08/05/2025
By Danielle Fretwell

The Francis College of Engineering, Department of Energy Engineering - Renewable, invites you to attend a Doctoral Dissertation Proposal defense by Andrew Boules on: "Nonthermal Plasma Hydrogen Production from Polymeric Plastic and Biomass Waste Models and Plastic Films."

Candidate Name: Andrew Boules
Degree: Doctoral
Defense Date: Monday, Aug. 18, 2025
Time: 1 - 3 p.m.
Location: Perry Hall 415

Committee:

  • Advisor: Juan Pablo Trelles, Professor, Department of Mechanical and Industrial Engineering, University of Massachusetts Lowell
  • David K. Ryan, Professor, Department of Chemistry, University of Massachusetts Lowell
  • Ertan Agar, Professor, Department of Mechanical and Industrial Engineering, University of Massachusetts Lowell
  • John H. Mack, Professor, Department of Mechanical and Industrial Engineering, University of Massachusetts Lowell

Abstract:
Nonthermal plasma processes are promising for the modular valorization of solid waste, especially into hydrogen and carbon materials, due to their high intensity, lack of reliance on catalysts or consumables, and suitability to be directly powered by electricity. In this doctoral research dissertation, we study the production of hydrogen via atmospheric pressure nonthermal streamer dielectric-barrier discharge (sDBD) plasma treatment of low-density polyethylene (LDPE) and cellulose (CE) powders, used as plastic and biomass waste models, respectively, as well as plastic films. Experimental results show that mixing LDPE and CE synergizes hydrogen production when nitrogen is used as the working gas, but not argon, with the LDPE:CE mixture of 1:2 yielding the highest hydrogen production, 37% larger than non-synergistic expectations. Subsequently, we investigate the production of hydrogen from low-density polyethylene via sDBD plasma utilizing a novel plasma reactor design. We examine the effects of process energy density (energy input per unit of feedstock mass), feedstock mass, and plasma intensity (electric voltage) on hydrogen yield and energy efficiency. Our investigation includes the characterization of the plasma using optical emission spectroscopy and electrical diagnostics, together with reactor-scale and nonlinear electrical circuit modeling. The characteristic temperature of free electrons in the sDBD plasma is approximately 15000 K (1.3 eV), and that of gas species 10 times lower, demonstrating strong thermal non-equilibrium that can lead to molecular bond scission via species impact. Experimental results show that higher energy densities lead to greater hydrogen production and diminishing energy efficiency. Larger feedstock masses and higher plasma intensity produce more hydrogen due to improved thermal retention, which leads to higher plasma temperatures, and enhanced energy fluxes to the feedstock. Finally, we plan on investigating the use of sDBD plasma for hydrogen production from several types of plastic films, including multi-layered films, as well as creating a nonthermal plasma hydrogen production model capable of describing the effects of the main process parameters.