Desenvolupament de processos de tractament per la millora de la qualitat del biogàs d'estacions depuradores d'aigües residuals

Abstract

The biogas generated in the wastewater treatment plants is a fuel used for power generation due to his high concentration of methane in its composition. The problem of biogas as an energy source is the presence of different trace elements such as hydrogen sulphide (H2S) or siloxane. The term siloxane refers to a subgroup of silicones containing Si-O bonds with organic radicals attached to the atom of silicon, this organics radicals can be formed by methyl, ethyl or other functional groups. Siloxanes are widely used in several industrial and household applications. During the transformation of biogas energy, the siloxane are transformed into a solid abrasive microcrystalline silica (silicate oxide) reducing the lifetime of the machine and affecting the combustion process. The elimination of this siloxane can be performed using different methods but there is one that is very efficient and it is relatively inexpensive which the adsorption on active carbon is. Although this technique is quite used to improve the biogas little is known about the mechanisms involved in the removal of these trace elements. Thus, the aim of this dissertation is to establish the siloxane adsorption mechanisms in order to enhance yield of the sequential adsorption technologies for siloxane. Two commercial carbons were selected and their ability to adsorption systems in dynamic and static was assessed where it was necessary to develop a static methodology. Using a system with artificial biogas a multicomponent and a dynamic analysis is conducted to known the behaviour in a real application. These results could determine which compound has more affinity for the carbons and to find out how the adsorption is done. Based on the experimental results it can be seen as one of the carbons has a high affinity for both siloxane studies in static and in dynamic, it is believed that this behaviour is based on the difference between these two surface active coals and the available space of the carbon which had the best adsorption