scholarly journals Thermodynamic Analysis of the Hydrogen Production from Ethanol: First and Second Laws Approaches

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yannay Casas-Ledón ◽  
Luis E. Arteaga-Perez ◽  
Mayra C. Morales-Perez ◽  
Luis M. Peralta-Suárez
Keyword(s):  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Direct Method ◽  
Positive Influence ◽  
State Equation ◽  
Molar Ratio ◽  
Ethanol Conversion ◽  
Hydrogen Yield ◽  
System Quality ◽  
Ethanol Steam

A thermodynamic analysis of hydrogen production from ethanol steam reforming (ESR) is carried out in the present paper. The influence of reactants molar ratio feed into the reforming stage (), temperature (573 to 1173 K) and pressure ( atm) over equilibrium compositions is studied. The direct method employed to analyze the system is the minimization of Gibbs free energy (MGFE) in conjunction with Lee-Kesler state equation, using the Kay mixing rules. The temperature and reactants molar ratio showed a positive influence on the hydrogen yield; ethanol conversion is 100% for the whole interval analyzed while the pressure affected greatly the hydrogen production. The carbon deposition exhibits a maximum value at temperatures around 773 K, and three reactions are proposed to describe the solid carbon formation in a wide temperature range based on thermodynamics and experimental predictions. The conditioning stages (mixing, vaporization, and heating) are studied in addition to the reaction to analyze the system quality by means of an exergetic method applying the 2nd law of thermodynamic.

Hydrogen Production from Ethanol Steam Reforming over Ni-Cu/ZnO Catalyst

2011 ◽  
Vol 236-238 ◽  
pp. 1067-1072
Author(s):  
Li Ping Liu ◽  
Xiao Jian Ma ◽  
Peng Zhang ◽  
Ya Nan Liu
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Fixed Bed ◽  
Surface Characteristics ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Molar Ratio ◽  
Ethanol Steam Reforming ◽  
Hydrogen Yield ◽  
Ethanol Steam

Hydrogen production by ethanol steam reforming over Ni-Cu/ZnO catalyst in the temperatures range of 250-550°C was studied on a fixed bed reactor. The effects of reaction temperature and water/ethanol molar ratio on hydrogen production were investigated. The structure and surface characteristics of the catalyst were measured by scanning electron microscopy (SEM), X-ray diffraction (XRD) and differential thermal analyzer (TG-DSC). The results show that the Ni-Cu/ZnO catalyst has good catalytic performance with higher hydrogen yield of 4.87molH2/molEtOH reacted. A comparison of hydrogen production from ethanol steam reforming over Ni-Cu/ZnO catalyst with over a commercial catalyst was made in this paper.

Thermodynamic Analysis of Hydrogen Production from Ethanol in Supercritical Water Oxidation

2011 ◽  
Vol 110-116 ◽  
pp. 77-82
Author(s):  
Nawadee Srisiriwat
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Supercritical Water ◽  
Water Oxidation ◽  
Equilibrium Composition ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Hydrogen Yield

A thermodynamic analysis was performed for hydrogen production from ethanol reforming and oxidation in supercritical water (SCW) conditions. The minimization of Gibbs free energy was used to calculate the equilibrium composition to investigate the effect of operating conditions, pressure, temperature, H2O2:EtOH molar ratio and H2O:EtOH molar ratio, on product yields. The theoretical results indicated that the yields of hydrogen and carbon monoxide decreased as the pressure increased but a H2/CO ratio at atmospheric pressure was lower than that at SCW conditions. High temperatures increased the efficiency of hydrogen production although the amount of carbon monoxide also increased. The presence of oxygen led to great decreases in methane oxidized to carbon dioxide and water. The spending of some hydrogen oxidized to water resulting in a lower hydrogen yield. High H2O:EtOH ratios increased the yields of hydrogen and carbon dioxide but decreased the methane and carbon monoxide production. It is possible to conclude that high temperature, high H2O:EtOH ratio and low addition of oxygen should lead to best results in the SCWO of ethanol.

