Abstract
The properties and versatility of plastic have established it as a staple and necessary material today. The problem is the disposal of that plastic in an environmentally sustainable way. With only 1.2% of all plastic since 1950 being recycled, the solution is to examine the life cycle of single use plastics and determine a better end-of-life use. Through Pyrolysis, the plastic is heated in the absence of oxygen and polymer chains are broken down into monomers, similar in the composition of crude oil. Undergoing fractional distillation, the plastic pyrolysis crude oil is separated out into a range of fuels comparable to diesel, kerosene, gasoline, and naphtha. This thesis examines the challenges associated with traditional recycling and presents a sensitivity analysis on the input factors of pyrolysis to yield a liquid product suitable for internal combustion engine use in both quantity and quality. From the findings of the sensitivity analysis, plastic type and reaction chamber temperature have the greatest influence on the quantity and quality of the output liquid pyrolysis product. The sensitivity analysis revealed interdependency between input variables and identified plastic types least suitable to the pyrolysis process for the desired outcome of liquid pyrolysis product as combustion fuel. Type 5 plastic is the most promising in producing a liquid fuel due to its abundance in consumption, low recyclability by traditional means, and when distilled in the “diesel” range, the pyrolysis fuel is most comparable to the literature characteristics of diesel fuel. Utilizing literature data, a poly-fit line and equation is derived to estimate the liquid pyrolysis product yield as a function of reactor chamber temperature. As plastic type and temperature are the most impactful input factors, this equation is applied to type 5 plastic to predict a maximum yield of 79.83wt% liquid yield per 100kg of feedstock under ideal conditions. Recycling by pyrolysis re-envisions the end-of-life for single use plastics to solve the problem of sustainably disposing of plastic waste and creating the product of a suitable fuel for use in internal combustion engines.