Experimental Study on a Compact Methanol-Fueled Reformer With Heat Regeneration Using Ceramic Honeycomb

2010 ◽  
Author(s):  
Yasuhiro Rai ◽  
Kazuya Tatsumi ◽  
Kazuyoshi Nakabe
Keyword(s):  
Hydrogen Production ◽  
Thermal Energy ◽  
The Other ◽  
Exhaust Gas ◽  
Downstream Side ◽  
Highly Efficient ◽  
Production Ratio ◽  
Production Of Hydrogen ◽  
Reaction Region ◽  
Ceramic Honeycomb

On the way to a new era of our society which will be based on hydrogen energy, it is needed to develop on-site hydrogen production systems to cover current insufficient infrastructures of hydrogen supply network systems. For this, a highly efficient compact reformer can be one of the most suitable solutions for on-site production of hydrogen which is supplied to distributed electric power-generation systems. But, the local and overall energy balance in the reformer should be precisely controlled since the reforming reaction processes of hydrocarbon fuels are very sensitive to reaction temperature in the reformer. For smaller reformers, in particular, the amount of heat loss through the outer surfaces is large enough to dominate the reactions. An appropriate way for thermal energy management, therefore, is necessary to accomplish highly efficient reformers. For these backgrounds, a compact tubular-typed fuel reformer was fabricated in this study, and was applied to produce hydrogen from methanol, focusing on the partial oxidation reaction (POR). The reformer was composed of a stainless steel pipe as the reactor exterior and ceramic honeycomb blocks inserted in two locations of the reactor. The honeycomb blocks are expected to assist the reforming reactions and transfer the thermal energy of the exhaust gas to the reaction region, acting as a heat regenerator. The upstream-side honeycomb block was aimed to perform an effective heat exchange from the reactor wall to the reactant gas. By inserting the block, the reforming reaction became stable at right after the block. The maximum hydrogen production was achieved in the condition of equivalence ratio, around 3.5. The other honeycomb block was inserted in the downstream of the reaction zone to convert the thermal energy of exhaust gas to radiation energy which can be transferred to the upstream reaction region. Comparing to the case without the downstream-side block, the temperature of the reaction region became higher. Gas temperatures in the downstream region, on the other hand, became lower. Methanol conversion ratio and hydrogen production ratio enhanced due to the higher temperature at the reaction region. These results indicate that the thermal energy possessed by the exhaust gas was regenerated in the reaction region by the downstream-side honeycomb block and contributes to enhance the efficiency of the fuel reformer.

scholarly journals 2D-Layered Non-Precious Electrocatalysts for Hydrogen Evolution Reaction: Fundamentals to Applications

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 689
Author(s):  
Prasanta Kumar Sahoo ◽  
Soubhagya Ranjan Bisoi ◽  
Yi-June Huang ◽  
Dung-Sheng Tsai ◽  
Chuan-Pei Lee
Keyword(s):  
Hydrogen Production ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Cost Effective ◽  
Clean Energy ◽  
Layered Materials ◽  
Scale Production ◽  
Highly Efficient ◽  
2D Layered Materials ◽  
Production Of Hydrogen

The production of hydrogen via the water splitting process is one of the most promising technologies for future clean energy requirements, and one of the best related challenges is the choice of the most highly efficient and cost effective electrocatalyst. Conventional electrocatalysts based on precious metals are rare and very-expensive for large-scale production of hydrogen, demanding the exploration for low-cost earth abundant alternatives. In this context, extensive works from both theoretical and experimental investigations have shown that two-dimensional (2D) layered materials have gained considerable attention as highly effective electrocatalytic materials for electrical-driven hydrogen production because of their unique layered structure and exciting electrical properties. This review highlights recent advancements on 2D layered materials, including graphene, transitional metal dichalcogenides (TMDs), layered double hydroxides (LDHs), MXene, and graphitic carbon nitride (g-C3N4) as cost-effective and highly efficient electrocatalysts for hydrogen production. In addition, some fundamental aspects of the hydrogen evolution reaction (HER) process and a wide ranging overview on several strategies to design and synthesize 2D layered material as HER electrocatalysts for commercial applications are introduced. Finally, the conclusion and futuristic prospects and challenges of the advancement of 2D layered materials as non-precious HER electrocatalysts are briefly discussed.

