Municipal Plastic Waste Research Articles

Performance Characteristics of a Compression Ignition (CI) Engine Using an Environmentally Friendly Waste Plastic Fuel

Due to growing demands and depleting reserves of petroleum-based fuel, there is a necessity to find an alternative fuel for IC engines. Also, environmental concerns and globally faced problems like lots of garbage generated through plastics is a major issue in India. There is a significant disparity between plastic production and waste plastic generation. Therefore, the need for alternative fuels derived from municipal plastic waste has emerged to enhance the performance of IC engines, decrease emissions, and address other environmental concerns in line with the “Swachh Bharat Mission of India”. In this study, the alternative fuel was produced from a municipal mix of plastic waste by pyrolysis process. The experiments were carried out with a constant speed of 1500 rpm at different load conditions and fueled with standard diesel, waste plastic fuel and other blends to investigate IC engine performance and combustion and emissions in terms of brake thermal efficiency, brake power, brake specific fuel consumption, cylinder pressure, net heat release, mean gas temperature, rate of pressure rise, andbrake specific CO2, NOx, CO and HC emissions parameters were investigated and it is compared with standard diesel. The overall result shows that WPO20D80 and WPO30D70 exhibit the peak performance (torque, BP, BTE and BSFC) and lowest emissions (HC, CO, NOx) at all load conditions. Moreover, according to all the performance results, the lowest BSFC with maximum brake thermal efficiency and variations was 24.01% and 0.346 Kg/kWh for the WPO30D70 blend at part load condition. The minimum brake-specific NOx produced by the diesel blend at peak load conditions (WPO20D80) is 138.66 ppm, which is higher than other blends. This phenomenon may be attributed to an elevated proportion of pre-combustion and an extended ignition duration, resulting in a high cylinder temperature and an enhanced rate of heat release. This analysis contributes to a deeper understanding of the environmental implications associated with different fuel blends and load conditions. Notably, the blends ranging from 10% to 50% showed good tendencies to be utilized with diesel engines and consistently exhibit favourable brakespecific emission profiles, suggesting its potential as an environmentally friendly alternative fuel.

Energy out of waste: kinetics and thermolysis of co-pyrolysis of biomass and municipal plastic waste

Energy out of waste: kinetics and thermolysis of co-pyrolysis of biomass and municipal plastic waste

Experimental Study of Plastic Bricks Made from Waste Plastics

This study describes the use of municipal plastic waste (MPW) in the construction industry. Plastic is a nonbiodegradable material that takes thousands of years to decompose and causes soil and water pollution. The amount of plastic waste in municipal solid waste (MSW) is increasing rapidly. Usage is estimated to double every decade. Plastic consumption is high and one of the largest plastic wastes is polyethylene (PE). The use of earth-derived clay materials has caused resource depletion and one of these efforts is the efficient use of plastic waste and laterite quarry waste, along with small amounts of asphalt, to meet the growing demand for traditional building materials, which are less absorbent than laterite bricks. The challenge is to develop alternative building materials, such as brick, that have little but sufficient strength. The use of MPW as a building material, especially in brick production, is one of the promising steps towards sustainable resource and waste management. Plastic waste can partially or completely replace one or more raw materials in brick production. Further research based on recent research and a better understanding of the use of waste plastics in bricks is needed to produce high-quality and durable bricks and to achieve an optimal balance in all aspects, especially in terms of cost and functionality.

Low-temperature dechlorination methods for pyrolysis oil of municipal plastic waste

Pyrolysis oil produced from municipal plastic waste can be utilized as fuel and various valuable chemicals as an alternative to petroleum. However, pyrolysis oil usually contains a relatively high concentration of chlorinated compounds, obstructing its utilization in the chemical industry. The present research reveals that pyrolysis oil contains inorganic chlorine and organochlorine compounds, and differentiated approaches should be considered to remove Cl from covalent and ionic chlorine linkages. Transition metal-based ZSM-5 catalysts showed remarkable dechlorination performance via mild C-Cl cracking of 1-chlorooctane and 4-chlorotoluene at 180 °C or below. The neutralization method of mixing pyrolysis oil with an alkaline solution quickly eliminated ionic chlorine from inorganic chlorine compounds, reducing Cl concentrations by up to 70 % at temperature below 40 °C. Based on the different dechlorinating pathways, an ideal combination of these two methods was suggested to enhance chlorine removal efficiency from pyrolysis oil.

