BACKGROUND

[0001] Polyolefins such as polyethylene (PE) and polypropylene (PP) may be used to manufacture a varied range of articles including films, molded products, foams, and the like. Polyolefins may have characteristics such as high processability, low production cost, flexibility, low density, and recyclability. While plastics such as polyethylene and polypropylene have many beneficial uses, there is a need for their correct disposal after use, or even their reuse or recycling, to minimize the environmental impact of plastic wastes.

[0002] Mechanical recycling techniques are being widely used due to their simplicity and relative low cost. Those techniques preserve the molecular structure of polymers. They usually comprise process steps such as sorting, shredding, washing, melting, etc. Although simple, mechanical recycling techniques present some limitations. The separation of different types of polymers and contaminants is a great challenge, especially when dealing with poor quality waste sources.

[0003] On the other hand, advanced recycling techniques are being considered as a promising alternative. The goal of those techniques is converting plastic waste into oil and building blocks (e.g. monomers) that would be ultimately fed back into the plastic production.

[0004] Some examples of advanced recycling are thermal degradation-based techniques such as thermal and catalytic depolymerization, hydrogenation, hydrocraking, oxycracking, gasification, and hydrothermal liquefaction, among others.

[0005] Advanced recycling processes are advantageous since they enable the production of high-quality products, however, there is still a need for processes with better efficiency and lower energy consumption. SUMMARY

[0006] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0007] In one aspect, embodiments disclosed herein are related to a method for producing an oil comprising

- feeding an olefin-based resin into a reactor,

- converting the olefin-based resin into an oil by thermal degradation reaction, and

- recovering the produced oil, wherein the olefin-based resin is a low molecular weight (LMW) olefin-based resin.

[0008] In another aspect, embodiments disclosed herein are related to the oil produced according to said method.

BRIEF DESCRIPTION OF DRAWINGS

[0009] FIG. 1 shows the molecular weight distribution of samples Wax LP and HDPE 1.

[0010] FIG. 2 shows the % of oil from HTL experiment of samples Wax LP and HDPE 1 at 450°C and Ih.

[0011] FIG. 3 shows shear rate analysis at 140 °C of samples HDPE1 and Wax LP.

[0012] FIG. 4 shows thermogravimetric analysis of samples HDPE1 and Wax LP.

[0013] FIG. 5 shows thermogravimetric analysis of samples PCR 1 and Wax 8.

[0014] FIG. 6 shows the molecular weight distribution of samples PCR 1 and Wax 8.

[0015] FIG. 7 shows shear rate analysis at 140 °C of samples PCR 1 and Wax 8.

[0016] FIG. 8 shows the % of oil of HTL experiment of samples PCR 1 and Wax 8 at

450 °C and Ih, 1.5h, and 2h.

[0017] FIG. 9 shows the % of oil of HTL experiment of samples Wax 1 and PCR 4. [0018] FIG. 10 shows thermogravimetric analysis of samples Wax 1 and PCR 4.

[0019] FIG. 11 shows the molecular weight distribution of samples Wax 1 and PCR 4.

[0020] FIG. 12 shows shear rate analysis at 140 °C of samples Wax 1 and PCR 4.

[0021] FIG. 13 shows the % of oil of HTL experiment of samples Wax 3 and PCR 3.

[0022] FIG. 14 shows thermogravimetric analysis of samples Wax 3 and PCR 3.

[0023] FIG. 15 shows the molecular weight distribution of samples Wax 3 and PCR 3.

[0024] FIG. 16 shows shear rate analysis at 140 °C of samples Wax 3 and PCR 3.

[0025] FIG. 17 shows a schematic representation of the extruder working at 250 °C and feeding a chemical reactor.

[0026] FIG. 18 shows a schematic representation of the extruder working at 450 °C and feeding a chemical reactor.

[0027] FIG. 19 shows the energetic demand for samples of different molecular weight.

