Chemical and Biochemical EngineeringWestern Engineering

Research Projects

My several past and present projects are associated with various reacting systems, such as simulated moving bed chromatographic reactors, photocatalytic reactors, oscillatory reactors, and polymer reactors. My research covers a broad range of topics in engineering of chemical reactions and processes, which can be categorized in the following areas to give a better overview:

(a) Simulated Moving Bed Systems and Integrated Reactor-Separator

Simulated Moving Bed (SMB) systems are used for separations that are either impossible or difficult using traditional separation techniques. SMB has become one of the most popular techniques finding its application in petrochemical and sugar industries, and of late, there has been an increased interest in pharmaceutical industry for enantio-separations. SMB systems can also be integrated to include reactions, which can provide economic benefit for equilibrium limited reversible reactions, such as many hydrogenation, isomerization, and esterification reactions. These are continuous flow reactors in which chemical reactions are carried out in the presence of solid adsorbents so that both separation and chemical reaction are integrated into a single process unit. In-situ separation of the products facilitates the reversible reaction to completion beyond thermodynamic equilibrium and at the same time obtaining products of high purity. Furthermore, the integration of reactor and separator can lead to considerable savings in capital and operating costs. The unique aspect of our research is to apply the concept of multi-objective optimization in innovative design of SMB systems.

The present investigations endeavor to determine to what extent the moving bed reactor advantages of high product purity and favorable equilibrium shifts are retained for various important chemical reactions. Our research addresses (a) experimental determination of adsorption and/or kinetic parameters, (b) modeling, experimentation and application of multi-objective optimization in the design of SMB systems, and (c) modeling, experimentation and multi-objective optimization of Varicol (based on non-synchronous switching) process, which is a new modification of more rigid traditional SMB systems. Systems studied and being studied based on SMB technology are:

  • Chiral drug separation (enantio-separation),
  • hybrid simulated moving bed (SMB) and crystallization process
  • Production of High Fructose Syrup by inversion of sucrose and isomerization of glucose,
  • Separation of xylene isomers - industrial Parex process
  • Hydrogenation of mesitylene to tri-methyl cyclohexane,
  • Synthesis of ethers and esters such as MTBE and Methyl acetate,
  • Oxidative coupling of methane (OCM) to ethane and ethylene,
  • Process intensification in biodiesel production from microalgae grown on waste  resources
  • Trans-esterification of oil or animal fats with alcohol to produce biodiesel
  • Intensified purification and refolding of inclusion body proteins

(b) Band-Engineered Photocatalysis … for Water Purification, Production of Clean Hydrogen Fuel and Self-cleaning of Building Surfaces

Photo-stimulated catalysis offers an attractive tool for applications in producing clean fuel and in degrading toxic organic pollutants (as well as removing toxic metal ions) for environmental cleanup. However, a specific problem associated with commonly used photo-catalysts is the large band-gap energy, which requires artificial light. Because of the ubiquity of sunlight the success of this technology depends on engineering of electronic bands of the catalyst for paradigm-shift to solar-based photocatalysis that could produce very large economic and social benefits. Two approaches address this issue in the on-going research. The first involves reducing the band-gap through addition of dopants, thereby permitting light absorption in the visible part of the spectrum. The second strategy involves dye-sensitization. The quintessence of dye-sensitization is the electron injection from the excited dye to the conduction band (CB) of TiO2 and the subsequent interfacial electron transfer. Successful synthesis of chemically modified photocatalyst through molecular band engineering will enable use of sunlight for splitting water into clean hydrogen fuel, sun-powered remediation of environmental pollutants (particularly use TiO2 tablets to get potable water), and creation of solar-driven self-cleaning and antifogging building materials. A transparent liquid form of the photocatalyst when sprayed onto building panels, glass surfaces, painted walls and (kitchen or bathroom) tiles will offer substantial self-cleaning and cost savings in maintenance.