Investigation of the mechanical, microstructure, and durability properties of concrete with fine uniform and non-uniform polyethylene terephthalate (PET) aggregates

Concrete manufacturing is highly resource-intensive and is a major source of greenhouse gas emission. Accelerating depletion of natural resources such as sand, which is the primary material for aggregate in concrete manufacture is a growing problem. At the same time, the disposal of vast volumes of non-biodegradable plastic waste poses a global environmental challenge. The incorporation of aggregates derived from municipal plastic waste to substitute for sand has the potential to help address both issues, while at the same time mitigating greenhouse gas emission. This study examines the potential of municipal polyethylene terephthalate (PET) plastic waste as a fine aggregate in concrete manufacturing. The primary focus was on PET aggregates with non-uniform and uniform shapes ranging in size from 2.36 to 4.75 mm. In the concrete mixtures, 0 %, 30 %, and 50 % of the fine natural aggregate by volume were replaced with fine PET aggregate with a water to cement ratio of 0.40. The obtained results showed a reduction in compressive and splitting tensile strength when compared to control specimens. However, replacing 30 % of fine natural aggregate with PET (both uniform and non-uniform shapes) significantly improved chloride resistance by 13 % and 12 %, respectively, while also enhancing the bond between cement paste and PET particles. This study characterizes the material properties of PET concrete, which represents a promising method for reusing municipal plastic waste and mitigating environmental concerns in concrete production.

Comparing carbon-saving potential of the pyrolysis of non-recycled municipal plastic waste: Influences of system scales and end products

Pyrolysis of non-recycled municipal plastic waste has the potential to mitigate the plastic waste crisis and to produce transport fuels (diesel or hydrogen), as compared with the conventional methods such as incineration or landfilling that have potential adverse environmental consequences. Transport fuel production from non-recycled municipal plastic waste contributes to the transition to more sustainable waste management. However, little is known about the influences of system scales and end product selection on the carbon footprints of the plastic waste treatment. Here, we applied the approach of life cycle assessment to compare the carbon-saving potential of centralized, large-scale and decentralized, small-scale pyrolysis systems producing diesel and hydrogen in the United Kingdom. It is shown that centralized systems had a lower global warming potential results than decentralized systems despite their greater transportation distances. The global warming potentials of diesel production for centralized and decentralized systems were 801 and 1345 kg CO2-eq. per tonne of non-recycled municipal plastic waste, respectively, whilst hydrogen production had much higher global warming potentials which are 7110 and 7990 kg CO2-eq per tonne of non-recycled municipal plastic waste, respectively. In hydrogen-producing systems, crude carbon nanotubes are also produced, and the purification process of carbon nanotubes requires significant material resource (hydrochloric acid and deionized water) inputs, resulting in high Scope 2 and 3 emissions. Also, it is worth noting that the global warming potential related to the Scope 1 emissions for the diesel-producing systems exceeds 80%, whereas the hydrogen-producing systems yield opposite results. The end use of diesel produced has a greater carbon footprint than the end use of hydrogen. The carbon saving from the displacement of fossil hydrogen was two times higher than that from diesel displacement. Decentralized, small-scale hydrogen production from plastic waste had the highest global warming potential among all as the conversion process of municipal plastic waste to hydrogen and carbon nanotubes for small-scale systems is more energy and resource intensive. Sensitivity analysis showed that various factors, such as feedstock composition and the heating energy consumption in the conversion process, had less influence on the global warming potential of centralized systems as compared to decentralized systems.

Pathways to zero plastic waste in Chinese cities: Implications of different disposal options under the zero waste cities policy

The disposal of municipal plastic waste (MPW) is crucial to the sustainable development of cities. China generates a large amount of MPW and the disposal methods vary with the level of urban development. This study analyzed the MPW disposal transformation in six groups of China cities at different development level. The results show that landfill is still the main disposal method in the fourth and fifth tier cities, while incineration has become the dominant disposal method in the higher-tier cities. The speed of transforming from landfill to incineration is faster at the higher-tier cities except the first-tier cities due to the large population and limited land resources. Scenario analysis implies that landfill and interim storage MPW could reduce 25%–35% by enhancing incineration and 51%–57% by enhancing recycling. There is still a big potential for lower-tier cities to enhance its incineration capacity, yet improving the recycling should be a more sustainable pathway especially for higher-tier cities.

