Patent Application
20230294107
The present disclosure relates to apparatus and processes for inspection, sortation, and pysrolysis of waste plastic feeds.
Society is becoming increasingly conscious of the vast amounts of plastic materials discarded after a single use. Valuable plastic materials continue to be landfilled despite the numerous technologies proposed to recover plastic from the trash. Many of these technologies are presently inefficient and costly. Thus, investors and communities prefer to continue the lower cost option of discarding the plastic-containing waste in landfills.
Waste plastics are mostly diverted to landfills or are incinerated, with a smaller fraction being diverted to recycling. However, over the years, with increased regulations and levies on landfills, the percentage of the post-consumer waste being recycled or incinerated for energy recovery is gradually increasing.
Attempts have been made to crack the plastic into useful products using conventional cracking apparatus that are used for cracking of petroleum derived feeds such as gas oils. For example, plastic feeds in powder form or pellets have been introduced into fluidized catalytic cracking reactors, which, for plastic feeds, require high temperatures.
In addition, the presence of chlorine in waste plastic (e.g., of polyvinylchloride) promotes corrosion of reactor internals, requiring a separate dechlorination process before the dechlorinated product can be introduced to a reactor and other components of an apparatus. Such additional dechlorination steps (and reactors for dechlorination) reduce throughput and yield of desired cracked products.
Further reducing throughput and yield are spent catalyst (formed in the pyrolysis reactor during pyrolysis). Spent catalyst can be regenerated in a conventional regenerator, but the amount of regeneration is insufficient particularly while using plastic feeds containing chlorine and trace metals.
It would be desirable to the industry to remove such problematic plastics from the feed stream prior to the cracking process. However, such processes of identification and sortation based on chemical compositions can be labour intensive, expensive, and often yield inaccurate results. Additionally, conventional sortation devices have low capacity, require multiple units, and are often inefficient and costly.
There is a need for apparatus and processes providing plastic waste recycling facilities to rapidly screen physical properties and chemical composition of waste plastic upon arrival to recycling facilities. Furthermore, there is a need for apparatus and processes for plastic waste sorting in order to increase throughput and reduce costs associated with plastic cracking processes.
In at least one embodiment, a method includes providing a bale comprising plastic to a scale and measuring a mass of the bale using the scale. The method includes rotating or linearly translating the bale to provide access of one or more exterior surfaces of the bale to a plurality of sensors. The method includes detecting a radiation or absence of the radiation of the bale using a radiation sensor of the plurality of sensors to obtain a first data set. The method includes detecting plastic types using a near-infrared spectrum camera of the plurality of sensors to obtain a second data set. The method includes measuring a distance from a fixed reference point during the rotating of the bale using a lidar system of the plurality of sensors to obtain a third data set. The method includes obtaining an exposure of one or more exterior surfaces of the bale using a visible light spectrum camera of the plurality of sensors to obtain a fourth data set. The method includes estimating a mass or a shape of plastic particles of the plastic of the bale using a control system device using the first data set, the second data set, the third data set, the fourth data set, or combination(s) thereof.
In some embodiments, a method, comprising shredding or disaggregating a bale comprising plastic to form a plurality of particles comprising the plastic and introducing the plurality of particles to a first conveyor. The method includes monitoring a first relative abundance of a target material of the plurality of particles using a first sensor device to obtain a first data set, the first relative abundance based on a first property of the target material of the plurality of particles. The method includes providing the first data set from the first sensor device to a second sensor device, transferring the plurality of portions to a second conveyor, and monitoring a second relative abundance of the target material of the plurality of portions using the second sensor device when the plurality of portions is disposed on the second conveyor to obtain a second data set, the second relative abundance based on a second property of the target material of the plurality of portions, wherein the second property is the same as or different than the first property. The method includes transferring one or more portions of the plurality of portions from the second conveyor to a third conveyor or a fourth conveyor depending on the first relative abundance, the second relative abundance, or combination(s) thereof. The method includes transferring one or more portions of the plurality of portions of the third conveyor or the fourth conveyor to a sorting equipment, and sorting the one or more portions of the plurality of portions transferred to the sorting equipment into constituent plastic components. These and other features and attributes of embodiments of the present disclosure and their advantageous applications and/or uses will be apparent from the detailed description which follows.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical aspects of this present disclosure and are therefore not to be considered limiting of its scope, for the present disclosure may admit to other equally effective aspects.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. The figures are not drawn to scale and may be simplified for clarity. It is contemplated that elements and features of one aspect may be beneficially incorporated in other aspects without further recitation.
The present disclosure relates to apparatus and processes for inspection, sortation, and pysrolysis of waste plastic feeds.
In some embodiments, provided is a system and method for intaking and inspecting plastic waste bales to determine the composition and physical characteristics of incoming plastic waste. The data obtained can be used to provide a database of received plastic waste compostion and physical characteristics, tracking and inventory management of such plastic waste, maximize recovery of target plastic waste, and optimize subsequent processing conditions.
In some embodiments, provided is a system and method for sorting and isolating target waste plastic materials for use as a feedstock in subsequent chemical recycling operations.
In some embodiments, provided is a process including introducing a plastic melt, consisting of the isolated target waste plastic, into a reactor via one or more nozzles coupled with the reactor. The process includes introducing a catalyst into the reactor using dilute-phase pneumatic transfer of regenerated catalyst coupled with the reactor via cyclone, standpipe, or vessel-dipleg system. The process includes pyrolyzing the plastic component to form a pyrolysis product. The process includes removing the pyrolysis product from the reactor via a second conduit disposed at a top ½ height of the reactor. The process includes removing the catalyst from the reactor via a third conduit disposed at a bottom ½ height of the reactor, wherein the catalyst removed from the reactor comprises ash. The process includes introducing the catalyst from the third conduit to a separator to form a catalyst-rich phase and an ash-rich phase in the separator.
In some embodiments, provided is an apparatus including one or more nozzles coupled with a reactor. The nozzle includes an inlet disposed substantially perpendicular to a horizontal conduit disposed in the nozzle. The apparatus includes a riser coupled with the reactor. The apparatus includes a first outlet conduit disposed at a top ½ height of the reactor. The first outlet conduit is coupled with a cyclone separator. The apparatus includes a second outlet conduit disposed at a bottom ½ height of the reactor. The second outlet conduit is coupled with a second separator. The apparatus includes a regenerator coupled with the second separator and the riser.
In some embodiments, the bale inspection and sorting process improves cost-effectiveness of the pyrolysis process pertaining to pyrolysis reactor conditions, catalyst composition, catalyst feed input, additive input, and combination(s) thereof. In some embodiments, the bale inspection and sorting process allows for tailorability of pyrolysis process by reducing the energy input required to attain the desired product.
In some embodiments, the bale inspection and sorting process allows for the removal of materials containing problematic heteroatoms prior to pyrolysis. Without being bound by theory, chlorine containing materials can cause corrosion within the pyrolysis reactor resulting in costly repairs and increased downtime. The ability to remove such materials from the plastic waste feedstock prior to pyrolysis mitigate such issues.
