Plastic Pyrolysis Research Articles

Study on kinetics of spent FCC catalyst applied to the living waste plastics

AbstractThe thermochemical method is one of the most potential ways to treat waste plastics. In order to reduce the energy consumption of pyrolysis, this study selected spent fluid catalytic cracking (FCC) catalyst as a catalyst for pyrolysis of waste plastics to explore the pyrolysis process of mixed waste plastics (polypropylene (PP)/polyethylene (PE)/polystyrene (PS)). The kinetic calculations show that there was a positive synergistic effect in the co‐pyrolysis of mixed plastics, which was beneficial to the reduction of activation energy. However, the participation of spent FCC catalysts can further reduce the pyrolysis temperature and activation energy of plastics, and increase the thermal degradation rate. Compared with non‐catalytic pyrolysis, the pyrolysis temperature corresponding to the maximum weight loss rate during catalytic pyrolysis was about 12 K earlier, the maximum degradation rate was about 41% higher, and the average activation energy decreased by about 22 kJ/mol. In order to further improve the catalytic efficiency of spent FCC catalysts, the spent FCC catalysts were modified by ball milling or ultrasonic method and then used for plastic pyrolysis. It was found that the modification effect of ball milling method was better than that of the ultrasonic method. Through thermodynamic analysis, it was found that the endothermic reaction occurred in the process of plastic pyrolysis and could not proceed spontaneously. The formed pyrolysis products reduced the disorder of a microscopic system. Combined with the experimental results of this paper, it can provide theoretical support for the catalytic pyrolysis of spent FCC catalysts for mixed waste plastics.

Feasibility Study of Plastic Waste Pyrolysis from Municipal Solid Waste Landfill with Spent FCC Catalyst

Globally, there is growing concern about the problem of plastic waste. The majority of plastic waste is dumped into landfills, where it occupies space, reducing landfill capacity and causing a variety of environmental issues. Plastic waste pyrolysis has gained popularity because it can reduce the volume of plastic waste while also producing alternative fuels. This study assessed the feasibility of producing fuel oil from plastic waste using the catalytic pyrolysis process. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) waste samples were collected from municipal solid waste (MSW) landfills on Samui Island, Surat Thani Province, Thailand. Pyrolysis was carried out in a 3-L bench-scale reactor at 450ºC using a 3% spent FCC catalyst. PE, PP, PS, and mixed plastic waste were used as feedstocks. The results showed that the pyrolysis of PS produced the most liquid product (91.44 wt%), whereas the pyrolysis of PE produced the highest percentage of diesel range product (36.60 wt%). Furthermore, the results of the analysis revealed that the characteristics of diesel from improved PE pyrolysis oil by naphtha removal were similar to those of commercial diesel B7. According to the cost-benefit analysis, the operating costs of pyrolysis oil and improved diesel were 0.37 and 0.65 USD/L, respectively, which were lower than the current market price of diesel B7. The findings of the study demonstrated the feasibility of converting plastic waste from MSW on Samui Island into alternative energy using eco-friendly and cost-effective technology.

Pyrolysis of waste LDPE and waste PP plastics into fuel oil in a low-cost, lab-scale pyrolyzing unit

Plastics cause severe environmental and societal issues when post-consumer plastics are discarded in the environment without proper management. Pyrolysis of plastic waste is a promising method for plastic waste management due to its valuable by-products such as fuel oil. The objective of the present study was to pyrolysis waste polypropylene (PP) and waste low-density polyethylene (LDPE) plastics into fuel oil in a low-cost, lab-scale apparatus at the maximum temperatures of 330°C and 355°C, respectively, and in turn to assess the physical properties, gross calorific value, density, kinematic viscosity, flash point, ash content, and sulfur content, of resultant fuel oil. Commercially available, recycled grades of LDPE and PP pellets, 70.0 g of each, were obtained, and pyrolysis was done in a lab-scale, low-cost batch reactor. The experiment was triplicated, and the resultant fuel oil was analyzed for physical properties by ASTM standard methods. The properties of resultant fuel oil were also compared with diesel grade criteria. Results revealed that the highest yield of fuel oil was obtained from waste PP at 79.57 wt.% while the waste LDPE resulted at 74.06 wt.% of fuel oil. No wax formation was observed in the waste PP pyrolysis process, unlike in the waste LDPE pyrolysis. The gross calorific values of waste PP and waste LDPE were 12 016 kcal/kg and 11 961 kcal/kg, respectively. It was higher than the standard value of commercial diesel. The distillation results indicated that short-chain hydrocarbon content is higher in the waste PP fuel oil sample than in the waste LDPE fuel oil sample. The results indicated that the resultant fuel oil samples were nearly closer to the diesel grade criteria. Therefore, the fuel oil produced from waste plastics is a viable alternative to traditional fossil fuels, with potential applications in power generation and transportation.

