steps and any naturally occurring impurities. For the purposes of defining the present technology, the transitional phrase “consisting essentially of” may be introduced in the claims to limit the scope of one or more claims to the recited elements, components, materials, or method steps as well as any non-recited elements, components, materials, or method steps that do not materially affect the novel characteristics of the claimed subject matter. The transitional phrases “consisting of” and “consisting essentially of” may be interpreted to be subsets of the open-ended transitional phrases, such as “comprising” and “including,” such that any use of an open ended phrase to introduce a recitation of a series of elements, components, materials, or steps should be interpreted to also disclose recitation of the series of elements, components, materials, or steps using the closed terms “consisting of” and “consisting essentially of.” For example, the recitation of a composition “comprising” components A, B, and C should be interpreted as also disclosing a composition “consisting of” components A, B, and C as well as a composition “consisting essentially of” components A, B, and C. Any quantitative value expressed in the present application may be considered to include open-ended embodiments consistent with the transitional phrases “comprising” or “including” as well as closed or partially closed embodiments consistent with the transitional phrases “consisting of” and “consisting essentially of.”
It is noted that one or more of the following claims utilize the term “where” as a transitional phrase. For the purposes of defining the present technology, it is noted that this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”
It should be understood that any two quantitative values assigned to a property may constitute a range of that property, and all combinations of ranges formed from all stated quantitative values of a given property are contemplated in this disclosure. That is, it is envisioned that each discrete value encompassed by the ranges are also included. Additionally, the ranges which may be formed by each discrete value encompassed by the explicitly disclosed ranges are equally envisioned. For brevity, the same is not explicitly indicated subsequent to each disclosed range and the present general indication is provided.
Throughout the disclosure there is indication of specific parameters being “less than” a value without a specified lower bound. It will be appreciated that such indication implicitly includes the range from zero to the specified value.
Having described the subject matter of the present disclosure in detail and by reference to specific embodiments, it is noted that the various details described in this disclosure should not be taken to imply that these details relate to elements that are essential components of the various embodiments described in this disclosure, even in cases where a particular element is illustrated in each of the drawings that accompany the present description. Rather, the claims appended hereto should be taken as the sole representation of the breadth of the present disclosure and the corresponding scope of the various embodiments described in this disclosure. Further, it will be apparent that modifications and variations are possible without departing from the scope of the appended claims.
