Capítols de llibre
http://hdl.handle.net/2117/79825
2024-03-29T08:07:47Z7 - Hydrogen production in microreactors
http://hdl.handle.net/2117/336270
7 - Hydrogen production in microreactors
Soler Turu, Lluís; Jiménez Divins, Nuria; Vendrell Villafruela, Xavier; Serrano Carreño, M. Isabel; Llorca Piqué, Jordi
Catalytic microreactors constitute a crucial technology for process intensification in the production of hydrogen, particularly for on-site and/or onboard applications intended to feed fuel cells. This chapter describes the main processes and materials involved in the catalytic and photocatalytic generation of hydrogen from a variety of sources using microreactors. Steam reforming; dry reforming; partial oxidation; autothermal reforming; and decomposition of methane, methanol, ethanol, polyalcohols, dimethyl ether, and ammonia to yield hydrogen-rich gas mixtures using microreactors are revised. Also the photogeneration of hydrogen with various microreactor devices is discussed. The small volume of the microchannels and their high surface area-to-volume ratio enhance mass, heat, and photon transfer; enable safe operation; and allow developing compact and robust fuel processors.
2021-02-01T11:03:05ZSoler Turu, LluísJiménez Divins, NuriaVendrell Villafruela, XavierSerrano Carreño, M. IsabelLlorca Piqué, JordiCatalytic microreactors constitute a crucial technology for process intensification in the production of hydrogen, particularly for on-site and/or onboard applications intended to feed fuel cells. This chapter describes the main processes and materials involved in the catalytic and photocatalytic generation of hydrogen from a variety of sources using microreactors. Steam reforming; dry reforming; partial oxidation; autothermal reforming; and decomposition of methane, methanol, ethanol, polyalcohols, dimethyl ether, and ammonia to yield hydrogen-rich gas mixtures using microreactors are revised. Also the photogeneration of hydrogen with various microreactor devices is discussed. The small volume of the microchannels and their high surface area-to-volume ratio enhance mass, heat, and photon transfer; enable safe operation; and allow developing compact and robust fuel processors.Thin films as a tool for nanoscale studies of cement systems and building materials
http://hdl.handle.net/2117/103519
Thin films as a tool for nanoscale studies of cement systems and building materials
Rheinheimer, Vanessa; Casanova Hormaechea, Ignasi
Many efforts have been made over the last decades to improve and develop new technologies for cement and chemical industries that can provide materials that are more durable and cost efficient, stronger and less environmentally harmful. Studies at small scale in cementitious materials usually require special sample preparation, which can damage the material and mislead the analysis. In nanoscale experiments, several techniques require samples to be extremely thin, while others need the samples to be very flat. The possibility of using thin films of clinker phases in cement research opens far-reaching opportunities for the development of this material and the materials associated to this. Testing different evaporation parameters, the deposition of films with a few tens of nanometers in thickness was achieved for all the clinker phases individually. This chapter will present the attempts for synthesizing thin films of all main clinker phases by the use of electron beam evaporation technique, as well as data on the hydration of the calcium silicate thin, flat and homogeneous samples. Changes are tracked chemically and mineralogically. This study redirects cement science to new perspectives of understanding the nanostructure of cement products. This leads to basis for developing stronger and more durable cement-based materials.
2017-04-18T14:35:21ZRheinheimer, VanessaCasanova Hormaechea, IgnasiMany efforts have been made over the last decades to improve and develop new technologies for cement and chemical industries that can provide materials that are more durable and cost efficient, stronger and less environmentally harmful. Studies at small scale in cementitious materials usually require special sample preparation, which can damage the material and mislead the analysis. In nanoscale experiments, several techniques require samples to be extremely thin, while others need the samples to be very flat. The possibility of using thin films of clinker phases in cement research opens far-reaching opportunities for the development of this material and the materials associated to this. Testing different evaporation parameters, the deposition of films with a few tens of nanometers in thickness was achieved for all the clinker phases individually. This chapter will present the attempts for synthesizing thin films of all main clinker phases by the use of electron beam evaporation technique, as well as data on the hydration of the calcium silicate thin, flat and homogeneous samples. Changes are tracked chemically and mineralogically. This study redirects cement science to new perspectives of understanding the nanostructure of cement products. This leads to basis for developing stronger and more durable cement-based materials.Alcohols and bio-alcohols steam and autothermal reforming in a membrane reactor
http://hdl.handle.net/2117/76793
Alcohols and bio-alcohols steam and autothermal reforming in a membrane reactor
Llorca Piqué, Jordi; Hedayati, Ali
Considerable work has been reported concerning catalytic steam reforming, partial oxidation and oxidative steam reforming (autothermal reforming) aimed at hydrogen generation from alcohol-water mixtures. They include methanol, ethanol, glycerol, and the exploitiation of renewable bio-alcohols. The use of catalytic membrane reactors, with simultaneous generation and separation of hydrogen, appears as an attractive approach to optimize downstream separation and to substantially simplify on-site/on-demand alcohol reformers. Catalytic membrane reactors reduce capital costs by combining the reforming process and hydrogen separation in one system, allow an enhancement of the alcohol conversion of the equilibrium-limited reforming processes, and are able to directly produce a high purity hydrogen stream for feeding fuel cells if dense Pd-based membranes are used.; Considerable work has been reported concerning catalytic steam reforming, partial oxidation and oxidative steam reforming (autothermal reforming) aimed at hydrogen generation from alcohol-water mixtures. They include methanol, ethanol, glycerol, and the exploitiation of renewable bio-alcohols. The use of catalytic membrane reactors, with simultaneous generation and separation of hydrogen, appears as an attractive approach to optimize downstream separation and to substantially simplify on-site/on-demand alcohol reformers. Catalytic membrane reactors reduce capital costs by combining the reforming process and hydrogen separation in one system, allow an enhancement of the alcohol conversion of the equilibrium-limited reforming processes, and are able to directly produce a high purity hydrogen stream for feeding fuel cells if dense Pd-based membranes are used.
2015-09-15T10:44:47ZLlorca Piqué, JordiHedayati, AliConsiderable work has been reported concerning catalytic steam reforming, partial oxidation and oxidative steam reforming (autothermal reforming) aimed at hydrogen generation from alcohol-water mixtures. They include methanol, ethanol, glycerol, and the exploitiation of renewable bio-alcohols. The use of catalytic membrane reactors, with simultaneous generation and separation of hydrogen, appears as an attractive approach to optimize downstream separation and to substantially simplify on-site/on-demand alcohol reformers. Catalytic membrane reactors reduce capital costs by combining the reforming process and hydrogen separation in one system, allow an enhancement of the alcohol conversion of the equilibrium-limited reforming processes, and are able to directly produce a high purity hydrogen stream for feeding fuel cells if dense Pd-based membranes are used.
Considerable work has been reported concerning catalytic steam reforming, partial oxidation and oxidative steam reforming (autothermal reforming) aimed at hydrogen generation from alcohol-water mixtures. They include methanol, ethanol, glycerol, and the exploitiation of renewable bio-alcohols. The use of catalytic membrane reactors, with simultaneous generation and separation of hydrogen, appears as an attractive approach to optimize downstream separation and to substantially simplify on-site/on-demand alcohol reformers. Catalytic membrane reactors reduce capital costs by combining the reforming process and hydrogen separation in one system, allow an enhancement of the alcohol conversion of the equilibrium-limited reforming processes, and are able to directly produce a high purity hydrogen stream for feeding fuel cells if dense Pd-based membranes are used.