Plastic waste can be sourced from one or more operations such as material recovery facilities (MRFs), paper and plastic recyclers, landfills, molding operations, and others that handle scrap plastic materials. Plastic materials can include, but are not limited to, one or more of high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polyvinylchloride (PVC), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinyl acetate (PVA), acrylonitrile-butadiene-styrene (ABS) plastic, various nylons, various epoxies, various polyurethanes, various polyureas, various polyesters, and other polymers, copolymers, or any combination(s) thereof used in packaging and product manufacture. In some embodiments, the plastic materials are mixed with other non-plastic materials, such as wire, used beverage cans, ferrous metal pieces, wood, paper, and other fiber materials, glass, wood waste, grit, and other inorganic matter. The plastic waste can vary in size and shape to include films, thin sheets, and bulky items. The plastic content can vary widely depending on the source, such as about 10 wt % to about 70 wt %, such as about 25 wt % to about 60 wt %, such as about 35 wt % to about 55 wt %.
The plastic waste materials typically arrive at waste recycling facilities in bales having various shapes, sizes, weights, and compositions. The size and weight can vary according to the source and type of baling device employed to compress and wrap the material. The composition of the bales can vary in physical form and content.
Currently, there is no known method to accurately determine the physical shape and composition of a plastic waste bale prior to and upon arrival at a recycling facility. Knowledge of the plastic waste composition and physical state in a bale is vital to selecting and operating downstream shredding, separation, sorting, washing, and density separation operations—for example, ballistic separators recover film materials from waste. Processes of the present disclosure implement a bale inspection system which can be installed proximate to where the recycling operation receives inbound plastic waste.
The bale inspection system measures the composition and physical characteristics of incoming plastic waste packaged in bales before conveyance to shredding, screening, and sorting operations. In some embodiments, the plastic waste bales have dimensions of height, length, and width.
In some embodiments, one or more sensors measure the size, shape, weight, plastic resin type, and elemental content in the baled material. The data obtained from the one ore more sensors can be recorded, parsed, and evaluated to:
In some embodiments, a bale inspection system includes four sub-modules. The first module comprises mechanical equipment to accept bales from existing material handling equipment proximate to where inbound materials are received from various sources. The mechanical equipment includes components that safely and securely receive and hold a bale in a specified position relative to an array of sensors, as shown in
Referring to
In some embodiments, the one or more sensors are a scale, a near-infrared light reflectance camera (NIR camera), a radiation sensor, a light detection and ranging sensor (LIDAR), a prompt gamma neutron activation analysis (PGNAA) sensor, a visible light camera, and any combination(s) thereof. The sensors provide information pertaining to the physical and compositional aspects of the plastic waste bale. For instance, the scale provides information corresponding to bale mass. The NIR camera takes multiple exposures of the outer surface to ascertain the plastic resin types located proximate to and disposed upon the external surface of the bale. The radiation sensor indicates whether the bale has been contaminated by a radiation source, such as 60Co, 137Cs 223Ra. The LIDAR sensor dynamically measures the distances from a fixed reference point as the bale is rotated or linearly translated on the motorized platter. A plurality of measurements obtained by the LIDAR system is evaluated to obtain a bale's three-dimensional model. The PGNAA sensor provides information regarding the elemental composition of the bale. The visible light camera define the location and texture of particles that are located on the exterior surfaces.
In some embodiments, individual bales 104 are advanced to an inspection station 110 where the one or more sensors have unobstructed access to the individual bale's 104 exposed surface. The an inspection station 110 includes a method of moving and rotating (107 and 108) the individual bale 104 into a position favorable to the one or more sensors. In some embodiments, the individual bale 104 is linearly translated in view of and/or in relation to the one ore more sensors, such that the one or more sensors is able to detect, collect, and convey the desired physical and/or compositional information pertaining to an individual bale 104. In some embodiments, the one or more sensors are rotated around the bale and/or moved linearly along the bale to detect, collect, and convey the desired physical and/or compositional information pertaining to an individual bale 104. The measurement and data collection process is conducted in near real-time to maintain a high level of production. After the measurements are obtained, the individual bale 104 is queued to a temporary inventory location to allow for the measurement evaluation and subsequent dispatch to the appropriate process.
A control system device 118 evaluates all measured data and issues instructions 119 to the facility material handling and process systems. For example, PLC logic can be used where a DCS controller can use prior bale data (bale composition, plastic content in the form of C/H or more detailed offline analysis, or time-logged data from other areas) and correlated back to similar bales compared by source and sensor data.
In some embodiments where the PGNAA sensor is included in the one or more sensors, the individual bale 104 is held in position for a brief period to obtain a measurement of elements, including the significant elements chlorine, sodium, potassium, sulfur, titanium, nickel, copper, aluminum, calcium, iron, silicon, nitrogen, carbon, and others. Information supplied by the PGNAA sensor is integrated with the information provided by the aforementioned sensors to provide knowledge of the proportion and mass of food waste, filler material, tramp metal, and inorganic residues.
Upon completion of the bale inspection process and measurement evaluation, the individual bale 104 is transferred to the processing equipment.
The bale inspection system can receive and integrate the data stream produced by the sensors to estimate one or more of (e.g., each of) the following parameters:
The characteristics of numerous bales processed over a specified period may be compared to the weights and purity of products and residues produced over the same period. The comparisons will update the predictive functions of the present systems.
With respect to conventional methods previously established, the bale inspection process and measurements produced is advantageous over the a priori method of processing bales currently practiced by the recycling industry. PLC logic where a DCS controller can use prior bale data (bale composition, plastic content in the form of C/H or more detailed offline analysis, or time-logged data from other areas) and correlated back to similar bales compared by source and sensor data. The net result of dynamically directing the bale to controllable operations provides excellent recovery of high-purity plastic products.
In some embodiments, bale sorting systems are installed proximate to where the recycling operation receives incoming plastic waste. The bale sorting system provides a process by which the contents that make up the at least one or more individual bales 104 are further sorted prior to pyrolysis, allowing for more efficient determination of processing conditions that will affect the outcome of subsequent pyrolysis and pyrolysis product recovery.
In some embodiments, the contents of the one or more individual bales 104 are subjected to a bulk reduction process prior to sorting the contents of one or more individual bales 104. The bulk reduction process includes any appropriate method of reducing the size of the plastic waste that make up the one or more individual bales 104. In some embodiments, the bulk reduction process includes any one of cutting, grinding, shredding, tearing, perforating, rolling, compressing, mechanically compromising, chemically compromising, electrically compromising, crushing, and any combination(s) thereof. The bulk reduction process increases the detectable surface are of the plastic waste particles 201 which can increase detection accuracy and sortation efficiency.