DETAILED DESCRIPTION

[0028] Embodiments disclosed herein generally relate to a method of producing an oil by feeding a low molecular weight (LMW) olefin-based resin into a reactor, converting the LMW olefin-based resin into an oil, and recovering said oil. According to the present disclosure, it was surprisingly found that feeding a thermal degradation reactor with low molecular weight olefin-based resins increases the process efficiency and reduces the energy consumption.

[0029] In one or more embodiments, the method for producing an oil comprises the following steps:

- feeding an olefin-based resin into a reactor,

- converting the olefin-based resin into an oil by thermal degradation reaction, and

- recovering the produced oil, wherein the olefin-based resin is a low molecular weight (LMW) olefin-based resin. [0030] The “thermal degradation reaction” refers to a reaction wherein polymer chains are broken down by heat and optionally in the presence of chemical components capable of breaking down the polymer chains (e.g. catalysts).

[0031] In some embodiments, LMW olefin-based resin has a molecular weight of less than 50,000 g/mol, preferably 40,000 g/mol, measured by high temperature gel permeation chromatography (GPC) according to ISO 16014-4.

[0032] The feeding step may occur by means of an extruder, preferably a twin-screw extruder.

[0033] In some embodiments, the LMW olefin-based resin is fed into the reactor in a molten state. Therefore, the LMW olefin-based resin may be fed above its melting temperature. In a preferred embodiment, the LMW olefin-based resin is maintained and fed at a temperature close to the reactor temperature, preferably equal to or greater than 300°C, preferably greater than 400 °C, more preferably greater than 450°C. In some embodiments, the LMW olefin-based resin is molten and fed (e.g. by using an extruder) in an environment substantially free of oxygen.

[0034] In some embodiments, the reactor is selected from a batch reactor, semi-batch reactor, continuous stirred tank reactor (CSTR), fluidized bed reactor, conical spouted bed reactor (CSBR), fixed bed reactor, or fluid catalytic cracking unit.

[0035] In one or more embodiments, the thermal degradation reaction is selected from two-stage thermal degradation systems, microwave-assisted thermal degradation, thermal degradation in supercritical water (SCW), hydrothermal liquefaction, fluid catalytic cracking, hydrogenation, hydrocraking, oxycracking, or gasification.

[0036] In one or more embodiments, the conversion step occurs at a temperature ranging from 400 to 800°C, and a residence time from 15 min to 2 h, and in an environment substantially free of oxygen. In one or more embodiments, the converting step occurs in the presence of a catalyst.

[0037] In one or more embodiments, the method further comprises a cracking step (that may be also referred as pre-treatment step, pre-process step or pre-cracking step) wherein a higher molecular (HMW) olefin-based resin is cracked to produce the LMW olefin-based resin that is fed into the reactor. [0038] In one or more embodiments, the cracking step may occur before or during the feeding step.

[0039] In one or more embodiments, the cracking step occurs by means of an extruder.

[0040] In one or more embodiments, the cracking step occurs in an extruder that is directly connected to the reactor. Therefore, in such embodiments, the LMW olefin- based resin is directly fed into the reactor.

[0041] In one or more embodiments, the extruder used in the cracking step is a twin- screw extruder.

[0042] In one or more embodiments, the molecular weight of the HMW olefin-based resin is reduced by at least 4 times (i.e. “4x”) in the cracking step.

[0043] In one or more embodiments, the cracking step may be performed above the onset degradation temperature, optionally in the presence of a visbreaking agent. The “onset degradation temperature” is the temperature wherein the polymer chains of the resin start to breakdown. This “onset degradation temperature” may be determined by thermogravimetric analysis (TGA), following ASTM El 131 standard method.

[0044] In one or more embodiments, the cracking step is performed at a temperature above the melting temperature and below the onset degradation temperature of the HMW olefin-based resin and in the presence of a visbreaking agent.

