Thermodynamic and kinetic processes associated with CO_1tn2-sequestration and CO_1tn2-enhanced coalbed methane production from unminable coal seams [Elektronische Ressource] / vorgelegt von Andreas Busch

Andreas Busch

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2005
• Nombre de lectures: 6
• Langue: English
• Poids de l'ouvrage: 1 Mo

Extrait

Thermodynamic and Kinetic Processes associated with CO -2
Sequestration and CO -Enhanced Coalbed Methane Production 2
from unminable Coal Seams


Von der Fakultät für Georessourcen und Materialtechnik der
Rheinisch -Westfälischen Technischen Hochschule Aachen

zur Erlangung des akademischen Grades eines
Doktors der Naturwissenschaften

genehmigte Dissertation


vorgelegt von Dipl.-Geol.

Andreas Busch

aus Koblenz





Berichter: Univ.-Prof. Dr. R. Littke
Univ.-Prof. Dr. Dr. h.c. D.H. Welte

Tag der mündlichen Prüfung: 13.05.2005


Diese Dissertation ist auf den Internetseiten der Hochschulbibliothek online verfügbar

















































to my parents



ACKNOWLEDGEMENTS
First of all, I would like to thank my supervisors, Prof. Dr. R. Littke and Dr. B.M. Krooß
for the opportunity to complete this thesis and for the best study conditions, one can
imagine. Especially the given opportunity to attend numerous national and interna-
tional meetings and conferences as well as to perform a three months stay at CSIRO
Australia raised my motivation exceedingly. In addition to the very intense and helpful
exchange of ideas with my supervisors, it allowed me to discuss the issues of my
research with scientists from many countries.
Furthermore, I gratefully acknowledge Prof. Dr. Dr. h.c. D. H. Welte for co-
supervising this thesis.
I would like to give my special regards to Y. Gensterblum, who introduced me in
many aspects of petrophysical laboratory work and who was always interested in
discussing the results of the experiments. His patience in explaining the basics of gas
chromatography, volumetric sorption experiments, lab-automation as well as the
small and big things in daily laboratory life improved this thesis tremendously.
Since the major part of this thesis has been conducted in the scope of an EU project
(RECOPOL), I acknowledge the help and support of all partners associated in this
project. Among these partners, I would like to express my thanks to Dr. H. Pagnier
and F. van Bergen who co-ordinated the project as well as to the fellows at TU Delft
(K.-H. Wolf, Dr. H. Bruining, N. Siemons and S. Mazumder) and IFP Paris (Dr. D.
Bossie-Codreanu). Prolific research is only possible with fruitful co-operations.
I gratefully acknowledge Dr. X. Choi (CSIRO Petroleum Division, Melbourne, Austra-
lia) for supervising me for three months in his department. His friendliness and pa-
tience helped me to understand the principles of reservoir simulation and reservoir
modeling. In this context I would like to thank the Heitfeld-Foundation for financial
support.
Productive research is also only possible with people that usually not appear as au-
thors on a publication but that give support in various time consuming administrative
subjects. Therefore, I would like to thank D. Kanellis and R. Wuropulos for giving me
this support.
5
Furthermore, I enjoyed all the time being surrounded by the students and staff at the
“Lehrstuhl für Geologie, Geochemie und Lagerstätten des Erdöls und der Kohle
(LEK)” at RWTH Aachen University. This conglomerate of open-minded and down-to-
earth people made work a leisure activity. Among these people, I would like to ex-
press my special thanks to R. Mildenberger (sample preparation) and my office-
mates K. Müller, J. Hollenstein and Dr. D. Prinz (in chronological order) for all the
small and big things not related to research. Among the former, I would like to thank
Dr. D. Prinz for being able to explain gas sorption on coal “in a different way”.
I would also like to thank all my friends for pretending to understand what my re-
search is all about and for helping me to forget about it.
My parents, to whom I would like to dedicate this thesis, and my brother are thanked
for supporting me over all the long years of education. This thesis could only be writ-
ten because they always accepted my views and my decisions.
And finally, I would like to thank E. Holuscha for her inspiration.