Characterization of a Polymeric Membrane for the Separation of Hydrogen in a Mixture with CO2

2016 ◽  
Vol 9 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Dionisio H. Malagón-Romero ◽  
Alexander Ladino ◽  
Nataly Ortiz ◽  
Liliana P. Green
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Production ◽  
Test Performance ◽  
Low Cost ◽  
Time Lag ◽  
Polymeric Membrane ◽  
Biological Processes ◽  
Scanning Calorimetry ◽  
Environmentally Sustainable ◽  
Production Of Hydrogen

Hydrogen is expected to play an important role as a clean, reliable and renewable energy source. A key challenge is the production of hydrogen in an economically and environmentally sustainable way on an industrial scale. One promising method of hydrogen production is via biological processes using agricultural resources, where the hydrogen is found to be mixed with other gases, such as carbon dioxide. Thus, to separate hydrogen from the mixture, it is challenging to implement and evaluate a simple, low cost, reliable and efficient separation process. So, the aim of this work was to develop a polymeric membrane for hydrogen separation. The developed membranes were made of polysulfone via phase inversion by a controlled evaporation method with 5 wt % and 10 wt % of polysulfone resulting in thicknesses of 132 and 239 micrometers, respectively. Membrane characterization was performed using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), atomic force microscopy (AFM), and ASTM D882 tensile test. Performance was characterized using a 23 factorial experiment using the time lag method, comparing the results with those from gas chromatography (GC). As a result, developed membranes exhibited dense microstructures, low values of RMS roughness, and glass transition temperatures of approximately 191.75 °C and 190.43 °C for the 5 wt % and 10 wt % membranes, respectively. Performance results for the given membranes showed a hydrogen selectivity of 8.20 for an evaluated gas mixture 54% hydrogen and 46% carbon dioxide. According to selectivity achieved, H2 separation from carbon dioxide is feasible with possibilities of scalability. These results are important for consolidating hydrogen production from biological processes.

Hot injection induced synthesis of ZnCdS-rGO/MoS2 heterostructures for efficient hydrogen production and CO2 photoreduction

2021 ◽  
Author(s):  
Amit Gautam ◽  
Saddam Sk ◽  
Amritanjali Tiwari ◽  
Moses Abraham Bokinala ◽  
P. Vijayanand ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Generation Rate ◽  
Co2 Photoreduction ◽  
H2 Generation ◽  
Highly Efficient ◽  
Hot Injection ◽  
And Control

A highly efficient hybrid ZnCdS-rGO/MoS2 heterostructure is successfully synthesized through a hot injection approach and control loading of rGO/MoS2. The synergism provides an unprecedently high H2-generation rate 193.4 mmol H2...

scholarly journals Catalytic Conversion of n-C7 Asphaltenes and Resins II into Hydrogen Using CeO2-Based Nanocatalysts

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1301
Author(s):  
Oscar E. Medina ◽  
Jaime Gallego ◽  
Sócrates Acevedo ◽  
Masoud Riazi ◽  
Raúl Ocampo-Pérez ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Low Temperatures ◽  
Gaseous Mixture ◽  
H2 Production ◽  
The Other ◽  
Hydrogen Release ◽  
Catalytic Gasification ◽  
Three Samples ◽  
Main Decomposition ◽  
Catalytic Capacity

