Start
Aug 14, 2014 - 17:00
End
Aug 14, 2014 - 18:00
Venue
Creativity Hall Room 118 Chemical Engineering
Event Type
Speaker
Ganesh Samdani PhD Student Chemical Engineering IITB
Title
Underground Coal Gasification: Kinetics Studies and Process Modeling
Abstract : In underground coal gasification (UCG) a cavity is formed in the coal seam due to consumption of coal. The irregular-shaped cavity consists of three distinct zones: a spalled-rubble zone on the cavity floor a cavity roof at the top and a void zone between the two. During UCG the coal seam between the injection and production wells undergoes two distinct growth phases. In phase-I coal/char near injection well gets consumed and cavity grows in a vertical (radial) direction and hits the overburden. Phase-II starts thereafter in which the cavity grows in the horizontal direction towards the production well. In this work unsteady-state models for gas production during both phase-I and phase-II are developed. Model requires reaction inputs such as kinetics spalling characteristics heat and mass transfer effects and flow patterns. To establish non-ideal flow patterns in the cavity a computationally less expensive compartment modeling approach based on computational flow dynamics (CFD) is used. Furthermore heterogeneous reaction kinetic parameters are experimentally determined; whereas parameters for heat and mass transfer and thermo-mechanical failure (spalling) of coal of interest are used for model development. In the process of kinetics modeling a novel reactor has been designed constructed and used for determination of faster reaction kinetics e.g. char combustion. The simulations are performed for a typical Indian lignite and the results are interpreted to demonstrate potential of the developed model. The simulation results are also compared with the results of the reported laboratory-scale experiments performed on the same coal under UCG-like conditions. As a logical extension of model development and validation this research involved study on finding optimum set of operating conditions and effects of coal properties on key performance indicators such as exit gas composition calorific value.