Pyrolysis Of High Density Polyethylene Research Articles

Catalytic upgrading of polyethylene plastic waste using GMOF catalyst: Morphology, pyrolysis, and product analysis

Since 2000, global plastic waste production and consumption have doubled, escalating from 250 to 500 million tonnes. Merely 9 % of plastic waste undergoes global recycling, leaving the majority either in landfills or poorly managed. This research introduces a new catalyst, GMOF, created by growing Metal-Organic Framework (MOFs) rods on the flaked, carpet-like structure of Graphene Oxide (GO) nanosheets. The aim is to enhance the quality of pyrolysis products derived from high-density polyethylene (HDPE) and low-density polyethylene (LDPE) waste using this GMOF catalyst. HDPE and LDPE, sourced from post-consumer plastic packaging, underwent specific treatment involving cleaning, drying, and shredding. Morphological and property evaluations of GO nanosheets before and after MOF decoration employed techniques including Field-Emission Scanning Electron Microscopy (FE-SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and Fourier Transform Infrared Spectroscopy (FTIR). Flash pyrolysis at 500 °C for 1 min using a sample-to-catalyst ratio of 4:1 in a Quartz Wool Matrix (QWM) reactor was conducted via a Thermogravimetric Analyzer (TGA) and Frontier LAB pyrolizers. Thermal stability and characteristics of feedstocks and catalysts were assessed using TGA. Gas Chromatography-Mass Spectrometry (GC–MS) analyzed and quantified pyrolysis product compounds, while a Micro GC Fusion system determined non-condensable pyrolyzate permanent gas distribution. Results showcased that the GMOF catalyst's unique morphology efficiently captured smaller radicals on its surface, providing increased surface area for effective radical–radical interactions during pyrolysis. In HDPE pyrolysis, the GMOF catalyst notably decreased selectivity of C21-C40 and C40 + wax fractions to 49.07 % and 7.73 %, respectively, while boosting C1-C20 olefin production by 2.54 %. Conversely, LDPE pyrolysis with the GMOF catalyst notably amplified the CO2 peak intensity by 3.17 %, signifying a gasification phase. Primary gases produced were C3 aliphatic hydrocarbons, propane, and propylene, yielding 79.46 % collectively.

Catalytic pyrolysis of high-density polyethylene (HDPE) over hierarchical ZSM-5 zeolites produced by microwave-assisted chelation-alkaline treatment

A new microwave (MW) assisted chelation-alkaline strategy was developed to produce hierarchical ZSM-5 zeolites (with external surface area of 203 m2/g) in minutes, leading to the formation of heterogeneous structure with a high-silica shell and aluminium-rich core (silicon-to-aluminium ratios of 49.2 and 37.6, respectively). The zeolites were assessed comparatively by catalytic pyrolysis of high-density polyethylene (HDPE). Compared to the mesoporous ZSM-5 zeolite prepared by the conventional alkaline treatment (via desilication by the NaOH aqueous solution), the hierarchical zeolite by the MW-assisted method showed comparable kinetics in catalytic pyrolysis of HDPE, but with the improved stability in the cyclic pyrolysis-regeneration tests. The improved stability could be due to the better-preserved structural integrity thanks to the relatively milder surface etching by the MW-assisted chelation dealumination method. In addition, compared to the parent ZSM-5, the product distribution of HDPE catalytic pyrolysis over the hierarchical ZSM-5 zeolite showed a higher portion of oil products (i.e., 12 wt% vs. 6.9 wt%) and an improved alkane-to-olefin ratio in the oil products (2.22 vs. 1.86, respectively) due to the reduced acidity and improved hydrogen transfer ability. The MW-assisted chelation-alkaline treatment could be a new strategy to regulate the trade-off between stability and activity of zeolites for catalytic applications.