Oxy-hydrogen, solar and wind assisted hydrogen ([formula omitted]) recovery from municipal plastic waste (MPW) and saltwater electrolysis for better environmental systems and ocean cleanup

The pyrolysis of plastic waste and the electrolysis of saltwater is a promising route to carbon neutrality in ocean cleanup and plastic waste management. Therefore, a solar and wind assisted H2-fuelled fast pyrolysis of MPW (municipal plastic waste) and electrolysis of desalinated saline were developed. The combined system uses an oxy-hydrogen furnace for thermal decomposition of MPW feed, CO2 as an inert reaction medium and both solar and wind energy systems to operate the electrical units. The deionised H2O feed to the electrolyser cell was produced from saltwater using the recovered heat from the fast pyrolyser unit. The process CO2 was captured and reused for soil improvement as current waste-to-energy routes of MPW recycling emit 695,850 tonnes of CO2. 2.65 kg/hrH2 fuel in an O2 environment was utilised to meet the decomposer operating temperature and heat duty which is approximately 29 % of the produced H2. Instability associated with bio-oil was prevented by using fast pyrolysis which release more volatiles. Compared to the related studies, this investigated work achieved the highest gas and carbon yields. Thermal NO < 0.1 ppm was recorded. The developed system is expected to reach ≥70 % energy efficiency and a sales price of < $3.89/kgH2.

Municipal Plastic Waste Recycling through Pyrogasification

Conventional mechanical recycling technologies cannot recycle all types and amounts of generated plastic waste. Pyrolysis can convert these municipal mixed plastic streams into products with significant calorific value, which are likely to be used as energy sources. The present work describes a technology used to expand the portfolio of technical approaches to drive plastics circularity, i.e., thermochemical recycling. A base case scenario considered a capacity of 1.000 kg/h of municipal plastic waste, consisting of a mixture of polypropylene (PP), polystyrene (PS), polyethylene (PE), and plastic associated with paper, which were converted into non-condensable gases, oil, and char through a pyrogasification system. Based on mass and energy balances and experimental data from the literature, a total of 199.4 kg (48 MJ/kg) of liquid fuel and 832.85 kg (16 MJ/kg) of gas could be obtained with no need for external heating sources. The thermal requirement for the pyrolysis of 1.000 kg of municipal plastic waste (1.316 MJ) was supplied by the gasification of a fraction of the produced pyrolysis oil and gases. This feasibility analysis confirmed the technical adequacy of the proposed technology, which that will be further complemented by a technoeconomic study of the proposed solution.

Kinetic study of pyrolysis of waste polystyrene and polyethylene mixture using novel non‐isothermal method

AbstractA tremendous increase in municipal plastic waste is observed due to high consumption of polymers. With the passage of time the available landfills for discarding of waste plastics decrease whereas, appropriate recycling methods for waste plastics gaining more and more importance. In the present work thermal decomposition of polystyrene (PS) and polyethylene (PE) waste mixture was carried out at different heating rates (5, 10, 15 and 20 °C/min) in a thermogravimetric analyzer (TGA). Thermogravimetric data obtained was further interpreted using new developed non‐isothermal integral method and compared it with several kinetic models i. e., Coats Redfern (CR), Ozawa Flynn Wall (OFW), Kissinger‐Akahira‐Sunose (KAS), Achar and Criado‐Dollimore (CD). The activation energy (Ea) calculated using CR, OFW, KAS, Achar and CD models were found to be in the range of 92.7–130.6, 85.3–120.1, 82.1–113.2, 114.8–162.1 and 95.4–134.4 kJmol−1 respectively, whereas Ea determined by using new developed non‐isothermal method was found to be in the range 70.9 to 106.3 kJmol−1.By comparison the activation energies, it has been concluded that new integral method gave the sharp range and consistent value with highest correlation coefficient, indicating that new developed non‐isothermal method is most suitable for determination of kinetic parameters. The kinetic parameters seem to be very helpful in investigating the reaction mechanism of the solid‐state reactions in real system and will give an opportunity to develop the mechanism of the decomposition reaction.