Another thrust aims at developing a technical solution to the design of a commercial (large-scale) photocatalytic reactor that provides a high ratio of activated immobilized catalyst surface area per unit reactor volume thereby allowing for much higher specific reactor capacity. All experiments involve novel reactor configurations and catalysts to achieve high selectivity. Modeling involves simulation of the processes and description of reaction mechanisms using detailed surface reaction steps. This research involves the interplay between surface and solution chemistry, catalysis and reaction engineering, and mass transfer effects. Main contributions on photocatalysis are (a) fundamental kinetic studies for photocatalytic degradation of organics to determine true kinetic rate parameters in slurry as well as fixed catalyst systems. (b) systematic thermodynamic analysis and kinetic study for removal of toxic metal ions such as Hg(II), Cr(VI) and As(III) from wastewater, and (c) design and development of novel large-scale photocatalytic reactors for water purification such as multiple tube reactor, tube light reactor, rotating tube reactor, pulsating reactor and Taylor vortex reactor. The design specifically addressed critical issues of increasing illuminated catalyst density, uniform distribution of light and mixing of fluids. Experiments were done to show the effectiveness and efficiency of these reactors. Detailed computer simulation of photocatalytic reactors using Fluent® has also been carried out.

(c) Modeling, Simulation and Multi-objective Optimization

Our research group is pioneer to apply the concept of multi-objective optimization in the design and operation of chemical reactors and processes. Chemical reactors are often the important equipment in many process industries. Multi-objective optimizations of industrial reactors are carried out to identify the optimal conditions for producing valuable products economically using different adaptations of genetic algorithm, which usually result in an optimal Pareto set. Detailed simulation models are first developed for industrial systems. These models are verified (sometimes tuned) using industrial data. Additional control variables, important objective functions, constraints of significance, accurate kinetic schemes and practical aspects of various physical processes are considered. All these make the optimization problem more complex but the ultimate results are far more meaningful. Better (optimal) operating conditions are computed using powerful and recently developed techniques like NSGA and Simulated Annealing. These studies help optimize several objectives while simultaneously satisfying several real-life constraints present in industry. Significant cost savings and enhanced productivity are achieved. In addition to application of the multi-objective optimization to different industrial applications, we are also involved on improving the optimization methodologies. Industrial process studied and being studied are (a) hydrogen production by steam reforming of hydrocarbons based on natural gas or higher hydrocarbon feed using side or top fired steam reformer, (b) industrial polymerization reactors for the production of Nylons, Polyesters, Perspex, polyethylene, polystyrene, etc., (c) beer dialysis using hollow fiber membranes, (d) industrial Styrene manufacturing process, (e) industrial Ethylene reactor, (f) catalytic membrane reactor for production of ethylene oxide and formaldehyde and oxidative coupling of methane reaction, and (g) multi-functional reactors such as SMBR and Varicol based on Simulated Moving Bed technology. These are continuous flow reactors in which chemical reactions are carried out in the presence of solid adsorbents so that both separation by adsorption and chemical reaction are integrated into a single process unit. Carrying out separation during chemical reaction helps to overcome reactant conversion limitation because of chemical equilibrium. Moreover, the integration of reactor and separator lead to considerable savings in capital and operating costs. Systems optimized are SMB and Varicol units for separation of chiral drugs, mixtures of C8 hydrocarbons, glucose-fructose mixture, and reactive systems such as synthesis of methyl acetate ester, MTBE, trimethyl cyclohexane, production of concentrated high fructose syrup by inversion of sucrose and isomerization of glucose, and production of ethylene by oxidative coupling of methane. Current projects involve hybrid SMB-Crystallization, biodiesel production, Process intensification in biodiesel production from microalgae grown on waste resources, and Intensified purification and refolding of inclusion body proteins.

(d) Performance Improvement of Chemical Reactors by Natural Oscillations

The dynamic behavior of two coupled continuous stirred-tank reactors in sequence was studied when the first reactor is operated under limit cycle regimes producing self-sustained natural oscillations. This new concept of coupling free and forced oscillation does not require any additional external energy but at times the overall performance of the system can be greatly enhanced. Systems studied are (a) wastewater treatment by activated sludge process, (b) synthesis of ethanol from glucose, (c) oxo reaction for production of aldehydes from olefins and synthesis gas, etc.

