03/24/2023
By Danielle Fretwell

The Francis College of Engineering, Energy Engineering Graduate Program, invites you to attend the doctoral dissertation defense by Benard Tabu on “Hydrogen Production from Polymeric Organic Solids via Atmospheric Pressure Nonthermal Plasma.”

Candidate Name: Benard Tabu
Defense Date: Friday, April 7, 2023
Time: 10 a.m. to noon
Location: Southwick 240. Those interested in attending virtually via Zoom should contact the student (Benard_Tabu@student.uml.edu) and committee advisor (Juan_Trelles@uml.edu) at least 24 hours prior to the defense to request access to the meeting.

Committee:

  • Advisor Juan Pablo Trelles, Associate Professor, Mechanical and Industrial Engineering, UMass Lowell
  • Juan Pablo Trelles, Associate Professor, Mechanical and Industrial Engineering, UMass Lowell
  • Maria Carreon, Assistant Professor, Department of Mechanical and Industrial Engineering, UMass Lowell
  • Hsi-Wu Wong, Associate Professor, Department of Chemical Engineering, UMass Lowell
  • John Hunter Mack, Associate Professor, Department of Mechanical and Industrial Engineering, UMass Lowell

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 via natural gas reforming or electrochemically through water splitting. Organic solid feedstocks rich in 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, leading to sustainable alternatives for upcycling plastic and biomass waste. This doctoral research dissertation focuses on the production of hydrogen from solids via atmospheric nonthermal plasma. First, two low-temperature atmospheric pressure plasma reactors, based on transferred arc (transarc) and gliding arc (glidarc) discharges and depicting complementary operational characteristics, are designed, built, and characterized to produce hydrogen from low-density polyethylene (LDPE) as a model plastic waste. Experimental results show that hydrogen production rate and efficiency increase monotonically with increasing voltage level in both reactors. Despite the markedly different modes of operation of the reactors, their hydrogen production performance metrics are comparable. The maximum hydrogen production efficiency and minimum energy cost are 0.16 mol/kWh and 3100 kWh/kg H2, respectively, for the transarc reactor, and 0.15 mol/kWh and 3300 kWh/kg H2, respectively, for the glidarc reactor. Based on these findings, a Streamer Dielectric-Barrier Discharge (SDBD) reactor is devised for the production of hydrogen and carbon co-products from LDPE and cellulose, the latter as a model of biomass waste feedstock. Spectroscopic and electrical diagnostics and modeling are used to estimate representative properties of the plasma, including electron and excitation temperatures, number density, and power consumption. Cellulose and LDPE are plasma-treated for different treatment times to characterize the evolution of the hydrogen production process. The maximum hydrogen production efficiency and minimum energy cost for cellulose treated by the SDBD reactor are 0.8 mol/kWh and 600 kWh/kg of H2, respectively, representing approximately twice the efficiency and half the energy cost attained during the SDBD treatment of LDPE. Solid products are characterized via scanning electron microscopy, revealing the distinct morphological structure of the two feedstocks treated, as well as by elemental analysis. The results demonstrate that SDBD plasma is effective at producing hydrogen from cellulose and LDPE at atmospheric pressure conditions in relatively low temperatures, rapid response, and compact processes.