Patent ID: 12202945

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENT(S)

A process of converting polymeric material, such as waste polymeric material, into wax is described below. The wax can then be employed to modify asphalt. Waxes are compatible with a wide variety of asphalt additives, and can be combined with a variety of materials commonly employed to improve the quality of asphalts.

In some embodiments, the addition of the wax improves the processing and physical characteristics of the polymer modified asphalt, including:reduction in blend time to achieve optimal or near-optimal dispersion of the polymer, resulting in higher throughputs;enablement of higher recycled asphalt (RAP) and recycled asphalt shingle (RAS) loading through reduced mix stiffness and increased lubricity; andcompaction and material handling.

In other or the same embodiments, the addition of wax improves the physical characteristics of the final asphalt product. The resulting final products can have various properties that differ from their unmodified forms. In some embodiments, the properties include, among other things, improved force ductility; increased softening point; thermal stability; improved polymer dispersion and viscosity. Improvements to elastomeric properties and energy of deformation are also observed in some embodiments.

The present method involves two main concepts: (1) the creation of the synthetic wax via depolymerization of plastics, and then (2) adding this wax to polymer modified asphalt. In some embodiments, the plastic stock employed to produce the synthetic wax is the same stock employed to produce the polymer modified asphalt.

FIG.1illustrates process600for creating synthetic waxes and then using those waxes to produce polymer modified asphalt. Process600can be run in batches, but more preferably is a continuous process. The parameters of Process600, including but not limited to temperature, flow rate of plastic and total number of pre-heat, reaction, or cooling segments, can be modified to produce end products of varying molecular weights and structural properties. For example raising the temperature and/or decreasing the flow rate through Wax Creation Stage 2000 will result in waxes of a lower molecular weight. Wax Creation Stage 2000 allows for precise targeting of specific wax characteristics, such as those that maximize the desire effect of blending.

In Material Selection Stage 1, polymeric feed is selected and/or prepared for treatment. In some embodiments, the polymeric feed in sorted/selected to include polyethylene material. The polymer can be HDPE, LDPE, LLDPE, or other variations of polyethylene.

In other embodiments, the polymeric feed in sorted/selected to include polypropylene material. In other embodiments, the polymeric feed in sorted/selected to include both polyethylene and polypropylene material. In some embodiments, the feed can contain up to 20% polypropylene, lower levels of polystyrene, PET, EVA, PVC, EVOH, and undesirable additives and/or contaminants, such as fillers, dyes, metals, various organic and inorganic additives, moisture, food waste, dirt, or other contaminating particles.

In some embodiments, the material selected in Material Selection Stage 1 comprises recycled plastics. In other or the same embodiments, the material selected in Material Selection Stage 1 comprises recycled plastics and/or virgin plastics.

The polymeric feed for Material Selection Stage 1 can come from either Plastic Feed A1 or Plastic Feed A2. When the feed comes from Plastic Feed A2, the resulting wax will have a similar composition when it is added with more plastic from Plastic Feed A2 to produce Finished Asphalt E. This leads to a more homogenous product with improved high temperature thermal and structural properties.

In some embodiments, the material selected in Material Selection Stage 1 is heated in an extruder and undergoes Pre-Filtration Process3. In some embodiments the extruder is employed to increase the temperature and/or pressure of the incoming plastic and is employed to control the flow rates of the plastic. In some embodiments, the extruder is complimented by or replaced entirely by pump/heater exchanger combination.

Pre-Filtration Process3can utilize both screen changers and filter beds, along with other filtering techniques/devices to remove contaminants from and purify the heated material. The resulting filtered material is then moved into an optional Pre-Heat Stage 4 which brings the filtered material to a higher temperature before it enters Depolymerization Stage 5. Pre-Heat Stage 4 can employ, among other devices and techniques, static and/or dynamic mixers and heat exchangers such as internal fins and heat pipes.

Material in Depolymerization Stage 5 undergoes depolymerization. This depolymerization can be a purely thermal reaction or it can employ catalysts. Depending on the starting material and the desired end product, depolymerization could be employed for a slight or extreme reduction of the molecular weight of the starting material.

In some embodiments, the catalyst employed is a zeolite or alumina supported system or a combination of the two. In some embodiments, the zeolite contains aluminum oxide. In some embodiments, the catalyst is prepared by binding a ferrous-copper complex to an alumina or zeolite support and reacting it with an inorganic acid.

Depolymerization Stage 5 can employ a variety of techniques/devices including, among other things, horizontal and/or vertical reactors fixed bed or batch reactors, and/or static mixers. In some embodiments, Reaction Stage 5 employs multiple reactors and/or reactors divided into multiple sections to produce a semi-continuous or continuous process.

After Depolymerization Stage 5, the depolymerized material either enters Cooling Stage 6 or is pumped via In-line Pump8and mixed with Pre-Wax Mixture H during Wax Adding Stage 9 to produce Finished Asphalt E.

Cooling Stage 6 can employ heat exchangers, along with other techniques/devices to bring the depolymerized material down to a workable temperature before it enters optional Purification Stage 7 or is pumped via In-line Pump8and mixed with Pre-Wax Mixture H during Wax Adding Stage 9 to produce Finished Asphalt E.

In some embodiments, cleaning/purification of the material via such methods such as nitrogen stripping occurs before Cooling Stage 6.