[0045] When present, the visbreaking agents may be free radical generators selected from peroxides, nitroxides, and combinations thereof. The peroxides may be selected from 3 -hydroxy- 1,1 -dimethylbutyl peroxyneodecanoate, a-cumyl peroxyneodecanoate, 2-hydroxy- 1,1 -dimethylbutyl peroxyneoheptanoate a-cumyl peroxyneoheptanoate, t-amyl peroxyneodecanoate, t-butyl peroxyneodecanoate, di(2- ethylhexyl) peroxydicarbonate, di(n-propyl) peroxydicarbonate, di(sec -butyl) peroxydicarbonate, t-butyl peroxyneoheptanoate, t-amyl peroxypivalate, t-butyl peroxypivalate, diisononanoyl peroxide, didodecanoyl peroxide, 3 -hydroxy- 1,1- dimethylbutylperoxy-2-ethylhexanoate, didecanoyl peroxide, 2,2'- azobis(isobutyronitrile), di(3 -carboxypropionyl) peroxide, 2,5-dimethyl-2,5-di(2- ethylhexanoylperoxy)hexane, dibenzoyl peroxide, t-amylperoxy 2-ethylhexanoate, t- butylperoxy 2-ethylhexanoate, t-butyl peroxyisobutyrate, t-butyl peroxy-(cis-3- carboxy)propenoate, 1 , 1 -di(t-amylperoxy)cyclohexane, 1 , 1 -di(t-butylperoxy)-3 ,3 ,5- trimethylcyclohexane, l,l-di(t-butylperoxy) cyclohexane, OO-t-amyl O-(2- ethylhexyl) monoperoxycarbonate, OO-t-butyl O-isopropyl monoperoxycarbonate, OO-t-butyl O-(2-ethylhexyl) monoperoxycarbonate, polyether tetrakis(t- butylperoxycarbonate), 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-amyl peroxyacetate, t-amyl peroxybenzoate, t-butyl peroxyisononanoate, t-butyl peroxyacetate, t-butyl peroxybenzoate, di-t-butyl diperoxyphthalate, 2,2-di(t- butylperoxy)butane, 2,2-di(t-amylperoxy)propane, n-butyl 4,4-di(t- butylperoxy)valerate, ethyl 3,3-di(t-amylperoxy)butyrate, ethyl 3,3-di(t- butylperoxy)butyrate, dicumyl peroxide, a,a'-bis(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy) hexane, di(t-amyl) peroxide, t-butyl a-cumyl peroxide, di(t-butyl) peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)-3-hexyne, dicetil peroxi-dicarbonato, 3,6,9-triethyl-3,6,9-trimethyl-l,4,7-triperoxonane, tertbutylperoxy 2-ethylhexyl carbonate, tert-butyl-peroxide n-butyl fumarate(benzoate), dimyristoyl peroxydiicarbonate, 3,3,5,7,7-pentamethyl-l,2,4-trioxepane, tert-butyl hydroperoxide, bis(4-t-butylcyclohexyl) peroxydicarbonate, and 1, 2, 4, 5,7,8- hexoxonane, 3,6,9-trimethyl-3,6,9-tris(ethyl and propyl derivatives). The nitroxides may be selected from nitroxide compound, such as 2,2,5,5-tetramethyl-l- pyrrolidinyloxy, 3-carboxy-2,2,5,5-tetramethyl-pyrrolidinyloxy, 2,2,6,6-tetramethyl- 1-piperidinyloxy, 4-hydroxy-2,2,6,6-tetramethyl-l-piperidinyloxy, 4-methoxy- 2,2,6,6-tetramethyl-l-piperidinyloxy, 4-oxo-2,2,6,6-tetramethyl-l-piperidinyloxy, bis-(l-oxyl-2,2,6,6-tetramethylpiperidine-4-yl)sebacate, 2,2,6,6-tetramethyl-4- hydroxypiperidine-l-oxyl)monophosphonate, N-tert-butyl-l-diethylphosphono-2,2- dimethyl propyl nitroxide, N-tert-butyl-l-dibenzylphosphono-2,2-dimethylpropyl nitroxide, N-tert-butyl-l-di(2,2,2-trifluoroethyl)phosphono-2,2dimethyl propyl nitroxide, N-tert-butyl-(l-diethylphosphono)-2-methyl-propyl nitroxide, N-(l- methylethyl)- 1 -cyclohexyl- 1 -(diethylphosphono) nitroxide, N-( 1 -phenylbenzyl)-( 1 - diethylphosphono)-l -methyl ethylnitroxide, N-phenyl-l-diethylphosphono-2,2- dimethyl propyl nitroxide, N-phenyl-l-diethylphosphono-l-methyl ethyl nitroxide, N-(l-phenyl 2-methyl propyl)- 1 -diethylphosphono- 1 -methyl ethyl nitroxide, N-tert- butyl-l-phenyl-2-methyl propyl nitroxide, and N-tert-butyl-l-(2-naphthyl)-2-methyl propyl nitroxide, or a mixture thereof.