Catalyst-mediated pyrolysis of waste plastics: tuning yield, composition, and nature of pyrolysis oil

With ever-increasing plastic waste, a robust and sustainable methodology to valorize the waste and tweak, the composition of the value added product is the need of the hour. The present study describes the effect of different heterogeneous catalyst systems on the yield, composition and nature of the pyrolysis oil produced from various waste polyolefins like high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), and polypropylene (PP). The waste polyolefins were subjected to thermal as well as catalytic pyrolysis. Liquid, gas, and solid products were obtained during the pyrolysis. Various catalysts such as activated alumina (AAL), ZSM-5, FCC catalyst, and halloysite clay (HNT) were used. Usage of catalysts has reduced the temperature of the pyrolysis reaction from 470 to 450°C with better liquid product yield. PP waste generated higher liquid yield compared to LLDPE and HDPE waste. The highest liquid yield of 70.0% was achieved with PP waste using AAL catalyst at 450°C. The sulfur and chloride content was found to be < 10 and < 20ppm respectively in all the pyrolysis liquid. Pyrolysis liquid products were analyzed using gas chromatography (GC), nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, X-ray fluorescence (XRF) spectroscopy, and gas chromatography coupled with mass spectrophotometry (GC-MS). The obtained liquid products consist of paraffin, naphthene, olefin and aromatic components. Catalyst regeneration experiments with AAL showed that the product distribution profile remains the same up to three cycles of regeneration.

Performance of red mud oxygen carriers in chemical-looping hydrogen production using different components of plastic waste pyrolytic gas

This study proposed plastic waste-fueled Chemical-looping Hydrogen Production (CLHP) based on the concept of three-reactor chemical-looping process for the purposes of sustainable treatment of plastic wastes while producing high purity H2 and separating CO2. Oxygen carrier prepared from red mud wastes (Bauxite residues) was suggested to be circulating materials to improve combustion efficiency and H2 yield. The feasibility of using pelletized oxygen carrier prepared from red mud wastes was experimentally investigated with major components (H2, CH4 and C2H4) of plastics pyrolysis gases as fuels. The red mud oxygen carrier composed of around 38 wt% Fe2O3 and 50 wt% inert materials, and CuO-promoted oxygen carriers composed of 8.0 wt% CuO and 92 wt% red mud wastes were used. The two oxygen carriers were examined by parallel experiments, focusing on the aspects of oxygen transport, stability, hydrogen productivity and carbon deposition. Temperature and different components of plastic pyrolysis gases had significant impacts on oxygen transport behaviors; reduction tests using CH4 or C2H4 fuels suggested that the operation temperature of Fuel Reactor should be higher than 800 °C for deep reduction and high H2 productivity. CuO addition significantly promoted oxygen carrier's reactivity and oxygen transport capacity with various fuel components. The cyclic CLHP experiments, performed over 10 redox cycles with C2H4 as fuels, showed that there was only a limited degradation in oxygen carriers caused by carbon deposition and element migration. The developed oxygen carriers can meet the requirements of long-term operation for CLHP process. Carbon deposition on the oxygen carriers derived from hydrocarbon fuel cracking seemed to be inevitable, which experimentally determined in the range of 0.01–0.043 g g−1 oxygen carriers as C2H4 was used as fuels. However, the reactivity of these carbon deposits was extremely low; their initial steam-gasification temperatures were around 750 °C, much higher than the temperature used for water splitting reaction. This provides the potential opportunities for an industrial CLHP process to produce high purity H2 (>97%) despite of carbon deposits presents in Fuel Reactor.

