Naoko Ellis, University of British Columbia
Chemical and Biological Engineering
Professor
Vancouver, British Columbia
nellis@chml.ubc.ca
Office:
(604) 822-1243
Expert In
Bio/Research
Many gas-solid fluidized bed processes (e.g. catalytic and gas-solid reactions, drying) operate in the turbulent flow regime owing to its excellent gas-solids contacting, favourable heat transfer, and relatively low axial dispersion of gases. It is commonly understood that in the turbulent fluidi...
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Bio/Research
Many gas-solid fluidized bed processes (e.g. catalytic and gas-solid reactions, drying) operate in the turbulent flow regime owing to its excellent gas-solids contacting, favourable heat transfer, and relatively low axial dispersion of gases. It is commonly understood that in the turbulent fluidized bed, discrete bubbles and voids are no longer observed while the bed surface is no longer clearly defined due to considerable splashing of the solids into the freeboard. Based on my Ph.D. work (read abstract), the understanding of the structural changes occurring during the transition to the turbulent fluidized flow regime has been extended considerably through experimental investigations. Simultaneous measurement of particle velocity and solid fraction has demonstrated an increase in particle turbulence and voidage in the dense phase. However, much needs to be studied yet, as clearly defined hydrodynamic structure of the turbulent fluidization regime is not yet known. With the advent of increased computational capabilities, computational fluid dynamics is emerging as a very promising new tool in modelling hydrodynamics. While it is now a standard tool for single-phase flows, it is still at the developmental stage for dense multiphase systems, such as fluidized beds. There is still much work required to make computational fluid dynamics suitable for fluidized bed reactor modelling and scale-up purposes.
One of the new applications of fluidized bed reactors is Chemical-Looping Combustion, CLC, based on the concept of interconnecting two fluidized beds, consisting of a fuel reactor, and an air reactor for power production. In conventional combustion units, oxygen is supplied through air for fuel combustion, resulting in high emission of NOx, along with high cost for recovering dilute concentration of CO2 from flue gas. However, in chemical-looping combustion, air is never mixed with fuel. The oxygen required for combustion of fuel is supplied by a metal oxide, which circulates in a loop connecting the two reactors: air and fuel reactors. This novel configuration prevents NOx formation, and produces pure stream of steam and CO2, from which CO2 is separated without energy penalty. Fluidized bed combustion of gasified fuel can produce energy while inherently separating the greenhouse gas, CO2, from the flue gases. This cost-effective alternative method of CO2 capture from energy production has the potential to become a viable choice in light of the pressure to reduce the release of greenhouse gases to meet the objectives of the Kyoto Accord.
The Biodiesel Project at UBC strives towards the production of an alternative fuel from a locally obtained waste and non-food grade cooking oil through alkali-catalyzed transesterification process. It is currently in the process of scaling up the unit to meet the demands on campus to fuel landscaping equipments. With the partnership of Environmental Youth Alliance (EYA), our goals are to provide concrete environmental solutions, research, and innovation, to assist in youth skill and career development, and to demonstrate sustainability.
Bio-oil produced from pyrolysis of biomass such as wood and agricultural wastes is emerging as an alternative source of sustainable energy for diesel engines, gas turbines, heating applications and for use as chemical feedstock. The benefits of bio-oil lie not only as a greenhouse gas (GHG) neutral energy source, but also as an opportunity to reduce reliance on fossil fuel, support sustainable forest development, etc. However, high viscosity, high acidity and high structural water content make bio-oil a difficult fuel to burn. In order to overcome these challenges, the upgrading of bio-oil through catalytic, electrical and hydrotreatment means are already underway. Additionally, emulsification of bio-oil with diesel fuel is shown to be an economical and viable fuel choice in diesel engines without the need for modifications. This project focuses on the investigation of bio-oil upgrading through emulsification with biodiesel fuel.
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One of the new applications of fluidized bed reactors is Chemical-Looping Combustion, CLC, based on the concept of interconnecting two fluidized beds, consisting of a fuel reactor, and an air reactor for power production. In conventional combustion units, oxygen is supplied through air for fuel combustion, resulting in high emission of NOx, along with high cost for recovering dilute concentration of CO2 from flue gas. However, in chemical-looping combustion, air is never mixed with fuel. The oxygen required for combustion of fuel is supplied by a metal oxide, which circulates in a loop connecting the two reactors: air and fuel reactors. This novel configuration prevents NOx formation, and produces pure stream of steam and CO2, from which CO2 is separated without energy penalty. Fluidized bed combustion of gasified fuel can produce energy while inherently separating the greenhouse gas, CO2, from the flue gases. This cost-effective alternative method of CO2 capture from energy production has the potential to become a viable choice in light of the pressure to reduce the release of greenhouse gases to meet the objectives of the Kyoto Accord.
The Biodiesel Project at UBC strives towards the production of an alternative fuel from a locally obtained waste and non-food grade cooking oil through alkali-catalyzed transesterification process. It is currently in the process of scaling up the unit to meet the demands on campus to fuel landscaping equipments. With the partnership of Environmental Youth Alliance (EYA), our goals are to provide concrete environmental solutions, research, and innovation, to assist in youth skill and career development, and to demonstrate sustainability.
Bio-oil produced from pyrolysis of biomass such as wood and agricultural wastes is emerging as an alternative source of sustainable energy for diesel engines, gas turbines, heating applications and for use as chemical feedstock. The benefits of bio-oil lie not only as a greenhouse gas (GHG) neutral energy source, but also as an opportunity to reduce reliance on fossil fuel, support sustainable forest development, etc. However, high viscosity, high acidity and high structural water content make bio-oil a difficult fuel to burn. In order to overcome these challenges, the upgrading of bio-oil through catalytic, electrical and hydrotreatment means are already underway. Additionally, emulsification of bio-oil with diesel fuel is shown to be an economical and viable fuel choice in diesel engines without the need for modifications. This project focuses on the investigation of bio-oil upgrading through emulsification with biodiesel fuel.
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