Simulation of Hydrogen Production by Using Concentrated Solar Energy Through Thermo-Chemical Water Splitting Process: Part II—Simulation of Zinc Hydrolysis Reaction to Generate Hydrogen

2011 ◽  
Author(s):  
Furqan Ahmad Khan ◽  
Kamran Siddiqui
Keyword(s):  
Hydrogen Production ◽  
Wall Temperature ◽  
Particle Diameter ◽  
Molar Ratio ◽  
Reactor Wall ◽  
Hydrogen Yield ◽  
Concentrated Solar Energy ◽  
Cylindrical Reactor ◽  
Chemical Cycle ◽  
Zinc Particle

This study is focused on the second step of ZnO/Zn thermo-chemical cycle, where zinc (produced in the first step of the cycle) reacts with steam to produce hydrogen and zinc oxide. The simulation of this hydrogen production step was carried out inside a cylindrical reactor using commercial CFD software, FLUENT. A parametric study was conducted based on the zinc particle diameter, reactor wall temperature, and steam/zinc molar ratio. The yield of hydrogen was found to increase with an increase in the reactor wall temperature, and with a decrease in the zinc particle diameter. However, steam/zinc molar ratio was found to have no effect on the hydrogen yield.

scholarly journals Hydrogen Production by Partial Oxidation Reforming of Methane over Ni Catalysts Supported on High and Low Surface Area Alumina and Zirconia

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 499 ◽  
Author(s):  
Anis Fakeeha ◽  
Ahmed A. Ibrahim ◽  
Hesham Aljuraywi ◽  
Yazeed Alqahtani ◽  
Ahmad Alkhodair ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Production ◽  
Surface Area ◽  
Partial Oxidation ◽  
Reaction Temperature ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Impregnation Method ◽  
H2 Yield ◽  
Partial Oxidation Reforming

The catalytic activity of the partial oxidation reforming reaction for hydrogen production over 10% Ni supported on high and low surface area alumina and zirconia was investigated. The reforming reactions, under atmospheric pressure, were performed with a feed molar ratio of CH4/O2 = 2.0. The reaction temperature was set to 450–650 °C. The catalytic activity, stability, and carbon formation were determined via TGA, TPO, Raman, and H2 yield. The catalysts were calcined at 600 and 800 °C. The catalysts were prepared via the wet-impregnation method. Various characterizations were conducted using BET, XRD, TPR, TGA, TPD, TPO, and Raman. The highest methane conversion (90%) and hydrogen yield (72%) were obtained at a 650 °C reaction temperature using Ni-Al-H-600, which also showed the highest stability for the ranges of the reaction temperatures investigated. Indeed, the time-on-stream for 7 h of the Ni-Al-H-600 catalyst displayed high activity and a stable profile when the reaction temperature was set to 650 °C.

scholarly journals Ni–Ru-containing mixed oxide-based composites as precursors for ethanol steam reforming catalysts: Effect of the synthesis methods on the structural and catalytic properties

2021 ◽  
Vol 19 (1) ◽  
pp. 696-708
Author(s):  
Symbat Muratbekovna Naurzkulova ◽  
Marina Vasilievna Arapova ◽  
Arcady Vladimirovich Ishchenko ◽  
Tamara Andreevna Krieger ◽  
Andrei Aleksandrovich Saraev ◽  
...  
Keyword(s):  
Steam Reforming ◽  
Specific Activity ◽  
Ethanol Conversion ◽  
Ethanol Steam Reforming ◽  
Synthesis Methods ◽  
Hydrogen Yield ◽  
High Concentration ◽  
Ultrasonic Dispersion ◽  
Metal Centers ◽  
Ethanol Steam

Abstract Ethanol steam reforming catalyst’s precursors, i.e., nanocomposites of complex oxides with the general formula [Pr0.15Sm0.15Ce0.35Zr0.35O2 + LaMn0.45Ni0.45Ru0.1O3] (1:1 by mass), were synthesized by three different methods. It was shown that two synthesis methods – ultrasonic dispersion and sequential polymeric method, lead to the formation of the nanocomposite perovskite–fluorite system with the specific surface area up to 50 m2/g. Reduction of samples at 400–500°C lead to the formation of Ni–Ru alloy nanoparticles strongly bound with the surface of oxide nanocomposite. Catalytic tests in ethanol steam reforming reaction at 500–600°C showed the highest specific activity of the sample prepared by the sequential polymeric method due to the location of Ni- and Ru-containing perovskite mainly on the surface of the composite providing a high concentration of active metal centers. At higher temperatures for all samples, ethanol conversion approached 100% with hydrogen yield varying in the range of 65–75%. A study of spent catalysts confirmed the absence of carbon deposits after long-term catalytic tests at 650°C.

