Browsing by Keyword "membranes"
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Item Advances in membranes and membrane reactors for the Fischer-Tropsch synthesis process for biofuel production(2022-01-01) Liuzzi, Dalia; Fernandez, Ekain; Perez, Susana; Ipiñazar, Enrique; Arteche, Amaya; Fierro, José Luís G.; Viviente, Jose Luis; Pacheco Tanaka, David Alfredo; Rojas, Sergio; TECNOLOGÍAS DE HIDRÓGENO; VALORIZACIÓN DE RESIDUOS; Mercado; TECNOLOGÍA DE MEMBRANAS E INTENSIFICACIÓN DE PROCESOSThe biomass-to-liquid (BtL) process is a promising technology to obtain clean, liquid, second-generation biofuels and chemicals. The BtL process, which comprises several steps, is based upon the gasification of biomass and the catalytic transformation of the syngas that is obtained via the Fischer-Tropsch synthesis (FTS) reaction, producing a hydrocarbon pool known as syncrude. The FTS process is a well-established technology, and there are currently very large FTS plants operating worldwide that produce liquid fuels and hydrocarbons from natural gas (NG) (gas-to-liquids, GtL process) and coal (coal-to-liquids, CtL process). Due to the limited availability of local biomass, the size of the BtL plants should be downscaled compared to that of a GtL or CtL plant. Since the feasibility of the XtL (X refers to any energy source that can be converted to liquid, including coal, NG, biomass, municipal solid waste, etc.) processes is strongly influenced by the economies of scale, the viability of small-scale BtL plants can be compromised. An interesting approach to overcome this issue is to increase the productivity of the FTS process by developing reactors and catalysts with higher productivities to generate the desired product fraction. Recently, by integrating membrane reactors with the FTS process the gas feeding and separation unit have been demonstrated in a single reactor. In this review, the most significant achievements in the field of catalytic membrane reactors for the FTS process will be discussed. Different types of membranes and configurations of membrane reactors, including H2O separation and H2-feed distribution, among others, will be analyzed.Item Carbon nanotubes and graphene into thermosetting composites: Synergy and combined effect(2018-07-20) Prolongo, S. G.; Moriche, R.; Ureña, A.; Flórez, S.; Gaztelumendi, I.; Arribas, C.; Prolongo, M. G.; POLIMEROSThis work analyzes the morphology and behavior of hybrid composites reinforced with carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs). In order to avoid the weak interface of laminar nanofillers, GNPs were functionalized with amine groups. Different tendencies were observed as a function of the measured property. Storage modulus showed a synergic trend, being the stiffness of hybrid CNT/GNP/epoxy composites higher than the corresponding ones measured in neat epoxy composites reinforced with CNTs or GNPs. In contrast, the thermal and electrical conductivity increased with the nanofiller addition, the final value of the mentioned properties in the hybrid composites was strongly influenced by specific graphitic nanofiller. Neat GNP/epoxy composites showed the highest thermal conductivity, while neat CNT/epoxy composites presented the highest electrical conductivity. This behavior is explained by the observed morphology. All composites exhibited a suitable nanofiller dispersion. However, on hybrid GNP/CNT/epoxy composites, CNTs tend to be placed between nanoplatelets, forming bridges between nanoplatelets. This morphology implies a less effective electrical network, limiting the synergic effect in the properties, which requires percolation. In spite of this, the hybrid GNP/CNT/epoxy composites showed a better combination of properties than the neat composites.