Browsing by Author "Uthpalani, P. G. I."

Now showing 1 - 2 of 2

Pyrolysis of plastic waste into liquid fuel
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Uthpalani, P. G. I.; De Silva, D. S. M.; Weerasinghe, V. P. A.; Premachandra, J. K.
The accumulation of plastic waste in the environment has emerged as a significant global concern. The versatile properties of plastics, such as low weight, low cost and durability which led to their widespread use as substituents for traditional materials like wood, metals, ceramics, and glasses. However, the improper handling and disposal of plastic waste have imposed negative consequences for the environment. The non-biodegradable nature of plastics makes them persist in the environment for extended periods, causing pollution and posing threats to ecosystems. Pyrolysis of plastic waste has been studied extensively in recent years as an effective solution, by exposing the plastic waste to high temperatures in an oxygen-free environment to decompose it into fuel oil, char, and gases. In this study, the waste of four types of plastics samples, low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP), and a mixture of these three types of plastics, were subjected to pyrolysis. Lab-scale, low-cost pyrolysis system was used to obtain liquid oils and herein, the non-condensed vapor was trapped into an organic solvent. Thermal pyrolysis or non-catalyzed pyrolysis resulted in a liquid yield of 65.64 ± 5.42 – 79.57 ± 1.66 wt.% at a temperature range of 340 – 360 ℃. Considering catalytic activity, high temperature stability, local availability, and abundance, four types of naturally available minerals were selected as potential catalysts for the pyrolysis of waste plastics. The mineral which resulted in the highest liquid yield was identified as the best-performing catalyst and used for further analysis. The catalyzed process resulted in an increased liquid yield of 71.79 ± 0.99 - 80.29 ± 1.76 wt.% at the temperature range of 290 – 320 ℃. The calorific value of the resulting oil in thermal and catalyzed pyrolysis processes were 10,850 -10,961 Kcal/kg and 10,556 - 11,473 Kcal/kg respectively. This reveals that the mineral selected is an ideal catalyst for pyrolysis of plastics and further indicates the quality enhancement of the fuel produced in catalyzed pyrolysis. Further, the fuel quality indicators; calorific values, density, kinematic viscosity, ash content, and water content of the resulting liquid oils under both catalyzed and uncatalyzed/thermal pyrolysis processes were significantly compatible with commercial grade diesel and kerosene fuel oils.
Pyrolysis of waste polypropylene to fuel oil
(Chemistry in Sri Lanka, 2022) Uthpalani, P. G. I.; Premachandra, J. K.; Weerasinghe, V. P. A.; De Silva, D. S. M.
Plastic waste accumulation in the environment has increased rapidly. This is mainly due to their versatile properties, which allow them to be used as substitutes for wood, metals, ceramics, and glass. They have diverse applications, as they are light-weight, durable, cost-effective, and stable products. However, the world is experiencing the adverse effects of plastic debris in the environment due to plastic waste mismanagement. Pyrolysis of plastic has been identified as an effective method of plastic waste management by converting the waste into fuel oil, char, and gases. The pyrolysis of waste polypropylene (PP) using a low-cost, simple lab-scale apparatus in the presence and absence of catalysts is discussed here. In the current research, the efficiency of the catalyst, Zeolite Socony Mobil-5 (ZSM- 5), in pyrolysis process was investigated. The generated volatile products were condensed into resultant liquid oil. Active carbon filters and organic solvents were used to trap the non-condensed gas fraction to prevent possible atmospheric pollution. The non-catalyzed pyrolysis of PP resulted a high liquid yield of 79.57 ± 1.66 wt. % with a low gaseous yield (14.64 ± 0.84 wt. %) at 330 °C while the ZSM-5 catalyzed process reduced the liquid yield to 56.88 ± 2.29 wt. % and increased the gaseous yield (38.13 ± 1.88 wt. %) at 280 °C. Then resultant liquids were fractionated based on the boiling points of several petroleum fractions (naphtha, kerosene, and diesel) and each fraction was analyzed by GC-MS to identify the constituent compounds. Accordingly, the non- catalyzed pyrolysis produced 3,3,5-trimethyl-heptane (C10H22), 4-methyl-2-undecene (C12H24), 1-dodecene (C12H24), and 2-methyl-1-hexadecanol (C17H36O) while the catalyzed pyrolysis with the ZSM-5 resulted 1-ethyl- 2-methyl-benzene (C9H12), 3,3,5-trimethyl-heptane (C10H22), (Cyclopentylmethyl)-cyclohexane (C12H22), and n-Nonylcyclohexane (C15H30) as the major constituents.