In some embodiments, as illustrated in
In some embodiments, the mixture of plastic waste particles 201 are advanced by a high-speed conveyor, such that the plastic waste particles 201 are in view of and detected by the one or more sensors 205. A diverter device, activated when plastic waste particles 201 of a target composition are detected by the one or more sensors 205, modifies the target particles' trajectory as it falls and moves away from the conveyor head pulley. Such a sorting action is referred to as a positive sort command. If the diverter device is programmed not to activate in response to a target particle detection, this is referred to as a negative sort command and such particles are not subject to the diverter device action, thus falling along a natural ballistic trajectory away from the conveyor head pulley. Different material handling systems carry the positively and negatively sorted plastic waste particles 251 to their intended destinations.
In some embodiments, a master sensor device 209 can be implemented to further differentiate and segregate the sorted plastic waste particles 251 having one or more specified target properties. The master sensor device 209 of the present disclosure is in communication with, at least, the one or more sensors 205, a diverter device 210, a negative sort takeaway conveyor 214 and corresponding motor 215, a positive sort takeaway conveyor 219 and corresponding motor 220, and any combination(s) thereof. In some embodiments, when sorted plastic waste particles 251 of one or more specified target properties, as determined by the one or more sensors 205, are in abundance greater than the capacity of the diverter device 210 to reliably move particles to the desired broader trajectory 213, the master sensor device 209 takes no control action. The moving plastic waste particles are discharged to fall in an uninterrupted natural ballistic trajectory 212 onto the negative sort takeaway conveyor 214. This negative sort takeaway conveyor 214 is propelled by a motor 215 whose direction is controlled by the master sensor device 209 via a signal 216 to carry the particles toward the head pulley where they are discharged 217 to receiving equipment or in a reverse direction to toward the tail pulley where they are discharged 218 to different receiving equipment.
In some embodiments, when sorted plastic waste particles 251 having a specified target property, as determined by the one or more sensors 205, are not in abundance greater than a specified value, then the master sensor device 209 activates a diverter device 210 that propels the particles into an alternate broader trajectory 213 using a puff of air 211. The diverted stream of plastic waste particles is moved to the positive sort takeaway conveyor 219 propelled by a motor 220 wherein the direction is controlled by a signal 221 from the master sensor device 209. The signal 221 indicates to the sort takeaway conveyor 219 to carry the particles toward the head pulley where they are discharged 223 to receiving equipment, or in a reverse direction to toward the tail pulley where they are discharged 222 to different receiving equipment.
In some embodiments where a master sensor device 209 is incorporated in a bale sortation system, the sortation is able to effectively sort plastic waste at any suitable rate. In some embodiments where a master sensor device is implemented, the relative abundance of plastic waste particle measurement has any suitable tolerance.
Sorting processes of the present disclosure dynamically modify a target sort command to produce a positive or negative sort action based on the relative abundance of particles possessing one or more target properties (e.g., depending on the chemical content of the polymers). For example, when a mixture of particles contains a low abundance of one or more targets, the particles can be positively sorted without significant recovery loss. As the abundance increases and the capacity of positive sorting are exceeded, the sort command would be given to sort the particles negatively. The negative sorting capacity is naturally much greater than the positive sorting capacity; thus, overall capacity is not reduced. In some embodiments the one or more target properties can include, but are not limited to, particle composition classification (e.g. polyesters, nylons, epoxies, acrylates, etc.), relative elemental abundance (e.g. chlorine content or content of other troublesome elements), particle size, and any combination(s) thereof. In some embodiments wherein relative elemental abundance is a target property, elements of interest can be, but are not limited to, chlorine, sodium, potassium, sulfur, titanium, nickel, copper, aluminum, calcium, iron, silicon, nitrogen, carbon, and any combination(s) thereof.
Two benefits result from dynamically changing the sorting command. First, maximum unit capacity is achieved, and second, the recovery of the target product increases due to less misplaced material.
The present systems and methods achieve dynamic sort commands by pre-inspecting the mixed material stream before it arrives at the sorting device. The relative abundance of one or more target plastic waste particles is measured, and this information is used to compute the optimum sort command, positive or negative. The operation of the material handling equipment downstream of the sorter is adjusted to keep sorted materials flowing to the intended destination. Reversing conveyors are one way to redirect material flow as required by changes in sorting commands.
In some embodiments, plastic particles from either the positive sortation 223 or negative sortation 218 are reintroduced to the bale sorting system, as transported by conveyer 202, to further increase the sortation efficiency and effectiveness of the bale sortation process. The bale sortation process can be reconducted until the positive sortation 223 or negative sortation 218 have the desired composition for pyrolysis.
Existing sorting systems can be upgraded with components of the present disclosure to provide systems with a pre-inspection sensor mounted upstream of the sorter, interface systems, software, and means to control and add to downstream material handling systems.
The bale inspection and sorting process disclosed herein provide improved capacity and recovery of target materials, such as various plastic types for tailored pyrolysis processes. For example, if two plastic materials, one having a high temperature of pyrolysis and one having a low pyrolysis temperature, are pyrolized together in the same reactor, the higher temperature would have to be achieved to have successful pyrolysis. However, if the high temperature pyrolysis material were not present, such an elevated temperature would be unnecessary. Requiring the elevated temperature could be undesirable due to higher energy requirements. The inspection and sorting process disclosed herein allows for the separation of such materials, thereby mitigating the energy input and increasing cost-effectiveness.
Another example of tailorability comes in the form of being able to select the most effective catalyst for the sorted plastic feed that will give the highest yield of the desired product. This will allow the user the ability to make cost-effective decisions regarding catalyst composition, input, and reactor conditions in order to fully optimize the pyrolysis process.
Additionally, the bale inspection and sorting process disclosed herein allow for the removal of materials containing potentially problematic heteroatoms prior to pyrolysis. For example and without being bound by theory, chlorine containing materials (e.g. PVC) can cause corrosion to occur within the pyrolysis reactor which could result in costly repairs and increased downtime. The ability to remove such materials from the plastic waste feedstock prior to pyrolysis can mitigate such issues.
Apparatus and processes of the present disclosure provide high throughput of pyrolysis products formed using pyrolysis of plastic waste. Processes can be performed as a single-stage process, providing higher yields than conventional processes for processing waste plastic. Apparatus and processes of the present disclosure provide elutriation of char, char ash, attrited catalyst, and co-injection material such that spent catalyst can be easily regenerated, providing improved throughput of the pyrolysis products in addition to higher purity of recycled catalyst to the reactor. In addition, use of catalyst having a narrow size distribution and larger average diameter than the co-injection material provides elutriation of co-injection material from the catalyst in the reactor. In addition, use of catalyst having a large average diameter, in addition to a reactor configured to provide bubble control, provides reduced plugging and wear of vessel conduits, valves, and other apparatus components, providing maintained integrity and a longer life cycle of apparatus of the present disclosure.
