03/03/2022
By Sokny Long

The Francis College of Engineering, Department of Mechanical Engineering, invites you to attend a doctoral proposal defense by Benard Tabu on "Hydrogen Production from Polymeric Organic Solids via Atmospheric Pressure Nonthermal Plasma."

Ph.D. Candidate: Benard Tabu
Defense Date: Thursday, March 17, 2022
Time: 10 to 11:30 a.m.
Location: This will be a virtual defense via Zoom. Those interested in attending should contact Benard_Tabu@student.uml.edu or committee chair, Juan_Trelles@uml.edu, at least 24 hours prior to the defense to request access to the meeting

Committee Chair (Advisor): Juan Pablo Trelles, Associate Professor, Department of Mechanical Engineering, UMass Lowell

Committee Members:

  • Maria Carreon, Assistant Professor, Department of Mechanical Engineering, UMass Lowell
  • Hsi-Wu Wong, Associate Professor, Department of Chemical Engineering, UMass Lowell
  • J. Hunter Mack, Associate Professor, Department of Mechanical Engineering, UMass Lowell

Brief Abstract:
The potential of using hydrogen as a sustainable energy carrier is attributed to its high energy density and its utilization without CO2 emissions. Existing technologies mainly produce hydrogen thermochemically from natural gas reforming or electrochemically from water splitting. Organic solid feedstocks rich of hydrogen, such as biomass and plastic waste, are under-utilized for this purpose. Approaches based on low temperature atmospheric pressure plasma powered by renewable electricity could lead to the production of green hydrogen more viably than current approaches, providing a sustainable alternative for upcycling the increasing amount of plastic and biomass waste. This doctoral research dissertation focuses on the production of hydrogen from solids via atmospheric nonthermal plasma. Plasma reactors based on transferred arc (transarc) and gliding arc (glidarc) discharges are designed, built, and experimentally characterized to produce hydrogen from low density polyethylene (LDPE) and cellulose (CE) as a model plastic and biomass waste, respectively. The reactors depict complementary operational advantages, i.e., the transarc reactor allows direct control of the power delivered onto the feedstock, and the glidarc reactor permits the electrically decoupled treatment of feedstock. Computational Fluid Dynamics thermal-fluid models are used to estimate operational characteristics from the reactor designs. The constructed reactors are experimentally characterized based on their main operational parameters, namely: flow rate, electrode-feedstock spacing, and voltage level, using electrical diagnostics, and optical and Schlieren imaging. Hydrogen production is quantified using gas chromatography. Experimental results show that hydrogen production rate and hydrogen production efficiency increase monotonically with increasing voltage level in both reactors. For the transarc reactor, smaller electrode-feedstock spacing favors greater hydrogen production, whereas for the glidarc reactor, greater hydrogen production is obtained at intermediate flow rates. Ongoing and future work focus on applying optical emission spectroscopy diagnostics to obtain plasma characteristics, particularly electron temperature and number density, and on the design of reactor components and processes for the dehydrogenation of LPDE and CE feedstocks.

All interested students and faculty members are invited to attend the online defense via remote access.