Hydrogen production by steam reforming of glycerol over Ni/Ce/Cu hydroxyapatite-supported catalysts

2013 ◽  
Vol 67 (7) ◽  
Author(s):  
Lukman Hakim ◽  
Zahira Yaakob ◽  
Manal Ismail ◽  
Wan Daud ◽  
Ratna Sari
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Fixed Bed ◽  
Supported Catalyst ◽  
Fixed Bed Reactor ◽  
Bet Surface Area ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Glycerol Conversion

AbstractHydroxyapatite-supported Ni-Ce-Cu catalysts were synthesised and tested to study their potential for use in the steam reforming of glycerol to produce hydrogen. The catalysts were prepared by the deposition-precipitation method with variable nickel, cerium, and copper loadings. The performance of the catalysts was evaluated in terms of hydrogen yield at 600°C in a tubular fixed-bed microreactor. All catalysts were characterised by the BET surface area, XRD, TPR, TEM, and FE-SEM techniques. The reaction time was 240 min in a fixed-bed reactor at 600°C and atmospheric pressure with a water-to-glycerol feed molar ratio of 8: 1. It was found that the Ni-Ce-Cu (3 mass %-7.5 mass %-7.5 mass %) hydroxyapatite-supported catalyst afforded the highest hydrogen yield (57.5 %), with a glycerol conversion rate of 97.3 %. The results indicate that Ni/Ce/Cu/hydroxyapatite has great potential as a catalyst for hydrogen production by steam reforming of glycerol.

Autothermal Reforming of Ethanol for Hydrogen Production: Thermodynamic Analysis

2013 ◽  
Vol 415 ◽  
pp. 658-665 ◽  
Author(s):  
Nawadee Srisiriwat ◽  
Chananchai Wutthithanyawat
Keyword(s):  
Carbon Monoxide ◽  
Hydrogen Production ◽  
Thermodynamic Analysis ◽  
Equilibrium Composition ◽  
Product Distribution ◽  
Autothermal Reforming ◽  
Hydrogen Yield ◽  
Molar Ratios ◽  
Carbon Monoxide Formation ◽  
Gibbs Free Energy Minimization

This work presents the autothermal reforming (ATR), or called oxidative steam reforming (OSR), of ethanol for hydrogen production. A thermodynamic analysis of product distribution for ATR from ethanol has been performed by using the method of Gibbs free energy minimization. The effect of steam-to-carbon (S:C) and air-to-carbon (A:C) molar ratios under adiabatic temperature of ATR reactor on chemical equilibrium composition of hydrogen rich stream is investigated. An increase of S:C ratio increases an efficiency of hydrogen production while carbon monoxide formation decreases but, however, more energy consumption for preheating reactants is also needed. An increase of A:C ratio in the range between 0 and 1.75 causes an increase of hydrogen yield but at greater A:C ratio, a decrease of hydrogen production and more water formation can be found. The results of the thermodynamic equilibrium show that the predicted hydrogen composition in the reaction of fuel-water-air system at constant temperature is higher than that obtained from experiment in both the absence and presence of catalysts in the OSR reaction when the temperature is fixed at 700 °C. The predicted carbon monoxide is lower than that obtained from the results of non-catalytic reaction but higher than that attained from the presence of catalyst in process.