Purification Stage 7 involves the refinement and/or decontamination of the depolymerized material. Techniques/devices that can be employed in Purification Stage 7 include, but are not limited to, flash separation, absorbent beds, clay polishing, distillation, vacuum distillation and filtration to remove solvents, oils, color bodies, ash, inorganics, and coke. In some embodiments a thin or wiped film evaporator is employed to remove gas, oil, and/or grease from the depolymerized material. In some embodiments the oil, gas and grease can in turn be burned to help run various Stages of Process10.

In some embodiments a wiped film evaporator is used to remove gas, oil, and/or grease from the depolymerized material. In some embodiments, the oil, gas and grease can in turn be burned to help run various Stages of Process2000. In some embodiments, the purified material is pumped via In-line Pump8and mixed with Pre-Wax Mixture H during Wax Adding Stage 9 to produce Finished Asphalt E. In other embodiments, the purified material is processed as a solid Finished Wax C that can then be employed as Wax Feed F in Asphalt Modification Stage 3000.

Wax Creation Stage 2000 ends at Wax C in which the initial starting material selected in Material Selection Stage 1 has been turned into Wax C. In at least some embodiments, Wax C is included as part of Wax Feed F. In some embodiments, Wax C is not highly branched and instead has a more linear structure.

Asphalt Modification Stage 3000 involves combining plastic from Plastic Feed A2 with a synthetic wax. In some embodiments, Plastic Feed A2, Filler Feed B and Polymer Feed G, which preferably comprises atactic polypropylene (APP) and/or styrene-butadiene-styrene (SBS), are mixed together to form Pre-Wax Mixture H. A synthetic wax is then added, either via In-line Pump8or Wax Feed F in Wax Adding Stage 9 before Finished Asphalt E is produced. In some embodiments, the synthetic wax can be added to Pre-Wax Mixture H; however tests have found improved properties when the wax is added afterwards.

When the synthetic wax is added via In-line Pump8, some steps in the process can be eliminated, such as cooling the wax (Cooling Stage 6), purifying the wax (Purification Stage 7) and/or transporting the wax from one location to another.

In some embodiments, the wax in Wax Feed F was produced via Wax Creation Stage 2000.

In some embodiments, the percentage of wax in the wax/asphalt compound is roughly 0.1 to 25 percent by weight. The above method can employ a variety of waxes, including those with melt points between 60-160° Celsius, and viscosities 5-3000 cps, preferable in the range 110-130° C., and 100-2000 cps.

Changes in melting point and viscosity of the wax can change the properties of the asphalt mixture.

Referring toFIG.2, System1000includes reactor700with five reactor modules102(a) through102(e). Reactor modules102can vary in dimensions and/or be connected in parallel and/or series. In other embodiments, various numbers of reactor modules102can be employed. The ability to customize the number of reactor modules102allows for greater control of the amount of depolymerization. System1000is often used in Wax Creation Stage 2000.

System1000can include hopper111for receiving polymeric material and/or directing the supply of the polymeric material to optional extruder106. In some embodiments, extruder106processes the polymeric material received from hopper111by generating a molten polymeric material. The temperature of the polymeric material being processed by extruder106is controlled by modulating the level of shear and/or the heat being applied to the polymeric material by extruder heater(s)105. Extruder heaters can use a variety of heat sources including, but not limited to, electric, thermal fluids, and/or combustion gases. The heat is modulated by a controller, in response to temperatures sensed by temperature sensor(s)107.

In some embodiments, pressure sensor109measures the pressure of the molten polymeric material being discharged from extruder106, to prevent, or at least reduce, risk of pressure spikes. The discharged molten polymeric material is pressurized by pump110to facilitate its flow through heating zone108and reactor100. While flowing through reactor100, the reactor-disposed molten polymeric material contacts a catalyst material which causes depolymerization.

Pressure sensor(s)109and/or temperature sensor(s)107can also be employed to measure temperature and/or pressure, respectively, of the reactor-disposed molten polymeric material as it flows through reactor100. Pressure sensor(s)109can monitor for plugs before and/or after each reaction zones. Pressure sensor(s)109can also maintain system pressure below a maximum pressure such as the maximum pressure of reactor700is designed for. Over-pressure can be controlled by feedback from pressure transmitter109to a controller which transmits a command signal to shut down extruder106and pump110, and thereby prevent the pressure from further increasing.

In cases when shutdown of extruder106does not relieve the over pressure, dump valve117can be opened into a container to remove material from system1000and avoid an over pressure situation. During shutdown dump valve117can be opened to purge system1000with nitrogen to remove leftover material to avoid clogs and degraded material during the next start up.

System1000can also include a pressure relief device, such as a relief valve or a rupture disk, disposed at the outlet of extruder106, to relieve pressure from system1000, in case of over-pressure.

Temperature sensor(s)107can facilitate control of the temperature of the reactor-disposed molten polymeric material being flowed through reactor100. This allows more precise control of the chemical reaction and the resulting polymerization. Temperature sensor(s)107also aid in maintaining the temperature below a predetermined maximum temperature, for example the maximum design temperature of reactor100.

The temperature is controlled by a controller (not shown), which modulates the heat being applied by heaters118disposed in heat transfer communication with the reaction zones102(a) through102(e) of reactor100, in response to the temperatures sensed by temperature sensor(s)119.

