Browsing USN Open Archive by Author "Agu, Cornelius Emeka"
Now showing items 1-19 of 19
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Algorithm with improved accuracy for real-time measurement of flow rate in open channel systems
Agu, Cornelius Emeka; Hjulstad, Åsmund; Elseth, Geir; Lie, Bernt (Journal article; Peer reviewed, 2017)Most methods for flow rate measurement in open channels usually have low accuracy over a range of flow rates due to varying fluid properties, flow conditions and channel length. This paper suggests an algorithm to improve ... -
Assessment of Combustion and Gasification Behavior in a Bubbling Fluidized Bed Reactor: A Comparison between Biomass with and without Chemical Additives
Agu, Cornelius Emeka; Moldestad, Britt Margrethe Emilie; Pfeifer, Christoph (Peer reviewed; Journal article, 2020)During the storage of biogenic materials for energy utilization, destructions by microbial attacks are inevitable. Besides material degradation, self-ignition of wood chip piles also occurs consistently. Treating the ... -
Behaviour of biomass particles in a bubbling fluidized bed: A comparison between wood pellets and wood chips
Agu, Cornelius Emeka; Tokheim, Lars-André; Pfeifer, Christoph; Moldestad, Britt Margrethe Emilie (Peer reviewed; Journal article, 2019)For successful operation and design of a bubbling fluidized bed reactor handling a specific biomass, in-depth knowledge about the bed behaviour is paramount. This study compares the behaviour of a bed of sand containing ... -
Bubbling Fluidized Bed Behaviour for Biomass Gasification
Agu, Cornelius Emeka (Doctoral dissertations at the University of South-Eastern Norway;35, Doctoral thesis, 2019-06-21)The need to cut down the high dependency on the fossil fuels requires sustainable alternative energy resources. Aside that the stock of fossil fuels is depreciable, the energy source also accounts for the major contribution ... -
Detailed One-Dimensional Model for Steam-Biomass Gasification in a Bubbling Fluidized Bed
Agu, Cornelius Emeka; Pfeifer, Christoph; Eikeland, Marianne Sørflaten; Tokheim, Lars-André; Moldestad, Britt Margrethe Emilie (Peer reviewed; Journal article, 2019)A one-dimensional unsteady state model is developed for simulation of biomass gasification in a bubbling fluidized bed. The proposed model accounts for the effect of hydrodynamic behavior of the fluidized bed by incorporating ... -
Determination of onset of bubbling and slugging in a fluidized bed using a dual-plane electric capacitance tomography system
Agu, Cornelius Emeka; Tokheim, Lars-André; Eikeland, Marianne Sørflaten; Halvorsen, Britt (Journal article; Peer reviewed, 2017)For a successful application of fluidized beds in chemical reactions and solids circulation, the boundary of regime of operation such as bubbling and slugging regimes, needs to be clearly defined. This study provides a ... -
Distribution of Solids in a Fluidized Bed Operated without a Gas Distributor
Agu, Cornelius Emeka; Moldestad, Britt Margrethe Emilie (Journal article; Peer reviewed, 2018)Despite several advantages of a gas distributor, there are also some challenges in its application. Using a gas distributor increases the fluidizing gas compression cost. Due to deposition of fine particles and product of ... -
Effect of Superficial Gas Velocity on Bubbling Fluidized Bed Behaviour in a Biomass Gasifier
Agu, Cornelius Emeka; Moldestad, Britt Margrethe Emilie (Journal article; Peer reviewed, 2019)This study investigates the behaviour of bubbling fluidized beds in biomass gasification processes based on the variation of superficial gas velocity at different temperatures and air flowrates. In the paper, the operating ... -
Evaluation of drag models for CFD simulation of fluidized bed biomass gasification
Solli, Kjell Arne; Agu, Cornelius Emeka (Journal article; Peer reviewed, 2017)Gasification of biomass into suitable feedstock has become a feasible alternative technology for reducing the use of energy feedstock from fossil sources. Usually, fluidized bed technology is used in the biomass gasification ... -
Improved Models for Predicting Bubble Velocity, Bubble Frequency and Bed Expansion in a Bubbling Fluidized Bed