Inherently separated syngas production from plastic waste fast pyrolysis integrated with volatile chemical looping conversion with CO2 splitting

To convert plastic waste into high-value products coupled with CO2 utilization, this study proposed a new concept to produce inherently separated syngas through fast pyrolysis integrated with volatile chemical looping CO2 splitting. Three conversion modes, i.e., redox, cracking and redox-cracking mixed modes, were evaluated using different catalyst, and found that cracking mode with Ni/Al2O3 or Ni/MgAl2O4 exhibited better fuel conversion and syngas separation performance than redox and mixed modes (using Ca2Fe2O5 and Ni/Ca2Fe2O5, respectively), achieving nearly full CO-H2 separation from the syngas product. Focusing on the cracking mode, higher temperature facilitated the fuel and coke conversion, due to the endothermic nature of both reaction stages. The syngas separation efficiency increased during 5 cycles and stabilized ∼95% while using Ni/MgAl2O4 catalyst. The redox between Ni0 and Ni2+ was inevitable for both cracking catalysts during multiple cycles due to the Ni-support interaction, limiting the full separation of syngas. The accumulation of low-reactive coke during multiple cycles was another important consideration. Ni/MgAl2O4 possessed weaker Ni-support interaction and less coke accumulation than Ni/Al2O3, thus performed better syngas separation efficiency. Therefore, it is crucial to minimize Ni-support interaction and the generation of high-graphitic coke for optimization.

Mechanism of paint removal by nanosecond pulsed laser plasma shock: simulation and experiment.

This paper establishes a new theoretical paint removal model of plasma shock based on Fabbro's model and Newton's second law. A two-dimensional axisymmetric finite element model is established to calculate the theoretical model. By comparing the theoretical and experimental results, it is found that the theoretical model can accurately predict the threshold of laser paint removal. It is indicated that plasma shock is an essential mechanism in laser paint removal. The threshold for laser paint removal is approximately 1.73J/c m 2. The experiments show that, with the increase of the laser fluence, the effect of laser paint removal first increases and then decreases. With the increase of the laser fluence, the paint removal effect is improved due to the increase of the paint removal mechanism. The competition between the plastic fracture and pyrolysis leads to a reduction in paint effectiveness. In summary, this study can provide a theoretical reference for studying the paint removal mechanism of plasma shock.

Catalytic upcycling of waste polypropylene for gram-scale production of FeCo@N-doped carbon nanotubes toward efficient oxygen reduction electrocatalysis

Exploring novel low-cost and high-efficiency non-precious metal catalysts for use in oxygen reduction reactions (ORR) is of key importance. Based on catalytic pyrolysis of waste plastics, a facile method for preparing N-doped Fe/Co-encapsulated carbon nanotubes (FexCoy@NCNTs) was proposed. Particularly, gram-scale yield of the composite catalyst (3.87 g) was achieved in one pot with considerable atomic conversion rate of carbon (∼57.3 %) from waste polypropylene to high-quality CNTs, suggesting great potential for waste plastics valorization. The effects of Fe-to-Co ratios were studied by testing the ORR performance of each sample, indicating that as the Fe proportion increased, the ORR performance initially increased and then decreased. The Fe1Co1@NCNTs catalyst showed optimal performance which was comparable with commercial Pt/C catalyst: Particularly, an initial potential of 0.97 V vs RHE, a half-wave potential of 0.81 V vs RHE, and a limiting current density of –5.68 mA cm−2 were recorded. The encapsulated Fe and Co species in N-doped CNTs enhanced catalytic activity, while the porous carbon structure augmented the exposure of active sites. This strategy offers an auspicious platform for reusing waste plastics in the mass production of CNTs, and also provides an innovative approach for preparing low-cost, high-performance, and non-precious metal-based electrocatalysts for ORRs.

Evaluation of modified bitumen properties using waste plastic pyrolysis wax as warm mix additives

The existing disposal methods of waste plastics are mainly landfill and incineration, and they will migrate to the surrounding ecosystems and bio-magnify in plants and animals that endanger the human food chain. To reduce environmental pollution and realize waste reuse, the waste plastics were recycled to produce the pyrolysis wax (PW) as warm mix additives of bitumen by using the high-temperature pyrolysis method in this study. The PW was produced at different pyrolysis temperatures (T) and pressures (P), and then bitumen was blended with different PW content (C). Firstly, the optimal production condition of PW modified bitumen was determined based on orthogonal experimental analysis. Then, the conventional, viscosity-temperature, storage stability, differential scanning calorimetry, Fourier transform infrared and rheological tests were conducted to evaluate the performances of the optimal PW modified bitumen before and after aging. Results show that the optimal production condition is T = 400 °C, P = 0.5 MPa, C = 6%. After adding matrix asphalt (MA), pyrolysis waxes can be used as a colloid dispersion medium, thus reducing the viscosity of MA. In addition, the PW led to a lower penetration, a higher softening point and a lower viscosity, and ductility was still within specification. The PW modified bitumen still has better storage stability and there is no obvious chemical reaction that occurred in the PW modified bitumen. Meanwhile, the incorporation of PW enhanced the viscoelastic properties, high-temperature performance, permanent deformation resistance, short-term and long-term aging resistance ability and anti-fatigue ability as revealed by the differential scanning calorimetry and rheological tests.

