Efficient fluid-bed plastics upgrading

Abstract

A system and method for upgrading waste plastic is provided, wherein the plastic is upgraded by pyrolysis in a fluid-bed upgrader while minimizing char and waxy molecule production. Additionally, the gas byproducts from the pyrolysis reaction are separated, compressed, and partially recycled to act as a fluidization agent.

Description

[0001] EFFICIENT FLUID-BED PLASTICS UPGRADING

[0002] TECHNICAL FIELD

[0003] The present disclosure is generally related to systems and methods for upgrading waste plastic using a fluid-bed upgrader.

[0004] BACKGROUND

[0005] Plastic recycling and upgrading technologies have been evolving quickly in the last two decades due to various environmental concerns, including minimizing waste and reducing reliance on fossil fuels. In recent years, pyrolysis reactors have been used to process plastics. Plastic recycling reactions conducted in pyrolysis reactions are highly endothermic, performed at high temperatures, and can require a very high residence time of 0.5-2 hours. This residence time is due to heat transfer limitations posed by the relatively slow heating methods and large size of the plastic pellets, cubes, or other particles being used. These plastic particles are typically large in size to prevent the formation of powder, which can cause air pollution and handling issues.

[0006] In some conventional waste plastic upgrading systems, plastics are first dissolved in hydrocarbon liquids and then injected into a fluid catalytic cracking (FCC) unit in a refinery. This, however, causes various issues in the operation of an FCC unit, which is an important part of the refinery. Examples of these issues include corrosion caused by impurities present in the waste plastics and throughput limitations on the FCC due to the waste plastic producing a product slate that is substantially different than what the FCC unit is designed for. Furthermore, plastic upgrading is also not an optimized process in a typical FCC unit for which the plastic feed is a veiy small portion of the total flow. Finally, the products of plastic recycling overwhelmingly end up in FCC products that are used as fuel. This releases the carbon they contain into the atmosphere as CO2, which is less environmentally desirable.

[0007] In other conventional plastic upgrading systems, solid acid catalysts are utilized in a dedicated fluidized bed which converts a significant amount of the plastic feed into char (also known as coke), due to the acidity of the catalyst. Burning char produces carbon dioxide emissions, which is also environmentally undesirable.

[0008] The present application addresses these and other challenges related to conventional plastic upgrading technologies.

[0009] SUMMARY

[0010] According to a first aspect, this invention is directed toward a system for upgrading waste plastic, comprising a fluid-bed upgrader configured for a pyrolysis reaction that has a top section, a middle section, and a bottom section. The top section of the upgrader is a freeboard, the bottom section includes a fluidized bed, and the middle section includes at least one inlet for a waste plastic feed. Furthermore, the bottom section is configured to be at least 100°F hotter than the top section and includes at least one inlet for a catalyst or an inert solid, and an outlet for withdrawal of charred solids. The fluid-bed upgrader also includes a separation section in fluid connection with the top section, wherein the separation section is configured to cool and separate a product stream of the upgrader into a liquid stream and a gas stream. The fluid-bed upgrader also includes a gas compressor fluidly connected to the separation section and configured to compress the gas stream to produce a light gas stream, and a recycle conduit connected to the bottom section of the upgrader. The recycle conduit is configured to transport a portion of the light gas stream to the upgrader, and the upgrader is configured to utilize the light gas stream as a fluidization agent. In another aspect, the top section of the upgrader includes solid and gas separation equipment.

[0011] In another aspect, the bottom section of the fluid-bed upgrader is configured to be more than 300°F hotter than the top section of the upgrader. In a further aspect, the fluidbed upgrader is configured to be heated via a flue gas, the bottom section of the upgrader include a flue gas inlet, and the middle section or the bottom section of the upgrader includes a flue gas outlet.

[0012] In another aspect, the fluid-bed upgrader comprises an electrical heating component or a microwave emitter configured to heat the upgrader. In a further aspect, the majority of the heat being transferred by the electrical heating component or the microwave emitter is transferred to the bottom section of the upgrader. In a further aspect, the recycle conduit comprises a heating element configured to heat the light gas stream. In a further aspect, the upgrader is configured to operate under a turbulent regime having an average superficial velocity of approximately 0.3 - 4 feet per second. In a further aspect, the upgrader is configured to accommodate plastic particles in the range of approximately 5-50,000 microns.

[0013] In another aspect, the light gas stream comprises ethane, propane, butane, or liquefied petroleum gas, or any combination thereof. In an even further aspect, the light gas stream is preheated to a temperature higher than 1000°F. In a further aspect, the light gas stream is an inert gas. In an even further aspect, the light gas stream comprises steam, H2, methane, or N2, or a combination thereof.

[0014] In another aspect, the system includes a melter upstream of the fluid-bed upgrader, where the melter comprises an inlet for the waste plastic feed, and one or more mechanical mixers, and the melter is configured to melt the waste plastic before it enters the fluid-bed upgrader. The system can further include a heating component upstream of the fluid-bed upgrader, the heating component comprising an air compressor and an inline burner configured to feed hot flue gas to internal heating tubes inside the fluid-bed upgrader. The heating component is configured to compress air and cause a combustion reaction by at least partially reacting air with fuel gas before the flue gas enters the internal heating tubes in the fluid-bed upgrader. The system can further include a pump fluidly connected to the melter and configured to pump the melted waste plastic from the melter to the fluid-bed upgrader and optionally recycle a portion of the melted waste plastic to the melter.

[0015] In another aspect, the system includes a first heat exchanger and a second heat exchanger. The first heat exchanger is configured to receive an outlet flue gas stream from the internal heating tubes of the fluid-bed upgrader and configured to reduce the temperature of said flue gas stream. The second heat exchanger is configured to receive flue gas from the first heat exchanger, and is configured to heat hot oil for further heat transfer in a third heat exchanger that is configured to heat recycled melted plastic and transfer it to the melter.

[0016] In a second aspect, a method for upgrading waste plastic using a fluid-bed upgrader is provided, with said fluid-bed upgrader having a top section, a middle section, and a bottom section. The top section of the upgrader is a freeboard, the bottom section includes a fluidized bed, and the middle section includes at least one inlet for a waste plastic feed, and the upgrader is configured for a pyrolysis reaction. The method comprises introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader, pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic to produce a product feed comprising liquid and gas hydrocarbons, wherein the fluid bed of the upgrader operates under a turbulent regime and wherein effluent of the upgrader is at a temperature in a range of approximately 700- 1700°F, and the heating in the upgrader results in a temperature of at least 50°F greater at the bottom portion of the upgrader relative to the middle portion of the upgrader. The method further comprises separating the product feed in a separation section, wherein a gas portion of the product feed is separated and transferred to a compressor, then compressing the gas portion of the product feed via the compressor to produce a light gas stream, then recycling a portion of the light gas stream to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader.

[0017] In another aspect, the top section of the upgrader comprises solid and gas separation equipment. In another aspect, the step of pyrolyzing the waste plastic comprises heating the fluid-bed upgrader via a flue gas, an electrical heating component, or microwaves. In a further aspect, the waste plastic feed is mechanically fed or carried by a fluid, or melted before being fed into the fluid-bed upgrader. In a further aspect, the waste plastic feed has an average particle size of 55-100 microns. In a further aspect, more than 85% of the waste plastic feed particles are between 5-95 microns. In a further aspect, the waste plastic feed has a residency time in the upgrader of less than 70 seconds. In a further aspect, the waste plastic feed has a residency time in the upgrader of less than 20 seconds. In a further aspect, the waste plastic feed has a residency time in the upgrader of less than 10 seconds.

[0018] In a further aspect, the light gas stream is heated before being recycled to the upgrader. In a further aspect, the inert solid is replaced or mixed with an acidic solid catalyst, such as a zeolite-based catalyst. In an even further aspect, the zeolite-based catalyst is a waste FCC equilibrium catalyst. In a further aspect, the light gas stream comprises C2-C4 gases. In a further aspect, the light gas stream comprises C2-C7 gases and H2. In a further aspect, the method further comprises withdrawing, from the upgrader, char-containing solids formed as a result of the pyrolysis reaction, and injecting air, Ch- containing gas, or an inert gas into the withdrawn char-containing solids to convert or strip a portion of the char, wherein said conversion products are primarily CO and water. In an even further aspect, the method comprises heating char-containing solids formed as a result of the pyrolysis reaction to recover a cracked portion of char cracking.

[0019] In another aspect, the method further comprises melting the waste plastic in a melter before it enters the fluid-bed upgrader, and optionally recycling a fraction of the product stream from the fluid-bed upgrader to the melter to control the viscosity of the melted plastic.