Contents of the positive sortation 223 can include a desired plastic material or composition that is heated to produce a plastic melt to be introduced to a reactor for pyrolysis. In some embodiments, provided is a process including introducing a plastic melt including a plastic component into a reactor via one or more nozzles coupled with the reactor. The process includes introducing a catalyst into the reactor by pneumatic transfer via a first conduit coupling the reactor with a riser. For example, the process may include introducing a catalyst into the reactor using dilute-phase pneumatic transfer of regenerated catalyst coupled with the reactor via cyclone-dipleg system. The process includes pyrolyzing the plastic component to form a pyrolysis product. The process includes removing the pyrolysis product from the reactor via a second conduit disposed at a top ½ height of the reactor and removing the catalyst from the reactor via a third conduit disposed at a bottom ½ height of the reactor.
A plastic melt is introduced into pyrolysis reactor 302 via nozzle 310. The plastic melt can include any suitable plastic material, such as plastic scrap, automotive plastic waste, thermoplastics, thermosets, or combination(s) thereof obtained from a sorting process of the present disclosure. The plastic melt can include one or more plastics such as polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyvinylchloride, or combination(s) thereof. The plastics can be obtained from recyclable plastics, which can be inspected, reduced into small particles, and sorted based on any one or more appropriate identifying target properties. In some embodiments the one or more target properties can include, but are not limited to, particle composition classification (e.g. polyesters, nylons, epoxies, acrylates, etc.), relative elemental abundance (e.g. chlorine content or content of other troublesome elements), particle size, and any combination(s) thereof. In some embodiments, the plastic melt is introduced into the reactor at a rate of about 60,000 lb/hr to about 100,000 lb/hr, such as about 75,000 lb/hr to about 85,000 lb/hr, alternatively about 30,000 lb/hr to about 50,000 lb/hr. The plastic melt can be provided to the nozzle 310 by a plastic melt source (not shown) that can be configured to provide heat to the plastic to form the plastic melt. In some embodiments, the plastic melt, upon being introduced to the reactor, has a solids (e.g., char) content of about 20 wt % or less upon introduction into reactor 302, such as about 15 wt % or less, such as about 10 wt % or less, such as about 5 wt % or less, such as about 1 wt % or less.
The plastic melt may further include a viscosity reducing agent. For example, a viscosity reducing agent can be a recycled portion of pyrolysis product, such as an organic compound (e.g., aromatic or mono-olefin), such as an ethylene, a propylene, a butene, a benzene, a toluene, a xylene, or combination(s) thereof. The viscosity reducing agent may, additionally or alternatively, include a paraffinic organic compound such as a C4-C100 paraffin, such as a C6-C50 paraffin, such as a C10-C30 paraffin. The viscosity reducing agent can be introduced to the plastic melt in the plastic melt source (not shown) or nozzle 310. In some embodiments, a weight ratio of plastic to viscosity reducing agent (upon introduction to the reactor) is about 0.5:1 to about 1.5:1, such as about 0.65:1 to about 1.35:1, such as about 0.8:1 to about 1.2:1, such as about 0.95:1 to about 1.05:1, such as about 1:1. In some embodiments where the plastic melt includes a viscosity reducing agent, the plastic melt is introduced into the reactor at a rate of about 60,000 lb/hr to about 200,000 lb/hr, such as about 120,000 lb/hr to about 200,000 lb/hr, such as about 148,000 lb/hr to about 172,000 lb/hr.
A catalyst can be introduced into the pyrolysis reactor 302 via a first conduit 312. Conduit 312 couples reactor 302 to riser 302a. Conduit 112 can be disposed at a top ½ height of the reactor (as shown in
The plastic melt and the catalyst in reactor 302 pyrolyze the plastic(s) to form a pyrolysis product. In some embodiments, the catalyst is introduced into reactor 302 via the first conduit 312 at a catalyst flow rate of about 5.5 tons per minute to about 13.8 tons per minute, such as about 7.5 tons per minute to about 12.4 tons per minute, alternatively about 2.5 tons per minute to about 8.8 tons per minute. In some embodiments, the catalyst disposed in the riser 302a has a minimum gas fluidization velocity of about 0.4 ft/sec to about 0.6 ft/sec, such as about 0.45 ft/sec to about 0.55 ft/sec, such as about 0.5 ft/sec to about 0.55 ft/sec. In some embodiments, a weight ratio of catalyst to feed (e.g., plastic melt with or without viscosity reducing agent) in reactor 302 is about 15:1 to about 5:1, such as about 11:1 to about 7:1, such as about 10:1 to about 8:1, such as about 9:1.
The pyrolysis product is removed from reactor 302 via a second conduit 314 disposed at a top ½ height of the reactor. The catalyst is removed from reactor 302 via a third conduit 316 disposed at a bottom ½ height of the reactor. For example, the catalyst can be removed from the reactor via third conduit 316, where third conduit 316 is disposed at a bottom surface of the reactor 302.
In some embodiments, reactor 302 is a bubbling bed reactor. Alternatively, a fluidized bed reactor, slurry reactor, rotating kiln reactor, or packed bed reactor may be used. The plastic melt (e.g., without viscosity reducing agent) can have a temperature of about 900° F. to about 1,100° F., such as about 1,000° F. to about 1,050° F., alternatively about 900° F. to about 1,020° F., during introducing the plastic melt into the reactor. Alternatively, the plastic melt (e.g., with viscosity reducing agent) can have a temperature of about 300° F. to about 700° F., during introducing the plastic melt into the reactor.
In some embodiments, a reactor temperature during pyrolysis of the plastic melt is about 900° F. to about 1,100° F., such as about 1,000° F. to about 1,050° F., alternatively about 900° F. to about 1,020° F. For example, pyrolyzing the plastic may be performed at a reactor temperature of about 900° F. to about 1,100° F., such as about 1,000° F. to about 1,050° F., and/or a reactor pressure of about 20 psig to about 40 psig, such as about 25 psig to about 35 psig, such as about 27 psig to about 33 psig.
Pyrolysis of the present disclosure can provide the pyrolysis product such that the pyrolysis product includes valuable monomers of light gas olefins and aromatics, such as benzene, toluene, xylenes, or combination(s) thereof. The process yields are tunable to the desired yields of olefins and aromatics by using a combination of the catalyst, reactor setup, and process operating conditions. The pyrolysis product can include an organic compound, such as a C2-C12 hydrocarbon. In some embodiments, the pyrolysis product includes an organic compound selected from the group consisting of ethylene, propylene, and combination(s) thereof. In some embodiments, the pyrolysis product includes an organic compound selected from the group consisting of an ethylene, a propylene, a butene, a benzene, a toluene, a xylene, and combination(s) thereof.