System1000can also include a pressure relief device, such as a relief valve or a rupture disk, disposed at the outlet of extruder106, to relieve pressure from system10, in case of over-pressure.

Flow control can also be provided for within system1000. In some embodiments, system1000includes valve115, disposed at the discharge of extruder106, for controlling flow from extruder106to other unit operations within system1000. Valve116facilitates recirculation. Valve117enables collection of product.

During operation, valve115can be closed in order to recirculate the molten polymeric material and increase the temperature of the molten polymeric material to a desired temperature. In this case valve116would be open, valve117would be closed, extruder106would be “OFF”, and pump110would be recirculating.

Generated molten product material112is cooled within heat exchanger114, which can be, among other ways, water jacketed, air cooled, and/or cooled by a refrigerant. A fraction of the cooled generated molten product material can be recirculated (in which case valve116would be open), for reprocessing and/or for energy conservation.

In some embodiments, system1000is configured for purging by nitrogen to mitigate oxidation of the molten product.

In System1000reactor700includes one or more reactor modules. Each reactor modules includes a respective module reaction zone in which the reactor-disposed molten polymeric material is brought into contact with a catalyst material over a module-defined residence time, thereby causing depolymerization of the flowing reactor-disposed molten polymeric material. In some of these embodiments, the module-defined residence time of at least two of the reactor modules is the same or substantially the same. In some of these embodiments, as between at least some of the plurality of module-defined residence times are different. In some embodiments, the catalyst material of at least two of the reactor modules is the same or substantially the same. In other embodiments, the catalyst material of at least two of the reactor modules is different.

In some embodiments, each of the reactor modules includes a reactor-disposed molten polymeric material-permeable container that contains the catalyst material. The container is configured to receive molten polymeric material such that at least partial depolymerization of at least a fraction of the received molten polymeric material is effected by the catalyst material, and to discharge a molten product material that includes depolymerization reaction products (and can also include unreacted molten polymeric material and intermediate reaction products, or both). Flowing of the reactor-disposed molten polymeric material through the reactor-disposed molten polymeric material-permeable container effects contacting between the catalyst material and the reactor-disposed molten polymeric material, for effecting the at least partial depolymerization of at least a fraction of the reactor-disposed molten polymeric material. In this respect, the flowing reactor-disposed molten polymeric material permeates through the catalyst material within the container, and while permeating through the catalyst material, contacts the catalyst material contained within the container, for effecting the at least partial depolymerization of at least a fraction of the reactor-disposed molten polymeric material.

In System1000a first reactor is assembled from the reactor modules. The first reactor has a first reaction zone and includes a total number of “P” reactor modules from “N” reactor modules, wherein “N” is a whole number that is greater than or equal to one.

Each one of the “N” reactor modules defines a respective module reaction zone including a catalyst material disposed therein, and is configured for conducting a flow of reactor-disposed molten polymeric material through the respective module reaction zone, such that, flowing of the reactor-disposed molten polymeric material through the respective module reaction zone brings it into contract with the catalyst material, thereby causing at least partial depolymerization of at least a fraction of the flowing reactor-disposed molten polymeric material. In this respect, the first reaction zone includes “P” module reaction zones.

When “N” is a whole number that is greater than or equal to two, each one of the “N” reactor modules is configured for connection, in series, to one or more of the other “N” reactor modules such that a plurality of reactor modules are connected to one another, in series, and includes a plurality of module reaction zones that are disposed in fluid communication within one another, in series, such that the total number of module reaction zones correspond to the total number of connected reactor modules. The plurality of connected reactor modules is configured for conducting a flow of reactor-disposed molten polymeric material through the plurality of module reaction zones, such that it comes into contact with the catalyst material, thereby effecting at least partial depolymerization of at least a fraction of the flowing reactor-disposed molten polymeric material.

When “P” is a whole number that is greater than or equal to two, the assembling of the first reactor includes connecting the “P” reactor modules to one another, in series, such that “P” reaction zones are disposed in fluid communication with one another in series.

In the embodiment illustrated inFIG.2, “P” is equal to five, such that reactor700includes five reactor modules102(a) through102(e), the reaction zone consisting of five module reaction zones104(a) through104(e), each one respective to a one of the five reactor modules. “P” can be more or less than five.

Molten polymeric material, for supplying to the constructed reactor, is generated by heating a polymeric material. In some embodiments, the heating is caused by a heater. InFIG.2the heating is produced by a combination of extruder106and separate heater108. In such embodiments, the generated molten polymeric material is forced from the extruder, flowed through a separate heater, and then supplied to the module reaction zone. In some embodiments, the extruders are configured to supply sufficient heat to the polymeric material such that the generated molten polymeric material is at a sufficiently high temperature for supply to the reactor, and a separate heater is not required.

InFIG.2, pump110receives molten polymeric material from extruder106and effects transport (or flowing) of the molten polymeric material through heater108, and then through the first reaction zone. In some embodiments, extruder106is configured to impart sufficient force to effect the desired flow of the generated molten polymeric material, such that pump110is optional.

In some embodiments, the molten polymeric material is derived from a polymeric material feed that is heated to effected generation of the molten polymeric material. In some embodiments, the polymeric material feed includes primary virgin granules of polyethylene. The virgin granules can include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), polypropylene (PP), or a mixture including combinations of LDPE, LLDPE, HDPE, and PP.

