Naoko Ellis
University of British Columbia, Chemical and Biological Engineering, Faculty Member
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While engineering education excels at training students to solve well-defined and highly structured problems, it struggles to support the development of students’ abilities to address highly complex, ill-structured, and contested... more
While engineering education excels at training students to solve well-defined and highly structured problems, it struggles to support the development of students’ abilities to address highly complex, ill-structured, and contested engineering problems that lack in definite solutions, where engineers are called on to work with non-engineers in a transdisciplinary environment. The challenge for engineering educators is to develop and teach constructively aligned curricula aimed at developing transdisciplinary skills so that, as practitioners, graduating engineering students contribute to addressing these types of problems within transdisciplinary environments. Efforts are underway in many institutions to close the gap between the transdisciplinary needs in practice and current engineering curricula. At the University of British Columbia (UBC), a team of faculty members and engineering practitioners have recently developed and are teaching a design-focused engineering course to all fir...
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Microwave-assisted catalytic pyrolysis was investigated using K3PO4 and clinoptilolite to enhance biochar sorption affinity for heavy metals. The performance of resulting biochar samples was characterized through their effects on plant... more
Microwave-assisted catalytic pyrolysis was investigated using K3PO4 and clinoptilolite to enhance biochar sorption affinity for heavy metals. The performance of resulting biochar samples was characterized through their effects on plant growth, bioavailability, phytotoxicity, and uptake of heavy metals in a sandy soil contaminated with Pb, Ni, and Co. The produced biochars have high cation-exchange capacity (CEC) and surface area, and rich in plant nutrients, which not only reduced heavy metals (Pb, Ni, and Co), bioavailability and phytotoxicity, but also increased plant growth rate by up to 145%. The effectiveness of biochar in terms of reduced phytotoxicity and plant uptake of heavy metals was further improved by mixing K3PO4 and clinoptilolite with biomass through microwave pyrolysis. This may be due to the predominance of different mechanisms as 10KP/10Clino biochar has the highest micropore surface area (405 m(2)/g), high concentrations of K (206 g/kg), Ca (26.5 g/kg), Mg (6.2 g...
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There has been an increasing interest in alternative fuels made from biomass which is abundant and renewable. Bio-oil and bio-diesel seem to be such promising liquid fuels. Bio-oil produced by fast pyrolysis of biomass is highly viscous,... more
There has been an increasing interest in alternative fuels made from biomass which is abundant and renewable. Bio-oil and bio-diesel seem to be such promising liquid fuels. Bio-oil produced by fast pyrolysis of biomass is highly viscous, acidic, and has high water content. To overcome these problems as a fuel, a method of emulsifying bio-oil with bio-diesel was performed in
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Engineered biochars produced from microwave-assisted catalytic pyrolysis of switchgrass have been evaluated in terms of their ability on improving water holding capacity (WHC), cation exchange capacity (CEC) and fertility of loamy sand... more
Engineered biochars produced from microwave-assisted catalytic pyrolysis of switchgrass have been evaluated in terms of their ability on improving water holding capacity (WHC), cation exchange capacity (CEC) and fertility of loamy sand soil. The addition of K3PO4, clinoptilolite and/or bentonite as catalysts during the pyrolysis process increased biochar surface area and plant nutrient contents. Adding biochar produced with 10wt.% K3PO4+10 wt.% clinoptilolite as catalysts to the soil at 2wt% load increased soil WHC by 98% and 57% compared to the treatments without biochar (control) and with 10wt.% clinoptilolite, respectively. Synergistic effects on increased soil WHC were manifested for biochars produced from combinations of two additives compared to single additive, which may be the result of increased biochar microporosity due to increased microwave heating rate. Biochar produced from microwave catalytic pyrolysis was more efficient in increasing the soil WHC due to its high poro...