[0020] In a third aspect, a method for upgrading waste plastic using a fluid-bed upgrader is provided, wherein said fluid-bed upgrader comprises a top section and a bottom section, where the top section of the upgrader is the freeboard which includes solid and gas separation equipment, and the bottom section includes a fluidized bed. The method comprises introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader above the top of the level of the fluidized bed, pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic to produce a product comprising liquid and gas hydrocarbons at approximately 100°F, wherein the fluidized bed operates under a turbulent regimen, further wherein the effluent of the upgrader is at a temperature in a range of approximately 700-1700°F, further wherein the heating for the pyrolysis in the upgrader results in a temperature of at least 50°F greater at the bottom portion of the upgrader relative to the top portion of the upgrader, further wherein a gaseous stream is introduced at the bottom of the bed to maintain turbulent regime fluidization in the bed.

[0021] In a further aspect, the bottom section of the upgrader is configured to be 150- 500°F hotter than the top section of the upgrader. In a further aspect, the method comprises separating a gas portion of the product feed, wherein the gas portion of the product feed is compressed to produce a light gas stream. In a further aspect, the method comprises recycling a portion of the light gas stream or a fraction of the light gas stream after fractionation to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader.

[0022] In a fourth aspect, a method for upgrading waste plastic using a fluid-bed upgrader is provided in which the fluid-bed upgrader has a top section, a middle section, and a bottom section, wherein the top section is a freeboard, the bottom section includes a fluidized bed, the middle section includes at least one inlet for a waste plastic feed, and the upgrader is configured for a pyrolysis reaction. In the method, a feed of waste plastic and an inert solid are introduced into the fluid-bed upgrader; the waste plastic is pyrolyzed in the upgrader at a temperature above the melting point of the plastic to produce a product feed comprising liquid and gas hydrocarbons, wherein the fluid bed of the upgrader operates under a turbulent regime above atmospheric pressure and at a temperature in a range of approximately 1150-1350°F. The product feed is then separated in a separation section, wherein a gas portion of the product feed is separated and transferred to a compressor. The gas portion of the product feed is then compressed via the compressor to produce a light gas stream. A portion of the light gas stream is recycled to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader and enhances the product yield of the upgrader, and wherein the light gas stream fluidizing the fluid-bed upgrader comprises reactive components. At least 60% of the waste plastics introduced into the fluid-bed upgrader are converted into the light gas stream which can be used to make plastics, and wherein the yield of waxy molecules byproducts and coke products are both limited to less than 2%.

[0023] In a fifth aspect, a method for upgrading waste plastic using a fluid-bed upgrader is provided, in which the fluid -bed upgrader comprises a top section and a bottom section, the top section is the freeboard which includes solid and gas separation equipment, and the bottom section includes a fluidized bed. In the method, a feed of waste plastic and an inert solid are introduced into the fluid-bed upgrader at the level of the fluidized bed or lower. The waste plastic is pyrolyzed in the upgrader at a temperature above the melting point of the plastic to produce a product feed comprising liquid and gas hydrocarbons, wherein the fluid bed of the upgrader operates under a turbulent regime and wherein effluent of the upgrader is at a temperature in a range of approximately 700- 1700°F. The product feed is separated in a separation section, wherein a gas portion of the product feed is separated and transferred to a compressor. The gas portion of the product feed is then compressed via the compressor to produce a light gas stream. A portion of the light gas stream is recycled to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader and enhances the product yield of the upgrader, and wherein the light gas stream fluidizing the fluid-bed upgrader comprises reactive components.

[0024] In a further aspect, the feed of waste plastic is introduced above the location of coils of the fluidized bed.

[0025] In a sixth aspect, a system for upgrading waste plastic is provided. The system includes a melter comprising at least one inlet for a waste plastic feed and optionally one or more mechanical mixers, wherein said melter is configured to melt the waste plastic. The system also includes a fluid-bed upgrader having at least a top section and a bottom section, wherein the top section is a freeboard, wherein the bottom section has a fluidized bed, wherein the fluid -bed upgrader includes at least a first inlet for receiving the melted waste plastic, and wherein the fluid-bed upgrader is configured to pyrolyze the melted waste plastic to produce a product stream. The system further includes a heating system comprising a compressor and an inlet with an in-line burner configured to provide hot flue gas to internal heating tubes in the fluid-bed upgrader, wherein the heating system is configured to compress and combust fuel gas with air before the flue gas enters internal heating tubes of the fluid-bed upgrader.

[0026] In another aspect, the bottom section of the fluid-bed upgrader is configured to be at least 100°F hotter than the top section and includes at least one inlet for a catalyst or an inert solid, and an outlet for withdrawal of charred solids.

[0027] In another aspect, the fluid-bed upgrader is configured to pyrolyze the melted waste plastic at a temperature above the melting point of the plastic, to produce the product stream, which comprises liquid and gas hydrocarbons when cooled to 100 °F. In a further aspect, the fluid bed of the fluid-bed upgrader is configured to operate under a turbulent regime and wherein effluent of the fluid-bed upgrader is at a temperature in a range of approximately 700-1700°F.

[0028] In another aspect, the system further includes a first heat exchanger in connection with the internal heating tubes of the fluid-bed upgrader and configured to receive a flue gas stream from the internal heating tubes of the fluid-bed upgrader and reduce the temperature of said flue gas stream. The system further includes a second heat exchanger in connection with the first heat exchanger, wherein the second heat exchanger is configured to heat, hot oil, for heating recycled melting plastic in a third heat exchanger and to transfer hot melted plastic to the melter.

[0029] In another aspect, the system further includes a pump connected to the melter and configured to pump the melted waste plastic from the melter to the fluid-bed upgrader and recycle a portion of the melted waste plastic back to the melter via a heat exchanger.

[0030] In another aspect, melter is configured to operate at a temperature of approximately 450°F to 700°F. In a further aspect, the melter is configured to operate at a temperature of approximately 615°F.

[0031] In another aspect, the fluid-bed upgrader further comprises a fluidization inlet in the bottom section of the fluid-bed upgrader, wherein the fluidization inlet is configured to introduce a fluidization gas into the fluid-bed upgrader. In a further aspect, the fluidization gas comprises hydrocarbons with 1 or more carbon atoms.

[0032] In another aspect, the system further includes at least one hopper in the fluid-bed upgrader, wherein the at least one hopper is configured to introduce solid material into the fluid-bed upgrader. In a further aspect, the solid material in the hopper is lime, a catalyst or an inert solid, or a charred solid, or fines to maintain the desired fluidization.

[0033] In another aspect, the temperature of the melter is maintained using the hot oil as a temperature stabilizer. In a further aspect, the hot oil is at a temperature of approximately 500-750°F.

[0034] BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0035] Fig. 1A describes an exemplary system for upgrading waste plastic using a three- section fluid-bed upgrader in accordance with one or more embodiments. Fig. IB describes an exemplary system for upgrading waste plastic using a two- section fluid-bed upgrader in accordance with one or more embodiments.

[0036] Fig. 1C describes an exemplary system for upgrading waste plastic using a fluidbed upgrader in combination with a melter in accordance with one or more embodiments.

[0037] Fig. 2 is a flow diagram describing the steps undertaken as part of exemplary methods of upgrading waste plastic using a fluid-bed upgrader in accordance with one or more embodiments.

[0038] Fig. 3 is a flow diagram describing the state of the waste plastic as it progresses through the methods of upgrading waste plastic using a fluid-bed upgrader in accordance with one or more embodiments.

[0039] DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0040] The present application discloses various systems and methods for upgrading waste plastic. The present systems and methods upgrade waste plastic to obtain a high yield of economically desirable products, such as naphtha plus light olefins, di-olefins and acetylenes, using a standalone fluid-bed pyrolysis upgrader (reactor). In certain embodiments, the fluid-bed reactor can comprise a bed section, a freeboard section, a convector, and an air pollution control device system. The bed section typically contains a porous plate, known as a distributor, supporting a solid catalyst material. Fluid can be forced from the distributor up through the solid catalyst material. This fluid velocity is increased until the solid catalyst material begins to behave in a fluid-like manner. This is referred to as a "fully fluidized state." Various flow regimes can be utilized in the reactor, depending on the properties of the solid catalyst material. Examples of flow regimes in fluidized bed reactors include, but are not limited to, homogeneous flow, bubbling flow, slugging flow, turbulent flow, fast fluidization flow, and pneumatic transport flow. Suitable materials for a fluid-bed reactor include, but are not limited to, flanged steel and ferritic stainless steel. In one or more embodiments, the reactor may also comprise a hot wall or cold wall vessel. The specific height of a reactor bed depends on various factors, including but not limited to, the type of reactor, the nature of the catalyst, and the desired process conditions, such as the residence time of the cracked product.

