TY - GEN A1 - Gluth, Gregor A1 - Gaggl, M. A1 - Zhang, W. A1 - Hillemeier, B. A1 - Behrendt, F. ED - Udomkichdecha, W. ED - Böllinghaus, T. ED - Manonukul, A. ED - Lexow, J. T1 - Membranes made of hardened cement paste for processing wood gas - Influence of paste composition and separation factors N2 - The efficiency of wood gasification can be improved by applying membrane based gas separation operations in several of its sub-processes. In the present study the use of membranes made of hardened cement pastes for this purpose was investigated to provide a low cost alternative to conventional membrane materials. The pastes were tested for their diffusional properties in a Wicke-Kallenbach cell and analyzed with regard to their pore structure. The use of low water to binder ratios and slag and/or pozzolans led to a finer pore structure and higher separation factors; in particular, an approximately linear dependence of the separation factors on the threshold radii was observed. The results implicated that Knudsen diffusion is the prevailing diffusion mechanism in the membranes. Deviations from the theoretically expected separation factors were found, which may be ascribed to concentration polarization and channeling effects. KW - Hardened cement paste KW - Pore structure KW - Diffusion KW - Gas separation PY - 2014 SN - 978-3-319-11339-5 SN - 978-3-319-11340-1 U6 - https://doi.org/10.1007/978-3-319-11340-1_20 SP - 199 EP - 209 PB - Springer AN - OPUS4-32065 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, W. A1 - Gaggl, M. A1 - Gluth, Gregor A1 - Behrendt, F. T1 - Gas separation using porous cement membrane N2 - Gas separation is a key issue in various industrial fields. Hydrogen has the potential for application in clean fuel technologies. Therefore, the separation and purification of hydrogen is an important research subject. CO2 capture and storage have important roles in 'green chemistry'. As an effective clean technology, gas separation using inorganic membranes has attracted much attention in the last several decades. Membrane processes have many applications in the field of gas separation. Cement is one type of inorganic material, with the advantages of a lower cost and a longer lifespan. An experimental setup has been created and improved to measure twenty different cement membranes. The purpose of this work was to investigate the influence of gas molecule properties on the material transport and to explore the influence of operating conditions and membrane composition on separation efficiency. The influences of the above parameters are determined, the best conditions and membrane type are found, it is shown that cementitious material has the ability to separate gas mixtures, and the gas transport mechanism is studied. KW - Gas separation KW - Porous membrane KW - Clean fuel KW - Cement membrane KW - Inorganic membranes PY - 2014 U6 - https://doi.org/10.1016/S1001-0742(13)60389-7 SN - 1001-0742 SN - 1878-7320 VL - 26 IS - 1 SP - 140 EP - 146 CY - Beijing, China AN - OPUS4-30039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gluth, Gregor A1 - Zhang, W. A1 - Gaggl, M. A1 - Hillemeier, B. A1 - Behrendt, F. T1 - Multicomponent gas diffusion in hardened cement paste at temperatures up to 350 °C N2 - Diffusional gas transport of a H2/CO2 mixture versus N2 in the pore system of hardened cement pastes was studied at four temperatures up to 350 °C in a Wicke-Kallenbach cell. The pastes possessed separation factors αH2,CO2 from 1.42 to 3.43, i.e. the diffusion of hydrogen took place considerably faster than the diffusion of carbon dioxide. The separation factors depended on the threshold radii of the pastes, smaller threshold radii leading to higher separation factors. The Knudsen numbers of the controlling constrictions of the pore system and the temperature dependence of the effective diffusion coefficients of the gases show that gas transport in these constrictions takes place in the transient regime between Knudsen diffusion and bulk diffusion, smaller constriction widths leading to predominating Knudsen diffusion. It is therefore possible to use cement paste membranes to separate gas components of low molecular weight from higher weight components. KW - Microstructure (B) KW - Mercury porosimetry (B) KW - Diffusion (C) KW - Cement paste (D) KW - Gas separation KW - Pore structure PY - 2012 U6 - https://doi.org/10.1016/j.cemconres.2012.02.001 SN - 0008-8846 SN - 1873-3948 VL - 42 IS - 5 SP - 656 EP - 664 PB - Pergamon Press CY - New York, NY AN - OPUS4-25655 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -