Pure Hydrogen Production from Steam Reforming of Bio-Sources

Two synthetic mixtures simulating biogas (CH4 /CO2 = 66.2/33.8) and bioethanol (H2O/EtOH = 13/1) have been used for producing hydrogen by steam reforming reaction in a commercial dense self-supported Pd-Ag membrane reactor. The experimental campaign was subdivided into two parts. Firstly, we studied biogas steam reforming reaction, evaluating the reaction pressure influence (between 200 and 350 kPa) at 450°C, H2O/CH4feed molar ratio = 4/1, GHSV =2370h-1, sweep gas flow rate (N2) = 28.55 mL/min and countercurrent configuration. As best result, we reached 60% CH4 conversion and 40% hydrogen recovery at 350kPa.Successively, we carried out bioethanol steam reforming reaction studying the influence of reaction temperature between 350 and 400°C at 300 kPa of reaction pressure, GHSV=700 h-1 in the presence of sweep gas (N2 = 28.55 mL/min) and countercurrent configuration, obtaining - at 400 °C - maximum ethanol conversion, hydrogen yield and recovery equal to 70%, 50% and 65%, respectively. In addition, we compared the membrane reactor performance with a traditional reactor exercised at the same conditions, only varying the reaction pressure between 200 and 300 kPa. The aim of this work is constituted by the pure hydrogen production from bio-sources exploitation in membrane reactors at bench scale, starting with the utilization of commercial membranes available in the market and in the perspective of scaling up the process for potential industrial development

Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications

[EN] ZIF-8 (Z8), ZIF-67 (Z67), and ZMix, a Zn/Co bimetallic zeolitic imidazolate framework (ZIF), were synthesized and doped with tetrabutylammonium hydroxide (ZIFsT). The obtained powders were used as fillers for polyetherimide (PEI) at a concentration of 20 wt %. The presence of the three ZIFsT in the polymeric matrix enhanced proton transport relative to that observed for PEI or ZIFs alone. The real and imaginary parts of the complex conductivity were obtained for each of the six materials, and the temperature and frequency dependence of the real part was analyzed. The results at different temperatures show that the dc-conductivity are about three orders of magnitude higher for the doped ZIFsT materials than for the PEI/ZIFsT membranes. In addition, the conductivity of the PEI/ZIFsT membranes increases five or six times when the temperature is changed from 25 °C to 55 °C. For these materials, the conductivity measurements have a linear dependency with frequency, which allowed for the creation of a master curve. It was also found that the PEI/ZMixT membrane activation energy is four times smaller than that of PEI/Z8T membranes and five times smaller than that of PEI/Z67T. Similarly, the real and imaginary parts of the complex dielectric constant were obtained, and the tan ¿ was evaluated. Using this value, the diffusion coefficient and the charge carrier density were obtained. A discussion of the proton transport mechanism through the membrane is given, and a comparison of this work with those on similar electrolyte membranes is included.This research has been supported by the ENE/2015-69203-R project, granted by the Ministerio de Economia y Competitividad (MINECO), Spain, and grants from National Mexican Council for Science and Technology for the scholarships of Ph.D. No. 356825 and mixed scholarship 2015 - MZO2016-mobility in the foreigner granted to Jesus Vega Moreno registered scholarship holder number 256015. Thanks to the CONACYT Program for the fellowship at the Universidad Politecnica de Valencia (UPV) and Universitat Jaume I that PhD student Jesus Vega used to carry out the experimental studies of this work. DGAPA-PAPIIT IG-100315.Vega, J.; Andrio, A.; Lemus, AA.; Del Castillo, LF.; Compañ Moreno, V. (2017). Conductivity study of Zeolitic Imidazolate Frameworks, Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks, and mixed matrix membranes of Polyetherimide/Tetrabutylammonium hydroxide doped with Zeolitic Imidazolate Frameworks for proton conducting applications. Electrochimica Acta. 258:153-166. https://doi.org/10.1016/j.electacta.2017.10.095S15316625

Methanol steam reforming for hydrogen generation via conventional and membrane reactors: A review