[0041] In the fluid-bed pyrolysis reactor (upgrader], a fluidization agent is used. Plastics, on their own, are not a good fluidization agent, as it generally takes some time for plastic to heat up and decompose. In previous systems, steam has been used as a fluidizing agent, but it creates too much wastewater, which is not environmentally friendly. Similarly, nitrogen (N2) has also been used in previous systems, but N2 is recovered from air using refrigeration which is also not environmentally desirable. Further, N2 causes fractionation inefficiency downstream as well as making the C2- product less valuable as either fuel gas or chemical feedstock. Accordingly, in the present systems and methods, a light gas fraction of the product of the pyrolysis reaction can be used as the fluidization agent for the fluid-bed pyrolysis reactor.

[0042] In the present system and methods, a feed of waste plastic and a solid powder are introduced into the fluid-bed upgrader (reactor] and the waste plastic is pyrolyzed in the upgrader to produce a product gas that is partially liquid at 100°F. A fluidization gas (fluidization agent] also enters the reactor to ensure proper mass and heat transfer enhancement. The fluidization gas (fluidization agent] can contain hydrocarbons with 1 or more carbon atoms (Ci+] that have partially reacted with the hot fluid-bed. These partial reactions can result in additional yield of useful carbon products. The product can then be separated in a separation section, such that the liquid and gas components are separated and the gas portion is transferred to a compressor. The gas portion can then be compressed to produce a light gas stream, where at least a portion or fraction of the light gas stream can be recycled via a recycle conduit to the fluid-bed upgrader to be fluidized. In one or more embodiments, the at least a portion of the fluidization gas is reactive, and the reactive gas can be a portion of the light gas stream. The pyrolysis product can be transported to the separation section via methods such as flowing via pumping, gravity, pressure gradient, among others. The separation section can comprise any suitable gas-liquid separator, such as a vapor-liquid separator, oil-gas separator, gasliquid separator, degasser, deliquilizer, scrubber, trap, flash dram, compressor suction dram, gravity separator, centrifugal separator, filter vane separator, mist eliminator pad, liquid-gas coalescer, distillation column, or any combination thereof.

[0043] Key goals of the present system and method include minimizing pyrolytic coke production during the plastic upgrading process, and maximizing yield of useful carbon products, such as naphtha plus light olefins, di-olefins and acetylenes.

[0044] These and other aspects of the present system and method are described in further detail below with reference to the accompanied drawing figures, in which one or more illustrated embodiments and / or arrangements of the apparatus and methods are shown.

[0045] As used herein, the term "pyrolysis” generally refers to the chemical decomposition of condensed substances by heating that occurs spontaneously at high enough temperatures. As used herein, "char," "coke," "pyrolytic coke" or "carbonaceous by-product" are generally used for self-generated by-products in the present systems and methods. The "carbonaceous by-product” or "char” may be composed of over 90% carbon.

[0046] Further, as used in the present application, the term "approximately” or "about” when used in conjunction with a numerical value refers to any number within 5, 3 or 1 % of the referenced numerical value, including the referenced numerical value.

[0047] Fig. 1A shows a diagram of an exemplary system 100 for upgrading waste plastic in accordance with one or more embodiments. With reference now to Fig. 1A, in one or more embodiments, the system 100 includes a fluid-bed upgrader 101 comprising a top section 102, a middle section 103, and a bottom section 104. The top section 102 can be a freeboard, which can include cyclones, and which preferably includes solid and gas separation equipment, the bottom section 104 can include a fluidized bed, and the middle section 103 can include at least one inlet for introduction of the waste plastic feed 105A. Another inlet, 105B, can introduce inert solid particles or catalyst particles into the bottom section 104 of the upgrader 101. Other inlets for removal of gaseous acids can be added to the top, middle, or bottom sections of the upgrader. In one or more embodiments, the plastic feed enters the upgrader at the level of the fluidized bed in the bottom section 104.

[0048] In one or more embodiments, the inert solid is partially or completely replaced by or mixed with silica or a zeolite-based catalyst. In one or more embodiments, the inert solid or catalyst 105B is regenerated by burning the pyrolytic coke and transferring the heat from the chamber in which the carbon was burned into the upgrader 101.

[0049] Furthermore, in one or more embodiments the bottom section 104 can be configured to be at least 50°F hotter, preferably at least 100°F hotter, and more preferably at least 200-600°F hotter than the top section 102. In at least one embodiment, the bottom section 104 is configured to be at least 300°F hotter than the top section 102. In at least one embodiment, the lower part of the bottom section of the fluid-bed upgrader is configured to be more than 30°F hotter than the bed level temperature.

[0050] In one or more embodiments, the upgrader 101 is configured to operate under a turbulent regime having an average superficial velocity of approximately 0.1 - 4 feet per second. In further embodiments, the average superficial velocity is approximately 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0 feet per second.

[0051] In one or more embodiments, the upgrader 101 is configured to accommodate waste plastic particles in the range of approximately 5-50,000 microns. In at least one embodiment, the plastic particles have an average size of 55-100 microns. In at least one embodiment, more than 85% of the plastic particles are between 5-95 microns in size. In a further aspect, the plastic feed is melted before being pumped or injected above the fluid bed of the upgrader, preferably at a temperature between 450°F and 700°F. In a further aspect, a distribution system may be utilized to optimize the injection of the plastic feed inside the upgrader. As part of this aspect, the injection point of the plastic feed can be varied from the bottom to the middle section of the upgrader.

[0052] In one or more embodiments, the waste plastic feed has a residence time in the upgrader of less than 70 seconds. In at least one embodiment, the waste plastic feed has a residence time in the upgrader of less than 20 seconds. In at least one embodiment, the waste plastic feed has a residence time in the upgrader of less than 10 seconds.

[0053] In one or more embodiments, the pressure of the fluid-bed upgrader can be modulated. In one or more embodiments, the pressure of the upgrader can be modulated from approximately atmospheric pressure to approximately 300 psia, preferably from approximately 30-150 psia.

[0054] In one or more embodiments, the height of the freeboard in the top section 102 can be adjusted. Adjusting the height of the freeboard, the injection point height, the height of the fluidization bed, the pressure, the temperature, the withdrawal rate of the solids, and / or the fluidization velocity enables optimization of the heat transfer and the residence time of the product gas in the upgrader. This in turn minimizes the yield of char and waxy carbon products. In one or more embodiments, the char residence time is controlled by the withdrawal rate of solids from the bed and the bed height.

[0055] With continued reference to Fig. 1A, in one or more embodiments the system 100 can also comprise a cooling and separation section 106 which separates the liquid pyrolysis products 107 from the gas pyrolysis products 108. The system 100 can further comprise a compressor 109 in which the gas pyrolysis products are compressed to produce a light gas stream 110. The system can further comprise a recycle conduit 111 configured to recycle a portion of the light gas stream to the upgrader 101 to act as a fluidization agent. In one or more embodiments, the recycled portion of the light gas stream is the off-gas from a first stage of a recovery section compressor 109. The fluidization agent can also be heated before entering the fluid-bed reactor for either heat efficiency or via high temperature cracking of paraffinic agent to produce more olefins. In one or more embodiments, a portion of the recycled light gas stream can react with the hot fluid-bed solids of the fluid-bed upgrader. This will contribute to the yield of desirable C2+ hydrocarbon products generated by the upgrader. In at least one embodiment, the fluidization agent (portion of light gas stream) can be heated before entering the fluidbed reactor (upgrader 101) for heat efficiency. In at least one embodiment, the recycle conduit 111 comprises a heating element configured to heat the light gas stream. The heating element can be an electrical heating component or a microwave emitter, for example.

[0056] In one or more embodiments, the waste plastic feed 105 A is mechanically fed or carried into the fluid-bed upgrader 101 by a fluid (e.g., the fluidizing agent). In at least one embodiment, the fluid or fluidizing agent is a gas. In at least one embodiment, the gas is steam, H2, methane, or N2. In at least one embodiment, the gas comprises C1-C4 gases, or in certain embodiments C2-C4 gases. In at least one embodiment, the gas comprises C1-C7 gases (or in certain embodiments C2-C7 gases) and H2. In at least one embodiment, the gas is ethane, propane, butane, or liquefied petroleum gas.