In some embodiments, in addition to the catalyst, a co-injection particle is introduced into reactor 302. For example, a co-injection particle can be introduced into reactor 302 via nozzle 310 at a rate of about 1,000 lb/hr to about 3,000 lb/hr. In some embodiments, a co-injection particle is a particle configured to trap halogens (e.g., fluorine, chlorine, bromine or iodine present in polymers or contaminants of the plastic melt). During the pyrolysis process, such halogens may appear as unwanted contaminants in desired pyrolysis products, or they may be deposited on or react with pyrolysis catalyst components, thereby reducing desirable catalyst properties such as activity and selectivity to desired pyrolysis products. Further, such halogens may be deposited on or react with mechanical components of the pyrolysis system, leading to damage, reduced efficiency or mechanical failure. Further, such halogens may appear as noxious gases or in liquid effluents from outlets of the pyrolysis system. Co-injection particles configured to trap or sequester halogens may include but are not limited to oxides, carbonates, calcium oxide, calcium carbonate, limestone, metal oxides, mixed metal oxides, clays, sands, earths, zeolites, or any other material or combination of materials able to combine with or sequester one or more halogens, in reversible or irreversible manners, thereby reducing or eliminating halogens from desired pyrolysis products, or thereby reducing or eliminating their deleterious deposition on or reaction with pyrolysis catalyst components, or thereby reducing or eliminating their deleterious deposition on or reaction with mechanical components of the pyrolysis system, or thereby reducing or eliminating their appearance as noxious gases or in liquid effluents from outlets of the pyrolysis system. For example, the co-injection particle can be oxides, carbonates, calcium oxide, calcium carbonate, limestone, metal oxides, mixed metal oxides, clays, sands, earths, zeolites, or any other material or combination(s) of materials capable of combining with and sequestering halogens.
In some embodiments, a co-injection particle comprises a material or combination of materials configured to trap or sequester metals and semi-metals that may be present in the plastic melt. A variety of metals and semi-metals may be present in plastic wastes, particularly post-consumer plastic wastes. These metals and semi-metals may include but are not limited to alkali metals, alkaline earth metals, transition metals, rare earths, iron, silver, copper, zinc, gray tin, lead, phosphorus and aluminum, and may be present as free elements or may be present as inorganic or organic or organometallic molecules, compounds, aggregations, mixtures or other combination(s). During the pyrolysis process, such metals and semi-metals may appear as unwanted contaminants in desired pyrolysis products, or they may be deposited on or react with pyrolysis catalyst components, thereby reducing desirable catalyst properties such as activity and selectivity to desired pyrolysis products. Further, such metals and semi-metals may be deposited on or react with mechanical components of the pyrolysis system, leading to damage, reduced efficiency or mechanical failure. Co-injection particles configured to trap or sequester metals and semi-metals may include but are not limited to oxides, carbonates, calcium oxide, calcium carbonate, limestone, metal oxides, mixed metal oxides, clays, sands, earths, zeolites, or any other material or combination of materials able to combine with or sequester one or more metals or semi-metals, in reversible or irreversible manners, thereby reducing or eliminating them from desired pyrolysis products, or thereby reducing or eliminating their deleterious deposition on or reaction with pyrolysis catalyst components, or thereby reducing or eliminating their deleterious deposition on or reaction with mechanical components of the pyrolysis system.
“4A zeolite” (also referred to as LTA zeolite) means a zeolite having pore openings of about 4 angstroms; and the term “5A zeolite” means a zeolite having pore openings of about 5 angstroms.
4A zeolites (Na2O·Al2O3·2SiO2·9/2H2O) have a continuous three-dimensional network of channels approximately 4 angstrom in diameter, in addition to larger “cages” approximately 7 Å in diameter. 4A zeolites can have one or more of the following properties: (1) an average particle size of about 3 microns; and/or (2) a silicon:aluminum ratio of about 1.
The pore structure of the 5A zeolites (¾CaO·¼Na2O·Al2O3·2SiO2·9/2H2O) is a three-dimensional network of intersecting channels. Entry to the channels is controlled by the eight oxygen atoms from which they are formed (approx. 3-5 Å diameter). Where the channels intersect, larger pores or cages with diameters of 11.4 Å are formed. 5 Å zeolites can have a bulk density of about 0.7 g/cm3 to about 0.75 g/cm3, such as about 0.72 g/cm3.
If calcium oxide is used, the calcium oxide can react with chlorine content of the polymer melt to form calcium chloride and gas product(s) such as carbon dioxide. In some embodiments, a weight ratio of catalyst to co-injection particle in reactor 302 is about 10:1 to about 30:1, such as about 15:1 to about 25:1, such as about 20:1.
The co-injection particle, or product thereof, after sequestration of one or more halogens, or after sequestration of one or more metals or semi-metals, or after sequestration of combinations of one or more halogens, metals or semi-metals, can be removed from the reactor via second conduit 314 and introduced into first separator 304 along with the pyrolysis product.
In some embodiments, the co-injection particle has a smaller average diameter than the average diameter of the pyrolysis catalyst. In such embodiments, in combination with other parameters of the pyrolysis reactor 302, the co-injection particle, or reaction product thereof, (and/or char and attrited catalyst) is able to be removed from reactor 302 to first separator 304 (via a conduit disposed at a top ½ height of the reactor), whereas the larger catalyst particles are removed from reactor 302 via third conduit 316 disposed at a bottom ½ height of the reactor. In some embodiments, a co-injection particle has an average diameter of less than 400 microns, such as less than 200 microns, such as about 50 microns to about 400 microns, such as about 75 microns to about 200 microns, and/or the catalyst has an average diameter of about 500 microns to about 600 microns and/or a narrow particle size distribution.
First separator 304 can be a cyclone separator that is configured to separate the co-injection particle, or product thereof, from the pyrolysis product. The co-injection particle, or product thereof, is removed from first separator 304 via fifth conduit 320 for storage or further processing (e.g., disposal or regeneration). The pyrolysis product is removed from first separator 304 via conduit 318 for storage or further processing (e.g., additional cyclonic separation and/or distillation of products). For example, a second stage of cyclone(s) for secondary removal can be used to increase separation efficiency. Subsequent devices for separation of solids and gases from pyrolysis product can include cyclones, hot gas filters, vortex separators, electrostatic separation, or combination(s) thereof, which can be further added to achieve desired solid removal efficiency.
The catalyst (e.g., spent catalyst) from reactor 302 is introduced into separator 106. In some embodiments, separator 306 is a solid-solid separator. A co-injection particle, or product thereof, from the pyrolysis product can also be removed from separator 306 via sixth conduit 322.
Spent catalyst and ash enter a mid-portion of separator 306. The spent catalyst and ash may further include any residual co-injection particle not separated from the catalyst/ash in the reactor 302.
In some embodiments, the mixture of spent catalyst and ash entering reactor 306 includes about 90 wt % or greater spent catalyst and about 10 wt % or less ash, such as about 0.5 wt % to about 4 wt % ash and about 96 wt % to about 99.9 wt % spent catalyst. Spent catalyst and ash is introduced into separator 306 at a temperature of about 800° F. to about 1,200° F., such as about 950° F. to about 1,050° F. In some embodiments, spent catalyst and ash are introduced to separator 306 at a rate of about 1 million lbs/hr to about 2 million lbs/hr, such as about 1.3 million lbs/hr to about 1.7 million lbs/hr, such as about 1.4 million lbs/hr to about 1.7 million lbs/hr.
