Page 9 - gas transport in porous media

CHAPTER 1

INTRODUCTION

CLIFFORD K. HO AND STEPHEN W. WEBB
Sandia National Laboratories, P. O. Box 5800, Albuquerque, NM 87185, USA

Gas and vapor transport in porous media occur in a number of important applications
including drying of industrial and food products, oil and gas exploration, environmen-
tal remediation of contaminated sites, and carbon sequestration. Understanding the
fundamental mechanisms and processes of gas and vapor transport in porous media
allows models to be used to evaluate and optimize the performance and design of
these systems.
In this book, gas and vapor are distinguished by their available states at stan-
◦
dard temperature and pressure (20 C, 101 kPa). If the gas-phase constituent can also
exist as a liquid phase at standard temperature and pressure (e.g., water, ethanol,
toluene, trichlorothylene), it is considered a vapor. If the gas-phase constituent is
non-condensable at standard temperature and pressure (e.g., oxygen, carbon diox-
ide, helium, hydrogen, propane), it is considered a gas. The distinction is important
because different processes affect the transport and behavior of gases and vapors in
porous media. For example, mechanisms specific to vapors include vapor-pressure
lowering and enhanced vapor diffusion, which are caused by the presence of a gas-
phase constituent interacting with its liquid phase in an unsaturated porous media. In
addition, the “heat-pipe” exploits isothermal latent heat exchange during evaporation
and condensation to effectively transfer heat in designed and natural systems.
The intent of this book is to expose the reader to a variety of important studies
of gas and vapor transport in porous and fractured media. The primary focus is on
the presentation of fundamental processes, state-of-the-art modeling, experiments,
and applications that are relevant to gas and vapor transport in porous and fractured
media. The topics in this book span multiple disciplines, ranging from soil science to
engineering. This has been done intentionally to integrate the broad audience in this
subject area and to provide a compilation of common areas of research. Historically,
the treatment of gas and vapor transport processes in porous and fractured media has
been segregated according to disciplines or journals. Approaches to understanding
these processes have evolved in soil science for many decades, but there has been
1
C. Ho and S. Webb (eds.), Gas Transport in Porous Media, 1–2.
© 2006 Springer.