Assessing the environmental footprint of plastic pyrolysis and gasification: A life cycle inventory study

Chemical recycling is a promising technology that can help alleviate the environmental burdens of plastic waste. This paper developed a comprehensive, scenario-based life cycle assessment (LCA) to quantify the environmental profile of different management options to treat polyethylene (PE) and polypropylene (PP), including landfill, pyrolysis, and gasification. Using a system expansion method and inventory data from various sources, the result showed that the recovery of ethylene and propylene monomers for plastic re-manufacturing, which resembled closed-loop recycling systems, offered the highest environmental benefits. Most notably, fossil fuel depletion, climate change, and human toxicity impacts were 36,761%, 1063%, and 329% lower than those of landfill disposal, respectively. Open-loop recycling scenarios, such as high-value chemical (HVC) and energy recovery from pyrolysis and gasification, were also investigated. Amongst these scenarios, pyrolysis for HVC recovery was the most environmentally favourable, followed by HVC recovery using gasification. Energy recovery scenarios offered limited benefits and had worse results than landfill in terrestrial acidification, freshwater and marine eutrophication impact categories. The main driver of impacts during end-of-life treatment using chemical recycling is the energy consumption needed to achieve appropriate temperature for the necessary reactions to take place. In terms of material consumption, the use of nitrogen gas to purge the reactor is the biggest contributor for pyrolysis whereas zeolite usage accounts for the majority of material impacts for gasification.

Carbon and H2 recoveries from plastic waste by using a metal-free porous biocarbon catalyst

Carbon and H2 recoveries from plastic waste enable high value-added utilizations of plastic waste while minimizing its GHG emissions. The objective of this study is to explore the use of a metal-free biocarbon catalyst for waste plastic pyrolysis and in-line catalytic cracking to produce H2-rich gases and carbon. The results show that the biocarbon catalyst exhibits a good catalytic effect and stability for various plastic wastes. Increasing the C/P ratio from 0 to 2, induce an increase in the conversion rate of C and H in plastics to carbon and H2 from 57.1% to 68.7%, and from 22.7% to 53.5%, respectively. Furthermore, a carbon yield as high as 580.6 mg/gplastic and an H2 yield as high as 68.6 mg/gplastic can be obtained. The hierarchical porous structure with tortuous channels of biocarbon extends the residence time of pyrolysis volatiles in the high-temperature catalytic region and thereby significantly promotes cracking reactions.

Pyrolysis of Saw Waste Biomass Mahogany Wood and Polypropylene Plastic

Fuel requirement increased along with the increased of population also industrial progress, meanwhile the alternative fuel always decreasing. People also faced by the problem of increasing amount of waste, either its organic or anorganic. In this case mahogany waste and polypropylene plastic waste which still rarely used by people can be a solution to make an alternative fuel processed by pyrolysis process. This study is using experiment method with analysis descriptive quantitative technique. This study conducted with pyrolysis process to mixed biomass sawdust mahogany and polypropylene plastic waste with the 100%-0%,75%:25%, 50%:50%, 25%:25%, and 0%:100% ratio, next are do pyrolysis oil test which was quantity test. there is an influence of variety mixed biomass sawdust mahogany and polypropylene plastic waste ratio to quantity of pyrolysis oil. The most quantity is produced by mixed variety 100% of polypropylene plastic as much as 1026,67 ml with 391°C temperature on T1, 345°C on T2, 367,75°C on T3.

Economic analysis of the circular economy based on waste plastic pyrolysis oil: a case of the university campus.