Third conduit 316 has a first end coupled with reactor 302 (of
Gas is introduced into separator 306 via seventh conduit 406 to fluidize the mixture of spent catalyst and ash. Gas can be provided at a rate of about 0.1 ft/s to about 1.5 ft/s, such as about 0.3 ft/s to about 0.7 ft/s, such as about 0.5 ft/s. The gas can have a temperature of about 150° F. to about 1050° F. The gas can have a lower temperature than the spent catalyst and ash entering separator 306 via third conduit 316 such that the gas can promote cooling of the spent catalyst and ash. In some embodiments, the gas introduced can replace the presence of the trapped reactor gases prior to the introduction into the regenerator combustion system. The rate of gas introduced into separator 306 via seventh conduit 406 can be such that a fine balance is reached between the gas' ability to promote separation of the spent catalyst from the ash and allow the spent catalyst's ability to separate/settle gravimetrically from the ash. Gas in the separator 306 can exit separator 306 via sixth conduit 322 and/or dipleg conduit 408. Ash of ash-rich phase 404 is removed from separator 306 via dipleg outlet 408.
As shown in
A separation carried out in separator 306 to form the multiple phases can be performed at any suitable pressure and temperature. In some embodiments, a pressure in separator 306 is about 20 psig to about 50 psig, such as about 25 psig to about 40 psig, such as about 30 psig to about 35 psig. In some embodiments, a temperature in separator 306 is about 700° F. to about 1,200° F., such as about 850° F. to about 1,050° F., such as about 950° F. to about 1,000° F.
In some embodiments, the spent catalyst obtained from separator 306 is about 90 wt % or greater, such as about 96 wt % to about 99.9 wt % spent catalyst, relative to the mixture of spent catalyst and ash introduced into separator 306. Likewise, the ash obtained from separator 306 is about 10 wt % or less, such as about 0.5 wt % to about 4 wt % ash, relative to the mixture of spent catalyst and ash introduced into separator 306.
In embodiments where sand is also used in reactor 302 in addition to catalyst, the sand can be separated in separator 306 (e.g., as part of the catalyst-rich phase or as a third phase in addition to the catalyst-rich phase and ash-rich phase). For example, the sand can be disposed in a sand-rich phase that is disposed above or below the catalyst-rich phase 402, and the sand-rich phase can be disposed below the ash-rich phase 404. In such embodiments, the sand-rich phase will be removed from separator 306 via a conduit (not shown) that is disposed below the ash-rich phase 404 and the sand of the sand-rich phase would be removed from separator 306 via the conduit (not shown) that is disposed below the conduit that removed the ash from separator 306.
Additionally or alternatively, in embodiments where trace metals (such as chromium) are separated from the spent catalyst in separator 306. Because trace metals can be denser than a spent catalyst, the trace metals can be separated from spent catalyst and settle as in separator 306 as a metal-rich phase that is disposed below the catalyst-rich phase 402. In such embodiments, the metal-rich phase will be removed from separator 306 via a conduit (not shown) that is disposed below the catalyst-rich phase 402 and the spent-catalyst of the catalyst-rich phase 402 would be removed from separator 306 via a conduit (not shown) that is disposed above the conduit that removed the trace metal from separator 306.
In some embodiments, the conduit used to remove the ash-rich phase from separator can be disposed towards another separator or divided walls acting in series or in stages. Each series or stage geometry can be configured to be separate vessels or discrete chambers integrated into one vessel. Gas can be provided at a rate of about 0.05 ft/s to about 1.5 ft/s, such as about 0.1 ft/s to about 0.3 ft/s, such as about 0.1 ft/s where separation of a third or fourth phase within the ash-rich phase can be achieved to increase separation efficiency from the catalyst-rich phase.
From separator 306, the catalyst (e.g., spent catalyst) is introduced into regenerator 308 via conduit 340 that is configured to form a regenerated catalyst. An oxygen-carrying gas, such as air, may be introduced into the regenerator 308 to regenerate the spent catalyst and combust material (e.g., carbonaceous material disposed on the catalyst such as ash). In some embodiments, air is introduced into the regenerator 308 at a rate of about 107,000 lb/hr to about 165,000 lb/hr, such as about 133,000 lb/hr to about 151,000 lb/hr, such as about 145,000 lb/hr.
The regenerated catalyst formed in regenerator 308 is then introduced into riser 302a.
In some embodiments, the plastic melt is not introduced to the riser 302a. A gas, such as pygas, product gases, reactant gases, recycle gases, or combination(s) thereof, is introduced to the riser 302a via inlet 332. For example, gas is introduced to the riser 302a at a rate of about 18,000 lb/hr to about 23,000 lb/hr, such as about 21,000 lb/hr to about 22,000 lb/hr.
In some embodiments, gas is introduced into reactor 302 via inlet 330. For example, gas can be introduced into reactor 302 via the nozzle at a rate of about 3,000 lb/hr to about 12,000 lb/hr, such as about 7,750 lb/hr to about 10,250 lb/hr. A nozzle can have an outlet having a diameter of about 6 mm to about 20 mm, such as about 13 mm.
The gas introduced to the riser 302a and/or reactor 302 can be refined, product recycled fluid (e.g., gas or liquid). The gas provides a fluidization medium in reactor 302 and also provides improved conversion/yield of reactor feed into pyrolysis product. For example, in embodiments where the gas is a recycled fluid, the recycled fluid can contain olefin material that provides conversion towards a pyrolysis product such as aromatics, increasing target product yield.
In some embodiments, gas (and/or co-injection material and/or recycle oil) is introduced into the reactor indirectly via an inlet of nozzle 310 and nozzle 310 has an outlet diameter that is smaller than a nozzle interior diameter (as shown in
During use, catalyst particles in reactor 302 can be in an emulsion phase. Because gas is introduced through riser 302a, into reactor 302, and chemical reaction effluent, bubbles can form within reactor 302. Reactor 302 can be configured to break bubbles that form in the reactor 302. By breaking bubbles in reactor 302, mass transfer of plastic melt to catalyst is promoted. For example, molecules of pyrolyzed plastic getting into pores of catalyst is promoted, which promotes better conversion of plastic to pyrolysis product(s). In addition, formation of large bubbles promotes mechanical vibrations within the reactor, so breaking of the bubbles can reduce or eliminate the occurrence of mechanical vibrations promoted by large bubbles.
In some embodiments, reactor 302 has a plurality of plates, mesh, or structure grid sheds (not shown) disposed within the reactor. For example, the plurality of plates, mesh, or structured grids can have an arrangement in a first row and a second row of plates, mesh, or structured grids, where the first row is horizontally offset from the second row. In some embodiments, one or more of the mesh or grid sheds have an angular apex cover in a vertical direction and have one or more openings along its cover.