Parametric Study of an Autothermal Micro Surface Reactor for Hydrogen Production

2010 ◽  
Author(s):  
M. H. Akbari ◽  
A. H. Sharafian Ardakani ◽  
M. Andisheh Tadbir
Keyword(s):  
Hydrogen Production ◽  
Rectangular Cross Section ◽  
Surface Reactions ◽  
Chemical Species ◽  
Space Velocity ◽  
Autothermal Reforming ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Governing Equations ◽  
Reactor Model

Hydrogen production through autothermal reforming (ATR) of hydrocarbons, such as methane, is one option of interest for mobile applications of hydrogen fuel cells. In the present study, a numerical investigation of catalytic autothermal reforming of methane in a surface microreactor is presented. A three-dimensional ATR reactor model is developed to simulate the flow and surface reactions in a microchannel of rectangular cross section with 340-μm sides, and total length of 8.5 mm. A four-reaction mechanism is implemented to simulate the surface reactions on a Ni/Al2O3 catalyst. The governing equations in the model include conservations of mass, momentum, energy and chemical species. A CFD code based on the finite-volume method has been developed in-house to solve the governing equations. Validation of the results against available data confirms the accuracy of the numerical approach. The simulation results reveal the dependency of hydrogen yield on space velocity (SV), air/fuel molar ratio (A/F), water/fuel molar ratio (W/F), and the gas feed temperature.

Hydrogen Production by Ethanol Steam Reforming: Experimental Study of a Pd-Ag Membrane Reactor and Traditional Reactor Behaviour

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Angelo Basile ◽  
Fausto Gallucci ◽  
Adolfo Iulianelli ◽  
Marcello De Falco ◽  
Simona Liguori
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Membrane Reactor ◽  
Experimental Tests ◽  
Cell System ◽  
Ethanol Conversion ◽  
Ethanol Steam Reforming ◽  
Dense Membrane ◽  
Free Hydrogen ◽  
Ethanol Steam

In this experimental work, the ethanol steam reforming reaction for producing hydrogen was studied in both a traditional reactor (TR) and a Pd-Ag dense membrane reactor (MR). Both reactors have been packed with a commercial Ru-based catalyst. The experimental tests have been performed in the temperature range 400-500 °C and in the pressure range 2.0-3.6 bar.The results are reported in terms of ethanol conversion, hydrogen production, product selectivities and hydrogen recovery (for the MR only). It has been found that the MR is able to increase the ethanol conversion as well as increase the hydrogen production with respect to a traditional reactor. Moreover, part of the hydrogen produced in the MR is recovered as a CO-free hydrogen stream and is suitable for feeding a PEM fuel cell system.

Steam-reforming of ethanol for hydrogen production

2011 ◽  
Vol 65 (3) ◽  
Author(s):  
Ahmed Bshish ◽  
Zahira Yaakob ◽  
Binitha Narayanan ◽  
Resmi Ramakrishnan ◽  
Ali Ebshish
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Molar Ratio ◽  
Ethanol Conversion ◽  
Impregnation Method ◽  
Reaction Conditions ◽  
Oxide Supports ◽  
Steam Reforming Of Ethanol ◽  
Production Of Hydrogen ◽  
Hydrogen Selectivity

AbstractProduction of hydrogen by steam-reforming of ethanol has been performed using different catalytic systems. The present review focuses on various catalyst systems used for this purpose. The activity of catalysts depends on several factors such as the nature of the active metal catalyst and the catalyst support, the precursor used, the method adopted for catalyst preparation, and the presence of promoters as well as reaction conditions like the water-to-ethanol molar ratio, temperature, and space velocity. Among the active metals used to date for hydrogen production from ethanol, promoted-Ni is found to be a suitable choice in terms of the activity of the resulting catalyst. Cu is the most commonly used promoter with nickel-based catalysts to overcome the inactivity of nickel in the water-gas shift reaction. γ-Al2O3 support has been preferred by many researchers because of its ability to withstand reaction conditions. However, γ-Al2O3, being acidic, possesses the disadvantage of favouring ethanol dehydration to ethylene which is considered to be a source of carbon deposit found on the catalyst. To overcome this difficulty and to obtain the long-term catalyst stability, basic oxide supports such as CeO2, MgO, La2O3, etc. are mixed with alumina which neutralises the acidic sites. Most of the catalysts which can provide higher ethanol conversion and hydrogen selectivity were prepared by a combination of impregnation method and sol-gel method. High temperature and high water-to-ethanol molar ratio are two important factors in increasing the ethanol conversion and hydrogen selectivity, whereas an increase in pressure can adversely affect hydrogen production.

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