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ABSTRACT Gasification of blends of biomass and coal can offer renewable fuels the scale and extent of deployment usually associated with fossil fuels. For significant penetration of renewables, however, co-utilization of significant... more
ABSTRACT Gasification of blends of biomass and coal can offer renewable fuels the scale and extent of deployment usually associated with fossil fuels. For significant penetration of renewables, however, co-utilization of significant quantities of biomass is required, which significantly impacts process performance. At a fundamental level, char reactivity affects many practical aspects of gasifier operation, and is complicated by the influence of blends of coal and biomass and their different behaviour during devolatilization. In this work, intrinsic gasification reaction kinetics of chars from biomass and coal mixtures with different proportions were studied: one set of chars produced separately and mixed prior to gasification; and another with chars produced from co-pyrolysis of biomass-coal blends. Lower specific and intrinsic rates were observed for the samples where the biomass and coal were pyrolyzed together than when they were pyrolyzed separately, suggesting some interaction during devolatilization that affects reactivity behaviour. XRD results showed that the catalytically-active calcium species in the biomass interacted with the aluminosilicate species in the coal mineral matter to form Ca2Al2SiO7 (gehlenite) crystals, which are catalytically inert. The conversion of catalytically-active Ca to catalytically-inactive Ca may have led to lower reactivity of co-pyrolyzed mixtures, highlighting the importance of understanding the type and nature of often catalytically-active species when investigating the gasification behaviour of blends of coal and biomass materials.
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Interest in biomass to produce heat, power, liquid fuels, hydrogen, and value-added chemicals with reduced greenhouse gas emissions is increasing worldwide. Gasification is becoming a promising technology for biomass utilization with a... more
Interest in biomass to produce heat, power, liquid fuels, hydrogen, and value-added chemicals with reduced greenhouse gas emissions is increasing worldwide. Gasification is becoming a promising technology for biomass utilization with a positive environmental impact. This review focuses speci-fically on woody biomass gasification and recent advances in the field. The physical properties, chemical structure, and composition of biomass greatly affect gasification performance, pretreatment, and handling. Primary and secondary catalysts are of key importance to improve the conversion and cracking of tars, and lime-enhanced gasification advantageously combines CO2 capture with gasification. These topics are covered here, including the reaction mechanisms and biomass characterization. Experimental research and industrial experience are investigated to elucidate concepts, processes, and characteristics of woody biomass gasification and to identify challenges.
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ABSTRACT Addressing recent environmental regulations on fossil fuel power systems and both biomass fuel supply and coal greenhouse gas issues, biomass/coal co-gasification could provide a feasible transition solution for power plants. In... more
ABSTRACT Addressing recent environmental regulations on fossil fuel power systems and both biomass fuel supply and coal greenhouse gas issues, biomass/coal co-gasification could provide a feasible transition solution for power plants. In the quest for an even more sustainable process, steam co-gasification of switchgrass and coal was integrated with in-situ CO2 capture, with limestone as the bed material and sorbent. Five gasification/carbonation (at <700 °C) and calcination (at >850 °C) cycles were performed in an atmospheric pilot scale bubbling fluidized bed reactor. Hydrogen production was enhanced significantly (∼22%) due to partial adsorption of CO2 by the CaO sorbent, shifting the gasification reactions forward, consistent with Le Châtelier's principle. Tar yield measurements showed that reducing the gasification temperature could be achieved without experiencing higher tar yield, indicating that the lime has a catalytic effect. The sorbent particles decayed and lost their calcium utilization efficiency in the course of cycling due to sintering. The co-existence of three types of solids (biomass, coal, lime) with different particle properties led to bed segregation. An equilibrium model was found to be useful in design of lime-enhanced gasification systems.
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ABSTRACT The extent and causes of attrition for three possible carbon dioxide capture sorbents for fluidized bed systems were investigated. The sorbents were crushed limestone, lime-based pellets containing calcium aluminate cement... more
ABSTRACT The extent and causes of attrition for three possible carbon dioxide capture sorbents for fluidized bed systems were investigated. The sorbents were crushed limestone, lime-based pellets containing calcium aluminate cement binder, and the same pellets coated by mesoporous silica without a binder. An air-jet apparatus based on the ASTM D5757 standard, with several improvements in testing capabilities, was used to conduct experiments for varying attrition periods, gas velocities, temperatures, relative humidities and initial particle sizes. The results indicate that the cement-bound pellets suffered similar or worse attrition than crushed limestone, and were highly sensitive to humidity because of the hygroscopic cement and formation of calcium hydroxide. The silica-coated pellets were found to have high attrition resistance in dry air at 500 °C. After 24 h of operation, compared to the coated sorbents, the lime mean diameter reduction and Air Jet Index were greater by factors of 2.4 and 3.4, respectively.
