Naoko Ellis | University of British Columbia (original) (raw)

Papers by Naoko Ellis

Proceedings of the Canadian Engineering Education Association (CEEA)

While engineering education excels at training students to solve well-defined and highly structur... 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...

Chemical Engineering Science

Environmental pollution (Barking, Essex : 1987), Jan 29, 2017

Microwave-assisted catalytic pyrolysis was investigated using K3PO4 and clinoptilolite to enhance... 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...

Korean Journal of Chemical Engineering, 2011

There has been an increasing interest in alternative fuels made from biomass which is abundant an... 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

The Science of the total environment, Jan 24, 2016

Engineered biochars produced from microwave-assisted catalytic pyrolysis of switchgrass have been... 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...

Chemical Engineering Journal, 2015

ABSTRACT Gasification of blends of biomass and coal can offer renewable fuels the scale and exten... 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.

Annual review of chemical and biomolecular engineering, Jan 24, 2015

Interest in biomass to produce heat, power, liquid fuels, hydrogen, and value-added chemicals wit... 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.

Energy, 2015

ABSTRACT Addressing recent environmental regulations on fossil fuel power systems and both biomas... 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.

Powder Technology, 2014

ABSTRACT The extent and causes of attrition for three possible carbon dioxide capture sorbents fo... 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.

Renewable and Sustainable Energy Reviews, 2010