[0057] In at least one embodiment, the fluid-bed upgrader 101 is configured to be heated via a flue gas. For example, the bottom section 104 of the upgrader can include a flue gas inlet 112, and the middle section 103 or the bottom section 104 ofthe upgrader 101 can include a flue gas outlet 113. The flue gas can comprise, for example, nitrogen, carbon dioxide, water vapor, carbon monoxide, and / or oxygen. In at least one embodiment, the fluid-bed reactor 101 is heated using molten salts.

[0058] In one or more embodiments, as exemplified in Fig. 1A, the flue gas enters the fluid-bed upgrader via inlet 112 atthe bottom of the fluid bed in the bottom section 104 and exits the upgrader at a level via outlet 113. Submerging the flue gas tubes in the lower portion of the fluidized bed protects the flue gas tubes from exposure to waxy pyrolysis byproducts and the unstable olefinic compounds that are produced as part of the pyrolysis of plastic. In one or more embodiments, the temperature for the flue gas inlet ranges from approximately 1, 500-3, 500°F. In certain preferred embodiments, the temperature for the flue gas inlet ranges from approximately 1, 700-2, 200°F. An example of how the temperature for the flue gas inlet can be controlled is by adjusting the excess air used in the burning of natural gas or other fuels generated by the production of the flue gas. In one or more embodiments, the bottom section 104 of the upgrader includes two or more coils 114 aligned horizontally or vertically in parallel to each other. In at least one embodiment, the coils 114 are submerged below the level of the fluidized bed, but above the distributor plate 115. In at least one embodiment, the flue gas that enters through the inlet 112 flows through the coils 114. In one or more embodiments, the bottom section 104 can include an outlet 116 for withdrawal of charred solids. The charred solids are formed as a result of the pyrolysis reaction in the upgrader. Optionally air, O2 gas, or an inert gas can be injected into the withdrawn char-containing solids to convert or strip a portion of the char, and the resulting conversion products are mainly CO and water. In at least one preferred embodiment, this outlet 116 is a char stripper. This char stripper comprises a vertical pipe that leads out of the fluid-bed upgrader 101 which may contain fractionation internals, such as packing discs or trays, to maximize the contact between vapor going up and solids going down. In at least one preferred embodiment, the char stripper uses N2 gas or steam to strip the char (e.g., strips hydrocarbons in voids and pores of the char solids], and the stripped char is removed from the fluid-bed upgrader 101 through the aforementioned vertical pipe. In at least one embodiment, the charred [char-containing] solids can be heated to recover a cracked portion of char cracking.

[0059] In at least one embodiment, the fluid-bed upgrader 101 comprises an electrical heating component or a microwave emitter (not shown] configured to heat the upgrader. For instance, in certain embodiments the majority of the heat being transferred by the electrical heating component or the microwave emitter is transferred to the bottom section 104 of the upgrader 101. In one or more embodiments, the electrical heating components are resistive heaters using alternate current. Embodiments using the heating component or microwave emitter preferably do not include the flue gas inlet 112 or the flue gas outlet 113, and vice versa.

[0060] Fig. IB describes another exemplary system 200 for upgrading waste plastic, the system 200 using a two-section fluid-bed upgrader in accordance with one or more embodiments. The system 200 operates similarly to the system 100 (Fig. 1A). In one or more embodiments, the system 200 comprises a fluid-bed upgrader 201, which in turn comprises a top section 202 and a bottom section 204, where the top section 202 can be a freeboard which can include cyclones, and which can include solid and gas separation equipment, and the bottom section 204 includes a fluidized bed.

[0061] In one or more embodiments, a feed of waste plastic 205A and an inert solid 205B are introduced into the fluid-bed upgrader 201 at or above the top of the level of the fluidized bed in the bottom section 204. In at least one embodiment, as exemplified in Fig. IB the waste plastic 205A can be introduced in the bottom section 204 at or above the level of the fluidized bed and the inert solid 205B is introduced at a lower portion of the in the bottom section 204. In one or more embodiments, the inert solid catalyst is in powder form. In at least one embodiment, the powder catalyst can be regenerated by burning the pyrolytic coke (formed in the upgrader) in a separate chamber and transferring the heat from the separate chamber in which the carbon was burned back into the upgrader.

[0062] The waste plastic is then pyrolyzed in the upgrader 201 at a temperature above the melting point of the waste plastic to produce a product feed comprising liquid and gas hydrocarbons. The fluidized bed of the upgrader 201 can operate under a turbulent regimen. In at least one embodiment, the upgrader 201 is configured to operate under a turbulent regime having an average superficial velocity of approximately 0.3 - 4 feet per second. In at least one embodiment, the average superficial velocity is approximately 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0 feet per second.

[0063] In one or more embodiments, the effluent of the upgrader 201 is at a temperature in a range of approximately 700-1700 °F and can be used to provide heat to the upgrader. In one or more embodiments, the heating for the pyrolysis in the upgrader 201 results in a temperature of at least 50°F greater (preferably at least 100°F hotter, and most preferably 200-600°F hotter] at the bottom portion 204 of the upgrader 201 relative to the top portion 202 ofthe upgrader 201. In one or more embodiments, a gaseous stream is introduced at the bottom of the bed to maintain turbulent regime fluidization in the bed. In at least one embodiment, the bottom section of the upgrader is configured to be more than 150°F hotter than the top section of the upgrader, or in certain embodiments 150-500°F hotter than the top section ofthe upgrader.

[0064] In one or more embodiments, the temperature of the fluidized bed of the upgrader is 300°F hotter than the temperature of a cyclone inlet at the top section 202 of the upgrader.

[0065] The product of the upgrader 201 is then transferred to a cooling and separation section 206, which separates the product into a liquid product stream 207 and gas product stream 208. The gas portion 208 of the product feed can then be compressed via a gas compressor 209 to produce a light gas stream 210. The pyrolysis product can be transported to the cooling and separation section 206 via methods such as flowing via pumping, gravity, pressure gradient, among others. The cooling and separation section 206 may comprise any suitable gas-liquid separator, such as a vapor-liquid separator, oil- gas separator, gas-liquid separator, degasser, deliquilizer, scrubber, trap, flash dram, compressor suction dram, gravity separator, centrifugal separator, filter vane separator, mist eliminator pad, liquid-gas coalescer, distillation column, or any combination thereof. In one or more embodiments, the cooling and separation section 206 comprises a fractionation process to separate the gas and liquid products.

[0066] In one or more embodiments, a portion of the light gas stream (or a fraction of the light gas stream after fractionation or membrane separation) is recycled to the upgrader 201 via a recycle conduit 211, wherein the recycled light gas stream fluidizes the fluidbed upgrader 201. In at least one embodiment, the light gas stream is an inert gas. In at least one embodiment, the light gas stream is steam, H2, methane, or N2. In one or more embodiments, the light gas stream comprises C1-C4 gases or C2-C4 gases. In at least one embodiment, the light gas stream comprises C1-C7 gases (or C2-C7 gases) and H2. In at least one embodiment, the light gas stream is ethane, propane, butane, or liquefied petroleum gas.

[0067] In one or more embodiments, the fluidization agent (e.g., recycled light gas stream) can be heated before entering the fluid-bed reactor for either heat efficiency or high temperature cracking of paraffinic agent to produce more olefins. In at least one embodiment, the fluidization agent is heated to approximately 500°F before entering the fluid-bed reactor to preventhigh temperature reactions before distribution into the fluidbed.

[0068] In at least one embodiment, the fluid-bed upgrader 201 comprises an electrical heating component or a microwave emitter 212 configured to heat the upgrader. For instance, in certain embodiments the majority of the heat being transferred by the electrical heating component or the microwave emitter is transferred to the bottom section 204 of the upgrader 201. In one or more embodiments, the electrical heating components are resistive heaters using alternate current. In one or more embodiments, the upgrader 201 further includes a distributor plate 215 and an outlet 216 for withdrawal of charred solids.

[0069] Fig. 1C shows a diagram of an exemplary system 300 for upgrading waste plastic in accordance with one or more embodiments. With reference now to Fig. 1C, in one or more embodiments, the system 300 includes a fluid-bed upgrader 301 comprising a top section 302, a middle section 303, and a bottom section 304. The top section 302 can be a freeboard, which can include cyclones, and which preferably includes solid and gas separation equipment, the bottom section 304 can include a fluidized bed, and the middle section 303 can include at least one inlet. In one or more embodiments, the fluid-bed upgrader 301 can include tubes for heat transfer into the fluid-bed using hot flue gas, for example.

