Thesis Abstract

Abstract
Polyethylene (PE) is one of the most widely used plastics in the world, with a significant portion of it ending up as waste in landfills and oceans. Recycling PE waste through pyrolysis, a thermochemical process that breaks down the polymer into smaller molecules in the absence of oxygen, offers a sustainable solution to reduce environmental pollution and the demand for virgin plastics. This research project aims to investigate the pyrolysis of waste PE materials to produce useful products such as fuels, chemicals, and waxes. The process parameters including temperature, residence time, and catalysts will be optimized to maximize the yield of valuable products while minimizing waste generation. Characterization techniques such as gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) will be employed to analyze the composition and properties of the pyrolysis products. The economic feasibility of the recycling process will be assessed through a techno-economic analysis to determine the cost-effectiveness and potential for commercialization. The environmental impact of recycling waste PE via pyrolysis will also be evaluated to compare with traditional disposal methods. The findings of this research will contribute to the development of sustainable waste management practices and the circular economy by converting PE waste into valuable resources, thus reducing the reliance on fossil fuels and mitigating the environmental impact of plastic pollution.

Thesis Overview

1.1 Background of study

Recycling is a process of changing waste materials into new products to prevent waste of potentially useful materials, reduce the consumption of fresh raw materials, energy usage, water and air pollution (from incineration), and lower greenhouse gas emissions as compared to plastic production. Recycling is a key component of modern waste reduction and is the third component of the “Reduce, Reuse and Recycle” waste hierarchy (lajeunesse,sara 2004).

The rate of consumption of plastic materials in the world is greatly expanding, more waste plastics are generated. In recent years, their generation amount in Korea becomes about four million per year, according to data from the National Institute of Environmental Research (Lajeunesse, Sara 2004). The disposal of waste plastic is mostly achieved by conventional ways such as landfill or incineration. However, these methods have a problem of a social resistance due to the air pollution, soil contamination, and the economical resistance caused by an increase of space and disposal cost. Thus, the recycling of plastic wastes as a cheap source of raw materials has become a predominant subject over all countries (Roach, John 2003). The development of technologies acceptable from the environmental and economical fields is one of the most important key factors. (Roach, John.2003). Plastic materials used for food storage, visible in all supermarkets, preserves freshness and flavor due to the ability to seal out contaminants. Polyethylene materials are useful over a wide temperature range, from frozen foods to microwavable packages1. Due to these benefits, plastics have become widely used. (lajeunesse,sara 2004).

Polyethylene plastic bags are petroleum-based so the manufacturing process releases harmful pollutants into the atmosphere. Some speculate that these emissions and other smog-related types of pollution accumulate over time in the atmosphere.

Countries and large corporations are beginning to realize the threat that these plastic bags pose to our planet. Many are proposing or have already enacted laws and taxes to decrease the use of polyethylene plastic bags. Many grocery stores are even rewarding customers for bringing reusable grocery bags as an alternative to these polyethylene plastic bags. Customers choosing not to use alternatives to plastic bags either find the alternatives are inconvenient or are simply unaware of the problem at hand.

Polyethylene recycling bags are currently being used all over the world but there is currently no environmentally friendly way to dispose of them.