Research Impact

• Western University Faculty Scholar Award, 2012.
• Western Engineering Prize for Achievement in Research, 2012.
• Most cited author in Western Engineering with h-index of 35 (35 articles cited at least 35 times by others), i10-index of 59 (59 articles received at least 10 new citations in the last 5 years); circa 400 citations per year in the last 5 years, total citations of over 3200 (based on Scopus database as of March 1, 2012).
• Member of Editorial Board, International Journal of Chemical Reactor Engineering, 2002.
• Member of Editorial Board, Euro-Asian Journal of Applied Sciences, 2004
• CrayQuest Award for excellence in R&D using high performance computing, 1999.
• Distinguished Young Alumnus Award, University of Calcutta, India, 2001.
• CMCSRI Distinguished Speakers Award, Indian Institute of Chemical Engineers (IIChE), 2007.
• Member of Working Party, Asia Pacific Chemical Reaction Engineering (APCRE), 2000-2006.
• Teaching Excellence Award, National University of Singapore, 2004.
• Nominated for Research Excellence Award, Western Engineering, 2008.
• Maurice Bergougnou Teaching Excellence Award, Western Engineering, 2010.
• Keynote Speaker on "Dye-Sensitized Photocatalysis" at the World Chem Eng Congress, 2009.
• Invited Speaker at Swiss Federal Institute of Technology, University of Akron, Auburn, University, McMaster University, University of New South Wales, and many others in India, Malaysia, Singapore, and many international conferences.
• Guest edited special issues of Asia Pacific Chemical Engineering Journal (2001, 2003, 2005) and currently guest editing a special issue for Polymer Engineering Science (October, 2011).
• Served in the scientific as well in organizing committees of several international conferences.

Top 40 Most Cited Articles (as of August 1, 2011 h-Index= 30)

[Scopus Database]

 

Five Significant Publications

Modeling and Experimentation of a New Large-scale Photocatalytic Reactor for Water Treatment”, Chemical Engineering Science, 54, p3113-3125, (1999)

In this paper, a new photocatalytic reactor design was presented that addressed the two most important parameters, namely, light distribution inside the reactor and high specific surface area of catalyst. The reactor consisted of several hollow test tubes employed as a means of light delivery to the catalyst present on the outside surface of the tubes. Model calculations were performed to evaluate the radial light intensity profile as a function of input light intensity and angle of incidence, diameter, length, wall thickness and surface roughness of tubes. The reactor was designed and constructed based on the modeling results, and experiments were conducted which showed very promising results. The new reactor was aimed at development of a technical solution to the design of a commercial-scale photocatalytic reactor. Later, computer simulation of the reactor was performed to study the complex interplay of flow, mass transfer, and chemical reaction to help achieve better reactor design. The later part of the work won the CrayQuest award in 1999.

Effect of mass transfer and catalyst layer thickness on photocatalytic reaction", AIChE Journal, 46(5), p1034-1045, (2000).

In this paper, a rational approach was proposed in determining the effect of mass transfer and catalyst layer thickness during photocatalytic reactions. The reaction occurs at the liquid-catalyst interface and therefore, when catalyst is immobilized, both external and internal mass transfer plays significant roles in overall photocatalytic processes. Several model parameters, namely, external mass transfer coefficient, dynamic adsorption equilibrium constant, adsorption rate constant, internal mass transfer coefficient and effective diffusivity were determined experimentally and later fitted with realistic models. All these parameters are extremely important in the design and development of photocatalytic processes, and were not available in literature. The effect of the internal mass transfer on the photocatalytic degradation rate over different catalyst layer thickness under two different operating configurations was also analyzed theoretically and later verified experimentally. It was shown both experimentally and theoretically that there exists an optimal catalyst layer thickness for substrate to catalyst illumination.