Molecular-level kinetic modelling for the pyrolysis of high-density polyethylene in a two-stage process

A two-stage process has been developed for the pyrolysis of high-density polyethylene to obtain light olefins, where probable mechanisms for each stage pyrolysis were proposed in our previous study. This work aims to establish molecular-level kinetic models for the first-stage pyrolysis at a lower temperature and for the second-stage pyrolysis at a higher temperature, respectively, to predict the overall reaction performances in accordance to the role of detailed mechanisms. A structure-oriented lumping (SOL) method based molecular-level kinetic model can effectively describe the first-stage pyrolysis, while a detailed molecular-level kinetic model is developed for the second-stage pyrolysis to track the evolutions of all alkanes, olefins, and diolefins, with special focus on the formation of light olefins. The established separate models can achieve the automatic generation of complex reaction networks and present good agreement with experimental data obtained from the first- and second-stage. In addition, the first-stage model indicates that the random scission plays an important role in the pyrolysis process at lower temperatures, while the chain-end scission mechanism dominates the second-stage reaction to produce light olefins at higher temperatures. As a whole, the molecular-level modelling scheme behaves excellently at a wide range of temperature, which provides guidance for upgrading the pyrolysis process.

Comparative Analysis of Kerosene Grade Fuel from Pyrolysis of HDPE and LDPE Waste Plastics

To curb the menace of plastic waste and energy crisis, this study investigated the conversion of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) grades of plastics to kerosene. Plastics sourced from dumpsites within Port Harcourt metropolis in Rivers State, Nigeria were shredded and pyrolyzed (thermally degraded under inert condition at a temperature range of 350-400oC). The obtained hydrocarbon liquid was distilled using distillation column at a temperature range of 150-270oC and characterised to evaluate the physico-chemical parameters such as flash point, density, copper corrosion, and calorific value and compared against the acceptable standard. The result showed that these properties were within the permissible limit. However, the sulphur content and smoke point of HDPE and LDPE were above and below the limits, respectively. The GC-MS and GC-FID results of kerosene samples obtained from both grades of plastics indicates that the product comprised C9 to C17 grades.

Artificial Neural Network based prediction of Specific Fuel Consumption in various Compression Ratio CI Engine Fueled with Various Plastic Composition Pyrolysis oil and Diesel

This study looks at the usage of Artificial Neural Network Modeling for predicting Specific Fuel Consumption for compression ignition engines running on Diesel, Low-Density Polyethylene Pyrolysis Oil (LDPE PO), High-Density Polyethylene Pyrolysis Oil (HDPE PO), and Polypropylene Pyrolysis Oil (PP PO). Using preliminary practical findings, The Model of ANN was built to estimate SFC by adjusting the parameters of the engine. SFC is anticipated by adjusting the parameters and utilizing the orthogonal array. The experiment is then carried out using an orthogonal array. The outcomes of experimental work are used to create an ANN model. In the case of a non-linear mapping between input & output, the classic back-propagation method and a multi-layer perception network are utilized. The values of Mean Square Error (MSE), Root Mean Square Error (RMSE), and Regression Coefficient (R2) for LM10TP architecture are 1.5143×10–06, 0.0012 & 1 in training & the validation values 1.2185×10–06, 0.0011 and 0.9999 respectively. It was discovered that neural networks are useful tools for prediction since they performed well in specific fuel consumption prediction in both training and validation.

Analysing the effects of process parameters on HDPE pyrolysis and in-line reforming

This study presents a comprehensive parametric investigation focusing on the pyrolysis and in-line reforming of High-Density Polyethylene (HDPE) at zero time on stream. The research explores the impact of varying operating parameters, specifically examining the effects of temperature, space time, and steam/plastic (S/P) ratio on conversion, hydrogen production, and product yields. The temperature was varied within the range of 600–750 °C, demonstrating notable influence on conversion efficiency and hydrogen production. Additionally, the effect of space-time (2.8–20.8 g catalyst min gHDPE−1) was thoroughly evaluated, revealing substantial improvements in both conversion and hydrogen yields. Moreover, the S/P ratio of 1 to 3 was investigated, showcasing significant enhancements in hydrogen and CO2 yields with increasing steam partial pressure. The study provides valuable insights into optimizing the process parameters for HDPE pyrolysis and in-line reforming, which are crucial for achieving efficient conversion and enhancing hydrogen production.

