Membranes Made of Hardened Cement Paste for Processing Wood Gas—Influence of Paste Composition on Separation Factors

Autor: Weiqi Zhang, Frank Behrendt, Bernd Hillemeier, Gregor J. G. Gluth, Maria Gaggl
Rok vydání: 2014
Předmět:
Zdroj: Materials Challenges and Testing for Manufacturing, Mobility, Biomedical Applications and Climate ISBN: 9783319113395
DOI: 10.1007/978-3-319-11340-1_20
Popis: 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.
Databáze: OpenAIRE