Pyrolysis of Mixed Plastic Waste: I. Kinetic Study

Dubdub, Ibrahim; Al-Yaari, Mohammed

doi:10.3390/ma13214912

Cited by 65 publications

(41 citation statements)

References 30 publications

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“…Although Figure 1 represents data of the equi-mass binary mixture of PP and PS, Figure 2 shows the TGA data of the equi-mass ternary mixture of PP, PS, and LDPE at different heating rates. Generally, as reported for individual plastics in previous works [ 15 , 16 , 17 ], thermograms of all mixtures have a similar inverted S-shape. However, they were shifted to higher temperatures as the heating rate increased (i.e., a faster heating rate implies a small weight loss at specific temperatures).…”

Section: Resultssupporting

confidence: 77%

“…Proximate and ultimate analysis was performed to characterize the polymer samples; these data are presented in Table 1 . Details of both tests are described elsewhere [ 15 ].…”

Section: Methodsmentioning

confidence: 99%

“…Recently, Dubdub and Al-Yaari (2020) [ 15 ] investigated the co-pyrolysis process of mixed polymers (PS/PP/HDPE/LDPE) at a single heating rate (60 K/min). The Coats–Redfern and Criado models were used to obtain the kinetic parameters and the most suitable reaction mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Thermal Behavior of Mixed Plastics at Different Heating Rates: I. Pyrolysis Kinetics

Dubdub

Al-Yaari

2021

Polymers

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The amount of generated plastic waste has increased dramatically, up to 20 times, over the past 70 years. More than 50% of municipal plastic waste is composed of polystyrene (PS), polypropylene (PP), and low-density polyethylene (LDPE) products. Therefore, this work has developed a kinetic model that can fully describe the thermal decomposition of plastic mixtures, contributing significantly towards the efficiency of plastic waste management and helping to save the environment. In this work, the pyrolysis of different plastic mixtures, consisting of PP, PS, and LDPE, was performed using a thermogravimetric analyzer (TGA) at three different heating rates (5, 20, and 40 K/min). Four isoconversional models, namely Friedman, Flynn–Wall–Qzawa (FWO), Kissinger–Akahira–Sunose (KAS), and Starink, have been used to obtain the kinetic parameters of the pyrolysis of different plastic mixtures with different compositions. For the equi-mass binary mixtures of PP and PS, the average values of the activation energies were 181, 144 ± 2 kJ/mol obtained using the Freidman and integral (FWO, KAS, and Starink) models, respectively. However, higher values were obtained for the equi-mass ternary plastic mixtures of PP, PS, and LDPE (Freidman: 255 kJ/mol, FWO: 222 kJ/mol, KAS: 223 kJ/mol, and Starink: 222 kJ/mol). The most suitable reaction mechanisms were obtained using the Coats–Redfern model. The results confirm that the most controlling reaction mechanisms obey the first-order (F1) and the third-order (F3) reactions for the pyrolysis of the equi-mass binary (PS and PP) and equi-mass ternary (PS, PP, and LDPE) mixtures, respectively. Finally, the values of the pre-exponential factor (A) were obtained using the four isoconversional models and the linear relationship between ln A and the activation energy was confirmed.

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Section: Resultssupporting

confidence: 77%

“…Proximate and ultimate analysis was performed to characterize the polymer samples; these data are presented in Table 1 . Details of both tests are described elsewhere [ 15 ].…”

Section: Methodsmentioning

confidence: 99%

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Thermal Behavior of Mixed Plastics at Different Heating Rates: I. Pyrolysis Kinetics

Dubdub

Al-Yaari

2021

Polymers

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“…It was observed that an increase of PP share caused a decrease of process temperature and losses yield, thus increasing product yield. This synergetic behaviour was in line with the findings of Dubdub and Al-Yaari for a batch process conducted in a thermogravimetric analyser (TGA) [ 47 ]. Surprisingly, the product yield in the process with Sample 5 was higher than for pure PP.…”

Section: Resultssupporting

confidence: 88%

Influence of the Feedstock on the Process Parameters, Product Composition and Pilot-Scale Cracking of Plastics