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A commercial process simulator was used to develop a detailed simulation of a biodiesel production process, and carry out case studies and optimization. The simulated process produced biodiesel from a feedstock containing 5 wt.% free... more
A commercial process simulator was used to develop a detailed simulation of a biodiesel production process, and carry out case studies and optimization. The simulated process produced biodiesel from a feedstock containing 5 wt.% free fatty acids in a fixed-bed reactor with sulfated-zirconia as an acidic catalyst. Sized unit operation blocks, material and energy flows were used to conduct an economic assessment of the process. Total capital investment, total manufacturing cost, after tax rate-of-return and production cost ($/kg) were all determined for the process. The process was then optimized by maximizing the after tax rate-of-return (ATROR). Based on our previous work, the most economical process for transesterification of waste vegetable oil at the scale of 8000 metric tones/yr of biodiesel production among the four processes examined was based on a solid acid catalyst reaction. Our results showed that the process is economically feasible, even without government subsidy, while...
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Multidisciplinary, Differential scanning calorimetry, Weight Loss, Fossil Fuels, Gel Permeation Chromatography, and 9 moreThermogravimetry, Greenhouse Gas, Glass Transition Temperature, Fourier transform infrared spectroscopy, Thermogravimetric Analysis, Structural Properties, Molecular weight, Energy Source, and Nuclear Magnetic Resonance Spectroscopy
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ABSTRACT a b s t r a c t Biodiesel, an alternative diesel additive made from renewable sources, has problems associated with their cloud points when used in colder climate. One method of improving the cloud point of biodiesel is... more
ABSTRACT a b s t r a c t Biodiesel, an alternative diesel additive made from renewable sources, has problems associated with their cloud points when used in colder climate. One method of improving the cloud point of biodiesel is hydroisomerization which branches the saturated portion of the biodiesel and lowers the cloud point of the compound. Palmitic acid methyl ester, which is the major saturated fatty acid in vegetable oils, is hydroisomerized with a 5 g kg À1 Pt impregnated beta zeolite catalyst at reaction conditions 200e285 C and 1.0e4.0 MPa H 2 pressure. FTIR and GC/MS analyses confirmed the branching and the identity of the reaction products. The cloud point of the material was lowered from 30 C to 20 C under reaction conditions of 285 C and 4.0 MPa H 2 pressure at the yield of 42% after 16 h. This study reports the hydroisomerization reaction being successful in branching the starting material in order to lower the cloud points of methyl esters.
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ABSTRACT Mesoporous carbon catalysts have received considerable interest in the scientific community because of their tunable porosity, hydrophobic surface, and ease of functionalization with active groups such as –SO3H. The formation of... more
ABSTRACT Mesoporous carbon catalysts have received considerable interest in the scientific community because of their tunable porosity, hydrophobic surface, and ease of functionalization with active groups such as –SO3H. The formation of silica templates is a typical method to prepare a mesoporous carbon, but little is understood on its role for effective sulfonation. In this study, silica templates were used to prepare mesoporous sugar char using the confined activation process. The char was functionalized with –SO3H groups before or after removing the silica templates. The roles of the silica templates were evaluated based on the physicochemical properties of the catalysts. The results showed that silica templates provided support to the internal porosity, but prevented the –SO3H groups from effectively reaching the internal surface. The esterification of oleic acid showed that the reactivity of the carbon-based catalysts is dependent on the total acidity, but independent of the surface area. These findings show that carbon-based catalysts are suitable for esterification which is useful for biodiesel production.
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A promising catalyst based on a biomass pyrolysis by-product, biochar, has been developed for the production of biodiesel. Two carbon-based solid acid catalysts were prepared by sulfonating pyrolysis char with concentrated or fuming... more
A promising catalyst based on a biomass pyrolysis by-product, biochar, has been developed for the production of biodiesel. Two carbon-based solid acid catalysts were prepared by sulfonating pyrolysis char with concentrated or fuming sulfuric acids. Prepared catalysts were studied ...
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Understanding engineering is an important factor in fully participating in civic decision-making, however there are few opportunities for those outside engineering to learn about it. We developed and offered a course on engineering for... more
Understanding engineering is an important factor in fully participating in civic decision-making, however there are few opportunities for those outside engineering to learn about it. We developed and offered a course on engineering for Arts (and Commerce) students, to increase technical literacy, which counted toward the Arts degree Science requirement. A teaching team from three disciplines presented four technical modules themed around specific technologies, and covering a wide range of engineering practice topics. Students participated in many hands-on activities and demonstrations, and instructors used flipped classroom techniques. Assessment for each module consisted of both a short technical online quiz and a blog post about a topic in the news, which allowed students to bring in their own disciplinary knowledge. The final assessment was a group video project where students aimed to advocate for a position on a technical/civic issue related to one of the modules. We detail in ...