Probing the interface structure of block copolymer compatibilizers in semicrystalline polymer blends

AbstractThe use of block copolymers to compatibilize immiscible plastics is an important strategy for upcycling municipal plastic wastes. Multiblock copolymers (MBCPs) have been proven to be more effective compatibilizers than di‐ and tri‐block copolymers. Herein, we probe the interface structure of an effective multiblock copolymer compatibilizer and compare that with an ineffective triblock copolymer (TBCP). The interface activity of the compatibilizers is understood through a combination of small‐angle neutron and x‐ray scatterings (SANS and SAXS), by using deuterated homopolymer matrix and protonated compatibilizers. SANS analysis suggests that the MBCP forms a thicker interface layer (7–9 nm) than the TBCP (0–4 nm). In addition, SANS data seems to point to a stronger tendency for the MBCP to locate at the interface. Both factors contribute to its effectiveness at compatibilizing immiscible homopolymers.

Plastic trade-off: Impact of export and import of waste plastic on plastic dynamics in Asian region

Environmental contamination by plastics has been receiving considerable attention from scientists, policy makers and the public, and waste plastic trade has become a major social issue in recent years. In this study, the authors applied eco-hydrology model coupled with plastic debris model in Asian regions by including effect of waste plastic trade in order to clarify this research gap. Result showed settling and resuspension of plastic particles have great impact on mobilisation of plastic and its high intra-annual variability, and that the plastic transport becomes drastically higher during the flood periods accounting for most of the annual flux. In particular, the model simulated the size distribution of plastics in the water and riverbed sediment of the global major rivers and showed that the coarser particles are more distributed in the riverbed than those in the water. Further, the authors evaluated impact of waste plastic trade on change in riverine plastic transport by newly including effect of plastic trade on Mismanaged plastic waste (MPW) in the extension of previous studies. They newly modified to calculate municipal plastic waste by including these effects of plastic trade and disposal, and revised MPW assuming that the import of plastics is treated as the same as the export of plastics as the first approximation, which is the innovation of this study. The modified MPW became smaller than the original one in the exporting countries and vice versa in the importing countries. Further, this analysis clarified waste plastic trade has promoted decrease of riverine plastic transport in Japanese rivers, its slight increase in Yangtze, Yellow, and Ganges Rivers, and almost its constant in Mekong, Indus, Irrawaddy, and Brahmaputra Rivers. Recently, there is a growing progress in compiling existing research results and setting policy making in various countries under the umbrella of an intergovernmental negotiating committee (INC) on plastic pollution. The present results help to quantify plastic trade-off about impact of export and import of waste plastic on plastic dynamics in regional scale and to support the achievement of sustainable development goals (SGDs).

Comparative Study on Various Properties of Paver Block Produced from Municipal Plastic Waste

In order to lower the cost of paver blocks and use waste plastic bottles in the manufacturing process instead of using conventional concrete paver blocks, this study proposes to substitute coarse aggregates with plastic trash in paver blocks. The project’s goals are to make paver blocks more affordable while also reducing environmental pollution and plastic waste in a beneficial way. For the experiment, three different types of nine paver blocks, each measuring 220 x 180 x 70 mm and 240 x 120 x 60 mm, were created. In this study, we combined various amounts of plastic trash with coarse gravel and sand. After the paver blocks were assembled and put through testing, the findings showed improved compressive strength and water absorption. Hydrocarbons, which can be obtained from a variety of sources including coal, oil, and certain minerals, are used to make plastic. There are many different types of plastic, such as Low Thickness Polyethylene (LDPE) and High Thickness Polyethylene (HDPE). These leftover polymers are then to be effectively utilized in the production of paver squares. To produce high-quality blocks with warm and sound protection qualities to deal with contamination and to lower the overall cost of development, low-thickness polyethylene is spotlessly mixed with the sand and aggregate at different rates. This is probably the most ideal approach to prevent the collection of plastic waste.

