Browsing by Author "Ochs, Steffen Oliver"

Now showing 1 - 1 of 1

Open Access
Steam injection into saturated porous media : process analysis including experimental and numerical investigations
(2007) Ochs, Steffen Oliver; Helmig, Rainer (Prof. Dr.-Ing.)
The extensive use of chemicals in industry coupled with the lack of understanding their potential threat to the environment and human health has resulted in substantial soil and groundwater contamination during the 20th century in many industrialized areas. Sites contaminated by dense non-aqueous phase liquids (DNAPL's) turned out to be rather problematic. The fact that DNAPL's have a higher density than water enables them to migrate below the ground water table causing extensive contaminations in the saturated zone. Conventional remediation techniques show major difficulties in the remediation of DNAPL and induced the development of innovative remediation techniques for such sites. One of the most promising is the injection of steam into the subsurface. This technique has been successfully applied to the remediation of DNAPL contaminations in the unsaturated zone. Today, the application of steam injection for the treatment of contaminations in the saturated zone is in the focus of research interest. Although the physical processes elapsing during steam injection are basically the same either in the saturated and unsaturated zone, there are distinct differences in their relevancy. This work contributes to increasing the insight into the non-isothermal multi-phase system emerging during steam injection into saturated porous media. An essential prerequisite for this is to identify and understand important processes and parameters influencing the system behavior. First, experimental investigations are carried out in a saturated two-dimensional flume. The established understanding of the system behavior was incorporated into the development of a numerical model. In this process, special attention was placed on an accurate description of system behavior and a robust operation of the model. Instabilities occurring at fully saturated conditions were analyzed, and appropriate measures were taken to prevent them. The developed model was subsequently used for simulating steam injection experiments and later utilized for the verification of the model code. In order to demonstrate the predictive qualities of the model, a field scale steam injection was simulated. The experimental and numerical investigations resulted in an improved understanding of the non-isothermal multi-phase system emerging during steam injection into saturated porous media. The relevant processes and parameters influencing the propagation of the steam front at saturated conditions could be identified. This provided the possibility of deriving characteristic typecurves for steam propagation in saturated porous media.