Disputas: Janitha Bandara

Janitha Bandara har til forsvar for graden philosophiae doctor (ph.d.) ved Universitetet i Sørøst-Norge (USN), Fakultet for teknologi, naturvitenskap og maritime fag (TNM), innlevert avhandling med tittelen: “Simulation and parameter optimization of fluidized-bed and biomass gasification”


27 Apr

Praktisk informasjon

  • Dato: 27. april 2021
  • Tid: kl. 09.30 - 14.00
  • Sted: Webinar, Zoom
  • Link til prøveforelesning og disputas på Zoom

    På grunn av koronasituasjonen gjennomføres prøveforelesningen og disputasen digitalt via Zoom.

    Program

    09.30: Prøveforelesning: 'Waste management: incineration or gasification?'

    12.00: Disputas: Janitha Bandara defends his PhD thesis 'Simulation and parameter optimization of fluidized-bed and biomass gasification'

    Bedømmelseskomité

    • Første opponent: Professor Rikard Gebart (Luleå University of Technology)
    • Andre opponent: Dr. Maria Puig-Arnavat (Ramboll)
    • Tredje opponent og administrator av komiteen: Førsteamanuensis Joachim Lundberg (USN)

    Hovedveileder

    • Professor Marianne Sørflaten Eikeland, USN

    Biveiledere

    • Professor Britt Margrethe Emilie Moldestad, USN
    • Professor Henrik Kofoed Nielsen, UiA

    Spørsmål (ex auditorio) til kandidaten kan sendes i forkant til administrator Joachim Lundberg:
    Joachim.Lundberg@usn.no

    Les hele avhandlingen her. 

Summary:

Janitha BandaraThe sustainable existence of the Earth is important before planning civilization on the moon. The global warming is becoming evident, which demands more scientific and technological researches devoted on limiting the greenhouse gas emissions. It is hardly unlikely to replace the full spectrum of fuel utilities with the electricity. Therefore, indisputably, development of bio-based energy and fuels are vital. Speaking of bioenergy logistics, it is important to collect and use all possible biomass feedstock within the peripheral of any conversion facility. In this scenario, gasification is the most suitable conversion method as it produces a standard gaseous mixture of carbon monoxide, hydrogen, methane and carbon dioxide.

The research was designed to understand the gasification of biomass in fluidized-bed reactors. The experimental studies could reveal that the minimum air requirement for bubbling fluidized-bed gasification of wood pellets at 800ºC temperature is 1.25 kg/kg of biomass for a complete conversion. However, an external heat source was required to maintain the reactor temperature. Grass is also an emerging feedstock because of the high yield and however, gasification of grass pellets above 800ºC was not successful due to clinker formation. Efforts were made to develop solutions for operational shortcomings such as modifying the screw feeding mechanism.  

Dual reactor circulating fluidized-bed (CFB) gasification uses steam in the gasification reactor and produces hydrogen rich gas that is suitable for the synthesis of chemicals and fuels. The rate of particle circulation in CFB gasification is a decisive parameter as it governs the heat flow into the gasification reactor. Computational particle fluid dynamic (CPFD) simulations can be used to operate a fluidized-bed gasification reactor virtually, which has emerged as an interesting tool for optimization and parametric studies. Initially, a CPFD particle hydrodynamic model for a CFB reactor was developed to analyze the particle circulation and successively, the model was extended into a fluidized-bed gasification system. Even though the developed CPFD model needs continuous experimental validation, it is competitive in predicting the gas composition of biomass gasification. Integrative use of experimental studies and CPFD simulations is an efficient way of optimizing a fluidized-bed gasification system.