BGR Bundesanstalt fur Geowissenschaften und Rohstoffe

Hannover, Germany

BGR Bundesanstalt fur Geowissenschaften und Rohstoffe

Hannover, Germany
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Pusch G.,Clausthal University of Technology | May F.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Bernstone C.,Vattenfall | Llwart J.H.O.,E.ON Gas Storage GmbH | And 3 more authors.
Oil Gas European Magazine | Year: 2010

Natural gas and CO2 storage in depleted gas reservoirs are effective technologies with respect to the field infrastructure required and the logistics of transport. The most convenient form of CO2 transport in liquid state causes either exorbitant heating cost or stresses the subsurface equipment of the well heavily. Gas phase transport of CO2 requires large pipeline dimensions and a limitation of temperature decrease below 0°C and can therefore be used only in the early stage of the process, when reservoir pressures are low. The handling of dry CO2 requires no other material standards as for natural gas. The injection well pattern must be carefully designed to start with single cluster injection operation and continue after the reservoir testing phase (three years) with multi-cluster injection to take advantage of the synergisms of compartment interference in large, compartmentalized reservoirs.

Kaufhold S.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Dohrmann R.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Klinkenberg M.,Jülich Research Center | Siegesmund S.,University of Gottingen | Ufer K.,TU Bergakademie Freiberg
Journal of Colloid and Interface Science | Year: 2010

The specific surface areas (SSAN2BET) of 36 different bentonites had larger values for Ca2+/Mg2+ bentonites than for Na+ bentonites. This trend could not be explained by the different d(001) values nor by the different microstructures. The investigation of Cu-triene-exchanged smectites, which on drying at 105°C still had a d(001) value accounting for approximately 13Å, proved that the SSAN2BET of low-charged smectites increased more than that of high-charged smectites. This could be explained by: (i) more space between the permanent charge sites in the case of low-charged smectites and (ii) the fact that the layers of Cu-triene smectites do not collapse at 105°C. In contrast the SSAN2BET of Ca2+-exchanged bentonites could not be related to the layer charge density (LCD) as in the case of the Cu-triene-exchanged bentonites which is probably due to the varying number of collapsed layers. In conclusion, the SSAN2BET of bentonites which is known to be largely variable is probably determined by microporosity resulting from the quasi-crystalline overlap region and accessible areas of the interlayer. The number of layers per stack and the microstructure are supposed to play a subordinate role. The larger SSAN2BET of Ca/Mg bentonites compared to Na bentonites probably can be explained by the larger space between the charges in the case of the presence of divalent cations. © 2010 Elsevier Inc.

Kaufhold S.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Baille W.,Ruhr University Bochum | Schanz T.,Ruhr University Bochum | Dohrmann R.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe
Applied Clay Science | Year: 2015

The swelling capacity is one of the most characteristic properties of bentonites. This property, along with others, made bentonite a candidate material for the safe disposal of high-level radioactive waste (HLRW). For HLRW-barrier systems the swelling pressure is of particular interest because it basically controls sealing properties (a large swelling pressure generally results in low permeability). Commonly, the swelling pressure is investigated as a function of compaction and hence plotted against the density, usually the dry density. Different dry density/swelling pressure relations of bentonites were published. Therefore, the aim of the present study was to identify reasons for these differences. To be able to compare a significant set of different bentonites, a small scale swelling pressure device was developed which is based on measuring a swelling pressure related value of 500. mg bentonite powder. This device allowed recording about 200 single values (in duplicate) and hence dry density/swelling pressure relations of thirty six different bentonites. The differences of the dry density/swelling pressure plots of different bentonites could be explained by i) different ways to obtain a range of dry densities (either constant load or constant water content), ii) different portions of uncompactable porosity of the different bentonites, and iii) different smectite contents. © 2015 Elsevier B.V.