In some embodiments, the polymeric material feed includes waste polymeric material feed. Suitable waste polymeric material feeds include mixed polyethylene waste, mixed polypropylene waste, and a mixture including mixed polyethylene waste and mixed polypropylene waste. The mixed polyethylene waste can include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), polypropylene (PP), or a mixture including combinations of LDPE, LLDPE, HDPE and PP. In some embodiments, the mixed polyethylene waste can include film bags, milk jugs or pouches, totes, pails, caps, agricultural film, and packaging material. In some embodiments, the waste polymeric material feed includes up to 10 weight % of material that is other than polymeric material, based on the total weight of the waste polymeric material feed.

The molten polymeric material is supplied to the reactor, and the molten polymeric material is flowed through the first reaction zone (i.e. including the “P” reaction zones) as reactor-disposed molten polymeric material. The flowing of the reactor-disposed molten polymeric material through the first reaction zone brings it into contact with the catalyst material generating a molten product material, including a depolymerization product material (and, in some embodiments, also includes unreacted molten polymeric material and/or intermediate reaction products). The molten product material is then collected.

In some embodiments, the catalyst is prepared by binding a ferrous-copper complex to an alumina support and reacting it with an inorganic acid to obtain the catalyst material. Other suitable catalyst materials include zeolite, mesoporous silica, alumina and H-mordenite. The system can also be run in the absence of a catalyst and produce waxes through thermal degradation.

The generated molten product material is discharged from and collected/recovered from the reactor. In some embodiments, the collection of the molten product material is effected by discharging a flow of the molten product material from the reactor. In those embodiments, with a plurality of reactor modules, the molten product material is discharged from the first reactor module and supplied to the next reactor module in the series for effecting further depolymerization within the next reactor module in the series, and this continues as-between each adjacent pair of reactor modules in the series.

In some embodiments, the generated depolymerization product material includes waxes, greases, oils, fuels, and C1-C4 gases, and grease-base stocks. Commercially available greases are generally made by mixing grease base stocks with small amounts of specific additives to provide them with desired physical properties. Generally, greases include four types: (a) a mixture of mineral oils and solid lubricants; (b) blends of residuum (residual material that remains after the distillation of petroleum hydrocarbons), uncombined fats, rosin oils, and pitches; (c) soap thickened mineral oils; and (d) synthetic greases, such as poly-alpha olefins and silicones.

In some embodiments, the polymeric feed material is one of, or a combination of, virgin polyethylene (any one of, or combinations of, HDPE, LDPE, LLDPE and medium-density polyethylene (MDPE)), virgin polypropylene, or post-consumer, or post-industrial, polyethylene or polypropylene (exemplary sources including bags, jugs, bottles, pails, and/or other items containing PE or PP), and it is desirable to convert such polymeric feed material into a higher melting point wax (having a melting point from 106° C. to 135° C.), a medium melting point wax (having melting point from 86° C. to 105° C.), and a lower melting point wax (having a melting point from 65° C. to 85° C.), an even lower melting point wax (having a melting point from 40° C. to 65° C.), using an embodiment of the system disclosed herein.

In each case, the conversion is effected by heating the polymeric feed material so as to generate molten polymeric material, and then contacting the molten polymeric material with the catalyst material within a reaction zone disposed at a temperature of between 325° C. and 450° C. The quality of wax (higher, medium, or lower melting point wax) that is generated depends on the residence time of the molten polymeric material within the reaction zone. When operating in a continuous system depending on the flowrate of the extruder or gear pump residence times vary from 1-120 minutes, preferably 5-60 minutes, with 1-12 reactor modules attached in series. In some of these embodiments, the supply and heating of the polymeric feed material is effected by a combination of an extruder and a pump, wherein the material discharged from the extruder is supplied to the pump. In some of these embodiments, extruder106is a 10 HP, 1.5 inch (3.81 cm) Cincinnati Milacron Pedestal Extruder, Model Apex 1.5, and the pump110is sized at 1.5 HP for a 1.5 inch (3.81 cm) line.

A pressure transducer PT01 monitors for plugs within the extruder (as well as prior to PT02, see below) for maintaining system pressure below a maximum pressure (namely, the maximum design pressure of the reactor100). Likewise, pressure transducer PT02 monitors for plugs elsewhere within the system. Over-pressure is controlled by feedback from the pressure transmitted by PT01 and PT02 to a controller which transmits a command signal to shut down the extruder106and the pump110, and thereby prevent the pressure from further increasing.

In some embodiments, reactor100is first reactor100, and the reaction zone of the first reactor is a first reaction zone, and the flowing of the molten polymeric material, through the first reaction zone, is suspended (such as, for example, discontinued).

When “P” is equal to one, the modifying includes connecting a total number of “R” of the “N−1” reactor modules, which have not been used in the assembly of the first reactor, to the first reactor, in which “R” is a whole number from 1 to “N−1”, such that another reactor is added and includes a total number of “R+1” reactor modules that are connected to one another, in series, and such that the another reactor includes a second reaction zone including “R+1” module reaction zones. Then another reactor is configured to conduct a flow of molten polymeric material, such that flowing of the reactor-disposed molten polymeric material through the second reaction zone effects generation of another depolymerization product material and its discharge from the another reactor.