[0046] In one or more embodiments, a pro-degradant is further added in the cracking step. The pro-degradant may be selected from pro-degradant stearates, which may be selected from the group consisting of zinc stearate, tin stearate, iron (II) stearate, iron (III) stearate, cobalt stearate, manganese stearate, and any combinations thereof.

[0047] In one or more embodiments, the cracking step may be performed for a residence time of less than 2 min, preferably less than 90 s, most preferably less than 70 s.

[0048] In one or more embodiments, the cracking step may be performed as disclosed in patent applications US20220153976A1 and US20220153883A1, which are herein incorporated by reference in their entirety.

[0049] In one or more embodiments, the HMW olefin-based resin has an initial molecular weight Mw of 50,000 g/mol up to 1,000,000 g/mol, preferably 50,000 g/mol up to 500,000 g/mol measured according to ISO 16014-4.

[0050] The method according to embodiments disclosed herein is particularly useful in the recycling field. Therefore, in a preferred embodiment the olefin-based resins (LMW and/or HMW) are selected from recycled resins (also known as “plastic waste”). Preferably, the olefin-based resins are selected from post-consumer resins, post-industrial resins, resin scraps, and combinations thereof. The olefin-based resins may also be produced from petrochemical sources, biobased sources, or combinations thereof.

[0051] In one or more embodiments, olefin-based resins are selected from resins comprising more than 50% of olefin monomers, preferably selected from ethylene, olefins comprising from 3 to 10 carbon atoms, and combinations thereof.

[0052] In one or more embodiments, the method comprises a further step of purifying the oil recovered from the reactor.

[0053] In one or more embodiments, the method comprises the following steps:

- feeding a HMW olefin-based resin into an extruder,

- cracking the HMW olefin-based resin to produce a LMW olefin-based resin,

- feeding the LMW olefin-based resin into a reactor,

- converting the LMW olefin-based resin into an oil by thermal degradation reaction, and - recovering the produced oil, wherein the HMW olefin-based resin is preferably plastic waste.

[0054] It has been found that by performing thermal degradation using a LMW olefin- based resin as feedstock, the condensables (also referred as liquid) yield of the thermal degradation reaction is increased. It was observed that in the presently disclosed method, the condensables yield in the converting step is at least 10% higher in comparison to the condensables yield when feeding HMW into the thermal degradation reactor.

[0055] The oil obtained according to the present disclosure may be further used in polymerization processes to produce new resins.

Experimental data

Measurement methods description

GPC

[0056] The molecular weight of samples was measured according to ISO 16014-4 using a high-temperature GPC experiments carried out in a gel permeation chromatograph coupled with an infrared detector IR6 from Polymer Char. A set of 4 columns (mixed bed, 13 pm, from Tosoh) at a temperature of 140°C is used. The conditions of the experiments are concentration of 1 mg/mL, flow rate of 1 mL/min, dissolution temperature and time of 160°C and 30 min, respectively, and an injection volume of 200 pL. The solvent used is ODCB (1,2-dichlorobenzene) stabilized with 100 ppm of BHT (butylated hydroxy toluene). Prior to the analyses, samples were dissolved for 60 min and filtered in an external filtration system (EFS, Polymer Char).

TGA

[0057] The thermogravimetric analysis of samples was measured according to the ASTM El 131, Compositional Analysis by Thermogravimetry.