This study focuses on evaluating the volumetric hydrogen content in the gaseous mixture released from the steam catalytic gasification of n-C7 asphaltenes and resins II at low temperatures (<230 °C). For this purpose, four nanocatalysts were selected: CeO2, CeO2 functionalized with Ni-Pd, Fe-Pd, and Co-Pd. The catalytic capacity was measured by non-isothermal (from 100 to 600 °C) and isothermal (220 °C) thermogravimetric analyses. The samples show the main decomposition peak between 200 and 230 °C for bi-elemental nanocatalysts and 300 °C for the CeO2 support, leading to reductions up to 50% in comparison with the samples in the absence of nanoparticles. At 220 °C, the conversion of both fractions increases in the order CeO2 < Fe-Pd < Co-Pd < Ni-Pd. Hydrogen release was quantified for the isothermal tests. The hydrogen production agrees with each material’s catalytic activity for decomposing both fractions at the evaluated conditions. CeNi1Pd1 showed the highest performance among the other three samples and led to the highest hydrogen production in the effluent gas with values of ~44 vol%. When the samples were heated at higher temperatures (i.e., 230 °C), H2 production increased up to 55 vol% during catalyzed n-C7 asphaltene and resin conversion, indicating an increase of up to 70% in comparison with the non-catalyzed systems at the same temperature conditions.

scholarly journals Hydrogen production from water electrolysis: role of catalysts

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shan Wang ◽  
Aolin Lu ◽  
Chuan-Jian Zhong
Keyword(s):  
Hydrogen Production ◽  
Water Splitting ◽  
Noble Metal ◽  
Active Sites ◽  
Current Knowledge ◽  
Low Cost ◽  
Critical Role ◽  
Water Electrolysis ◽  
Efficient Production ◽  
Production Of Hydrogen

AbstractAs a promising substitute for fossil fuels, hydrogen has emerged as a clean and renewable energy. A key challenge is the efficient production of hydrogen to meet the commercial-scale demand of hydrogen. Water splitting electrolysis is a promising pathway to achieve the efficient hydrogen production in terms of energy conversion and storage in which catalysis or electrocatalysis plays a critical role. The development of active, stable, and low-cost catalysts or electrocatalysts is an essential prerequisite for achieving the desired electrocatalytic hydrogen production from water splitting for practical use, which constitutes the central focus of this review. It will start with an introduction of the water splitting performance evaluation of various electrocatalysts in terms of activity, stability, and efficiency. This will be followed by outlining current knowledge on the two half-cell reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), in terms of reaction mechanisms in alkaline and acidic media. Recent advances in the design and preparation of nanostructured noble-metal and non-noble metal-based electrocatalysts will be discussed. New strategies and insights in exploring the synergistic structure, morphology, composition, and active sites of the nanostructured electrocatalysts for increasing the electrocatalytic activity and stability in HER and OER will be highlighted. Finally, future challenges and perspectives in the design of active and robust electrocatalysts for HER and OER towards efficient production of hydrogen from water splitting electrolysis will also be outlined.

scholarly journals A Process for Hydrogen Production from the Catalytic Decomposition of Formic Acid over Iridium—Palladium Nanoparticles

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3258
Author(s):  
Hamed M. Alshammari ◽  
Mohammad Hayal Alotaibi ◽  
Obaid F. Aldosari ◽  
Abdulellah S. Alsolami ◽  
Nuha A. Alotaibi ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Formic Acid ◽  
Activated Charcoal ◽  
Palladium Nanoparticles ◽  
Room Temperature ◽  
Catalytic Decomposition ◽  
Conversion Yield ◽  
Production Of Hydrogen ◽  
Commercial Applications

The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition, reaching conversion to 81%. The reported process could potentially be used in commercial applications.

scholarly journals The Synergy of Two Biofuel Additives on Combustion Process to Simultaneously Reduce NOx and PM Emissions

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2784
Author(s):  
Jerzy Cisek ◽  
Szymon Lesniak ◽  
Winicjusz Stanik ◽  
Włodzimierz Przybylski
Keyword(s):  
Heat Release ◽  
Combustion Rate ◽  
Combustion Process ◽  
The Other ◽  
Fuel Additive ◽  
Exhaust Gas ◽  
Synergy Effect ◽  
Engine Exhaust ◽  
Other Hand ◽  
Heat Released