Kaufhold S.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Ufer K.,TU Bergakademie Freiberg | Kaufhold A.,Martin Luther University of Halle Wittenberg | Stucki J.W.,Urbana University | And 3 more authors.
Clays and Clay Minerals | Year: 2010

Allophane is a very fine-grained clay mineral which is especially common in Andosols. Its importance in soils derives from its large reactive surface area. Owing to its short-range order, allophane cannot be quantified by powder X-ray diffraction (XRD) directly. It is commonly dissolved from the soil by applying extraction methods. In the present study the standard extraction method (oxalate) was judged to be unsuitable for the quantification of allophane in a soil/clay deposit from Ecuador, probably because of the large allophane content (>60 wt.%). This standard extraction method systematically underestimated the allophane content but the weakness was less pronounced in samples with small allophane contents. In the case of allophane-rich materials, the Rietveld XRD technique, using an internal standard to determine the sum of X-ray amorphous phases, is recommended if appropriate structural models are available for the other phases present in the sample. The allophane (+imogolite) content is measured by subtracting the amount of oxalate-soluble phases (e.g. ferrihydrite). No correction would be required if oxalate-soluble Fe were incorporated in the allophane structure. The present study, however, provides no evidence for this hypothesis. Mössbauer and scanning electron microscopy investigations indicate that goethite and poorly ordered hematite are the dominant Fe minerals and occur as very fine grains (or coatings) being dispersed in the cloud-like allophane aggregates. Allophane is known to adsorb appreciable amounts of water, depending on ambient conditions. The mass fraction of the sample attributed to this mineral thus changes accordingly; the choice of a reference hydration state is, therefore, a fundamental factor in the quantification of allophane in a sample. Results from the present study revealed that (1) drying at 105°C produced a suitable reference state, and (2) water adsorption has no effect on quantification by XRD analysis.

Cervini-Silva J.,Metropolitan Autonomous University | Cervini-Silva J.,Lawrence Berkeley National Laboratory | Cervini-Silva J.,NASA | Nieto-Camacho A.,National Autonomous University of Mexico | And 5 more authors.
Microporous and Mesoporous Materials | Year: 2016

Natural zeolites are microporous crystalline aluminosilicates with channels and cavities of molecular dimensions of interest for biomedical applications. The antiphlogistic effect was investigated on the basis of a murine inflammation model using 12-O-tetradecanoylphorbol-13-acetate (TPA) as inflammatory agent and the quantification of the activity of myeloperoxidase (MPO), an enzyme that serves as an indicator for neutrophil migration. The zeolite used in this study was collected from San Andrés, Cuba, and it provided evidence to show the quantitative adsorption of histamine, a biogenic compound strongly involved in inflammation processes. Furthermore, a related work showed that this zeolite sample is free of hazardous materials and apt for health use. The zeolite of this study contained 65% clinoptilolite, 30% mordenite, and 5% smectite. The application of this zeolite reduced the edema formation induced by TPA within 24 h by 57.2 ± 18%, while the migration of neutrophils was not altered. The anti-inflammatory activity of zeolite was explained in part due to the quantitative adsorption of histamine, whilst natural cell repair mechanisms appeared not to be influenced. The outcome of this work expanded on reports concluding that antiphlogistic properties of zeolite proven in vivo with mice for inflammatory diseases are important for both oral application (gastrointestinal tract) and topical treatment (skin), too. © 2016 Elsevier Inc. All rights reserved.

Kaufhold S.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Dohrmann R.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Abidin Z.,Ehime University | Abidin Z.,University of Indonesia | And 5 more authors.
Applied Clay Science | Year: 2010

Worldwide F- contaminated groundwaters pose a serious health problem. For purification of these waters different adsorber materials are used such as activated aluminium oxide, iron oxyhydroxide (e.g. GEH®), or synthetic OH-Apatite (e.g. Fluorolith®). In some regions, however, inexpensive solutions are required motivating scientists to study the F- sorption of natural materials such as clays. The clay mineral allophane possesses a high affinity towards F-. In the present study different allophane samples are compared with other clay minerals as well as with Fluorolith®, a technically produced OH-apatite that is most commonly used in practice.Results obtained confirmed that allophane has the highest F- sorption capacity compared with kaolinite and goethite. The F- sorption capacity of some allophane samples is similar to the well-established F- adsorber material Fluorolith® and ranges from 3 to 5mg F-/g. Sorption depends on the experimental conditions, particularly the pH value (present study: 8-9). The different sorption capacity of the different allophanes could be explained by the amount of aluminol groups, which is independent of the specific surface area. The comparison of the fluoride uptake plots of allophanes with those of Fluorolith®, however, proved that Fluorolith® is particularly advantageous at low F- concentrations suggesting a higher affinity of the Fluorolith® surface towards F-. Sorption kinetics, however, were similar. Fluorolith® adsorbs F- by exchange of the structural anion OH-. The comparison of the uptake plots, however, suggests that different reactions have to be considered in the case of allophane. The sorption mechanism of fluoride on allophane could not be characterized further. © 2010 Elsevier B.V.

