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Chen, Wan-Ting

Publications and source records attributed to Chen, Wan-Ting.

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Chemical Recycling of Mixed Plastics in Electronic Waste Using Solvent-Based Processing

Currently, less than 20% of electronic waste (E-waste) produced in the U.S. is recycled. To improve the recycling rate of E-waste, the study aimed to: (1) identify the major plastics found within electronic shredder residue (ESR), (2) design solvents and processing conditions capable of separating out 90% of the plastic in ESR, and (3) estimate the energy efficiency of the solvent-based process developed. Preliminary screening showed 25 wt.% of the ESR was composed of plastics, with two polymers dominating the sorted plastic fraction—polystyrene (PS, 40 wt.%) and acrylonitrile butadiene styrene (ABS, 25 wt.%). Subsequently, solvents and anti-solvents were screened using Hansen Solubility Parameter Theory for PS, ABS, and ESR dissolution. The pre-screening results showed dichloromethane (DCM) and tetrahydrofuran (THF) as the most effective solvents for PS and ABS, with methanol (MeOH) and ethylene glycol (EG) as the most effective anti-solvents. By optimizing the dissolution time and the solvents used, the highest polymer dissolution yield (99 wt.%) was achieved using DCM for 48 h. Both MeOH and EG precipitated 71 wt.% of the polymer fraction of ESR. EG removed more phosphorus containing flame retardants (94 wt.%) than MeOH (69 wt.%). Energy analysis indicated that the solvent-based processes could save 25–60% of the embodied energy for PS and ABS. Characterization showed that the solvent-based processing could preserve the high molecular weight fraction of the polymers while removing flame retardants at the same time. The results from this study prove the potential of solvent-based processing to produce secondary plastic materials from E-waste for cross-industry reuse.

Anderson, Lester↗
DOE OSTI2021

Life Cycle Assessment of Recycling High-Density Polyethylene Plastic Waste

Increasing production and use of various novel plastics products, a low recycling rate, and lack of effective recycling/disposal methods have resulted in an exponential growth in plastic waste accumulation in landfills and in the environment. To better understand the effects of plastic waste, Life Cycle Analysis (LCA) was done to compare the effects of various production and disposal methods. LCA shows the specific effects of the cradle-to-grave or cradle-to-cradle scenarios for landfill, incineration, and mechanical recycling. The analysis clearly indicates that increasing recycling of plastics can significantly save energy and eliminate harmful emissions of various carcinogens and GHGs into the environment. As recycling increases, the need for virgin-plastic production can be greatly reduced. Furthermore, the results of this study may help improve current mechanical recycling processes as well as potential future recycling methods, such as chemical recycling. Concerns about the current recycling/disposal methods for plastics have brought increasing attention to the waste accumulation problem. However, with the current COVID-19 pandemic, plastic accumulation is expected to increase significantly in the near future. A better understanding of the quantitative effects of the various disposal methods can help guide policies and future research toward effective solutions of the plastic waste problem.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Spray and combustion characteristics of pure hydrothermal liquefaction biofuel and mixture blends with diesel

Hydrothermal liquefaction (HTL) is the process in which biological compounds can be converted into biocrude diesel; various feedstocks, such as algae and wet biowaste, can be utilized. Almost 20 million dry tons of wet biowaste is deposited in U.S. municipal wastewaters annually. If recovered and converted into biodiesel, it can act as a massive source of renewable energy. Preliminary experiments on a diesel engine show that HTL fuel can achieve similar performance and emission levels to diesel. In order to further understand the influence of the HTL fuel properties, the HTL fuel and blends with diesel are observed in a constant volume chamber. Previously, 10% and 20% of the HTL fuel were blended with diesel by volume and demonstrated properties that roughly matched diesel in terms of combustion. In this study, 50% and 100% HTL fuel blends are tested on the same apparatus. It was discovered that the workability of HTL is almost the same as that of diesel and is less sensitive to ambient temperatures. When the ambient temperature is reduced from 1200 K to 800 K, the change ratio of ignition delay is only 62% of diesel. By analyzing the combustion process, it can be seen that there is no need to make major modifications to the engine control strategy if HTL fuel is applied to diesel engines. Though, under low temperature and low oxygen conditions, the soot luminosity peak of HTL100 is 3.12 times than that of diesel.

09 BIOMASS FUELS↗