Agu, Cornelius Emeka; Tokheim, Lars-André; Eikeland, Marianne Sørflaten; Moldestad, Britt Margrethe Emilie (Journal article; Peer reviewed, 2018)An efficient design and operational control of a fluidized bed reactor relies on accurate prediction of bubble properties. This paper employs measurement of bed void fraction in determining the bubble velocity in a given ... -
Investigation of bubbling behavior in deep fluidized beds at different gas velocities using electrical capacitance tomography
Agu, Cornelius Emeka; Ugwu, Ambrose; Pfeifer, Christoph; Eikeland, Marianne Sørflaten; Tokheim, Lars-André; Moldestad, Britt Margrethe Emilie (Peer reviewed; Journal article, 2019)Deep bubbling fluidized beds have some advantages that make them attractive for industrial applications. Using different powders, this paper investigates the bubbling behavior in deep beds. The results show that bubbles ... -
Measurement and characterization of biomass mean residence time in an air-blown bubbling fluidized bed gasification reactor
Agu, Cornelius Emeka; Pfeifer, Christoph; Eikeland, Marianne Sørflaten; Tokheim, Lars-André; Moldestad, Britt Margrethe Emilie (Peer reviewed; Journal article, 2019)Gasification of biomass in bubbling fluidized beds can be limited by accumulation of unconverted char particles during the process. The amount of unconverted biomass depends on the residence time of the fuel particles. ... -
Models for Predicting Average Bubble Diameter and Volumetric Bubble Flux in Deep Fluidized Beds
Agu, Cornelius Emeka; Pfeifer, Christoph; Eikeland, Marianne Sørflaten; Tokheim, Lars-André; Moldestad, Britt Margrethe Emilie (Journal article; Peer reviewed, 2018)The average bubble diameter and volumetric bubble flux give indications about the overall bed expansion in a fluidized bed. As these properties depend on the particle properties and fluidized bed regime, their accurate ... -
A new Approach for Scaling Up from a Small Cold to a Large Hot Bed for Biomass Conversion in a Bubbling Fluidized Bed Reactor
Agu, Cornelius Emeka; Thapa, Rajan Kumar; Pfeifer, Christoph; Tokheim, Lars-Andre; Moldestad, Britt Margrethe Emilie (Peer reviewed; Journal article, 2020)Bubbling fluidized beds are simple and attractive means of achieving efficient conversion of biomass if particle segregation and the associated effects are minimized. To improve the knowledge of fluidized bed reactor design, ... -
Numerical solution of the Saint Venant equation for Non-Newtonian fluid
Agu, Cornelius Emeka; Lie, Bernt (Journal article; Peer reviewed, 2014)Non-Newtonian fluid flow through a Venturi channel is studied using the Saint Venant equation. The nonlinear hyperbolic equation is numerically tricky to solve, therefore in this study, we consider the finite volume method ... -
Prediction of void fraction and minimum fluidization velocity of a binary mixture of particles: Bed material and fuel particles
Agu, Cornelius Emeka; Pfeifer, Christoph; Moldestad, Britt Margrethe Emilie (Peer reviewed; Journal article, 2019)For operational control and design of a fluidized bed reactor containing different types of solid particles, the bed void fraction and minimum fluidization velocity are vital parameters. This paper demonstrates a method ... -
Simulation of Simplified Model for Reaction Kinetics in Biomass Gasification
Agu, Cornelius Emeka; Thapa, Rajan Kumar; Halvorsen, Britt (Conference object; Peer reviewed, 2015-11-25)Due to complexity in interactions between solid particles and between particles and carrier fluid, modeling of biomass gasification kinetics has been shown to be very challenging. Some commercial packages such as Barracuda ... -
Simulation of Transcritical Flow in Hydraulic Structures
Agu, Cornelius Emeka; Lie, Bernt; Elseth, Geir (Journal article; Peer reviewed, 2015-11-25)In hydraulic engineering, transcritical flows are often required in some applications. One example is in a Venturi channel where the occurrence of critical depth is used to estimate flow rate in the channel. In this paper, ... -
Study of fluidized bed regimes using Computational Particle Fluid Dynamics
Jaiswal, Rajan; Agu, Cornelius Emeka; Thapa, Rajan Kumar; Moldestad, Britt Margrethe Emilie (Journal article; Peer reviewed, 2018)The fluidization technology has a wide range of applications. In chemical synthesis, fluidized bed is used to enhance heat and mass transfer between the reacting species. More application of this technology can also be ...