Recently, the concept of a circular economy for carbon neutrality is emerging. In particular, waste plastics are one of the key wastes, and efforts are being made to recycle them as energy rather than dispose of them. Accordingly, the technology of producing and utilizing pyrolysis oil from waste plastics attracts attention. As it is an early stage of technology development, however, there are not many demonstrations and papers that analyze the technology broadly. The goal of this study is to propose building a circular economy on a university campus through waste plastic pyrolysis oil technology. To show its feasibility, waste plastic pyrolysis oil technology is analyzed comprehensively from economic, environmental, and policy perspectives using the scenario analysis technique on the university campus level. A methodology of the scenario analysis technique enables predicting the uncertainties. Since plastic pyrolysis oil technologies and carbon neutrality are accompanied by many uncertainties, this technique is expected to be an appropriate methodology for this study. First, the amount of pyrolysis oil production from waste plastics from the campus is estimated. Then, the cost and carbon emissions from waste plastics are estimated if the pyrolysis oil technology is used instead of the traditional waste disposal process. As a result, the total economic profits of up to 425,484,022 won/year (354,570.01 $/year) are expected when a circular economy is built using waste plastic pyrolysis oil. In addition, it is also confirmed that greenhouse gas (GHG) emissions can be reduced by up to 840,891 kgCO2eq/year. The waste plastic pyrolysis oil satisfies Korea's gas pollutant standards and is consistent with the GHG reduction policy. It can be concluded that building a circular economy at the university campus level using waste plastic pyrolysis oil technology is suitable from economic, environmental, and policy perspectives.

Hydrogen Production by Steam Reforming of Pyrolysis Oil from Waste Plastic over 3 wt.% Ni/Ce-Zr-Mg/Al2O3 Catalyst

Sustained increase in plastic use has placed a significant burden on waste disposal infrastructure. Pyrolysis is the process of decomposing high-molecular-weight compounds by heating waste plastics at 500–1000 °C without oxygen. This process considerably reduces greenhouse gas emissions and has a high alternative energy effect (0.57 TOE ton−1). After a separation process, the oil produced by pyrolysis (C5–C20) can yield naphtha oil (C6–C7). Subsequently, hydrogen can be produced through a reforming reaction of this naphtha oil. Here, we produced hydrogen from waste plastic pyrolysis oil over a Ni/Ce-Zr-Mg/Al2O3 catalyst using a steam reforming process. A model oil combining the major substances of C6 and C7 (hexane, hexene, heptane, heptene, and toluene) was formed. From the reaction products, the hydrogen yield was obtained based on analysis of H2, CO, and CO2 concentrations using gas chromatography. The effect of N2 and O2 addition on hydrogen yield was analyzed within a temperature range of 750–850 °C, steam/carbon (S/C) ratio of 0.6–4, and space velocity of 7600–19,100 h−1. In addition, a durability test was performed using 3 wt.% Ni/Ce-Zr-Mg/Al2O3 catalysts for 100 h; a hydrogen yield of 91.3% was maintained from the refined waste plastic oil.

Microwave-assisted pyrolysis of waste plastics for their resource reuse: A technical review

Rapidly increasing plastics have been used and finally become wastes, resulting in increasing pressures to the environment. Microwave-assisted pyrolysis is a promising technology for converting organic wastes as waste plastics into value-added products. At present, many works on microwave-assisted pyrolysis of plastics have been published, but the achievements, challenges, and future directions of microwave-assisted pyrolysis of waste plastics have not been well summarized and discussed. In this work, the principle of microwave-assisted pyrolysis technology is introduced. Then, the progress of its application to recover useful products from plastics is reviewed and discussed in terms of key parameters including microwave power, pyrolysis temperature, reaction time, types of catalyst, microwave absorbents and feedstock mixing ratio. Especially, the yields and properties of the produced oil, gas and char are correlated with the process parameters. Finally, the existing challenges and prospects of disposal/reuse of waste plastics by microwave-assisted pyrolysis technology are discussed.

Self-Healing and Thermomechanical Properties of Activated Carbon Pyrochar Derived from Municipal Mixed Plastic Waste Pyrolysis with Self-Healing Epoxy Vitrimer Composites

An ecological vitrimer is being developed using activated carbon pyrochar from municipal mixed plastic waste pyrolysis into an epoxy composite. Durable vitrimeric materials may be created by adding pyrochar to polymeric composites. Due to their ductility, reusability, and recyclability, vitrimeric materials have become popular and reliable materials. As a result, the self-healing temperature of composite vitrimers is lower via disulfide exchanges than that of virgin epoxy vitrimers. Additionally, compressive studies have been used to study self-healing capacities, and modulus variations have been used to highlight changes in the healing efficiency of the materials.