Aromatization of HDPE and PP over Ga-promoted zeolite: Effects of pretreatment and zeolite type

The effects of pretreatment and structure of zeolite on aromatization of high-density polyethylene (HDPE) and polypropylene (PP) over different Ga-promoted zeolites (HZSM-5, hierarchical HZSM-5, HY, Hβ, and USY) were investigated. Hydrogen reduction of Ga-promoted HZSM-5 resulted in a higher yield of alkenes during HDPE pyrolysis but did not lead to increased production of total aromatic hydrocarbons. The reduction and subsequent oxidation of Ga/Z5 led to the formation of GaO+ species with high dehydrogenation activity. This resulted in a remarkable 65% yield of aromatics, with a BTEX (benzene, toluene ethylbenzene and xylene) overall yield of 60% and a selectivity of 90% of the liquid product. Increasing the Ga loading decreased the BTEX yield due to pore blockage and a decrease in the amount of Brønsted acid sites. The BTEX yield over Ga-promoted zeolites was found to be strongly related to the pore size of the zeolite, whereas its yield over the parent zeolite was not strongly dependent on the pore size. Diffusion of the cracking intermediates was found to have a more significant impact on the aromatization of PP than HDPE. The highest BTEX yield for HDPE was achieved with Ga-promoted HZSM-5, while Ga-promoted hierarchical HZSM-5 exhibited the highest BTEX yield for PP. Furthermore, Ga(1)/Hβ-Redox demonstrated remarkable selectivity (90%) towards ethylene and propylene in the gas phase, surpassing other zeolites (37%-68%).

Thermogravimetric catalytic pyrolysis of high-density polyethylene over iron modified chicken eggshell wastes

Among the major concerns of our current world include the accumulation of plastic wastes and the exhaustion of petroleum resources. Efforts to resolve these issues have contributed to multiple research and alternatives to be explored. One of the attractive alternatives that have been approached is the pyrolysis of plastic wastes. The use of catalysts offers multiple advantages in pyrolysis and different types of catalysts have been investigated in recent years. The potential of discarded natural wastes is acknowledged and studies to use food waste as a catalyst are to be developed in this research. The main objective of this project is to investigate the pyrolysis of high-density polyethylene (HDPE) over iron (Fe) modified waste chicken eggshell (WCE) as the catalyst. The pyrolysis was conducted at a temperature of 30 – 700℃ via a Thermogravimetric analyzer (TGA). WCE was washed, dried, and calcined in the furnace at 900℃ for 4 h. Fe was loaded (5 wt%) on the calcined WCE via the incipient wetness impregnation (IWI) method. The catalyst to HDPE mass ratio was fixed at 1:1. For comparison purposes, the commercial calcium oxide (CaO), calcined WCE, and Hydrogen exchanged Zeolite Socony Mobil − 5 (HZSM-5) were utilised in the pyrolysis of HDPE. Catalytic pyrolysis of HDPE over WCE and CaO had almost completely degraded with mass loss of 99.50% and 99.83% respectively at Phase II followed by pyrolysis of HDPE (94.05%), HZSM-5 (77.50%) and Fe/WCE (31.40%) samples. Among tested catalytic samples, the WCE catalyst works best to degrade HDPE into the highest volatile matter which attributes to higher pyrolysis oil yield.

Catalytic pyrolysis of high-density polyethylene for the production of carbon nanomaterials: effect of pyrolysis temperature

Catalytic pyrolysis of high-density polyethylene for the production of carbon nanomaterials: effect of pyrolysis temperature

Chemical Recycling of Polyolefins with the Molten Metal Reactor at 460 °C

AbstractThis paper describes the pyrolysis of high‐density polyethylene (HDPE) in a molten metal reactor, where the HDPE is initially in direct contact with molten metal at 460 °C. Due to the equal temperature across the molten metal, secondary reactions are minimised, and long‐chain waxes with boiling points over 600 °C accumulate on the molten metal. Once enough wax has accumulated, further HDPE pyrolysis occurs within the wax in a direct heat transfer reaction.