[0070] In one or more embodiments, the system 300 feeds (e.g., mechanically feeds) or carries a waste plastic feed 305A through a melter 306 to generate a feed of melted plastic 307. In one or more embodiments, the melter 306 operates at a temperature range of approximately 450°F to 700°F. In one or more embodiments, the melter 306 operates at a temperature range of approximately 570°F to 670°F or approximately 600°F to 630°F. In at least one embodiment, the melter is operated at a temperature of approximately 615°F. In at least one embodiment, the optimal operating temperature of the melter is selected based, at least in part, on the lowest viscosity of the waste plastic to allow suitable circulation and distribution into the upgrader 301. In one or more embodiments, the viscosity of plastic melt goes through a minimum as temperature is varied. In at least one preferred embodiment, the melted plastic leaves the melter at a temperature that results in the lowest viscosity to minimize pump power usage, pressure drop and potential plugging issues. A preferred temperature range is approximately 575°F to 650°F. In this temperature range, any PVC content of the mixed plastics decomposes in the melter resulting in production of light hydrocarbons and HC1. In one or more embodiments, the melter is operated at a pressure of approximately 0-10 psig. In at least one embodiment, the melter 306 is designed to have a residence time of approximately 1-20 minutes for the waste plastic 3 OSA. In at least one preferred embodiment, the residence time of the waste plastic feed 305A is approximately 1-5 minutes.

[0071] The melted plastic 307 is then fed or carried into the fluid-bed upgrader 301. For instance, the melted plastic 307 can be fed or carrier into the upgrader 301 by means of the at least one inlet in the middle section 303. In at least one embodiment, the melted plastic 307 is pumped from the bottoms of the melter 306 into the middle section 303 using a pump 322 with variable speeds. In at least one embodiment, the system 300 includes a feed of basic agent 305B that is also fed or carried through the melter 306 to reacted with HC1 or any acid present in the melted plastic. Examples of a basic agent include, but are not limited to, lime (also known as calcium oxide), potassium hydroxide (KOH), and caustic. In one or more embodiments, the melter 306 contains a mechanical mixing system. In a preferred embodiment, the mechanical mixing system provides multiple mixing points at multiple heights below the established liquid level of the melted plastic. In one or more embodiments, the mechanical mixing system can comprise one or more impellers to assist in mixing the melted plastic. In one or more embodiments, the basic agent 305B can be injected into the melter 306 at or around the same level as the mechanical mixing system in the melter 306. This helps to reduce viscosity of the melted plastics and allows better contact with the basic agent 305B, which helps to remove acids like HC1 that are entrapped in the melted plastic. It is noted that the waste plastic feed can sometimes comprise a mixture of various types of plastics and polyvinyl chloride (PVC) may be present typically in low concentrations. PVC typically cracks under melter operating conditions and produces some HC1 in gas form, but some of the HC1 can be entrapped in the melted plastic. This entrapped HC1 can be captured using the basic agent 305B (e.g., lime). In at least one embodiment, the basic agent can be injected into the melter before the outlet vapor stream to capture HC1 in the vapor as well, and any unreacted basic agent (e.g., lime) can help remove any HC1 in the liquid phase.

[0072] In at least one embodiment ,the melter 306 can utilize mixing recycled fluid injections (recycled melted plastic) at different vertical levels to provided additional mixing as well as providing heat for melting and at least partially decomposing the plastics from halides. In at least one embodiment, the typical ratio of recycled fluid to plastic weight entering the melter is in the range of approximately 5-20: 1. In at least one embodiment, the melter 306 produces acidic gas 308 as a by-product of the plastic melting process. This acidic gas can be removed from the melter 306 by means of a vapor outlet. In at least one embodiment, the acidic gas 308 is partly HC1. The vapor outlet can also be used to remove other cracked products as well as any inert gas that entered the melter 306 along with the waste plastic.

[0073] In one or more embodiments, the melter 306 can be heat jacketed to prevent fouling due to temperature loss. It is noted that, in one or more embodiments, the melter 306 can form part of the system 100 to melt the plastic feed 105A before it is fed or carried into the fluid-bed upgrader 101 (see Fig. 1A). Similarly, in one or more preferred embodiments, the melter 306 can form part of the system 200 to melt the plastic feed 205A before it is fed or carried into the fluid-bed upgrader 201 (see Fig. IB). In further reference to Fig. 1C, the system 300 also comprises a heating system (heating component) comprising an air compressor 309A and an in-line burner 309B which uses fuel gas or natural gas as fuel that reacts with air. Specifically, in at least one embodiment, a fuel gas or natural gas 311 is added to the burner 309B of the heating system to facilitate heating. In at least one embodiment, the fuel gas 311 comprises hydrogen, carbon monoxide, and / or one or more hydrocarbons (e.g., methane, propane, etc.) and mixtures thereof. The in-line burner 309B connects to the fluid-bed upgrader 301 via an inlet. In at least one embodiment, the compressor 309A of the heating system compresses air 310 that enters the compressor 309A. Then the in-line burner 309B at least partially reacts (e.g., combusts) fuel gas or natural gas 311 with the compressed air from compressor 390A. Hot flue gas formed as a result of the combustion reaction in the in-line burner 309B then enters internal heating tubes 314 of the fluid-bed upgrader 301.

[0074] In at least one embodiment, at least a portion of the acidic gas 308 produced by the melter 306 is captured, neutralized via a fixed bed of a basic agent. After neutralization, the gas 308 can be fed to the air compressor 309A of the heating system to burn the hydrocarbon content of the gas 308 while using the N2 content of the gas 308 as a diluent for the in-line burner 309B. In at least one embodiment, the basic agent used to neutralize the acidic gas 308 is lime, potassium hydroxide, or caustic.

[0075] In further reference to Fig. 1C, the melted plastic 307 that has been transported into the fluid-bed upgrader 301 is upgraded as is described for upgrader 101 in the system 100 (Fig. 1A). In one or more embodiments, a fluidization gas 312 is added to the bottom section of the fluid-bed upgrader 301 via a fluidization inlet, for example. In at least one embodiment, the fluidization gas can contain hydrocarbons with 1 or more carbon atoms (Ci+). In one or more preferred embodiments, at least one hopper 313 is used for feeding solids into the fluid-bed upgrader 301. The at least one hopper 313, alone or in conjunction with other hopper(s), can be located in or connected to the fluidbed upgrader and is used to introduce solid material into the fluid-bed upgrader 301 to improve the flow of material for the pyrolysis reaction. Suitable materials for the hopper 313 include, but are not limited to, lime, a catalyst or an inert solid, or a charred solid, or fines to maintain the desired fluidization. In at least one embodiment, one hopper is utilized for injection of fresh solids that have no char on them. The particles sizes of these solids can be controlled to help obtain or maintain appropriate fluidization and solid entrainment to control reaction heat transfer. Another optional hopper for striped charred solids can also be used for storage prior to transport of the charred solids. In one or more preferred embodiments, the solid products from the pyrolysis reaction are removed, and the gas and liquid products of the pyrolysis reaction are sent to a quench system 325. In at least one optional embodiment, a portion of the products of the pyrolysis reaction sent to the quench system 325 can be recycled back to the melter or the reactor (fluid-bed upgrader), which helps to control the viscosity of the melted plastic.

[0076] In further reference to Fig. 1C, the somewhat cooled flue gas is removed from the internal heating tubes or coils 314 of the fluid-bed upgrader 301 and sent to a first heat exchanger 315. Similar to the embodiment of Fig. 1A, in one or more embodiments, the bottom section 304 of the upgrader 301 includes two or heating tubes or coils 314 aligned horizontally or vertically in parallel to each other. In at least one embodiment, the tubes / coils 314 are submerged below the level of the fluidized bed. In at least one embodiment, the somewhat cooled flue gas that is sent to the first heat exchanger 315 is cooled by exposure to boiler feedwater 316. This process results in high pressure steam 317. In one or more embodiments, the further cooled flue gas is then sent to a second heat exchanger 318. In one or more embodiments, the second heat exchanger 318 is connected to a pump 324 that is used to circulate hot oil 319 through exchanger 318 for eventually heating the bottom stream of the melter 306. In at least one preferred embodiment, the second heat exchanger 318 is operated at a temperature below 750°F to avoid undesired hot oil fouling. In at least one embodiment, the second heat exchanger 318 is configured to heat the hot oil 319 and uses further cooled flue gas to ensure that the heat exchanger’s tube temperature does not exceed 750°F. In this context, hot oil 319 is fluid with good heat transfer characteristics that is utilized as a heat transfer means. For example, in at least one embodiment, hot oil belts can be used to transfer heat from a hot source to a cold source without heating the fluid to too high of a temperature. In one or more embodiments, the hot oil 319 can be used to keep the melter and the accompanying piping at an elevated temperature using heat jacketing. In one or more embodiments, the hot oil 319 is used in the system to transfer heat from flue gas to the melted plastic circulated to the melter 306. In one or more embodiments, a portion of the melted plastic 307 is recycled to the melter 306 (e.g., an inlet of the melter 306) via the third heat exchanger 323. In one or more embodiments, the hot oil 319 heated by the second heat exchanger 318 can be used for further heat transfer in the third heat exchanger 323 (e.g., heating the recycled melted plastic).