"A Taylor vortex photocatalytic reactor for water purification", Industrial and Engineering Chemistry Research, 40(23), p5268-5281, (2001)

A detailed analysis was performed for a heterogeneous photocatalytic Taylor vortex photocatalytic reactor that uses flow instability to recirculate fluid continually from the vicinity of the rotating inner cylindrical surface to the stationary outer cylindrical surface of an annulus. In the paper a detailed time accurate computation was performed that showed the different stages of flow evolution and the effects of finite length of the reactor in creating eddies, the overall effects of which showed very high efficiency of photocatalytic conversion. The physical arrangement considered was such that pollutant degradation was maximized by the motion of fluid particles in a specific regime of centrifugal instability. In the paper, a detailed flow structures for the chosen parameters and when the reactor started impulsively were also presented. Later in a subsequent publication, the effect Reynolds number and aspect ratio were studied. Recently, the reactor was constructed and experiments were performed to determine the potential of the reactor in purifying water.

Multi-objective optimization of an industrial wiped-film PolyEthylene Terephthalate reactor", AIChE Journal, 46(5), p1046-1058, (2000).

Process industries aim at maximizing their production capacities while simultaneously maintaining the product quality. Usually, there exists a trade-off between these two requirements. This is particularly true in the manufacture of polymers where the properties of the product are crucial and reactors have to be operated under conditions, which yield products, which satisfy relatively narrow specifications. At the same time, the operating variables must be at their optimal conditions to maximize the throughput. It is well established that the average molecular weight of the polymer produced determines several important physical properties of the material, e.g., strength, impact resistance, etc. In addition, the concentrations of a few side products need to be below low limits or between narrow limits to ensure some other properties like color, dyeability, etc., to lie within specifications. Thus, the design and operation of polymerization reactors require optimization using multiple objective functions and constraints, which are often conflicting.

A multiobjective optimization technique has been used to study an industrial, third-stage wiped film reactor producing fibre-grade polyethylene terephthalate (PET). Since the reaction mass is very viscous, the finishing reactor has a special construction to enhance mass transfer and the removal of by-product, ethylene glycol, so as to drive the reaction in the forward direction and to give a product having a high value of DP. The finisher is usually a jacketed cylindrical vessel with a horizontal agitator, with large screens mounted on the latter. The two objective functions minimized are the acid and vinyl end group concentrations in the product. These are two of the undesirable side products produced in the reactor, and hence, the minimization of these two end groups improves the quality of the polymer product. The optimization problem incorporated a constraint to give a desired value of the degree of polymerization (DP) of the product. In addition, the concentration of the di-ethylene glycol end group in the product is constrained to lie within a certain range of values. Non-dominated sorting genetic algorithm (NSGA) was used to obtain the optimal values of the decision variables. Optimal solutions were generated for several values of DP of industrial significance. It was interesting that the optimal solutions obtained also resulted in the lowest residence time of the reaction mass in the reactor, leading to a higher throughput from the continuous polymerization unit.

The application of multi-objective optimization was later extended to other important industrial systems like hydrogen production by steam reforming of methane and naphtha, ethylene and styrene production, and currently being applied to catalytic hydrocracking process, polyethylene productions, etc.

Multi-objective optimization of simulated moving bed system and Varicol process for chiral separation", AIChE Journal, 48(12), p2800-2816, (2002).

The multiobjective optimization of continuous countercurrent chromatography separation units, such as simulated moving bed (SMB) and Varicol, was performed for the first time. The Varicol system is based on a non-synchronous shift of the inlet and outlet ports instead of the synchronous one used in the SMB technology. The optimization problem involved relatively large number of decision variables that include continuous variables, such as flow rates and lengths, as well as discontinuous ones, such as column number and configuration. The importance of reformulating the optimization problem as multiobjective was demonstrated since the factors affecting the economy of a given separation process were multiple and often in conflict with each other. A typical example solved was the productivity of the process and the purity of the corresponding products. The new optimization procedure based on a genetic algorithm was presented that allowed handling these complex optimization problems. Using a literature chiral separation model the potential of this optimization procedure was illustrated. This also offered a unique opportunity to compare the optimal separation performance that can be achieved with the SMB and the Varicol technologies. Later the above concept of application of multiobjective optimization in the design of SMB was not only extended to reactive systems but also verified experimentally for important chemical and biochemical systems.