IMPACT OF NANOPARTICLES AS A HOMOGENEOUS CATALYST IN IGNITION CHARACTERISTICS OF WASTE PLASTIC OIL

A novel approach was employed to develop alternative fuels by blending pyro-oil from used plastic with graphene, which acted as a combustion additive. The biofuels were produced through pyrolysis of high-density polyethylene (HDPE). When evaluating the fuel blends, the fuel properties were analyzed and compared to commercially available diesel fuel, while Fourier transform infrared (FTIR) spectrometry was employed to know the fuel character. The findings demonstrate that including graphene as a combustion additive significantly enhances the Fuel's performance. The phenomena suggest that graphene effectively weakens the dispersion forces among the triglyceride molecules. Consequently, the droplet is easier to burn. By incorporating graphene, the alternative fuels droplet exhibits improved ignition properties, offering potential benefits in terms of efficiency and performance. The additive plays a crucial part in modifying the molecular structure of the Fuel, resulting in enhanced reactivity and ignition characteristics. Furthermore, the analysis of physical properties and spectroscopic data provides valuable insights into alternative fuels' molecular composition and behavior.

Synergistic Activity of the Fe2O3/Al2O3 Catalyst for Hydrogen Production through Pyrolysis-Catalytic Decomposition of Plastics

Plastic recycling through thermochemical conversion for the production of fuels and chemicals is a promising way for simultaneous waste processing and utilization. In the current study, high-density polyethylene (HDPE) was subjected to pyrolysis and then catalytic upgrading to produce hydrogen in the presence of a novel Fe2O3/Al2O3 catalyst with a grain boundary. To understand the catalyst–support interaction as well as the resulting synergistic catalytic effects, catalytic pyrolysis of HDPE with supported Fe2O3/Al2O3 was compared with those over Fe2O3, Al2O3, and a cascade combination of both. It was found that the performance of Fe2O3/Al2O3 was superior to that of other catalysts in terms of chain cracking and C–C/C–H bond cleavage. The hydrogen yield with Fe2O3/Al2O3 was 50.53 mmol·gplastic–1, equivalent to more than 70% of hydrogen in plastic. Besides, alkanes/alkenes ranging from C2 to C9 dominated the hydrocarbon products. The analysis of the cycle performance revealed that the reduction pathway of Fe2O3/Al2O3 was different from those of other Fe2O3-containing catalysts, which was also confirmed by temperature-programmed reduction. To investigate the essential role and reaction mechanism with Fe2O3/Al2O3, characterizations of Fe2O3/Al2O3 before and after the reaction were conducted. The grain boundary between Fe2O3 and Al2O3 enhanced the adsorption of gaseous products. More importantly, the catalyst–support interaction to form FeAl2O4 during the pyrolysis reaction, determined by X-ray photoelectron spectroscopy, was responsible for effective proton adsorption and C–H bond cleavage. This study provides an insightful understanding of catalyst transformation during plastic catalytic pyrolysis for hydrogen production.

Synergistic interactions between sewage sludge, polypropylene, and high-density polyethylene during co-pyrolysis: An investigation based on iso-conversional model-free methods and master plot analysis

Sewage sludge (SS) is a hazardous by-product of wastewater treatment processes that requires careful management for minimal environmental impacts and effective resource recovery. Through thermochemical processes such as pyrolysis, clean energy is recovered from SS in the form of bio-oil, biogas, and biochar. To improve the yield and quality of products, the co-pyrolysis of more than two materials is increasingly gaining interest. Here, the thermal behaviour, kinetics, and synergistic interactions during the co-pyrolysis of SS with polypropylene (PP) and high-density polyethylene (HDPE) were comparatively evaluated with thermogravimetric analysis at different mixing ratios and heat rates. Activation energies and reaction mechanisms were determined through iso-conversional model-free methods and master plot analysis. Evolved gases were monitored with thermogravimetric-mass spectrometry. Increased volatile conversion and degradation rates, and reduced activation energies during co-pyrolysis were mediated by synergistic interactions between H-radicals of PP/HDPE and oxygenated intermediates of SS. Contrary to the pyrolysis of SS, PP and HDPE, the co-pyrolysis processes are predominantly diffusion-controlled. Insights into the co-pyrolysis processes of SS/PP and SS/HDPE gained from this work provide the theoretical support for subsequent investigation, facilitate design of waste-to-energy reactor, and aid the adoption of the technology to harness the bioenergy potential of the feedstocks.