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ABSTRACT
The present thesis investigates the thermodynamic and kinetic processes associated
with gas sorption (CO , CH ) on coal. It is incorporated into a research field which 2 4
studies CO -sequestration in combination with CO -enhanced coalbed methane pro-2 2
duction in unminable coal seams. This combination is regarded as a viable and
promising option to reduce anthropogenic CO -emissions. 2
At the moment numerous world-wide research projects investigate the feasibility of
this concept under different geological and technical conditions. Among these pro-
jects, the RECOPOL-project („Reduction of CO Emissions by means of CO Storage 2 2
in the Silesian Basin in Poland”) is working on a European level and includes labora-
tory experiments, reservoir modeling, and geophysics as well as a field test in the
Upper Silesian Basin in Poland.
As a partner in this broad international consortium, it was the task to perform single-
and mixed-gas sorption experiments on coals from the test site under the prevailing
in situ reservoir conditions. Further coal samples from different coal basins all over
the world have been integrated into this study to strengthen gained results and to
address the diversity of coal samples in terms of rank, maceral composition, and
moisture.
Experiments have been performed on 14 different coal samples. Analytical tempera-
tures were 22, 32 and 45°C at pressures up to 230 bar (23 MPa).
The thesis is divided into three major chapters, each of them dealing with a different,
well defined question:
• The first part contains measurements that arose from a Round Robin initiated by
the US Department of Energy. The different laboratories were supposed to inves-
tigate five different samples from the Argonne Premium Sample Programme.
Measurements performed included CO single-gas isotherms on dry coals at 2
22°C and pressures up to about 50 bar (5 MPa). Additionally, CH experiments 4
under the same experimental conditions as well as CO /CH mixed-gas sorption 2 4
experiments at 45°C and pressures up to 180 bar (18 MPa) have been carried
out. The emphasis of the study was to compare single- and mixed-gas sorption
experiments and to perform a detailed characterisation of the five different sam-
ples.
• The second part investigates the kinetics of gas sorption on coal. To address this
issue, CO and CH adsorption/diffusion experiments on one coal sample from 2 4
the Upper Silesian Basin in Poland have been conducted on different grain sizes
and temperatures (32 and 45°C) as well as on dry and moist coals. The emphasis
of this chapter was to obtain qualitative differences between the different meas-
7
urements as well as to derive a kinetic model which describes gas sorption on
coal by a simple and realistic formulation that can readily be implemented in exist-
ing reservoir simulators.
• The third part concentrates on the preferential sorption from CO /CH gas-2 4
mixtures on coal. Measurements have been performed on ten different coal sam-
ples at 45°C and pressures up to 230 bar (23 MPa). Dry and moisture-
equilibrated coals as well as different source gas compositions have been used.
The emphasis here was to demonstrate dependencies of different coal properties
(rank, maceral composition, and moisture content) and different pressure ranges
on the preferential sorption behaviour of coal.
The main results of the three studies can be summarised as follows:
o The ratio of CO /CH sorption capacities from single-gas measurements varies 2 4
strongly and is not constant as stated in several previous studies.
o The sorption capacities of mixed-gases (CO /CH ) can not be calculated from 2 4
single-gas experiments.
o The sorption rate for CO is always faster than for CH . Sorption rates decrease 2 4
as grain sizes and moisture contents increase and temperature decreases.
sto The sorption kinetics can be described by a simple, semi-empirical 1 -order ki-
netic model under the assumption of a fast and a slow sorption process.
o Preferential adsorption of CO and preferential desorption of CH occurs, against 2 4
general expectations, only in some instances and is dependent on coal proper-
ties.
o The preferential sorption from a CO /CH gas mixture on coal varies widely and 2 4
only shows minor trends with different ranks and maceral compositions.
o The source gas composition does not influence the preferential sorption behav-
iour. The moisture reduces and the inertinite content increases the selectivity for
CO . 2

8
ZUSAMMENFASSUNG
In der vorliegenden Studie wurde die Thermodynamik und Kinetik der Gassorption
(CH , CO ) an Kohle untersucht. Sie ist eingebunden in ein Untersuchungsfeld, wel-4 2
ches die CO -Sequestrierung sowie die dadur