When “P” is a whole number that is greater than or equal to two, but less than or equal to “N−1”, the modifying includes either one of:(a) removing a total number of “Q” of the “P” reactor modules from the first reactor, wherein “Q” is a whole number from one to “P-1”, such that another reactor is added and includes a total number of “P-Q” reactor modules that are connected to one another, in series, and such that the another reactor includes a second reaction zone including “P-Q” module reaction zones, wherein the another reactor is configured to conduct a flow of molten polymeric material, such that flowing of the reactor-disposed molten polymeric material through the second reaction zone effects of generation of another depolymerization product material and its discharge from the another reactor, or(b) connecting a total number of “R” of the “N−P” reactor modules, which have not been employed in the assembly of the first reactor, to the first reactor, wherein “R” is a whole number from 1 to “N−P”, such that another reactor is added and includes a total number of “P+R” reactor modules that are connected to one another, in series, and also includes a second reaction zone including “P+R” module reaction zones, wherein the another reactor is configured to conduct a flow of molten polymeric material, such that flowing of the reactor-disposed molten polymeric material through the second reaction zone effects generation of another depolymerization product material and its discharge from the another reactor;

When “P” is equal to “N”, the modifying includes removing a total number of “Q” of the “P” reactor modules from the first reactor, wherein “Q” is a whole number from one to “P−1”, such that another reactor is added and includes a total number of “P-Q” reactor modules that are connected to one another, in series, and such that the another reactor includes a second reaction zone, including “P-Q” module reaction zones. The another reactor is configured to conduct a flow of molten polymeric material, such that flowing of the reactor-disposed molten polymeric material through the second reaction zone effects generation of another depolymerization product material and its discharge from the another reactor.

In some embodiments, after the modifying of the first reactor to effect creation of another reactor (by either one of connecting/adding or removing reactor modules), another reactor is employed to generate a second depolymerization product material. In this respect, polymeric material is heated to generate a molten polymeric material, and the molten polymeric material is flowed through the second reaction zone, to effect generation of a second depolymerization product material. The second depolymerization product material is then collected from the reactor.

In some embodiments, the same catalyst material is disposed within each one of the “N” reactor modules. [00%] In some embodiments, the reaction zone of each one of the “N” reactor modules is the same or substantially the same.

FIG.3shows a cross-section side-elevation view of catalytic reactor700with removable static mixer710configured to be heated via thermal fluid and/or molten salt. Static mixer710provides greater mixing in catalytic reactor700and can result in the need of a lower operating temperature. In other embodiments, catalytic reactor700can include an annular insert. In other embodiments, catalytic reactor700can have empty internals. In certain embodiments, catalytic reactor700employs electric heating.

The tubular configuration of catalytic reactor700offers several advantages in addition to those already mentioned above. In particular, use of tubular reactors connected in series allows for dependable and consistent parameters, which allows for a consistent product. Specifically, a consistent flow through the tubular sections produces a more predictable and narrow range of end products than would be produced using a continuous stirred reactor, as the surface area of the catalyst and heat input is maximized. One advantage over continuous stirred reactors is elimination of shortcutting, flow in tubular section hypothetically moves as a plug. Each hypothetical plug spends the same amount of time in the reactor. Tubular catalytic reactors can be operated vertically, horizontally, or at any angle in between. Tubular catalytic reactors (the reactor sections) and the corresponding pre-heat sections and cooling sections can be a universal size or one of several standard sizes. This allows not only for a consistent flow of the material, but also allows for tubular elements to be designed to be interchangeable among the various section and easily added, removed, cleaned, and repaired. In at least some embodiments, the inner face of the tubular sections are made of304or316steel.

The thermal fluid and/or molten salt can enter jacket720via inlet/outlets730. In some embodiments, catalytic reactor700ais configured to be mounted with a thermocouple/pressure transducer (not shown) and includes relevant notches735. Notches735are used to bring the thermocouple/pressure transducer in physical contact with the fluid. In some embodiments the thermocouple/pressure transducer will be mounted in a well, which reduces the material in-between the fluid and the sensor.

In some embodiments, catalytic reactor700includes removable screen760that can hold the catalyst. Removable screen760can be easily replaced overcoming disadvantages associated with packed bed reactors, including thermal gradients and challenging maintenance requirements and resulting downtime. In some embodiments, the standardization of removable screen760results in a consistent product leaving each section and/or allows for standardization across multiple reactors.

In other or the same embodiments, catalytic reactor700acan include removable adaptor740with cut-outs for static mixer supports. Static mixer supports reduce the force on static mixers710allowing for more forceful/rapid removal. The cut-outs of adaptor740improve the seal between the adapter and the screens. Catalytic reactor700acan include flanges750on one or both ends to connect catalytic reactor700ato other reactors, extruders or the like.

FIG.4is a cross-section front-elevation view of a group of catalytic reactors700like the one shown inFIG.3arranged in parallel. Parallel arrangements allow for the total rate of production to be more readily increase/decreased as desired with minimal changes to the overall arrangement and allow multiple different levels of depolymerization to occur at once.

Housing800allows catalytic reactors700to be bathed in thermal oil-molten salt which is often more effective than electric. The thermal oil-molten salt is contained in chamber780. In some embodiments, flange770allows for multiple housings to be joined together.

FIG.5is a cross-section side-elevation view of the parallel catalytic reactor arrangement ofFIG.25show in a horizontal configuration. Parallel arrangement allows for higher flowrate units to be built with smaller pressure drops that could cause issues as compared to a single tube arrangement. Horizontal configurations are often more convenient to operate/maintain. The parallel catalytic reactor arrangement can also be oriented in a vertical configuration.