Investigation of high-density polyethylene pyrolyzed wax for asphalt binder modification: Mechanism, thermal properties, and ageing performance

The thermal pyrolysis of high-density polyethylene in a fixed bed reactor has been studied in the temperature range of 450–550 °C with two different nitrogen carrier gas flowrates, 2 and 4nullLnullmin−1, to study the effect of these process parameters as well as the resultant vapour residence times on the formation of wax and its chemical and thermal properties. The technology had a high selectivity to waxes, with a yield of up to 91.87% wax from high-density polyethylene at 500 °C using a nitrogen carrier gas flowrate of 4nullLnullmin−1 and subsequent 1.76 second vapour residence time, calculated using the ideal gas law. The waxes were characterised using techniques including gas-chromatography-mass spectroscopy (GC-MS), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The process operating temperature especially and its subsequent effect on vapour residence times within the reactor had a considerable impact on both the chemical and thermal properties of the waxes. Higher operating temperatures yielded more olefinic waxes due to the promotion of degradation radical mechanisms such as β-scission. They were observed to have higher melting points and thermal stability. An investigation was conducted to assess the thermal properties and ageing performance of the waxes. Thermal conditioning in an ashing oven at 170 °C for 0–6 hours was conducted with a detailed analysis of GC-MS and FTIR at each stage of thermal exposure to further support thermal characterisation results. The changes in chemical composition were attributed mainly to oxidation and polymerization ageing reactions and were seen to be more prominent in the more unsaturated waxes produced at higher pyrolysis temperatures. The wax produced at 550 °C was determined the optimal wax for binder modification in hot-mix asphalt pavement design due to lower volatile/mass loss. A lower temperature range was suggested for optimal blending conditions to further reduce loss of volatiles with initial blending and storage.

Estimating the efficiency of catalysts for catalytic pyrolysis of polyethylene

The paper is devoted to investigation of the catalytic pyrolysis of high-density polyethylene (PE) in the presence of HBEA, HZSM-5 and HFER catalysts and natural clay. Catalytic pyrolysis of plastic materials is a promising method for treatment of secondary raw materials because it allows converting polymers into chemical compounds, which further serve as a source for chemical industry. Physicochemical parameters of the catalysts were estimated using various methods: IR Fourier spectroscopy, X-ray diffraction analysis, physical adsorption of N2, thermogravimetric analysis, and pyrolytic gas chromatography. Temperature dependences of PE destruction were obtained as well as the dependence of chemical composition of the catalytic pyrolysis products on the catalyst type. Two main factors were shown to determine the efficiency of cracking and the qualitative composition of products – structural and acidic parameters of the catalyst. The presence of Broensted acid sites in zeolites promoted the cracking and aromatization reactions. The possibility of using the clay sample for thermal decomposition of PE was estimated.

