Advances in Automobile Engineering
Open Access

Utilising Pyrolysis Oil from Waste Plastic Bottles as an Alternative Fuel

Gardener Tom^{* *}Correspondence: Gardener Tom, Department of Mechanical Engineering, Monash University, Melbourne, Australia, Email:

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About the Study

Thailand has been dealing with environmental pollution, particularly in the form of massive amounts of plastic waste, which increased dramatically during the COVID-19 pandemic due to an increase in the use of plastic products as a result of online food delivery and take-away packaging during this time period. Because plastic garbage cannot be decomposed by natural creatures and takes hundreds of years to decompose, it has a substantial impact on human health and creates environmental contamination. This condition generates a large amount of plastic garbage. According to the Pollution Control Department of Thailand Report, roughly two million tonnes of plastic garbage were generated in 2020, accounting for around 12% of total Municipal Solid Waste (MSW) by weight. Because of their great combination of qualities that make them suited for containers, plastic materials such as poly(ethylene terephthalate) (PET) are frequently used for beverage packaging (particularly drinking water and soft drinks). The widespread usage of plastic PET bottles results in a large amount of collected PET garbage in landfills. Furthermore, waste PET bottles are a component of municipal plastic trash. Thailand currently consumes more than 4000 million plastic PET bottles every year. To address the plastic waste problem, a waste management approach is required, which involves reducing, reusing, recycling, recovering, and disposal.

In fact, only 0.5 million tonnes of plastic trash containers were retrieved for recycling, with the remainder ending up in landfills. This predicament is the result of an inefficient management system. The process of energy recovery from plastic trash is of great interest in converting waste to fuel for energy resources since it can help Thailand reduce plastic waste and restore the environment.

Many researchers have examined the use of plastic waste in fuel generation as an alternative fuel in Compression Ignition (CI) engines, according to a survey of the literature. This is due to the fact that plastic garbage is a petrochemical product with a high energy content that mostly consists of carbon and hydrogen atoms. The pyrolysis method, which is the most appropriate technology for converting polymer waste into fuel, may extract fuel from plastic waste. Previous research discovered that the fuel qualities of Waste Plastic Oil (WPO) were similar to those of diesel fuel, particularly the physical and chemical property characteristics of WPO, which varied based on feedstock type and pyrolysis process parameters. (e.g pressure, residence time, heating rate). The manufacturing of pyrolysis fuel from various plastic waste types such as Polystyrene (PS), Polypropylene (PP), high-density polyethylene (HDPE), Low-Density Polyethylene (LDPE), poly(vinyl chloride) (PVC), poly(ethylene terephthalate) (PET), and mixed plastics. Because of the differences in composition, it is possible to deduce that the plastic type altered the characteristics and quality of the fuel produced.

When compared to diesel fuel, the experimental results of numerous investigators revealed that the use of WPO in diesel engines exhibited an upward trend in Brake-Specific Fuel Consumption (BSFC) and Brake Thermal Efficiency (BTE). However, the exhaust emissions caused by WPO combustion, such as Nitrogen Oxides (NOX), unburned Hydrocarbons (HC), Carbon Monoxide (CO), and smoke emission, tend to rise with WPO use. Furthermore, WPO has a considerable impact on engine combustion characteristics, with the use of WPO increasing the ignition delay period as well as the Rate of Heat Release (RoHR) and In-Cylinder Pressure (ICP), all of which are critical criteria in the combustion characteristics of CI engines. However, some researchers discovered that using WPO as a fuel in CI engines increased engine performance while decreasing NOX, CO, and smoke emissions. This is because WPO contains chemical components. Furthermore, the characteristics of Particulate Matter (PM) emissions induced by alternate fuel combustion in CI engines were explored for an explanation of PM compositions. Thermogravimetric Analysis (TGA) was used to characterize volatile materials and soot as PM compositions of waste source fuel. TGA characterizes volatile matters and soot as PM compositions by monitoring mass loss as temperature rises. As a result, the TGA approach is particularly appealing for analyzing PM emissions from diesel engines that use WPO.

Conclusion

The goal of this study is to look at the usage of Waste Plastic Oil (WPO) derived from the pyrolysis of waste Polyethylene Terephthalate (PET) bottles as an alternative fuel for replacing fossil diesel fuel in CI engines. Its impacts on engine performance, combustion, and exhaust gas emissions were investigated. Furthermore, the soot oxidation temperature of PM formed by WPO combustion was examined.