FIG.6is a cross-section side-elevation view of vertical helical internal catalytic reactor arrangement900with two reactors700like the one shown inFIG.3connected in series. Horizontal helical mixer pre-heat section820is connected to one reactor700. Helical mixers can lead to better mixing by avoiding stagnancies and hot spots.

Helical mixer cooling segment830is shown connected to the other reactor700at a 45° decline. The decline allows for the product to flow via gravity, while the 45 degree angle allows for sufficient contact between the cooling medium and the product.

In the embodiments shown, vertical helical internal catalytic reactor arrangement900has several inlet/outlets to allow for the use of thermal fluid/molten salt mixtures however other warming techniques (such as, but not limited to, electric heating) can be employed as well. In other embodiments, annular catalytic reactor and/or reactors with empty internal volumes can be employed. In the same or other embodiments, electric heating can employed to heat reactor700.

FIG.7is a perspective view of horizontal reactor configuration910with internal helical reactor700configured to employ electric heaters870like the one shown inFIG.3. InFIG.7the reactor shell has been removed from part of horizontal reactor configuration910to aid in visualizing the location of internal helical reactor700.

Specific Examples of Plastics Modified by Synthetic Waxes

In an illustrative embodiment of the present process, wax was produced from the depolymerization of post-consumer polyethylene. 3% by weight of the wax (melting point 115° C.) was mixed with an asphalt composition, the softening point increased from 217° C. (with no wax) to 243° C., the penetration decreased from 15 dmm to 11 dmm.

In another embodiment of the present process, 2% of wax, melting point 115° C. is added to polymer modified bitumen. The addition of wax reduces mixing time from 10.5 hours to 8 hours and the viscosity of asphalt mixture is reduced. Softening point of the mixture is increased, penetration is reduced and elastomeric properties are improved. Dimensional stability at 80° C. is improved, with 5 times reduced deflection in the transverse, 3 times reduced deflection in parallel. Force ductility at 25° C. is improved by 100%.

In another embodiment of the present process, 4% of wax, melting point 125° C. is added to polymer modified bitumen. The addition of wax reduces mixing time from 10.5 hours to 7 hours. Softening point of the mixture is increased, penetration is reduced and elastomeric properties are improved. Dimensional stability is improved, with 5 times reduced deflection in the transverse, 5 times reduced deflection in parallel. Force ductility is improved by 100%. Mixing can be achieved by any method common in asphalt processing.

Specific Examples of Plastics Modified by Synthetic Waxes

In an illustrative embodiment of the present process is for the addition of 3% of wax, melting point 115° C., resulting from the depolymerization of post-consumer polyethylene. When mixed with an asphalt composition, the softening point increased from 217° C. (with no wax) to 243° C., the penetration decreased from 15 dmm to 11 dmm.

In another embodiment of the present process, 2% of wax, melting point 115° C. is added to polymer modified bitumen. The addition of wax reduces mixing time from 10.5 hours to 8 hours and the viscosity of asphalt mixture is reduced. Softening point of the mixture is increased, penetration is reduced and elastomeric properties are improved. Dimensional stability at 80° C. is improved, with 5 times reduced deflection in the transverse, 3 times reduced deflection in parallel. Force ductility at 25° C. is improved by 100%.

In another embodiment of the present process, 4% of wax, melting point 125° C. is added to polymer modified bitumen. The addition of wax reduces mixing time from 10.5 hours to 7 hours. Softening point of the mixture is increased, penetration is reduced and elastomeric properties are improved. Dimensional stability is improved, with 5 times reduced deflection in the transverse, 5 times reduced deflection in parallel. Force ductility is improved by 100%.

In the mixing of the present polyethylene waxes, the melting point ranging from 45° C. to 135° C., viscosity ranging from 3 to 4000 centipoise (cP) at 140° C. with asphalt. Mixing can be achieved by any method common in asphalt processing.

Effect of Two Different Waxes on Selected Properties of a Modified Bitumen Compound Used for Commercial Roofing

As set forth in Table 2 below, Control Formulation consisted of 90% by weight of Base Asphalt (PRI Stock: Mid Continent) and 10% by weight of SBS (Kraton D1101).

Wax Blend Formulation 1 consisted of 86% by weight of Base Asphalt (PRI Stock: Mid Continent), 10% by weight of SBS (Kraton D1101) and 4% by weight of Wax 1 (melting point 115° C.; produced by depolymerization of post-consumer polyethylene).

Wax Blend Formulation 2 consisted of 86% by weight of Base Asphalt (PRI Stock: Mid Continent), 10% by weight of SBS (Kraton D1101) and 4% by weight of Wax 2 (melting point 125° C.; produced by depolymerization of post-consumer polyethylene).

TABLE 1Sample DataIngredientGrade/TypeSourceAsphalt150/200 PenetrationPRI Stock:MidSBSSBS LinearKraton D1101LimestoneLimestone FillerTamko(Shingle)WaxWax 1ApplicantWax 2

The preparation of the three blends for testing in this example (unfilled and filled with limestone) was as follows:(1) The asphalt was heated to 180° C.(2) 10% by weight SBS was added to the asphalt while high sheared mixing condition was maintained for 30 minutes, followed by 4% wax addition when applicable, then low shear agitation was established for the remaining of the mixing until full dispersion was achieved.(3) During the maturation phase, aliquot samples were taken for microscopy fluorescence analysis.(4) For the filled samples, 20% by weight of limestone was added while low shear agitation was maintained during 1 h at 180° C.