Co-pyrolysis of pinewood and HDPE: pyrolysis characteristics and kinetic behaviors study

Abstract Co-pyrolysis of lignocellulosic biomass and hydrogen-rich petroleum-based polyolefin plastics is a promising to way to improve bio-oil quality and alleviate the waste plastic pollution issues. In this study, co-pyrolysis of pinewood and HDPE was systematically investigated. The addition of HDPE decreased yield of char and gas while increased that of bio-oil, enhancing the selectivity to alcohols and hydrocarbons. The most obvious synergistic effect was observed at the HDPE mixing proportion of 0.25, at which hydrocarbon selectivity derived from co-pyrolysis experiments was 41.19% higher than the calculated weighted average values. As pyrolysis temperature increased from 500°C to 700°C, the yield of bio-oil from co-pyrolysis at the HDPE mixing proportion of 0.25 decreased from 69.11 wt.% to 50.33 wt.%, alkanes selectivity decreased from 27.41% to 3.67% and olefins selectivity increased from 14.96% to 47.12%. At 700°C, aromatics started to produce with a selectivity of 15.50%. The surface morphologies of char were not significantly affected by the HDPE mixing proportion and pyrolysis temperature. The thermogravimetric analysis results revealed that the global co-pyrolysis process can be divided into two major degradation stages, based on which multi-step method was adopted to analyze the kinetics of the process. The average apparent activation energies of stage I and stage II were 167.73 kJ/mol and 274.74 kJ/mol, respectively. The results from this work provide a theoretical guide for further development of co-pyrolysis of pinewood and high-density polyethylene (HDPE).

Oxidative Fast Pyrolysis of High-Density Polyethylene on a Spent Fluid Catalytic Cracking Catalyst in a Fountain Confined Conical Spouted Bed Reactor.

The oxidative fast pyrolysis of plastics was studied in a conical spouted bed reactor with a fountain confiner and draft tube. An inexpensive fluid catalytic cracking (FCC) spent catalyst was proposed for in situ catalytic cracking in order to narrow the product distribution obtained in thermal pyrolysis. Suitable equivalence ratio (ER) values required to attain autothermal operation were assessed in this study, i.e., 0.0, 0.1, and 0.2. The experiments were carried out in continuous regime at 550 °C and using a space-time of 15 gcatalyst min gHDPE -1. The influence of an oxygen presence in the pyrolysis reactor was analyzed in detail, with special focus on product yields and their compositions. Operation under oxidative pyrolysis conditions remarkably improved the FCC catalyst performance, as it enhanced the production of gaseous products, especially light olefins, whose yields increased from 18% under conventional pyrolysis (ER = 0) to 30% under oxidative conditions (ER = 0.1 and 0.2). Thus, conventional catalytic pyrolysis led mainly to the gasoline fraction, whereas light olefins were the prevailing products in oxidative pyrolysis. Moreover, the oxygen presence in the pyrolysis reactor contributed to reducing the heavy oil fraction yield by 46%. The proposed strategy is of great relevance for the development of this process, given that, on one hand, oxygen cofeeding allows solving the heat supply to the reactor, and on the other hand, product distribution and reactor throughput are improved.

Plastic pyrolysis over HZSM-5 zeolite and fluid catalytic cracking catalyst under ultra-fast heating

Plastic pollution compromises the environment and human well-being, and a global transition to a circular economy of plastics is vital to address this challenge. Pyrolysis is a key technology for the end-of-life recycling of plastics, although high energy consumption limits the economic feasibility of the process. Various research has shown that the application of induction heating in biomass pyrolysis reduces energy consumption when compared to conventional heating. Nevertheless, the potential of induction heating in plastic pyrolysis is rarely explored. This paper presents an exploratory study on the thermal and catalytic pyrolysis of high-density polyethylene, low-density polyethylene, and polypropylene in a fixed bed reactor through induction heating. An MFI-type HZSM-5 zeolite (SiO2/Al2O3 = 23) and an FAU-type spent fluid catalytic cracking (FCC) catalyst with distinctive Brønsted acidity and textural properties were used. A complete conversion of the plastic feedstocks was achieved within 10 min, even without a catalyst. Thermal pyrolysis produced wax (72.4–73.9 wt%) and gas products, indicating a limited degree of polymer cracking. Catalytic pyrolysis over HZSM-5 and FCC catalyst significantly improved polymer cracking, leading to higher gas (up to 75.2 wt%) and liquid product (up to 35.9 wt%) yields at the expense of wax yield (up to 25.4 wt%). In general, the gas products were rich in C3 and C4 compounds. The liquid product composition was highly dependent on the catalyst properties, for example, the HZSM-5 produced high aromatics, while the FCC catalyst produced high alkenes in the liquid products. The catalyst acidity and textural properties played an essential role in plastic pyrolysis within the short reaction time. This study demonstrated the feasibility of a fast, energy-efficient, and versatile plastic valorization technology based on the application of induction heating, where the plastic feed can be converted into wax, gas, and liquid products depending on the end-use applications.