The article presents the results of research on the influence of two fuel additives that selectively affect the combustion process in a diesel engine cylinder. The addition of NitrON® reduces the concentration of nitrogen oxides (NOx), due to a reduction in the kinetic combustion rate, at the cost of a slight increase in the concentration of particulate matter (PM) in the engine exhaust gas. The Reduxco® additive reduces PM emissions by increasing the diffusion combustion rate, while slightly increasing the NOx concentration in the engine exhaust gas. Research conducted by the authors confirmed that the simultaneous use of both of these additives in the fuel not only reduced both NOx and PM emissions in the exhaust gas but additionally the reduction of NOx and PM emissions was greater than the sum of the effects of these additives—the synergy effect. Findings indicated that the waveforms of the heat release rate (dQ/dα) responsible for the emission of NOx and PM in the exhaust gas differed for the four tested fuels in relation to the maximum value (selectively and independently in the kinetic and diffusion stage), and they were also phase shifted. Due to this, the heat release process Q(α) was characterized by a lower amount of heat released in the kinetic phase compared to fuel with NitrON® only and a greater amount of heat released in the diffusion phase compared to fuel with Reduxco® alone, which explained the lowest NOx and PM emissions in the exhaust gas at that time. For example for the NOx concentration in the engine exhaust: the Nitrocet® fuel additive (in the used amount of 1500 ppm) reduces the NOx concentration in the exhaust gas by 18% compared to the base fuel. The addition of a Reduxco® catalyst to the fuel (1500 ppm) unfortunately increases the NOx concentration by up to 20%. On the other hand, the combustion of the complete tested fuel, containing both additives simultaneously, is characterized, thanks to the synergy effect, by the lowest NOx concentration (reduction by 22% in relation to the base). For example for PM emissions: the Nitrocet® fuel additive does not significantly affect the PM emissions in the engine exhaust (up to a few per cent compared to the base fuel). The addition of a Reduxco® catalyst to the fuel greatly reduces PM emissions in the engine exhaust, up to 35% compared to the base fuel. On the other hand, the combustion of the complete tested fuel containing both additives simultaneously is characterized by the synergy effect with the lowest PM emission (reduction of 39% compared to the base fuel).

scholarly journals Flower-like MoS2 microspheres compounded with irregular CdS pyramid heterojunctions: highly efficient and stable photocatalysts for hydrogen production from water

RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 23064-23072
Author(s):  
Kai He ◽  
Liejin Guo
Keyword(s):  
Hydrogen Production ◽  
Photogenerated Carrier ◽  
Schematic Diagram ◽  
Highly Efficient

Schematic diagram of the photogenerated carrier migration between CdS and MoS2.

scholarly journals Iridium Complex Catalyzed Hydrogen Production from Glucose and Various Monosaccharides

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 891
Author(s):  
Ken-ichi Fujita ◽  
Takayoshi Inoue ◽  
Toshiki Tanaka ◽  
Jaeyoung Jeong ◽  
Shohichi Furukawa ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Catalytic System ◽  
Catalytic Reaction ◽  
Hydrogen Gas ◽  
Water Soluble ◽  
Starting Material ◽  
Iridium Complex ◽  
Production Of Hydrogen ◽  
Bipyridine Ligand

A new catalytic system has been developed for hydrogen production from various monosaccharides, mainly glucose, as a starting material under reflux conditions in water in the presence of a water-soluble dicationic iridium complex bearing a functional bipyridine ligand. For example, the reaction of D-glucose in water under reflux for 20 h in the presence of [Cp*Ir(6,6′-dihydroxy-2,2′-bipyridine)(H2O)][OTf]2 (1.0 mol %) (Cp*: pentamethylcyclopentadienyl, OTf: trifluoromethanesulfonate) resulted in the production of hydrogen gas in 95% yield. In the present catalytic reaction, it was experimentally suggested that dehydrogenation of the alcoholic moiety at 1-position of glucose proceeded.

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