TABLE 2Summary of Blends and Mix TimesControlWax BlendWax BlendIngredientSourceFormulationFormulation 1Formulation 2Base Asphalt, wt %PRI Stock: Mid908686ContinentSBS, wt %Kraton D1101101010Wax, wt %Wax 1004Wax 2040PropertyResults:MixControlWax BlendWax BlendTime, hrsSpecificationFormulationFormulation 1Formulation 2Fluorescence2Achieve phaseundispersedundispersedundispersedMicroscopy3inversion andundispersedundispersedundispersed4therefore fullundispersedundispersedundispersed5dispersionundispersedundispersedundispersed6undispersedundispersedundispersed7undispersedfully dispersedFully dispersed8undispersed——9undispersed——10undispersed——10.5fully dispersed——

TABLE 3Filled Modified Bitumen PropertiesResults:WaxWaxBlendBlendControlFormu-Formu-Formulationlation 1lation 2CTMB (Fail Temperature), ° C.D5147M−23.9−23.9−23.9Softening Point, ° C.D3693.6105.8102.2Penetration, dmm4° C.D541343525° C.50403946° C.906055Elastic Recovery, %4° C.D608476.256.363.810° C.B90.090.086.2525° C.95.095.090.0Heat StabilityTransverseD5147/+10+1.2+2(dimensionalDirectionD1204stability)*, % ChangeParallel+6.4+1.6+1.2directionForceForce ratio25° C.T 300M0.370.540.52Ductility(f1/f2)Deformation3.25.46.0Energy,(J/cm2)

FIG.8is a table of micrographs showing polymer fluorescence under ultraviolet (UV) light exposure for Control Formulation, Wax Blend Formulation 1, and Wax Blend Formulation 2. For highly modified asphalt, a phase inversion occurs and the asphalt (black areas) becomes the dispersed phase within the polymer phase. The compatibility is deemed satisfactory when a homogenous dispersion of the asphalt within the polymer matrix is achieved.

FIG.9is a set of photographs showing linear dimensional changes of 25 cm by 25 cm samples stored for 24 hrs at 80° C. for Control Formulation, Wax Blend Formulation 1, and Wax Blend Formulation 2, in accordance with ASTM D1204.

FIG.10is a set of photographs of weathering panels for Control Formulation, Wax Blend Formulation 1, and Wax Blend Formulation 2. The panels were monitored for visual changes to include wax exudation as well as dimensional changes and weight loss due to UV and/or thermal degradation of the polymer.

The following conclusions can be drawn from the foregoing test results:The addition of both Wax 1 and Wax 2 reduces the mixing time necessary to achieve the optimum polymer dispersion (phase inversion) compared to the control Modified Bitumen (MB).The addition of Wax Blend Formulations 1 and 2 increases the softening point and viscosity of the MB while reducing the penetration at 25° C. The increase in viscosity and reduction in penetration is typically not desirable and might be mitigated by a wax and SBS content adjustment.The low temperature flexibility assessed by the Cold Temperature Mandrel Bending test was not affected by the addition of Wax Blend Formulations 1 and 2.Both waxes significantly improved the heat stability at 80° C. of the MB compared to the control MB.The elastomeric properties were reduced for Wax Blend Formulations 2 at 4° C., 10° C. and 20° C., but were maintained for Wax Blend Formulation 1 at 10° C. and 20° C. but reduced at 4° C.The energy of deformation at 25° C. was significantly improved by the addition of both Wax Blend Formulations 1 and 2, as compared to the control MB.The addition of both Wax Blend Formulations 1 and 2 reduced the storage stability of the filled MB compound.

Effect of Processing Conditions on the Characteristics and Performances of the Polymer Modified Bitumen (PMB) Formulated with 2% of Wax 2

As set forth in Table 5 below, Control Formulation consisted of 90% by weight of Base Asphalt (PRI Stock: Mid Continent) and 10% by weight of SBS (Kraton D1101).

Wax Blend Formulation 3 (pre-polymer addition) consisted of 98% by weight of Base Asphalt (PRI Stock: Mid Continent), 0% by weight of SBS (Kraton D 1101) and 2% by weight of Wax 2 (melting point 125° C.; produced by depolymerization of post-consumer polyethylene).

Wax Blend Formulation 3 (post-polymer addition) consisted of 88% by weight of Base Asphalt (PRI Stock: Mid Continent), 10% by weight of SBS (Kraton D 1101) and 2% by weight of Wax 2 (melting point 125° C.; produced by depolymerization of post-consumer polyethylene).

TABLE 4Sample DataIngredientGrade/TypeSourceAsphalt150/200 PenetrationPRI Stock: MidContinentSBSSBS LinearKraton D1101LimestoneLimestone FillerTamko (ShingleFiller)WaxWax 1Applicant

The preparation of the Wax Blend Formulation 3 for testing in this example (unfilled and filled with limestone) was as follows:(1) The asphalt was heated to 180° C.(2) 2% of the wax blend formulation was added under agitation for 1 hour.(3) 10% SBS was added to the asphalt while high sheared mixing condition was maintained for 30 minutes, then low shear agitation was established for the remaining of the mixing.(4) During the maturation phase, aliquot samples were taken for microscopy fluorescence analysis.(5) For the filled samples, 20% of limestone was added while low shear agitation was maintained during 1 h at 180° C.(6) For Wax Blend Formulation 4, the wax was added 30 minutes after the polymer addition, in a manner similar the preparation of Wax Blend Formulations 1 and 2 previously discussed.