The catalyst(s) used for pyrolysis of the plastic melt can be any suitable pyrolysis catalyst. In some embodiments, a catalyst is a composite body with multiple components. These components may include one or more materials that are catalytically active in the conversion of plastics in the reactor feed to desired pyrolysis products. These components may, for example, include but are not limited to zeolites, clays, acid impregnated clays, aluminas, silicas, silica-aluminas, spent FCC catalysts, equilibrium FCC catalysts, metal oxides, mixed metal oxides, or combination(s) thereof. The catalyst components may also include one or more materials to bind the catalyst components together to improve their physical strength. Such binder materials may for example include, but are not limited to various aluminas, silicas, magnesias, clays and other earths and minerals. The catalyst components may also include one or more materials to modify other aspects of the composite catalyst bodies, for example density, porosity and pore size distribution. Such modifying materials may include, but are not limited to various aluminum oxides, aluminum hydroxides, aluminum oxyhydroxides, clays, earths, fillers, or combination(s) thereof. Further, such modifying materials may function as hardeners, densifiers, burn out materials to enhance porosity, stabilizers, diluents, activity promoters, activity stabilizers, or combination(s) thereof. Further such modifying materials may include one or more components to sequester feed contaminants such as metals, semi-metals or halogens. Further, such modifying materials may include one or more components to reduce emissions of sulfur oxides, nitrogen oxides, or acid gases from the pyrolysis system. Further, such modifying materials may include one or more components to control and regulate the combustion of carbon and emissions of carbon oxides from the pyrolysis system regenerator. In some embodiments, an additive material is a matrix formed from an active material, such as an active alumina material (amorphous or crystalline), a binder material (such as alumina or silica), an inert filler (such as kaolin), or combination(s) thereof. For example, the catalyst can include a zeolite material disposed in the matrix.
In some embodiments, the various catalyst components are in bodies of one homogeneous composition. In other embodiments, the various components are distributed between two or more bodies that can be physically mixed to achieve the overall desired amounts of the various individual components.
In some embodiments, the catalyst is a Group VIII metal or compound thereof, a Group VIB metal or a metal compound thereof, a Group VIIB metal or a metal compound thereof, or a Group JIB metal or a metal compound thereof, or combination(s) thereof. For example, a Group VIB metal or compound thereof can include molybdenum and/or tungsten. A Group VIII metal or a compound thereof may include nickel and/or cobalt. A Group VIIB metal or a compound thereof may include manganese and/or rhenium. A Group JIB metal or a compound thereof may include zinc and/or cadmium. In some embodiments, a catalyst is a sulfided catalyst. In some embodiments, a catalyst is a cobalt-molybdenum catalyst, a nickel-molybdenum catalyst, a tungsten-molybdenum catalyst, sulfide(s) thereof, or combination(s) thereof. In some embodiments, the catalyst is a platinum-molybdenum catalyst, a tin-platinum catalyst, a platinum gallium catalyst, a platinum-chromium catalyst, a platinum-rhenium, or combination(s) thereof. In some embodiments, a catalyst includes cobalt and molybdenum, nickel and molybdenum, iron and molybdenum, palladium and molybdenum, platinum and molybdenum, or nickel and platinum. A Group IIIB metal or a compound thereof may include lanthanum and/or cerium.
In some embodiments, catalytically active components may include one or more zeolites, which may include but are not limited to X-types, Y-types, mordenites, may be an X-type zeolite, a Y-type zeolite, USY-type zeolite, mordenite, faujasite, nano-crystalline zeolite, an MCM mesoporous material, SBA-15, a silico-alumino phosphate, a gallophosphate, a titanophosphate. In some embodiments, the catalyst may include one or more zeolites (or metal loaded zeolites). In some embodiments, a zeolite is ZSM-5, ZSM-11, aluminosilicate zeolite, ferrierite, heulandite, zeolite A, erionite, chabazite, or combination(s) thereof.
In some embodiments, a catalytically active component is a zeolite, such as a medium-pore zeolite, such as a ZSM-5 zeolite. ZSM-5 zeolite is a molecular sieve that is a porous material having intersecting two-dimensional pore structure with 10-membered oxygen-containing rings. Zeolite materials with such 10-membered oxygen ring pore structure are often classified as medium-pore zeolites. Such medium-pore zeolites typically have pore diameters of 5.0 Angstroms (Å) to 7.0 Å. ZSM-5 zeolite is a medium pore-size zeolite having a pore diameter of about 5.1 Å to about 5.6 Å.
Other properties of ZSM-5 zeolite can include one or more of the following: (1) a SiO2/Al2O3 molar ratio of about 20 to about 600, such as about 30; (2) a Brunauer-Emmett-Teller (BET) surface area (m2/g) of about 320 or greater, such as about 340 or greater, such as about 320 to about 380, such as about 340; and/or (3) in the hydrogen or ammonium ion exchange form.
Catalysts of the present disclosure can have a particle size small enough (1) to allow homogeneous reactor and regenerator fluidization without extreme velocities required, (2) to provide good contacting of catalyst to feed (e.g., plastic melt, recycled pygas, etc.) and reduce/minimize external diffusion barriers, (3) to allow for smooth regeneration without hot spots that might arise if particles are too large, and/or (4) to allow for smooth pneumatic transport without a need for high gas velocities. Catalysts of the present disclosure can have a large enough particle size and density (1) to allow high ratio of catalyst to feed during pyrolysis, (2) to allow higher space velocities (throughput) while minimizing entrainment, (3) to allow for good catalyst separation and discharge from reactor bottom and regenerator bottom, and/or (4) allow efficient separation from lighter, smaller ash or separable phase (non-catalyst solids such as char, co-injected materials) if a separator is used. In some embodiments, the catalyst has an average diameter of about 450 microns to about 650 microns, such as about 500 microns to about 600 microns, such as about 540 microns to about 560 microns.
In some embodiments, the catalyst can have a narrow diameter distribution. For example, the catalyst may have a diameter distribution of about +/−200 microns of the average diameter of the catalyst, such as about +/−150 microns, such as about +/−75 microns. In some embodiments, the catalyst has a D1% value of about 380 microns to about 420 microns, such as about 400 microns. D1% is the diameter of the catalyst such that 99 wt % of the catalyst has a diameter greater than the D1% value. In some embodiments, the catalyst has D99% value of about 680 microns to about 720 microns, such as about 700 microns. D99% is the diameter of the catalyst such that 99 wt % of the catalyst has a diameter less than the D99% value. A narrow size (e.g., diameter) distribution of a catalyst can (1) reduce or minimize dense phase segregation in the reactor and the regenerator, (2) reduce or minimize preferential transport and dilute phase transport at high feed or regenerator air rates, and/or (3) reduce or minimize plugging at vessel discharge ports, slide valves, Y-joints, etc.