In the recent years, hydrogen has gained a considerable interest as an energy carrier useful for variousapplications and, particularly, for polymer electrolyte membrane fuel cells (PEMFCs) supply. Nevertheless, PEMFCs require high purity hydrogen as a feeding fuel, which shows some limitations regardingstorage and transportation. Therefore, to overcome these problems, the in situ hydrogen generation hasmade attractive both alcohols and hydrocarbons steam reforming reaction. Among other fuels, methanolis an interesting hydrogen source because it is liquid at ambient conditions, possesses relatively high H/Cratio, low reforming temperature (200-300 1C) and it is also producible from biomass. Meanwhile, thereis a comprehensive literature about inorganic membrane reactors utilization for hydrogen generationvia methanol steam reforming reaction. This review illustrates the earlier state of the art from anexperimental point of view about hydrogen production from methanol reforming performed in bothconventional and membrane reactors. Furthermore, a short overview about methanol reforming catalystsas well as a discussion on the impact of methanol steam reforming process via inorganic membranereactors to produce hydrogen for PEMFCs supply is given

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CO-free hydrogen production by ethanol steam reforming in a Pd-Ag membrane reactor

In this work, the ethanol steam reforming (ESR) reaction has been studied by using a dense Pd-Ag membrane reactor (MR) by varying the water/ethanol molar ratio between 3:1 and 9:1 in a temperature range of 300-400°C and at 1.3 bar as reaction pressure. The MR was packed with a commercial Ru-based catalyst and a constant sweep gas flow rate in counter current mode was used. The influence of the temperature and the feed molar ratio on different parameters such as the ethanol conversion, the hydrogen production, the hydrogen yield and the CO-free hydrogen recovery has been evaluated. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA. 10.1002/fuce.20070001

Membrane Engineering in the Circular Economy: Renewable Sources Valorization in Energy and Downstream Processing in Agro-food Industry

Membrane Engineering in the Circular Economy: Renewable Sources Valorization in Energy and Downstream Processing in Agro-food Industry describes the modification of the general concept of "waste," including waste valorization as added-value products that are useful for energy production and biotechnology industries. Speaking to the relevance of this new vision, the book highlights the fundamentals of membrane operations in the exploitation of renewable sources for energy production and the valorization of agro-food waste at the industrial level.  This book is an excellent resource for researchers, biologists, membranologists and engineers in chemistry, biochemical engineering, food sciences and the agro-food refinery industry. © 2022 Elsevier Inc. All rights reserved

CO-free hydrogen production by ethanol steam reforming in a Pd-Ag membrane reactor

In this work, the ethanol steam reforming (ESR) reaction has been studied by using a dense Pd-Ag membrane reactor (MR) by varying the water/ethanol molar ratio between 3:1 and 9:1 in a temperature range of 300-400°C and at 1.3 bar as reaction pressure. The MR was packed with a commercial Ru-based catalyst and a constant sweep gas flow rate in counter current mode was used. The influence of the temperature and the feed molar ratio on different parameters such as the ethanol conversion, the hydrogen production, the hydrogen yield and the CO-free hydrogen recovery has been evaluated. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA. 10.1002/fuce.20070001

Methanol and ethanol steam reforming in membrane reactors : an experimental study

In this work a comparison between methanol steam reforming (MSR) reaction and ethanol steam reforming (ESR) reaction to produce hydrogen in membrane reactors (MRs) is discussed from an experimental point of view. Both reaction systems have been investigated by considering the influence of the membrane characteristics as well as the influence of the operating temperature. In the case of a dense membrane, the sweep gas flow rate and the different flux configurations have also been analysed. Experimental results, in terms of reactant conversions as well as hydrogen production and gases selectivity in MRs and in a traditional reactor (TR), are presented. Catalyst stability in both reaction systems has also been tested. © 2006 International Association for Hydrogen Energy. 10.1016/j.ijhydene.2006.11.01

Artificial neural network model for water gas shift reaction in a dense Pd-Ag membrane reactor

The water gas shift reaction was studied in membrane reactors for training an artificial neural network model. In particular, we have lead experiment varying many parameters as the reaction pressure, reaction temperature, gas hourly space velocity, sweep gas flow rate, H2O/CO feed molar ratio and feed configuration have been considered from both a modelling and an experimental point of view in order to analyze their influence on the water gas shift performance in two membrane reactors. Meanwhile, the artificial neural network model has been validated by using experimental tests as training results and it was validated whit a new data set, obtained optimizing the system to achieve as much as possible high hydrogen recovery. The model predicted the experimental performance of the water gas shift membrane reactors with an error on CO conversion lower than 0.5% and around 10% for the H2 recovery