[0077] In one or more preferred embodiments, the recycled melted plastic 307 is injected into the melter 306 at different vertical levels to provide additional mixing and distributed heat to affect the melting process. In at least one preferred embodiment, a portion of melted plastic 307 is preferably distributed at or above the top of the liquid level on the melter 306 to help melt the plastic as soon as it enters the liquid phase. In at least one preferred embodiment, the weight ratio between the recycled portions of waste plastic 305A and melted plastic 307 in the melter 306 is between approximately 5:1 and 15:1. In at least one embodiment, the flue gas in the second heat exchanger 318 is cooled as it exists as flue gas 320. The flue gas can comprise, for example, nitrogen, carbon dioxide, water vapor, carbon monoxide, and / or oxygen. In at least one preferred embodiment, a portion of the flue gas 320 is recycled by passing it through the compressor 309A and inline burner 309B and then introducing it into the internal heating tubes 314 of the fluid-bed.

[0078] Fig- 2 is a flow diagram describing the steps undertaken as part of the methods of upgrading waste plastic using a fluid-bed upgrader in accordance with one or more embodiments, including the previously described systems. With reference now to Fig. 2, in one or more embodiments, the method comprises introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader in accordance with step S105. In at least one embodiment, the waste plastic can be melted first via a melter in accordance with the system and methods described above in reference to Fig. 1C, for example. In one or more embodiments, the inert solid is replaced or mixed with a silica or a solid acid such as a zeolite-based catalyst. In at least one embodiment, the zeolite-based catalyst is a waste FCC equilibrium catalyst. In at least one embodiment, the waste FCC catalyst contains high amounts of Ni and V.

[0079] With continued reference to Fig. 2, at step SI 10, the waste plastic is pyrolyzed in the upgrader at a temperature above the melting point of the plastic to produce a product feed comprising liquid and gas hydrocarbons. In at least one embodiment, the step of pyrolysis comprises heating the fluid-bed upgrader via a flue gas, an electrical heating component, or microwaves. In one or more embodiments, the upgrader operates under a turbulent regime and the effluent of the upgrader is at a temperature in a range of approximately 700-1700°F, such that the heating in the upgrader results in a temperature of at least 100°F greater at the bottom portion of the upgrader relative to the middle portion of the upgrader. This turbulent regime also serves to remove sticky pyrolysis by-products from the outside walls of the submerged coils (tubes), and thus maintain the heat transfer capability required by the upgrader. In at least one embodiment, the effluent of the upgrader is at a temperature in the range of approximately 700-1300°F. In at least one embodiment, the upgrader is configured to operate under a turbulent regime having an average superficial velocity of approximately 0.3 - 4 feet per second. In one or more embodiments, the average superficial velocity is approximately 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.0 feet per second.

[0080] The method continues at step SI 15, where the product feed is transferred to a separation section, then separated and cooled into a liquid portion and a gas portion. The pyrolysis product feed can be transported to the separation section. The separation section may comprise any suitable gas-liquid separator, such as a vapor-liquid separator, oil-gas separator, gas-liquid separator, degasser, deliquilizer, scrubber, trap, flash dram, compressor suction dram, gravity separator, centrifugal separator, filter vane separator, mist eliminator pad, liquid-gas coalescer, distillation column, or any combination thereof.

[0081] At step S120, the gas portion of the product feed is then transferred to a compressor and compressed to produce a light gas stream. At step S125, a portion or fraction of the light gas stream is then recycled and returned to the fluid-bed upgrader, and the recycled light gas stream fluidizes the fluid-bed upgrader as part of step SI 30.

[0082] In at least one embodiment, the method further comprises withdrawing charcontaining solids formed as a result of the pyrolysis reaction from the upgrader and optionally injecting air, 0? gas, or an inert gas into the withdrawn char-containing solids to convert or strip a portion of the char, wherein said conversion products are mainly CO and water. In an even further embodiment, the method comprises heating the charcontaining solids to recover a cracked portion of char cracking.

[0083] In another embodiment of the method, the inert solid catalyst is regenerated by burning the pyrolytic coke, and transferring the heat from the chamber in which the carbon was burned into the upgrader.

[0084] The apparatus and methods of the present application are not limited in any way to the illustrated embodiment and / or arrangement. It should be understood that the apparatus and methods as shown in the accompanying figures are merely exemplary of the apparatus and methods of the present application, which can be embodied in various forms as appreciated by one skilled in the art. Therefore, it is to be understood that any structural and functional details disclosed herein are not to be interpreted as limiting the present apparatus and methods, but rather are provided as a representative embodiment and / or arrangement for teaching one skilled in the art one or more ways to implement the present apparatus and methods.

[0085] Fig. 3 is a flow diagram describing the state of the waste plastic as it progresses through the methods of upgrading waste plastic using a fluid-bed upgrader in accordance with one or more embodiments. This flow diagram describes the reactions that lead to the waste plastic being transformed into liquid and gas pyrolysis products, the separation of these products, the compression of the gas product to form a light gas stream, the recycling of said gas stream to forma a fluidization agent, and the reusing of that fluidization agent to upgrade more waste plastic. It also describes optional reactions in the waste plastic upgrading method, such as the recovery of char-containing solids and using heat to recover portions of the char cracking, and conversion to recover. In one or more embodiments, when a fluid-bed upgrader of the present systems operate at a pressure above atmospheric pressure, and at a temperature above approximately 900°F, preferably at approximately 1150-1350°F, C2+ components in the fluidization gas can be partially cracked and upgraded to increase yields of valuable products like light olefins and diolefins. Thus, the present systems and methods upgrades more than 50% and preferably more than 60% of the waste plastics introduced into the system to light olefins that can be used to make plastics, while limiting yield of +700°F waxy molecules to less than 2% and yield of coke to less than 2%.

[0086] Although much of the foregoing description has been directed to an apparatus and methods for the upgrading of waste plastic using a fluid-bed upgrader, a cooling and separation section, a gas compressor, a recycling conduit, and a light gas stream used as a fluidization agent, the apparatus and methods disclosed herein can be similarly deployed and / or implemented in scenarios, situations, and settings far beyond the referenced scenarios. It should be further understood that any such implementation and / or deployment is within the scope of the methods described herein.

[0087] It is to be further understood that like numerals in the drawings represent like elements through the several figures, and that not all components and / or steps described and illustrated with reference to the figures are required for all embodiments or arrangements. Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms ""including," "comprising," or "having," "containing," "involving," and variations thereof herein, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0088] It should be noted that use of ordinal terms such as "first," "second," "third," etc., in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term] to distinguish the claim elements.

[0089] Notably, the figures and examples above are not meant to limit the scope of the present disclosure to a single implementation, as other implementations are possible by way of interchange of some or all the described or illustrated elements. Moreover, where certain elements of the present disclosure can be partially or fully implemented using known components, only those portions of such known components that are necessary for an understanding of the present disclosure are described, and detailed descriptions of other portions of such known components are omitted so as not to obscure the disclosure. In the present specification, an implementation showing a singular component should not necessarily be limited to other implementations including a plurality of the same component, and vice-versa, unless explicitly stated otherwise herein. Moreover, applicants do not intend for any term in the specification or claims to be ascribed an uncommon or special meaning unless explicitly set forth as such. Further, the present disclosure encompasses present and future known equivalents to the known components referred to herein by way of illustration. The foregoing description of the specific implementations will so fully reveal the general nature of the disclosure that others can, by applying knowledge within the skill of the relevant art(s), readily modify and / or adapt for various applications such specific implementations, without undue experimentation, without departing from the general concept of the present disclosure. Such adaptations and modifications are therefore intended to be within the meaning and range of equivalents of the disclosed implementations, based on the teaching and guidance presented herein. It is to be understood that the phraseology or terminology herein is for the purpose of description and not of limitation, such that the terminology or phraseology of the present specification is to be interpreted by the skilled artisan in light of the teachings and guidance presented herein, in combination with the knowledge of one skilled in the relevant art(s). It is to be understood that dimensions discussed or shown are drawings are shown accordingly to one example and other dimensions can be used without departing from the disclosure.