Automobile fuels (diesel and petrol) from plastic pyrolysis oil—Production and characterisation

Plastics like high-density polyethylene (HDPE), polystyrene (PS), and Polypropylene (PP) constitute a large portion of municipal solid waste. Plastics can be pyrolysed for reuse, but the end-product qualities are critical to industry refining processes. Pilot-scale pyrolysis and vacuum distillation were used to thermally degrade the plastics and convert it to petrol (gasoline) and diesel. Batch pyrolysis of HDPE, PS, and PP at 540 oC yielded plastic pyrolysis crude oils. The crude oil was separated into different fractions starting with distillation temperatures of less than 170 OC, 170 to 380 °C, and above 380 °C. The quality of the produced crude oil, gasoline, and diesel cuts was evaluated analytically according to the fuel specifications. This study demonstrated that pyrolysis of plastics can convert up to 80% of solids by weight) into liquid crude oil. HDPE pyrolysis produces lower quantities of oil due to the production of wax. A high calorific value (38.1 to 42.9 MJ/kg) similar to fossil fuels indicates that the liquid product of plastic pyrolysis could be a viable energy source. Plastic pyrolysis crude oil from PS mostly yielded gasoline at around 70% by weight, while HDPE and PP yield predominantly diesel at more than 50% by weight. The distilled oil characterisation results were outstanding, confirming that the quality of produced petrol and diesel from plastics pyrolysis oil suppress minimum specifications for automotive fuel standards. The cetane index of HDPE and PP diesel was found to be 60 and 55 respectively, significantly above the required value of 46 for automotive diesel. Higher heating values of most petrol cuts were in the range of 41.1 to 44.6 MJ/kg. These and other fuel qualities are within or near the approved range for automotive fuel. Thus, the findings can be used to build a foundation for the industrial manufacture of automotive quality fuels from plastic solid waste.

Copper catalyzed co‐pyrolysis of polyethylene terephthalate with low and high density polyethylene for liquid fuel production

AbstractBACKGROUNDMunicipal waste contains low density polyethylene (LDPE), high density polyethylene (HDPE), and polyethylene terephthalate (PET) in enormous amount. As these plastics are non‐biodegradable and pose serious threats to the environment, efforts have been made towards their safe disposal with energy recovery and value added chemicals by subjecting them to heat under oxygen deficient conditions. This study deals with the co‐pyrolysis of the three types of waste polymers, with special focus on the conversion of PET into liquid fuel by its interaction with the other two polymers.ResultsThe individual pyrolysis of LDPE and HDPE produced pyrolysis oil, whereas PET produced only wax. The co‐pyrolysis of the three polymers with different mixing ratios showed that PET hindered oil formation and increasing its amount more than 20 wt% in the polymer mixture resulted in wax formation. The thermal process produced 8 wt% pyrolysis oil, 32.3 wt% wax, 39.7 wt% pyro‐gases and 20 wt% coke while the catalytic process with copper catalyst produced 32.5 wt% pyrolysis oil, 3 wt% wax, 46.5 wt% pyro‐gases, and 18 wt% coke under optimum conditions.ConclusionThe thermal pyrolysis oil contained long chain paraffins as major components, while short chain isoparaffin and naphthenes were predominant in the catalytic pyrolysis oil owing to which marked differences were observed in the physicochemical properties of both oils. The fractionally distilled fractions of catalytic pyrolysis oil in gasoline, kerosene, and diesel range showed profound similarities with standard fuels in terms of fuel properties particularly the gasoline range fraction. © 2022 Society of Chemical Industry (SCI).