[0058] The analysis was performed using a TA Instruments Model Q500 with a temperature ramp rate of 20 °C/min from room temperature to 800 °C in a nitrogen atmosphere. 10 mg of sample were used for each analysis. Rheometry

[0059] Rheological measurements were performed in flow regime at 140°C, using 25 mm cone and plate geometry, with a shear rate varying from 0.1 up to 1000 s’ ¹ . A soaking time of 60s was used.

Density

[0060] All density data was obtained following ASTM D792.

Melt flow index (MFI)

[0061] All MFI data was obtained according to ASTM D1238. For PE samples, conditions used were 190°C and 2.16kg.

Description of the HTL methodology

[0062] A fixed amount of 1 g of sample (polymer or wax) with a specific amount of D.I. water (such that it reaches the supercritical point) were added to a HTL reactor. To determine the amount of water, the supercritical density was obtained by consulting https://webbook.nist.gov/chemistry/fluid/; the amount is based on targeted temperature and tubular reactor volume. The HTL reactor was then purged three times with nitrogen gas (100 psi) to eliminate the residual air.

[0063] The HTL reactor system comprised a tubular batch reactor (33-36 ml) coupled with stainless-steel tube, reactor valve, and pressure gauge system, while for temperature control a tubular furnace (Lindberg Blue M Tube Furnace, Thermo Scientific, Waltham, MA) was used. After the HTL reaction, run for the specified time and temperature, the gas pressure generated was recorded using the pressure gauge.

Examples

[0064] To demonstrate the benefits of a pre-process that decreases the molecular weight of polymer materials before the entrance into the chemical recycling reactor, a Hydrothermal liquefaction (HTL) process, which uses super-critical water as reaction media, was used. It has been proved to be a robust and energy-efficient method for valorizing plastic waste. However, HTL of PE still requires high temperatures (450- 475°C). To improve the energy efficiency of HTL, mechanical preprocessing was used to decrease the molecular weight of the PE feedstock. Samples with lower molecular weight present a higher oil yield. [0065] The different HTL products are described as liquid (or condensable or oil), gas (or volatile), and solid residue. The best result is to obtain a higher concentration of liquid, and consequently, less solid residue in the reactor.

[0066] The HTL reactor was filled with 1/6 of its volume with water (condition needed to reach the pressure appropriated for super critical condition at the work temperature) and around 1g of sample. Then the temperature is raised to 450°C. The tests were conducted at 450°C for 1, 1.5h, and 2h.

[0067] Virgin material

[0068] To show that a lower molecular weight can give better condensable (oil) yield results, two samples of virgin material with different molecular weight, as Figure 1 shows, and same composition (HDPE) were tested in the system previously described. The oil yield, shown in Figure 2, increased 3.7 times when the MW decreased 60 times. Table 1 lists the Mw values and oil yield for each sample.

[0069] Sample HDPE 1 is a commercial resin from Braskem, having MFI 0.35 g/lOmin and density 0.954. Wax LP is an ethylene-based wax.

Table 1. Oil yield and Mw of HDPE samples (LMW and HMW)

[0070] The Mw influence on the viscosity can be seen in Figure 3, where the viscosity value for sample Wax LP is almost 5 orders of magnitude lower than the HDPE.

[0071] TGA analysis is usually used to correlate pyrolysis results because it can simulate, on a small scale, a proof of concept for the thermal behavior of polymers.

[0072] TGA analysis comparing the samples of this example indicates the influence of molar mass on thermal behavior, as shown in Figure 4. It is shown that the T onset (temperature of the beginning of degradation) is lower for samples with LMW and higher for samples of HMW. PCR Example 1

[0073] Sample Wax 8 (LMW) was prepared through the extrusion of sample PCR1 (HMW) under the conditions described in the present disclosure (extrusion process at 450°C, residence time around 60 seconds) in the presence of a peroxide. Sample PCR1 is a Braskem PCR sample, with MFI ranging from 0.10 up to 0.90 g/lOmin and density ranging from 0.910 up to 0.915g/cm ³ , its main component is LLDPE.