Arduino Controlled Catalytic Pyrolysis of Plastic/Municipal Waste to Higher Hydrocarbons

Worldwide, the broad usage of plastic has resulted in the massive production of plastic pollution. In this work, it was demonstrated that municipal plastic waste could be converted into valuable liquid products. This study shows the catalytic and non-catalytic pyrolysis of low-density polyethylene (LDPE), polypropylene (PP), and high-density polyethylene (HDPE). Pyrolysis was carried out in the absence of Oxygen, and three types of fractions: gas, liquid, and solid residues were obtained. The proportions of liquid or gas residue depend on the operating conditions such as temperature and the type of catalyst. The product obtained was then characterized through ASTM D-97, ASTM D-86, ASTM D-4294, Cloud Point, Conradson Carbon Residue, FTIR Analysis, ASTM D-611, Density and Specific Gravity. The use of catalysts showed more quantity of lower boiling points products due to further cracking of carbon chains and pour points decrease was also observed generally with the use of catalyst specially by using bentonite. A decrease in Pour Point indicated a decrease in paraffin content, therefore, reducing wax content, and so it indicated better flow properties at lower temperatures. Pour point and viscosity observed were interconnected with each other, sample having high pour points had high viscosity, hence showing the flowing ability of the liquid. Also, the Sulphur contents of all the samples falling under Euro II and Euro II category. C-Stretching, C=Stretching and C-Bending bonds were noted using the FTIR analysis. One of the important purposes of this study was to convert the waxes obtained from thermal pyrolysis of HDPE and LDPE to higher chain hydrocarbons, which was achieved by using bentonite as the catalyst and also flowing properties of the liquid improved by using the catalyst. HDPE with bentonite gave the highest percent of liquid fuel (75.15%) obtained which in turn shows the best result obtained through all our experiments.

The Recycling of Municipal Plastic Wastes into an Alternative Hydrocarbon Fuel via Enhanced Zeolite-Based Catalytic Pyrolysis

The Recycling of Municipal Plastic Wastes into an Alternative Hydrocarbon Fuel via Enhanced Zeolite-Based Catalytic Pyrolysis

Pyrolysis of municipal plastic waste: Chlorine distribution and formation of organic chlorinated compounds

The release of chlorine during the pyrolysis of actual municipal plastic waste (MPW) was studied. Firstly, thermogravimetry-Fourier transform infrared (TG-FTIR) was analyzed to investigate the chlorine release behavior. Then, the effect of temperature on chlorine migrations was investigated by fast pyrolysis experiments in a fixed bed reactor. Results showed that chlorine released mainly between 241 and 353 °C in the form of HCl or chloroesters during MPW pyrolysis. After pyrolysis, chlorine was mainly distributed in the pyrolytic gas (74.34–82.89 %) and char (10.17–21.29 %). However, the release of chlorine was inhibited due to the melting behavior of MPW at <350 °C. Besides, the relative contents and types of organic chlorinated compounds in liquid products were both decreased with temperature. It was observed that polyethylene terephthalate (PET) was the greatest contributor to the formation of organic chlorinated compounds during MPW pyrolysis. Meanwhile, the pyrolysis of PET was significantly promoted by the HCl released from polyvinyl chloride (PVC). Subsequently, the pathways for the formation of organic chlorinated compounds through the co-pyrolysis of PVC and PET were proposed, including the initial degradation and subsequent chlorination of PET. These findings provided new insights into the release and regulation of chlorine-containing pollutants during actual MPW pyrolysis.

Thermochemical Characterization and Kinetics of Biomass, Municipal Plastic Waste, and Coal Blends and Their Potential for Energy Generation via Gasification

Thermochemical Characterization and Kinetics of Biomass, Municipal Plastic Waste, and Coal Blends and Their Potential for Energy Generation via Gasification