Reitze A.,SOCON Sonar Control Kavernenvermessung GmbH | Von Tryller H.,SOCON Sonar Control Kavernenvermessung GmbH | Ma Z.,SOCON Sonar Control Kavernenvermessung GmbH | Behlau J.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe
Underground Storage of CO2 and Energy - Proceedings of the Sino-German Conference, and the Sino-German Workshop "Eor and New Drilling Technology | Year: 2010

The echometric surveillance of caverns is especially important with regards to their safe and effective operation. As opposed to brine production caverns, storage caverns are generally subject only to convergence and do not undergo large and irregular changes of shape under normal conditions. Echometric surveillance is therefore primarily employed to obtain proof of the cavern stability and convergence. Applying the state-of-the-art tool technology, it is possible during an echometric survey to measure and process besides the geometry all relevant parameters such as speed of sound, pressure and temperature with a single tool run. Only when considering the physical parameters could it then be possible to achieve high-accurate results from sonar surveys. In the first instance of the presentation, the techniques used for surveying caverns as well as the survey procedure are described in general. Subsequently, some interesting results of sonar surveys in storage caverns are presented as well as the development of geological 3D-model on the basis of the sonar surveys. Geological 3D-models are used an increasing degree for the planning and development of new salt caverns. The geological structure of the site can spaciously be illustrated by the model and thus the potentially hazardous horizons can be identified. The numerous analysis options of the model allow the target-oriented localisation of the optimal cavern site. The different basic data can be linked with each other for the purpose of the modelling, and the methodology is applicable for salt rock as well as hard rock. Thus a broad application spectrum is offered.

Kaufhold S.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Dohrmann R.,BGR Bundesanstalt fur Geowissenschaften und Rohstoffe | Stucki J.W.,Urbana University | Anastacio A.S.,Urbana University
Clays and Clay Minerals | Year: 2011

The layer charge density (LCD) of montmorillonite represents the permanent negative charge, its most important property. The LCD can be determined by two different methods, the structural formula method(SF M) and the alkylammonium method(AAM). Other methods of determining the LCD are calibrated against one or the other of these. The results of the two methods differ systematically: SFM values are larger than AAM values and the difference increases with increasing layer charge density. In the present study, the critical parameters of both methods were considered quantitatively in order to identify the most likely reason for the systematic difference. One particularly important argument against the validity of the SFM is that typical SFM values correspond to unrealistically large CEC values that have never been reported. In addition, SFM does not consider the variable charge which causes cations to be adsorbed to the outer surface (at pH >4). In contrast to minor constituents, which can of course also affect SFM values, the variable charge can explain only part of the systematic difference. The exchange of pure smectite samples with both Cu-trien andalkyla mmonium revealedthe presence of non-exchangeable, nonstructural cations (Na, K, Ca). These cations, together with 10% (or more) variable charge, may explain the differences in LCD values. The non-exchangeable, non-structural cations could stem from undetected traces of feldspar or volcanic glass. The present samples indicated that the systematic difference in LCD values between the two methods is related to the amount of non-exchangeable, non-structural cations only, indicating that the two LCD methods probe different features of smectites. Using the SFM on pure smectite provides a value for the total number of charges (permanent with andwithout fixed(= non-exchangeable, non-structural) cations plus variable charge). The AAM, on the other hand, provides the charge density of the exchangeable cations (without variable charge).

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