Suresh Bhatia Ph.D.
Equilibrium and Transport of Fluids in Confined Spaces
Our research interests and activities in this area center around nanostructured porous materials, focusing on their characterization as well as the equilibrium and transport properties of fluids confined in their nanostructure. The research is heavily grounded in fundamentals, and aims at developing new understanding of the equilibrium and dynamics useful in furthering their applications in separation, catalysis and novel nanotechnologies. Achieving an improved understanding of the influence of interactions of guest molecules with the solid surface in nanoporous materials, and the consequences for adsorption and transport, underpins much of the on-going activity. Among the current projects are new approaches to characterization of carbons, MCM-41 and newer nanoporous materials. Density functional theory has been extended to consider pore wall heterogeneity in carbons, and is being implemented for improved characterization of activated carbon fibers and other microporous carbons. The results will be subsequently compared with alternative characterizations involving molecular models of carbons determined by reverse Monte Carlo computation-based fitting of x-ray structure factor data. Adsorption equilibria of hydrocarbons in mesoporous materials as well as activated carbons have been experimentally studied and are being theoretically interpreted. Dynamics of adsorption in nanoporous materials is another focus where we have developed new approaches for interpreting experimental adsorption kinetics. Most recently we are developing fundamental approaches based on molecular interactions to predict transport coefficients in nanopores, both in siliceous materials and carbons, and these are being validated by molecular dynamics calculations.
Among the key achievements is the development of a new exact theory of transport at low density, incorporating realistic fluid-solid interactions, that has been verified for mesopores and micropores with the help of molecular dynamics simulations. The theory is a significant step forward over the widely used century-old Knudsen theory that considers non-interacting systems, and finally provides a viable approach for the important regime of single file diffusion crucial to zeolites and other narrow pore materials. For higher densities improved approaches considering fluid-fluid interactions via a modified local average density model have also been developed and validated.
Heterogeneous Reaction Engineering
Our research in this area emphasises problems related to transport and reaction processes in porous solids. All of the research incorporates an appropriate blend of theory, computation and experiment, and the projects undertaken have fundamental as well as practical significance. Some topics of recent interest have been the development of correlated random walk models for transport in pore networks, experimental and computational studies of hysteresis and multiplicity in multiphase catalytic reactions, and the reactivity of chars and microporous solids. In all of these situations the structure of the porous medium plays an important role, and is probed by an array of techniques such as gas adsorption, mercury porosimetry, x-ray diffraction, scanning and transmission electron microscopy as well as small angle x-ray and neutron scattering. The results of such characterization studies provide essential data and information for modelling of the structure, and ultimately its influence on the physical and chemical phenomena occurring in it - a crucial component of the research. For example, in the field of multiphase catalytic reactions we have incorporated the interplay of capillary condensation phenomena along with reaction and heat and mass transfer processes in the solid, and thereby explained observations of hysteresis and rate multiplicity. Other important features are present when the solid phase is consumed, as in char gasification, which lead to progressive modification of the structure. Models for predicting the evolution of the pore structure and reactivity in gas solid reactions have been developed by us, and verified against experimental data for char gasification. More advanced approaches based on modeling and evolution of the underlying turbostratic crystalline structure of carbons have also been developed and validated by us.
Among the currently on-going projects we are examining the reactivity of carbon-carbon composites, and its relation with the structure. Several applications, such as aluminium smelting using sacrificial carbon anodes, which is very widely used, employ carbon composites, and the results are of potential importance in improving process efficiency. In another project we are examining the catalytic degradation of plastics into liquid fuels. Studies of kinetics and effect of process variables using a variety of catalysts are being undertaken using a screw extrusion reactor, and appropriate process models being developed. Given the large quantities of waste plastics being landfilled world-wide, the conversion of waste plastics into useful products is a vitally important area that can help alleviate a serious environmental problem
EducationB.Tech., Chem. Eng., Indian Institute of Technology, Kanpur; M.S.E., Chem. Eng., University of Pennsylvania; Ph.D., Chem. Eng., University of Pennsylvania
AwardsHonors and Awards
By this Researcher