Methodology

A conceptual design of an economic and environment-friendly UCG-CCS technology will be conducted within the first step of this project. This is followed by the gasification of coal samples under in-situ conditions and detailed analyses of the gasification residues and their surrounding rock. Furthermore, the CO2 storage potentials of the gasified coal samples and their surround rock will be investigated. This will also involve the calculation of UCG-CCS economics. Finally, experimental results will be used for parametrization of numerical models, which will be applied to verify the CO2 storage potentials and injectivity of the gasified coal seams.

Coal gasification

Conceptual design and environmental impacts

A review of UCG techniques with regard to the state of the art and environmental impacts based on international projects, publications and reports is scheduled for the first part of the project. Additionally, environmental impacts of UCG application will be investigated by a study of international data.

Sample acquisition, gasification and analysis

Coal and cap rock samples will be taken at different German hard coal districts and subsequently gasified to produce residues comparable to those accruing during the UCG process. Consequently, cap rock and gasified coal samples will be characterized at different laboratories of the RWTH Aachen University and geotechnical tests on the gasified coal samples will be conducted at the LIH laboratory. Porosity and permeability of both sample types at in-situ pressure conditions will be examined. Furthermore, CO2 and N2 adsorption capacities of both sample types will be determined.

Technology potentials and economics

Based on the conceptual and experimental studies conducted within this project as well as first reliable results of the numerical simulation runs, storage potentials will be calculated for a gasification and storage technology developed within the conceptual design. The economics of a combined UCG-CCS-technology will be calculated considering market development with regard to cost of investment and operation.

Numerical modeling

Numerical modeling

Numerical software modules of the MUFTE_UG software package will be adapted to integrate specific deposit parameters considering post-gasification conditions in the storage formation and the surrounding bedrock. This is followed by an implementation of CO2 and N2 sorption processes as retarding factors for the transport in the porous media. A model will be set up for a selected area suitable for UCG and CCS. The results from the experimental work conducted within this study and from international studies will be used to parametrize and subsequently validate the model after first simulation runs. Finally, a sensitivity analysis is scheduled to examine parameters dependent on their relevance for CO2 storage potentials and security in gasified coal seams.