My research group is engaged in fundamental and applied research in the areas including fluidization and multiphase flow, particulate reaction engineering, and particle technology. These areas are of relevance to energy and environmental systems and of direct interest to chemical, petrochemical, mineral, and material industries. The specifics of current research efforts in these areas are briefed below. 

We are investigating the turbulent diffusion of particles from the core-to-wall region and probing into the origin of particle clusters in the core region of a segregated flow in a circulating fluidized bed. Our study also extends to examining the flow structure and mixing characteristics of a turbulent fluidized bed under high-pressure and hightemperature conditions and the effects of fine particles on the fluidization behavior. This research group has developed a unique large-scale flow visualization apparatus in conjunction with a particle image velocimetry system to analyze the high-pressure and high-temperature phenomena in gasliquid bubble columns, slurry bubble columns, and three-phase fluidized beds. Our research has addressed the key issues that dictate the fluid dynamics and transport behavior of these systems such as bubble instability, bubble formation and jetting, flow regime transition, and heat and mass transfer mechanisms. A computational code for discrete-phase simulation for three-phase flow has been developed and has been verified to mimic the real flow situations. We have also developed Electrical Capacitance Tomography (ECT) for three-dimensional, real-time imaging of two- and threephase flows. 

Our research resulted in the synthesis of calcium-based sorbents with tailored internal structures that are effective in flue gas emission control for coal combustion. Based on this patented concept, a new coal combustion process system is being commercially demonstrated. Recent studies are focused on examining ionic diffusion through solids, ultrafast powder reaction engineering, and kinetics of the reaction between calcium-based powder with H2S and other toxic substances (selenium and arsenic). The kinetic data are obtained using a specially designed high-pressure, high-temperature differential-bed reactor capable of being operated under fixed, fluidized, and entrained-bed conditions at pressures up to 3.5 MPa and temperatures up to 1000ºC. Measurements of the powder properties, e.g., surface charge and internal angle of friction, are conducted in the well-equipped powder testing laboratory of this group. 

In addition to federal and state agencies, an industrial consortium is supporting the program with an annual consortium symposium hosted by this research group. The interaction with the consortium members has proven to be of great benefit to our group members over the years.