Pyrolysis of Municipal Plastic Waste to Produce Alternate Fuel

This research concentrates on the pyrolysis of municipal plastic waste (MPW) to produce an alternate fuel and its thermal comparison with petrol and diesel. It is a viable response to the growing problem of plastic waste disposal. Fuels made from petroleum and plastics contain carbon and hydrogen and are classified as hydrocarbons. Plastics are made up of fossil fuel-based chemicals such as natural gas or crude oil. It is non-biodegradable waste, mainly consisting of approx 15% of total Municipal Solid Waste (MSW). Plastics are pivotal in today's world and are excessively used in households, industry and other fields due to their lightweight, durability, flexibility and inexpensive ability to produce. The need for plastics is expanding every day, posing a significant danger to the climate.The pyrolysis process is a waste-to-energy technological option for producing alternative fuels to replace fossil fuels. It is a thermochemical decomposition of organic material at high temperatures without oxygen or an inert gas atmosphere. Municipal Plastic Waste is depolymerized, pyrolyzed, catalytically cracked, and fractionally distilled to produce various value-added petroleum-derived fuels via pyrolysis which can be used to replace low diesel oils. The pyrolysis method has the benefit of being able to handle unsorted polymers. The material's pretreatment is simple. Plastics must be sorted, dried, and shredded. Pyrolysis, instead of incineration, doesn't emit harmful or hazardous gases. Transforming municipal plastic waste into energy has significant environmental, climatic, and economic implications.

Catalytic pyrolysis of plastic waste to gasoline, jet fuel and diesel with nano MOF derived-loaded Y zeolite: Evaluation of temperature, zeolite crystallization and catalyst loading effects

Catalytic pyrolysis of municipal plastic waste can serve as a means of refining nature from the non-degradable plastic pollutants while producing a significant amount of liquid fuel required for the transportation industry. The low quality of the produced liquid fuel is often a fundamental challenge in pyrolysis, which can be overcome by utilizing catalysts. In this study, an upgraded zeolite Y catalyst has been employed. However, one of the main issues with zeolites is their small pore size, which restricts the entry of heavy polymer compounds and only allows small molecules to enter. To address this limitation, an innovative approach has been applied in this research where MIL-53 (Cu) is loaded onto the surface of the zeolite. After pyrolysis, it was determined that a composite of copper and its oxides, enclosed in a carbon nanocarbon shell C60 and C70, has been loaded onto the surface of the zeolite. This inexpensive composite exhibit behavior similar to noble and expensive metals due to its high electron transfer density. Additionally, analyses XRD, FTIR, BET, XRF, EDX, GC–MS, NH3-TPD and CHNSO were utilized for the characterization of the catalyst and the liquid fuel. Furthermore, three key parameters were selected for experimental design: temperature (375–525 °C), catalyst loading in the reactor (2.5–17.5 %), and support crystallinity percentage (0–100 %). Using a response surface approach, the impact of these parameters on the liquid fuel production efficiency was investigated. Ultimately, the produced liquid fuel was separated into three fractions: gasoline, jet fuel, and diesel. The effects of these primary parameters on the efficiency of each fuel type were determined using the response surface methodology.

Evaluation of mixed #3–7 plastic waste from material recovery facilities (MRFs) in the United States

Plastic recycling rates are still low in the United States (U.S.), with less than 10% of municipal solid waste (MSW) plastic being recycled. Most unrecycled plastics are identified by Resin Identification Codes (RIC) from #3–7, which are commonly destined for landfill or waste-to-energy facilities (WTE). Therefore, the composition and quality of outbound bales containing #3–7 plastics were assessed to understand the potential to increase recycling rates. Three bales were sourced from three different Material Recovery Facilities (MRFs) located in the United States. Each bale was manually sorted and characterized for quality and performance via multiple plastic characterization techniques. Considerable differences in bale composition were observed between MRFs, which correlated with the technology used by each MRF in the sorting process. The differences were substantial in the residual levels of poly(ethylene terephthalate) (PET) and high-density polyethylene (HDPE), which are highly desired for mechanical recycling processes and not expected in #3–7 plastics bales. Traditional recycling processes including washing, extrusion, and injection molding of the sorted material were employed prior to the physical, thermal, and molecular characterization. Despite differences in bale composition by plastic type, some polymer properties were similar across MRFs. This research suggests that landfill-diverted mixed plastic waste can be utilized in the mechanical recycling of currently unrecycled materials, as processes can be designed to work with consistent polymer properties. It also highlights the need to upgrade the sorting systems to prevent waste feedstocks, which can be recycled with current technologies, from contaminating other plastic streams or reach landfills.