[0090] The subject matter described above is provided by way of illustration only and should not be construed as limiting. Various modifications and changes can be made to the subject matter described herein without following the example embodiments and applications illustrated and described, and without departing from the true spirit and scope of the invention encompassed by the present disclosure, which is defined by the set of recitations in the following claims and by structures and functions or steps which are equivalent to these recitations.

Claims

What is claimed:

1. A system for upgrading waste plastic, comprising: a fluid-bed upgrader having a top section, a middle section, and a bottom section, wherein the top section is a freeboard, wherein the bottom section includes a fluidized bed, wherein the middle section includes at least one inlet for a waste plastic feed, wherein the upgrader is configured for a pyrolysis reaction, and wherein the bottom section is configured to be at least 100°F hotter than the top section and includes at least one inlet for a catalyst or an inert solid, and an outlet for withdrawal of charred solids; a separation section in fluid connection with the top section of the fluid-bed upgrader, wherein the separation section is configured to cool and separate a product stream of the upgrader into a liquid stream and a gas stream; a gas compressor fluidly connected to the separation section and configured to compress the gas stream to produce a light gas stream; and a recycle conduit connected to the bottom section of the upgrader, wherein the recycle conduit is configured to transport a portion of the light gas stream to the upgrader and wherein the upgrader is configured to utilize the light gas stream as a fluidization agent.

2. The system of claim 1, wherein the top section of the upgrader includes solid and gas separation equipment.

3. The system of claim 1, wherein the bottom section of the upgrader is configured to be more than 300°F hotter than the top section of the upgrader.

4. The system of claim 1, wherein the upgrader is configured to be heated via a flue gas and wherein the bottom section of the upgrader includes a flue gas inlet and the middle section or the bottom section of the upgrader includes a flue gas outlet.

5. The system of claim 1, wherein the upgrader comprises an electrical heating component or a microwave emitter configured to heat the upgrader.

6. The system of claim 5, wherein the majority of the heat being transferred by the electrical heating component or the microwave emitter is being transferred to the bottom section of the upgrader.

7. The system of claim 1, wherein the recycle conduit comprises a heating element configured to heat the light gas stream.

8. The system of claim 1, wherein the upgrader is configured to operate under a turbulent regime having an average superficial velocity of approximately 0.3 - 4 feet per second.

9. The system of claim 1, wherein the upgrader is configured to accommodate plastic particles in the range of approximately 5-50,000 microns.

10. The system of claim 1, wherein the light gas stream comprises ethane, propane, butane, liquefied petroleum gas, or any combination thereof.

11. The system of claim 10, wherein the light gas stream is preheated to a temperature higher than 1000°F.

12. The system of claim 1, wherein the light gas stream is an inert gas.

13. The system of claim 12, wherein the light gas stream comprises steam, H2, methane, or N2, or a combination thereof.

14. The system of claim 1, wherein the waste plastic feed is mechanically fed, carried by a fluid, or melted before being fed into the fluid-bed upgrader.

15. A method for upgrading waste plastic using a fluid-bed upgrader, said fluid-bed upgrader having a top section, a middle section, and a bottom section, wherein the top section is a freeboard, the bottom section includes a fluidized bed, wherein the middle section includes at least one inlet for a waste plastic feed, wherein the upgrader is configured for a pyrolysis reaction, the method comprising: introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader; pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic, to produce a product stream comprising liquid and gas hydrocarbons, wherein the fluid bed of the upgrader operates under a turbulent regime and wherein effluent of the upgrader is at a temperature in a range of approximately 700-1700°F, and wherein the heating in the upgrader results in a temperature of at least 50°F greater at the bottom portion of the upgrader relative to the middle portion of the upgrader; separating the product stream in a separation section, wherein a gas portion of the product stream is separated and transferred to a compressor; compressing the gas portion of the product stream via the compressor to produce a light gas stream; and recycling a portion of the light gas stream to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader and enhances the product yield of the upgrader.

16. The method of claim 15, wherein the top section of the upgrader comprises solid and gas separation equipment.

17. The method of claim 15, wherein the step of pyrolyzing the waste plastic comprises heating the fluid-bed upgrader via a flue gas, an electrical heating component, or microwaves.

18. The method of claim 15, wherein the waste plastic feed is mechanically fed, carried by a fluid, or melted before being fed into the fluid-bed upgrader.

19. The method of claim 15, wherein the waste plastic feed has an average particle size of 55-100 microns.

20. The method of claim 15, wherein more than 85% ofthe waste plastic feed particles are between 5-95 microns.

21. The method of claim 15, wherein the waste plastic feed has a residence time in the upgrader of less than 70 seconds.

22. The method of claim 21, wherein the waste plastic feed has a residence time in the upgrader of less than 20 seconds.

23. The method of claim 21, wherein the waste plastic feed has a residence time in the upgrader of less than 10 seconds.

24. The method of claim 15, wherein the light gas stream is heated before being recycled to the upgrader.

25. The method of claim 15, wherein the inert solid is replaced or mixed with an acidic solid acid catalyst.

26. The method of claim 25, wherein the solid acid catalyst is a waste FCC equilibrium catalyst.

27. The method of claim 15, wherein the light gas stream comprises C2-C4 gases.

28. The method of claim 15, wherein the light gas stream comprises C2-C7 gases and H2.

29. The method of claim 15, further comprising: withdrawing, from the upgrader, char-containing solids formed as a result of the pyrolysis reaction; injecting air, Ch-containing gas, or an inert gas into the withdrawn char-containing solids to convert and / or strip a portion of the char, wherein said conversion products are primarily CO and water.

30. The method of claim 15, further comprising heating char-containing solids formed as a result of the pyrolysis reaction to recover a cracked portion of char cracking.

31. A method for upgrading waste plastic using a fluid-bed upgrader, wherein said fluid-bed upgrader comprises a top section and a bottom section, further wherein the top section is the freeboard which includes solid and gas separation equipment, further wherein the bottom section includes a fluidized bed, the method comprising: introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader above the top of the level of the fluidized bed; pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic to produce a product comprising liquid and gas hydrocarbons at approximately 100°F, wherein the fluidized bed operates under a turbulent regimen, further wherein the effluent of the upgrader is at a temperature in a range of approximately 700-1700°F, further wherein the heating for the pyrolysis in the upgrader results in a temperature of at least 50°F greater at the bottom portion of the upgraderrelative to the top portion of the upgrader, further wherein a gaseous stream is introduced at the bottom of the bed to maintain turbulent regime fluidization in the bed.

32. The method of claim 31, wherein the bottom section of the upgrader is configured to be 150-500°F hotter than the top section of the upgrader.

33. The method of claim 31, further comprising separating a gas portion of the product, wherein the gas portion of the product is compressed to produce a light gas stream.

34. The method of claim 33, further comprising recycling a portion of the light gas stream or a fraction of the light gas stream after fractionation to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader.

35. The method of claim 31, wherein the waste plastic feed is mechanically fed, carried by a fluid, or melted before being fed into the fluid-bed upgrader.

36. A method for upgrading waste plastic using a fluid-bed upgrader, said fluid-bed upgrader having a top section, a middle section, and a bottom section, wherein the top section is a freeboard, the bottom section includes a fluidized bed, wherein the middle section includes at least one inlet for a waste plastic feed, wherein the upgrader is configured for a pyrolysis reaction, the method comprising: introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader; pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic, to produce a product stream comprising liquid and gas hydrocarbons at 100 °F, wherein the fluid bed of the upgrader operates under a turbulent regime above atmospheric pressure and at a temperature in a range of approximately 1150-1350°F;separating the product stream in a separation section, wherein a gas portion of the product stream is separated and transferred to a compressor; compressing the gas portion of the product stream via the compressor to produce a light gas stream; and recycling a portion of the light gas stream to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader and enhances the product yield of the upgrader, and wherein the light gas stream fluidizing the fluid-bed upgrader comprises reactive components, wherein at least 60% of the waste plastics introduced into the fluid-bed upgrader are converted into the light gas stream which can be used to make plastics, and wherein the yield of waxy molecules byproducts and coke products are both limited to less than 2%.

37. The method of claim 36, wherein the waste plastic feed is mechanically fed, carried by a fluid, or melted before being fed into the fluid-bed upgrader.