TABLE 5Summary of Blends and Mix TimesWax BlendWax BlendFormulation 3Formulation 3Neat(pre-polymer(post-polymerControlIngredientSourceBitumenaddition)addition)FormulationBase Asphalt, wt %Phillips 66100988890SBS, wt %Kraton D1101001010Wax, wt %Applicant0220Results:PropertyWax BlendWax BlendMixFormulation 3Formulation 3Time,Neat(pre-polymer(post-polymerControlhrsSpecificationBitumenaddition)addition)FormulationFluorescence2Achieve phase—undispersedundispersedundispersedMicroscopy3inversion—undispersedundispersedundispersed4and—undispersedundispersedundispersed5therefore full—undispersedundispersedundispersed6dispersion—undispersedundispersedundispersed7—undispersedundispersedundispersed8—fully dispersedfully dispersedundispersed9—fully dispersedfully dispersedundispersed10.5—fully dispersedfully dispersedfullydispersed

TABLE 6Polymer Modified Bitumen PropertiesResults:WaxWaxBlendBlendFormu-Formu-lation 3lation 3Wax(pre-(post-BlendControlTestpolymerpolymerFormu-Formu-PropertyMethodaddition)addition)lation 2lation 1CTMB (Failure Temperature), ° C.D5147M−10.0−21.1−23.9−23.9Softening Point, ° C.D36104.2101.4105.893.6Penetration, dmm4° C.D53441344125° C.4353405046° C.991346090Elastic Recovery, %4° C.D608485.877.556.376.210° C.B87.583.390.09025° C.97.596.895.095HeatTransverse80° C.D5147/+0.4+2.0+1.2+10StabilityDirectionD1204(dimensionalParallel+0.8+2.0+1.6+6.4stability), %directionChangeForceForce ratio25° C.T 300M0.290.180.540.37Ductility(f1/f2)Deformation4.513.145.43.2Energy,(J/cm2)

FIG.11is a table of micrographs showing polymer fluorescence under ultraviolet (UV) light exposure for Control Formulation, Wax Blend Formulation 3 (pre-polymer addition), and Wax Blend Formulation 3 (post-polymer addition. For highly modified asphalt, a phase inversion occurs and the asphalt (black areas) becomes the dispersed phase within the polymer phase. The compatibility is deemed satisfactory when a homogenous dispersion of the asphalt within the polymer matrix is achieved.

FIG.12is a set of photographs showing linear dimensional changes of 25 cm by 25 cm samples stored for 24 hrs at 80° C. for Control Formulation, Wax Blend Formulation 3 (pre-polymer addition), and Wax Blend Formulation 3, in accordance with ASTM D1204. The polymer added to Wax Blend Formulation 3 was poly(styrene-butadiene-styrene) (SBS).

FIG.13is a pair of photographs showing linear dimensional changes of 25 cm by 25 cm samples stored for 24 hrs at 80° C. for Wax Blend Formulation 3 (pre-polymer addition) and Wax Blend Formulation 3 (post-polymer addition). The polymer added to Wax Blend Formulation 3 was SBS.

FIG.16is a set of photographs of weathering panels for Control Formulation, Wax Blend Formulation 3 (pre-polymer addition) and Wax Blend Formulation 3 (post-polymer addition). The panels were monitored for visual changes to include wax exudation as well as dimensional changes and weight loss due to UV and/or thermal degradation of the polymer.

FIG.15is a pair of photographs showing the results of a Stain Index test (ASTM D2746) for Wax Blend Formulation 3 (pre-polymer addition) and Wax Blend Formulation 3 (post-polymer addition). The Stain Index test measures the tendency for oil components to separate spontaneously from asphalt. The separation of oil components can cause staining in asphalt roofing products and adjacent materials in storage and use. The results show no staining in comparison to the control, which is expected due to the wax improving thermal stability of the asphalt.

The following conclusions can be drawn from the foregoing test results:(1) The addition of Wax 2 in Wax Blend Formulation 3:(a) reduced the mixing time necessary to achieve the optimum polymer dispersion (phase inversion) compared to Control Formulation Modified Bitumen (MB) previously tested.(b) reduced slightly the viscosity of the neat bitumen.(2) The order of addition of the wax had a significant impact on the product characteristics and performances:(a) The pre-polymer addition process was detrimental to all properties except for the softening point, the elastomeric and cohesion properties and the dimensional stability.(b) The post-polymer addition process improved a series of properties over the control blend:(i) Viscosity reduction(ii) Higher softening point(iii) Improved dimensional stability.(3) No noticeable stain formation was detected for both of Wax Blend Formulation 3 (pre-polymer addition) and Wax Blend Formulation 3 (post-polymer addition).

While particular elements, embodiments and applications of the present invention have been shown and described, it will be understood, that the invention is not limited thereto since modifications can be made without departing from the scope of the present disclosure, particularly in light of the foregoing teachings.