Kelly Hawboldt

Ranking Canadian universities: a quantitative approach for sustainability assessment using uD-SiM

This paper introduces a model that enables a comparison between universities based on sustainability indicators related to environmental, economic, social and educational aspects. The proposed model is based on a driving force-pressure-state-exposure-effect-action (DPSEEA) framework and is called uncertainty-based DPSEEA-Sustainability index Model (uD-SiM). The uD-SiM applies the concept of causality and develops sustainability index (SI), which is an outcome of nonlinear relationships of sustainability indicators in different stages of DPSEEA. In this paper, this fuzzy-based multi-criteria decision-making model is used to evaluate the sustainability of five Canadian universities, namely the University of British Columbia, the University of Toronto, the University of Alberta, the McGill University and the Memorial University. The final ranking results are compared with the Green report card ranking for 2010 through SI. The application of various actions and strategies that can be applied to different stages of the framework to improve sustainability in higher education institutions is also discussed.

Numerical modelling of a fast pyrolysis process in a bubbling fluidized bed reactor

In this study, the Eulerian-Granular approach is applied to simulate a fast pyrolysis bubbling fluidized bed reactor. Fast pyrolysis converts biomass to bio-products through thermochemical conversion in absence of oxygen. The aim of this study is to employ a numerical framework for simulation of the fast pyrolysis process and extend this to more complex reactor geometries. The framework first needs to be validated and this was accomplished by modelling a lab-scale pyrolysis fluidized bed reactor in 2-D and comparing with published data. A multi-phase CFD model has been employed to obtain clearer insights into the physical phenomena associated with flow dynamics and heat transfer, and by extension the impact on reaction rates. Biomass thermally decomposes to solid, condensable and non-condensable and therefore a multi-fluid model is used. A simplified reaction model is sued where the many components are grouped into a solid reacting phase, condensable/non-condensable phase, and non-reacting solid phase (the heat carrier). The biomass decomposition is simplified to four reaction mechanisms based on the thermal decomposition of cellulose. A time-splitting method is used for coupling of multi-fluid model and reaction rates. A good agreement is witnessed in the products yield between the CFD simulation and the experiment.