In some embodiments, the catalyst has an average particle density of about 300 g/l to about 1,200 g/l, such as about 500 g/l to about 1,000 g/l, such as about 600 g/l to about 800 g/l.
In some embodiments, the catalyst has a sphericity of about 0.9 or greater, such as about 0.95 or greater, such as about 0.99 or greater.
In some embodiments, the catalyst has an active catalyst (e.g., zeolite) loading amount of about 50 wt % or greater, such as about 60 wt % or greater, such as about 75 wt % or greater, such as about 85 wt % or greater, where a remainder balance of the catalyst comprises additive material. For example, additive material can include any suitable binder material.
A catalyst of the present disclosure can have an attrition resistance referred to as an attrition resistance index of less than 10 when measured in a jet cup apparatus at an air jet velocity of 200 ft/sec.
A catalyst of the present disclosure can have a crush strength greater than 1 Newton as measured in a single bead anvil test apparatus, such as greater than 5 Newtons.
In some embodiments, a catalyst is in the form of granules, pellets, extrudates, cut extrudates, ligated extrudates, beads, tablets, spheres, or combination(s) thereof.
Catalysts of the present disclosure may be obtained by any suitable process (such as spray drying) and/or may be obtained from a commercial source. For example, a catalyst can be formed by spray drying, prilling, oil dropping, water dropping, granulating, fluid bed agglomerization, spray coating tableting, extruding, or any combination(s) thereof. Catalysts can be cut, crushed, milled, or screened to provide any suitable size (e.g., diameter) distribution. Catalysts can be further prepared by polishing, densifying, or spheronizing in rotating pans, rotating drums, and the like.
More than one type of catalyst may be introduced to the reactor 302. For example, a first catalyst is introduced to the reactor 302 by a conduit and a second catalyst is introduced to the reactor 302 by a different conduit. The first catalyst and the second catalyst can be introduced into the reactor 302 at the same or different flow rates to control relative amounts of catalyst in reactor 302 at any given time. A remainder balance of the first catalyst and/or the second catalyst can include additive material, such as binder material.
Additionally or alternatively, a first catalyst and a second catalyst are introduced to reactor 302 via a single conduit (as a mixture of catalysts). For example, the mixture of catalysts can be a single-body catalyst including the two catalysts. A remainder balance of the single-body catalyst can include additive material, such as binder material.
In some embodiments, sand of a density of about 1450 g/l to about 1680 g/l can be mixed with a catalyst. Examples of sand include quartz sand, silica sand, sand containing metal or metal oxide, or combination(s) thereof. The use of sand may inhibit fouling of the catalyst by contaminants produced during the pyrolysis. Sand can also provide control of thermal and catalytic activities of pyrolysis occurring in the reactor. Sand may be used at an amount of up to about 99 wt % based on the total amount of sand+catalyst.
The present disclosure provides, among others, the following aspects, each of which may be considered as optionally including any alternate aspects.
Overall, systems and methods of the present disclosure provide increased recovery of high-purity plastic materials from bales, reducing or eliminating a need for waste plastic to be discarded at a conventional landfill. Additionally, systems and methods of the present disclosure provide improved capacity and recovery of target materials such as various plastic types for tailored pyrolysis processes. Pyrolysis processes and apparatus of the present disclosure provide high throughput plastic pyrolysis to form pyrolysis products. Processes can be performed as a single-stage process, providing higher yields than conventional processes for processing waste plastic.
The term “pyrolysis” includes an on-average endothermic reaction for converting molecules into (i) atoms and/or (ii) molecules of lesser molecular weight, and/or optionally (iii) molecules of greater molecular weight, e.g., processes for forming C2-C12 unsaturates such as ethylene, propylene, acetylene, benzene, toluene, xylene, or combination(s) thereof.
The term “catalyst activity” includes the weight of volatile matter converted per catalyst weight over a given amount of time.
The term “spent catalyst” includes any catalyst that has less activity at the same reaction conditions (e.g., temperature, pressure, inlet flows) than the catalyst had when it was originally exposed to the process. This can be due to a number of reasons, several non-limiting examples of causes of catalyst deactivation are coking or char sorption or accumulation, metals sorption or accumulation, attrition, morphological changes including changes in pore sizes, cation or anion substitution, and/or chemical or compositional changes. Spent catalyst can include an amount of catalyst that is not spent (e.g., has not been deactivated) in addition to catalyst that is spent.
The term “regenerated catalyst” includes a catalyst that had become spent, as defined above, and was then subjected to a process that increased its activity, as defined above, to a level greater than it had as a spent catalyst. This may involve, for example, reversing transformations or removing contaminants outlined above as possible causes of reduced activity. The regenerated catalyst may have an activity greater than or equal to the fresh catalyst (typically referred to herein as “catalyst” unless otherwise noted), but typically, regenerated catalyst has an activity that is between the spent and fresh catalyst.
The term “pygas” includes a hydrocarbon fluid (gas or liquid) that is derived from waste plastic material. Pygas can exist as either a raw effluent stream from a reactor or a refined material recycled via a recycle stream for use of fluidization or further conversion in the reactor system.
The term “ash” includes ash that is removed from the reactor and separated from other material. The ash is a solid phase that is considered not part of the size fraction of the catalyst that is circulating through the apparatus. Ash can be attrited catalyst fines, char from plastics, and/or co-injected materials which could be metal-oxides or catalyst by material.
The phrases, unless otherwise specified, “consists essentially of” and “consisting essentially of” do not exclude the presence of other steps, elements, or materials, whether or not, specifically mentioned in this specification, so long as such steps, elements, or materials, do not affect the basic and novel characteristics of the present disclosure, additionally, they do not exclude impurities and variances normally associated with the elements and materials used.
For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, within a range includes every point or individual value between its end points even though not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.
All numerical values within the detailed description herein are modified by “about” the indicated value, and take into account experimental error and variations that would be expected by a person having ordinary skill in the art.
All documents described herein are incorporated by reference herein, including any priority documents and or testing procedures to the extent they are not inconsistent with this text. As is apparent from the foregoing general description and the specific embodiments, while forms of the present disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the present disclosure. Accordingly, it is not intended that the present disclosure be limited thereby. Likewise, the term “comprising” is considered synonymous with the term “including” for purposes of United States law. Likewise whenever a composition, an element or a group of elements is preceded with the transitional phrase “comprising,” it is understood that we also contemplate the same composition or group of elements with transitional phrases “consisting essentially of,” “consisting of,” “selected from the group of consisting of,” or “is” preceding the recitation of the composition, element, or elements and vice versa.
While the present disclosure has been described with respect to a number of embodiments and examples, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope and spirit of the present disclosure.
This application claims benefits of co-pending U.S. Provisional Application No. 63/320,737, filed Mar. 17, 2022 and U.S. Provisional Application No. 63/320,752, filed Mar. 17, 2022.
| Number | Date | Country | |
|---|---|---|---|
| 63320737 | Mar 2022 | US | |
| 63320752 | Mar 2022 | US |