[0074] TGA analysis comparing the samples of this example (Figure 5) shows the influence of molar mass on thermal behavior. It is shown that the T onset (temperature of the beginning of degradation) is lower for samples with LMW and higher for samples of HMW.

[0075] GPC analysis shows that the molecular weight distribution (MWD) and Mw values (Figure 6) are affected by the pre-cracking process. Sample Wax 8 presents a Mw more than 15 times lower than the initial HMW sample PCR 1, as is shown in Table 2. In addition to the Mw difference, an important difference in the MWD is observed.

[0076] The difference in Mw can be clearly seen in the viscosity profiles, measured at 140°C, shown in Figure 7, where it can be seen that sample Wax 8 has a viscosity of about 2 orders of magnitude lower than the PCR1.

Table 2. Molecular weight values for samples LMW and HMW

[0077] The oil yields obtained when the samples were cracked in an HTL reactor in three different conditions are listed in Figure 8 and the sample Wax 8 has an oil yield of around 67% with Ih of reaction, while sample PCR 1 needs 1.5h to achieve the same yield. Similarly, sample Wax 8 get a yield of around 90% of oil with Ih of reaction at 450°C, while sample PCR 1 needs 2h to get the same yield. This means that the pre-cracking of samples before the advanced recycling process can give an improvement of productivity and energy savings for HTL process. PCR Example 2

[0078] Sample Wax 1 was prepared using the procedure described in the present disclosure. The sample of PCR LLDPE (PCR 4) was processed in an extruder at 450°C, with a residence time of around 50 s, and in this case an amount of 400 ppm of iron II stearate as additive was added. Sample PCR 4 is a Braskem PCR sample, with MFI ranging from 0.10 up to 0.90 g/lOmin and density ranging from 0.910 up to 0.915g/cm ³ , its main component is LLDPE. Both samples PCR 4 and Wax 1 were submitted to a HTL process at 450°C for Ih and the oil yield can be seen in Table 3. The oil yield of sample pre-cracked Wax 1 is around 15% higher than the original sample PCR 4 (Figure 9).

Table 3. Oil yield and Mw of LLDPE PCR samples (LMW and HMW)

[0079] TGA analysis comparing the samples of this example (Figure 10) shows the influence of molar mass on thermal behavior. It is shown that the T onset (temperature of the beginning of degradation) is lower for samples with LMW and higher for samples of HMW.

[0080] GPC analysis shows that the molecular weight distribution and Mw values (Figure 11) are very affected by the pre-cracking process. Sample Wax 1 presents a Mw more than 8 times lower than the initial HMW sample PCR 4, as is shown in Table 2. In addition to the Mw difference, an important difference in the MWD is observed.

[0081] The difference in Mw can be clearly seen in the viscosity profiles, measured at 140°C, shown in Figure 12, where it can be seen that sample Wax 1 has a viscosity of about 3 orders of magnitude lower than the PCR 4.

PCR Example 3

[0082] Sample Wax 3 was prepared using the procedure described in the present disclosure, wherein the sample of PCR HDPE (PCR 3) was processed in an extruder at 450°C, with a residence time of 50 s. HDPE PCR 3 is high density polyethylene obtained from a post-consumer material with MFI ranging from 0.10 up to 0.25 g/lOmin and density ranging from 0.945 up to 0.970 g/cm ³ . Both samples PCR 3 and Wax 3 were submitted to a HTL process at 450°C for Ih and the oil yield can be seen in Table 4. The oil yield of sample pre-cracked Wax 3 is around 70% higher than the original sample PCR 3, that have a MW around 20 times higher than the Wax 3 (Figure 13).

Table 4. Oil yield and Mw of HDPE PCR samples (LMW and HMW)

[0083] TGA analysis comparing the samples of this example (Figure 14) shows the influence of molar mass on thermal behavior. It is shown that the T onset (temperature of the beginning of degradation) is lower for samples with LMW and higher for samples of HMW.