Frączak¹,

Fabiś²,

Orlińska

2021

Materials

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Chemical recycling of polymers can lead to many different products and play a significant role in the circular economy through the use of plastic waste as a feedstock in the production of valuable materials. The polyolefins: polyethylene (PE) and polypropylene (PP), together with polystyrene (PS), can be chemically recycled by the thermal cracking (pyrolysis) process. In this study, continuous cracking of polyolefins and polystyrene in different proportions and with the addition of other polymers, like polyethylene terephthalate (PET) and polyvinyl chloride (PVC), was investigated at the pilot scale in terms of the process parameters and product yields. Gas chromatography with mass spectrometry (GC-MS) was used for the detailed analysis of the products’ compositions. The boiling temperature distribution and the bromine number were used for additional characterization of products. It was found that an increase of PP share caused a decrease in the process temperature, an increase of the product yield and a shift of the boiling range towards lighter products, increasing the content levels for unsaturates and branched hydrocarbons. It was observed that the addition of 5% PS, PET and PVC reduced the overall product yield, resulting in the creation of a lower-boiling product and increasing the conversion of polyethylene. An addition of 10% polystyrene increased the PP conversion and resulted in a higher product yield, without significant change in the boiling temperatures distribution.

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“…al [10] built a mathematical model of single-particle biomass under the pyrolysis process and compared the results with experimental measurements and other different types of wood samples, the ultimate analyses for the composition have been reported. Dubdub and Al-Yaari [11] investigated the kinetics of mixed plastic waste. Their results showed that using a single thermal degradation stage, the pyrolysis of pure polymer samples happens in the following order: PS, PP, LDPE, and HDPE.…”

Section: Introductionmentioning

confidence: 99%

Conversion of Mixed Waste of Wood and Plastic to Clean Fuels Using Pyrolysis in Nigeria – Numerical Study

Aziz¹,

Al-Dadah²,

Kuznetsova³

et al. 2021

World Congress on Mechanical, Chemical, and Material Engineering

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Waste management is a major challenge in Nigeria, where around 32 million tons of waste is generated annually including 13 million tonnes of agricultural waste and 2.5 million tons of plastic waste. Currently, the waste management system is very inefficient where almost 70% of the waste ends up in landfills, sewers, beaches and water bodies causing serious environmental and health problems. This work numerically investigates the conversion of mixed wastes (wood and plastics) to produce clean and affordable solid, liquid and gaseous fuels that can be used for cooking, heating and electricity generation. Pyrolysis process which involves heating the waste at different rates in the absence of Oxygen has received significant research interest since it can convert various types of waste to clean fuels thus reducing fossil fuel consumption and CO2 emission. For example, wood waste can be converted to high-quality syngas, oil, and char while plastic waste can be converted to high-quality syngas, oil, light and heavy waxes. Also, it generates lower emissions compared to other waste conversion processes such as combustion, gasification, and plasma treatment. In this study, a numerical model is developed to simulate the pyrolysis process of mixed wood and plastic waste materials to predict the outputs in terms of char, syngas, oil and wax production. The model is based on the kinetics of the reactions associated with wood and plastic when subjected to different heating rates from 320 to 923 Kelvin for 20 minutes. Results showed that for 1kg of mixed waste (30% plastic and 70% wood) and after 20 minutes of heating, the output consists of 50.13% syngas, 8.35% oil, 9.5% char, 10.8% light Wax and 8.33% heavy wax. This modelling allows for controlling the output composition based on varying the input waste constituents which can optimize the waste conversion process.

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Pyrolysis of Mixed Plastic Waste: I. Kinetic Study

Cited by 65 publications

References 30 publications

Thermal Behavior of Mixed Plastics at Different Heating Rates: I. Pyrolysis Kinetics

Thermal Behavior of Mixed Plastics at Different Heating Rates: I. Pyrolysis Kinetics

Influence of the Feedstock on the Process Parameters, Product Composition and Pilot-Scale Cracking of Plastics

Conversion of Mixed Waste of Wood and Plastic to Clean Fuels Using Pyrolysis in Nigeria – Numerical Study

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