Location: Bio-oils Research Unit
Title: Production, characterization and fuel properties of alternative diesel fuel from pyrolysis of waste plastic grocery bags Authors
Submitted to: Fuel Processing Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 18, 2014
Publication Date: February 13, 2014
Citation: Sharma, B.K., Moser, B.R., Vermillion, K., Doll, K.M., Rajagopalan, N. 2014. Production, characterization and fuel properties of alternative diesel fuel from pyrolysis of waste plastic grocery bags. Fuel Processing Technology. 122:79-90. Interpretive Summary: This research revealed that waste plastic grocery bags are suitable as pyrolysis feedstocks for production of alternative diesel fuel. Pyrolysis is defined as decomposition of material at elevated temperatures (above 570°F.) in the absence of oxygen. The principal benefit of pyrolysis is conversion of low energy density substrates into higher density liquid and solid fractions. In the case of waste plastic grocery bags, the liquid fraction was suitable as diesel fuel, as determined by comparing its fuel properties to those of conventional petroleum diesel as well as internationally accepted diesel fuel standards. Waste plastic grocery bags were studied as a feedstock because of their proliferation in the environment. Although they are recyclable, the U.S. EPA notes that only 13% were recycled of the approximately one trillion produced in 2009. The remainder are disposed of in landfills or released into the environment as litter. The objective of the current study was to explore their utility as a feedstock for production of liquid transportation fuels, thus reducing their impact on the environment while simultaneously reducing American dependence on foreign sources of petroleum oil. These results will be important to the alternative fuels industry, municipalities with landfills and litter issues, petroleum companies, plastics manufacturers, environmental organizations, and consumers. This research may ultimately improve market penetration, availability, and public perception of domestically produced alternative diesel fuels, thus affording greater independence from imported petroleum-based fuels while simultaneously enhancing economic opportunities across America.
Technical Abstract: Pyrolysis of HDPE waste grocery bags followed by distillation resulted in a liquid hydrocarbon mixture that consisted of saturated aliphatic paraffins (96.8%), aliphatic olefins (2.6%), and aromatics (0.6%) that corresponded to the boiling range of conventional petroleum diesel fuel (#1 diesel 182–290°C and #2 diesel 260–338°C). Characterization of the liquid hydrocarbon mixture was accomplished with gas chromatography-mass spectroscopy, infrared and nuclear magnetic resonance spectroscopies, size exclusion chromatography, and simulated distillation. No oxygenated species such as carboxylic acids, aldehydes, ethers, ketones, or alcohols were detected. Comparison of the fuel properties to the petrodiesel fuel standards ASTM D975 and EN 590 revealed that the synthetic product was within all specifications after addition of antioxidants with the exception of density (802 kg/m3). Notably, the derived cetane number (73.4) and lubricity (198 um, 60°C, ASTM D6890) represented significant enhancements over those of conventional petroleum diesel fuel. Other fuel properties included a kinematic viscosity (40°C) of 2.96 mm2/s, cloud point of 4.7°C, flash point of 81.5°C, and energy content of 46.16 MJ/kg. In summary, liquid hydrocarbons with appropriate boiling range produced from pyrolysis of waste plastic appear suitable as blend components for conventional petroleum diesel fuel.