[0084] GPC analysis shows that the molecular weight distribution and Mw values (Figure 15) are affected by the pre-cracking process. Sample Wax 3 presents a Mw almost 20 times lower than the initial HMW sample PCR 3, as is shown in Table 2. In addition to the Mw difference, an important difference in the MWD is observed.

[0085] The difference in Mw can be clearly seen in the viscosity profiles, measured at 140°C, shown in Figure 16, where it can be seen that sample Wax 3 has a viscosity of about 3 orders of magnitude lower than the PCR 3.

Energetic Benefit Example

Extruder Energy

[0086] In order to quantify the energy spent to melt and crack the polymer in the extruder, the equations used are described in Table 3 and Equation 1. This calculation method is according to the following literature references: 2010 - Rauwendaal, C. - How to Get Peak Performance & Efficiency Out of Your Extrusion Line, Part I, 2014 - Abeykoon et al - Process efficiency in polymer extrusion: Correlation between the energy demand and melt thermal stability, 2014 - Abeykoon et al - Investigation of the process energy demand in polymer extrusion: A brief review and an experimental study, 2021 - Abeykoon et al - Energy efficiency in extrusion-related polymer processing: A review of state of the art and potential efficiency improvements.

Table 3. Equations for calculation of different kinds of heat during extrusion processes equation 1

Chemical Recycling Reactor Energy

[0087] In order to quantify the energy spent to melt and crack the polymer in the thermal degradation reactor, the equations used are described in Table 4 and Equation 2. This calculation method is according to the following literature reference: Szostak, Elzbieta, et al. "Characteristics of plastic waste processing in the modern recycling plant operating in Poland." Energies 14.1 (2021): 35.

Table 4. Equations for calculation of different kinds of heat during thermal degradation in the chemical recycling reactor Heat loss through insulation (Qi) -10%

Heat loss due to gas carrier (Qfg) -40%

Chemical Recycling Reactor

[0088] In this scenario, the chemical recycling reactor is fed with the polymer at room temperature (around 25 °C). The starting polymer has a molecular weight of around 200,000 g/mol. In the chemical recycling reactor, the polymer is heated from 25°C up to 500°C. In the reactor the polymer is cracked until C25 - C35.

Table 5. Energy spent to heat samples, considering two different MW.

Extruder operating at 250°C + Chemical Recycling Reactor

[0089] In this scenario, as represented in Figure 17, the chemical recycling reactor is fed by an extruder operating at 250°C. The polymer is heated from room temperature (around 25°C) up to 250°C. The starting polymer has a molecular weight of around 200,000 g/mol. The molecular weight does not change in the extruder. In the chemical recycling reactor, the polymer is heated from 250°C up to 500°C. In the reactor the polymer is cracked until C25 - C35, or less.

Extruder operating at 450°C + Chemical Recycling Reactor

[0090] According to the present disclosure, the chemical recycling reactor is fed by an extruder operating at 450°C. The polymer is heated from room temperature (around 25°C) up to 450°C, in less than 2 minutes (Figure 18). The starting polymer has a molecular weight of around 200,000 g/mol and breaks during the extrusion, in a cracking reaction, ending the extrusion process and entering the chemical recycling reactor with a molecular weight of around 10,000 g/mol. In the reactor, the polymer is cracked until C25 - C35, or less.

Table 6. Energy spent to heat and crack samples in the extruder and reactor, considering two different MW.

[0091] Considering the performance of the high amount of condensables as demonstrated in the previous example, the chemical recycling reactor can operate at 450°C, consuming even less energy.

Table 7. Energy spent to heat and crack samples in the extruder and reactor, considering two different MW

[0092] Considering the calculations discussed above, it is possible to save around 30% of energy when an extruder operating at 450°C is feeding inline the thermal degradation reactor and the entering material (LMW) is cracked during the extrusion, reaching a low viscosity characteristic that improves the heating transfer.

Energetic benefit example 2

[0093] A potentiometer was used to measure the energy needed to heat samples of different molecular weight from 200°C up to 450°C. The results are listed in Figure 19 and it is observed that the energy required to heat samples of LMW is at least 40% lower than the HMW.