38. A method for upgrading waste plastic using a fluid-bed upgrader, wherein the fluid-bed upgrader comprises a top section and a bottom section, the top section is the freeboard which includes solid and gas separation equipment, and the bottom section includes a fluidized bed, the method comprising: introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader at the level of the fluidized bed; pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic, to produce a product stream comprising liquid and gas hydrocarbons at 100 °F, wherein the fluid bed of the upgrader operates under a turbulent regime andwherein effluent of the upgrader is at a temperature in a range of approximately 700- 1700°F; separating the product stream in a separation section, wherein a gas portion of the product feed is separated and transferred to a compressor; compressing the gas portion of the product stream via the compressor to produce a light gas stream; and recycling a portion of the light gas stream to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader and enhances the product yield of the upgrader, and wherein the light gas stream fluidizing the fluid-bed upgrader comprises reactive components.

39. The method of claim 38, wherein the feed of waste plastic is introduced above the location of coils of the fluidized bed.

40. The method of claim 38, wherein the waste plastic feed is mechanically fed, carried by a fluid, or melted before being fed into the fluid-bed upgrader.

41. A system for upgrading waste plastic, comprising: a fluid-bed upgrader having a top section, a middle section, and a bottom section, wherein the top section is a freeboard, wherein the bottom section includes a fluidized bed, wherein the middle section includes at least one inlet for a waste plastic feed, wherein the upgrader is configured for a pyrolysis reaction, and wherein the bottom section is configured to be at least 100°F hotter than the top section and includes at least one inlet for a catalyst or an inert solid, and an outlet for withdrawal of charred solids.

42. The system of claim 41, further comprising:a separation section in fluid connection with the top section of the fluid-bed upgrader, wherein the separation section is configured to cool and separate a product stream of the upgrader into a liquid stream and a gas stream; and a gas compressor fluidly connected to the separation section and configured to compress the gas stream to produce a light gas stream.

43. The system of claim 42, wherein the system is further configured to recycle a portion of the light gas stream to the upgrader to fluidize the fluidized bed.

44. A method for upgrading waste plastic using a fluid-bed upgrader, said fluid-bed upgrader having a top section, a middle section, and a bottom section, wherein the top section is a freeboard, the bottom section includes a fluidized bed, wherein the middle section includes at least one inlet for a waste plastic feed, wherein the upgrader is configured for a pyrolysis reaction, the method comprising: introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader, and; pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic, to produce a product stream comprising liquid and gas hydrocarbons, wherein the product stream of liquid and gas hydrocarbons is at a temperature of 100 °F, and wherein the fluid bed of the upgrader operates under a turbulent regime above atmospheric pressure and at a temperature in a range of approximately 1150- 1350°F.

45. A method for upgrading waste plastic using a fluid-bed upgrader, said fluid-bed upgrader having a top section, a middle section, and a bottom section, wherein the top section is a freeboard, the bottom section includes a fluidized bed, wherein the middlesection includes at least one inlet for a waste plastic feed, wherein the upgrader is configured for a pyrolysis reaction, the method comprising: introducing a feed of waste plastic and an inert solid into the fluid-bed upgrader, and; pyrolyzing the waste plastic in the upgrader at a temperature above the melting point of the plastic, to produce a product stream comprising liquid and gas hydrocarbons, wherein the fluid bed of the upgrader operates under a turbulent regime and wherein effluent of the upgrader is at a temperature in a range of approximately 700- 1700°F, and wherein the heating in the upgrader results in a temperature of at least 50°F greater at the bottom portion of the upgrader relative to the middle portion of the upgrader.

46. The method of claim 44 or 45, further comprising: separating the product stream into a liquid stream and a gas stream; compressing the gas stream to produce a light gas stream; and recycling a portion of the light gas stream to the fluid-bed upgrader, wherein the recycled light gas stream fluidizes the fluid-bed upgrader and enhances the product yield of the upgrader.

47. The method of claim 46, wherein the light gas stream fluidizing the fluid-bed upgrader comprises reactive components, and wherein at least 60% of the waste plastics introduced into the fluid-bed upgrader are converted into the light gas stream which can be used to make plastics, and wherein the yield of waxy molecules byproducts and coke products are both limited to less than 2%.

48. The system of claim 1 or 41, further comprising: a melter upstream of the fluid-bed upgrader, the melter comprising an inlet for the waste plastic feed, and one or more mechanical mixers, wherein said melter is configured to melt the waste plastic before it enters the fluid-bed upgrader; a heating component upstream of the fluid-bed upgrader, the heating component comprising an air compressor and an in-line burner configured to feed hot flue gas to internal heating tubes inside the fluid-bed upgrader, wherein the heating component is configured to compress air and cause a combustion reaction by at least partially reacting air with fuel gas before the flue gas enters the internal heating tubes in the fluid-bed upgrader; and a pump connected to the melter and configured to pump the melted waste plastic from the melter to the fluid-bed upgrader and optionally recycle a portion of the melted waste plastic to the melter.

49. The system of claim 48, further comprising: a first heat exchanger configured to receive outlet flue gas stream from the internal heating tubes of the fluid-bed upgrader and configured to reduce the temperature of said flue gas stream; a second heat exchanger configured to receive flue gas from the first heat exchanger, wherein the second heat exchanger is configured to heat hot oil for further heat transfer in a third heat exchanger that is configured to heat recycle melted plastic and transfer it to the melter.

50. The method of any one of claims 15, 31, or 36 further comprising: melting the waste plastic in a melter before it enters the fluid-bed upgrader; andoptionally recycling a fraction of the product stream from the fluid-bed upgrader to the melter to control the viscosity of the melted plastic.

51. A system for upgrading waste plastic, comprising: a melter comprising at least one inlet for a waste plastic feed and optionally one or more mechanical mixers, wherein said melter is configured to melt the waste plastic; a fluid-bed upgrader having at least a top section and a bottom section, wherein the top section is a freeboard, wherein the bottom section has a fluidized bed, wherein the fluid-bed upgrader includes at least a first inlet for receiving the melted waste plastic, and wherein the fluid-bed upgrader is configured to pyrolyze the melted waste plastic to produce a product stream; and a heating system comprising a compressor and an in-line burner configured to provide hot flue gas to internal heating tubes in the fluid-bed upgrader, wherein the heating system is configured to compress and combust fuel gas with air before the flue gas enters internal heating tubes of the fluid-bed upgrader.

52. The system of claim 51, wherein the bottom section of the fluid-bed upgrader is configured to be at least 100°F hotter than the top section and includes at least one inlet for a catalyst or an inert solid, and an outlet for withdrawal of charred solids.

53. The system of claim 51, wherein the fluid-bed upgrader is configured to pyrolyze the melted waste plastic at a temperature above the melting point of the plastic, to produce the product stream, which comprises liquid and gas hydrocarbons when cooled tolOO °F.

54. The system of claim 53, wherein the fluid bed of the fluid-bed upgrader is configured to operate under a turbulent regime and wherein the effluent of the fluid-bed upgrader is at a temperature in a range of approximately 700-1700°F.

55. The system of claim 51, further comprising: a first heat exchanger in connection with the internal heating tubes of the fluidbed upgrader and configured to receive a flue gas stream from the internal heating tubes of the fluid-bed upgrader and reduce the temperature of said flue gas stream; a second heat exchanger in connection with the first heat exchanger, wherein the second heat exchanger is configured to heat hot oil for heating recycled melting plastic in a third heat exchanger to transfer hot melted plastic to the melter.

56. The system of claim 51, further comprising: a pump connected to the melter and configured to pump the melted waste plastic from the melter to the fluid-bed upgrader and recycle a portion of the melted waste plastic back to the melter via a heat exchanger.

57. The system of claim 51, wherein the melter is configured to operate at a temperature of approximately 450°F to 700°F.

58. The system of claim 57, wherein the melter is configured to operate at a temperature of approximately 615°F.

59. The system of claim 51, wherein the fluid-bed upgrader further comprises a fluidization inlet in the bottom section of the fluid-bed upgrader, wherein the fluidization inlet is configured to introduce a fluidization gas into the fluid-bed upgrader.

60. The system of claim 59, wherein the fluidization gas comprises hydrocarbons with1 or more carbon atoms.

61. The system of claim 51, further comprising at least one hopper in the fluid-bed upgrader, wherein the at least one hopper is configured to introduce solid material into the fluid-bed upgrader.

62. The system of claim 61, wherein the solid material in the hopper is lime, a catalyst or an inert solid, or a charred solid, or fines to maintain the desired fluidization.

63. The system of claim 55, wherein the temperature of the melter is maintained using the hot oil as a temperature stabilizer.

64. The system of claim 63, wherein the hot oil is at a temperature of approximately500-750°F.

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