Current Projects

Accelerate development of new technologies and applications for advanced water treatment
Principal Investigator 
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration: 2015/7 - 2018/6

 

Clean technologies for water refining and nutrient and energy recovery
Co-Investigator
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2012/4 - 2018/3


Integrated approaches and technologies to ensure safe drinking water supply in Beijing: Water diversion from South to North China
Co-Investigator
Funding: Ontario-China Research and Innovation Fund (OCRIF)
Duration: 2014/4 - 2017/3


Advanced Reaction and Process Engineering for Applications in Energy, Environment, Food and Health
Principal Investigator
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2011/4 - 2016/3

Completed Projects

Development and Validation of Innovative Purification Technologies using an Innovation Process Roadmap (IPR) Approach
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration: 2012/5 - 2015/5

Development of Innovative Technology for Aluminum Removal from Potable Water
(Principal Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2014/1 - 2014/6

Contaminant Treatment in Water using Photocatalysis
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration: 2013/1 - 2013/12

Nanomaterials for Photocatalysis: Enhancing Hydrogen Production from Solar Energy
(Co-Investigator)
Funding: Ontario Center of Excellence (OCE)
Duration:2010/7 - 2013/6

New Directions and Challenges in Large Scale Integrated Micro-algal Technologies for The Canadian Farm Economy
(Co-Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2010/7 - 2013/6

Program to Advance the Treatment of Opaque Fluids using UV Technologies
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration:  2010/7 - 2013/6

Understanding UV Dose Distribution and Reactor Performance using Bioassay Data
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration:  2012/4 - 2013/3

Modelling Microbial Transport and Inactivation in an Open Channel UV Reactor at Various Hydraulic Regimes
(Principal Investigator)
Funding : Mitacs (Partner Organization: Trojan Technologies)
Duration: 2011/9 - 2012/8

Lagrangian Actinometry for UV Disinfection Applications involving Low Transmittance Liquids
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration: 2010/9 - 2012/8

Photocatalytic Treatment of Contaminants in Water
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration: 2011/7 - 2012/6

Efficiency Analysis of UV Irradiated AOP using Computational Modelling
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration: 2011/7 - 2012/6  

Biomass gasification: product quantification and reaction kinetics
(Co-Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2009/4 - 2012/3

Purification and Refolding of Inclusion Body Proteins using SMB Technology
(Principal Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2011/4 - 2012/3

Green Energy and Environmentally Friendly Chemical Technologies
(Co-Investigator)
Funding: Canada Foundation for Innovation (CFI) Leading Edge Fund
Duration: 2007/4 - 2012/3

Novel Photocatalysis and SMB Technology Laboratory
(Principal Investigator)
Funding: Canada Foundation for Innovation (CFI) Leaders Opportunity Fund
Duration: 2006/9 - 2011/8
 
Innovations in Renewable Energy Production: Biodiesel from Microalgae grown on Waste Resources using Liquid-Solid Circulating Fluidized Beds and Photo-bioreactors
(Co-Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2008/7 - 2011/6

Enhanced UV Treatment of Fluids through Fluid Instabilities
(Principal Investigator)
Funding: Mitacs (Partner Organization: Trojan Technologies)
Duration: 2010/7 - 2011/6

Applications of Multi-objective optimization in the design of SMB systems
(Principal Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery
Duration: 2006/4 - 2011/3

TiO2 Nanotube Arrays Synthesis, bandgap engineering and solar energy applications
(Co-Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2007/7 - 2010/6

Development of Reliable, efficient and economic chiral drug separation process
(Co-Investigator)
Funding: Natural Sciences and Engineering Research Council of Canada (NSERC)
Duration: 2007/7 - 2010/6 

Engineering of Chemical Reactions and Processes

Reaction Engineering 
Process Systems and Engineering
Separation and Purification Technology
Environmental Science and Technology
Photocatalytic Reactors Oscillatory Reactors
Polymerization Reactors Multifunctional Reactors
Integrated Reactor-Separators Catalytic Membrane Reactors
Simulated Moving Bed Reactor-Separators
Semiconductor Photocatalysis
Chiral Drug Separation
Modeling, Simulation & Multi-objective Optimization of Industrial Processes