Production of fuels by pyrolysis of waste plastics: technical notes

This paper described the plant scale catalytic process of the plastic waste materials in order to obtain an alternative fuel from three plastic wastes Polypropylene (PP), Polystyrene (PS) and Polyethylene (PE). Pyrolysis is the thermochemical decomposition of plastics at elevated temperatures (in absence or little supply of oxygen) into a range of useful products: gas, liquid, and solid residue. These waste have plastics consisting of PP, PE and PS, are first sorted manually and crushed by using crusher and finally feed in the reactor enclosed in the burner maintaining the reaction temperature about 500°C. Nitrogen gas is used to create inert environment and for fluidization in reactor. The produced cracked gas is now sent to be condensed to a condenser followed by the series of cyclone separator and electrostatic precipitator then finally feed into the liquid vapor separator. The plastic pyrolysis plant is design of capacity 3.2 tons of plastics each day, obtained 80% gaseous fuel and 7% Liquid and remaining as residue. The variation of yield of the products according to increase in temperature is also shown in this paper.

Production and characterization of plastic oil from mixed plastic waste through the pyrolysis process

With increasing population, modernization, and industrialization, plastic usage is increasing daily, resulting in massive plastic waste. The current research investigated the generation of plastic oil from mixed plastic waste. The pyrolysis process is a thermochemical reaction between 340 °C and 440 °C. The process residence time was one hour per batch. Thermal breakdown of plastic waste at optimal temperature produces volatile matter, which passes through a series of condensation processes in a water-circulating heat exchanger to make plastic oil. The maximum yield of plastic oil was obtained at 425 °C. The heating value of plastic oil measured was around 42.5 MJ kg−1, which signifies the utilization of plastic oil in various process industries. Non-condensable gases were collected and analyzed. Pyro-char is a solid byproduct of the plastic pyrolysis process that is mostly employed in road laying.

Chemical Upcycling of Waste Plastics to High Value-Added Products via Pyrolysis: Current Trends, Future Perspectives, and Techno-Feasibility Analysis.

Chemical upcycling of waste plastics into high-value-added products is one of the most effective, cost-efficient, and environmentally beneficial solutions. Many studies have been published over the past few years on the topic of recycling plastics into usable materials through a process called catalytic pyrolysis. There is a significant research gap that must be bridged in order to use catalytic pyrolysis of waste plastics to produce high-value products. This review focuses on the enhanced catalytic pyrolysis of waste plastics to produce jet fuel, diesel oil, lubricants, aromatic compounds, syngas, and other gases. Moreover, the reaction mechanism, a brief and critical comparison of different catalytic pyrolysis studies, as well as the techno-feasibility analysis of waste plastic pyrolysis and the proposed catalytic plastic pyrolysis setup for commercialization is also covered.

Conversion of Polyethylene to High-Yield Fuel Oil at Low Temperatures and Atmospheric Initial Pressure.

The transformation of waste plastics into fuels via energy-efficient and low-cost pyrolysis could incentivize better waste plastic management. Here, we report pressure-induced phase transitions in polyethylene, which continue to heat up without additional heat sources, prompting the thermal cracking of plastics into premium fuel products. When the nitrogen initial pressure is increased from 2 to 21 bar, a monotonically increasing peak temperature is observed (from 428.1 °C to 476.7 °C). At 21 bar pressure under different atmosphere conditions, the temperature change driven by high-pressure helium is lower than that driven by nitrogen or argon, indicating that phase transition is related to the interaction between long-chain hydrocarbons and intercalated high-pressure medium layers. In view of the high cost of high-pressure inert gases, the promotion or inhibition effect of low-boiling hydrocarbons (transitioning into the gaseous state with increasing temperature) on phase transition is explored, and a series of light components are used as phase transition initiators to replace high-pressure inert gases to experiment. The reason that the quantitative conversion of polyethylene to high-quality fuel products is realized through the addition of 1-hexene at a set temperature of 340 °C and the initial atmospheric pressure. This discovery provides a method for recycling plastics by low energy pyrolysis. In addition, we envisage recovering some of the light components after plastic pyrolysis as phase change initiators for the next batch of the process. This method is able to reduce the cost of light hydrocarbons or high-pressure gas insertion, reduce heat input, and improve material and energy utilization.