Energy Analysis of Hydrogen Production from Methanol under Atmospheric Pressure and Supercritical Water Conditions

2015 ◽  
Vol 1119 ◽  
pp. 548-553
Author(s):  
Nawadee Srisiriwat
Keyword(s):  
Hydrogen Production ◽  
Reaction Temperature ◽  
Supercritical Water ◽  
Atmospheric Pressure ◽  
Energy Analysis ◽  
Ideal Gas ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Hydrogen Yield ◽  
Water Amount

The energy analysis of hydrogen production from the methanol reforming and oxidation under atmospheric (ATM) pressure and supercritical water (SCW) conditions was performed. The equilibrium hydrogen was investigated by the minimization of the Gibbs free energy based on Peng-Robinson equation of state for high pressure and ideal gas equation for atmospheric pressure. An objective of this study was to obtain the optimum operating conditions to maximize the net hydrogen yield, defined as the hydrogen yield taking into account also the methanol consumed by combustion to generate heat. This was done by investigating the effect of operating parameters over the following ranges: temperatures between 773 and 1273 K, pressures between 0.1 and 25.0 MPa, water-to-methanol (H2O:MeOH) ratios between 1 and 5, and oxygen-to-methanol (O2:MeOH) ratios between 0 and 1.05. At ATM pressure, it was found that the equilibrium hydrogen yield increases with increasing H2O:MeOH ratio but the peak of equilibrium H2yield is at 973 K for higher H2O:MeOH ratio than 1:1. Additionally, the total heat load increases significantly as the reaction temperature and the water amount increase. Therefore, the optimum net H2yield is at the H2O:MeOH ratio of 2:1 and the reaction temperature at 973 K. Under SCW conditions, an increase of temperature and water amount in the system constantly increases the equilibrium H2yield. It means that the high H2O:MeOH ratio and temperature are required in SCW. The presence of oxygen in hydrogen production was investigated that an increase of O2:MeOH ratio constantly decreases the H2yield and also the net H2yield for reaction at ATM pressure whereas under SCW conditions, the equilibrium H2yield and the net H2yield increase with increasing oxygen up to 0.42 and 0.84, respectively.

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.

Thermodynamic Analysis of Hydrogen Production from Methanol Reforming in Supercritical Water

2014 ◽  
Vol 619 ◽  
pp. 99-104 ◽  
Author(s):  
Nawadee Srisiriwat ◽  
Chananchai Wutthithanyawat
Keyword(s):  
Hydrogen Production ◽  
Reaction Temperature ◽  
Supercritical Water ◽  
Heat Load ◽  
Operating Pressure ◽  
Hydrogen Yield ◽  
Minimization Method ◽  
Methanol Reforming ◽  
Fuel Processor ◽  
Load Increase

The hydrogen production via methanol reforming in supercritical water (SCW) condition has been thermodynamically investigated by a Gibbs free energy minimization method to determine equilibrium yields and energy requirements in fuel processor over the temperature range between 673 and 1273 K and water-to-methanol (H2O:MeOH) ratio of 1 – 5 corresponding to the methanol concentration from 64 to 26 wt%, respectively. In this research, the main objective is to compare the influence of operating pressure from atmospheric (ATM) pressure to SCW condition on the product yields. At ATM pressure, a hydrogen production increases with increasing reaction temperature up to 973 K while under SCW condition, an increase of temperature constantly increases the formation of hydrogen. As the reaction temperature increases, the hydrogen production and the total heat load increase but the hydrogen to carbon monoxide (H2/CO) ratio decreases. Although the hydrogen yield is constantly higher at ATM pressure than under SCW condition, the H2/CO ratios are always greater in SCW at temperatures above approximately 700 K. The amount of hydrogen and the heat load of both the preheater and the reactor also increase significantly as the H2O:MeOH ratio increases.

Hydrogen Production via Catalytic Autothermal Reforming of Desulfurized Jet-A Fuel

2016 ◽  
Author(s):  
Shuyang Zhang ◽  
Xiaoxin Wang ◽  
Peiwen Li
Keyword(s):  
Energy Efficiency ◽  
Hydrogen Production ◽  
Hydrogen Storage ◽  
Coke Formation ◽  
Autothermal Reforming ◽  
Operating Conditions ◽  
Hydrogen Yield ◽  
Fuel Conversion ◽  
Optimal Operating ◽  
Reaction Equilibrium

On-board hydrogen production via catalytic autothermal reforming is beneficial to vehicles using fuel cells because it eliminates the challenges of hydrogen storage. As the primary fuel for both civilian and military air flight application, Jet-A fuel (after desulfurization) was reformed for making hydrogen-rich fuels in this study using an in-house-made Rh/NiO/K-La-Ce-Al-OX ATR catalyst under various operating conditions. Based on the preliminary thermodynamic analysis of reaction equilibrium, important parameters such as ratios of H2O/C and O2/C were selected, in the range of 1.1–2.5 and 0.5–1.0, respectively. The optimal operating conditions were experimentally obtained at the reactor’s temperature of 696.2 °C, which gave H2O/C = 2.5 and O2/C = 0.5, and the obtained fuel conversion percentage, hydrogen yield (can be large than 1 from definition), and energy efficiency were 88.66%, 143.84%, and 64.74%, respectively. In addition, a discussion of the concentration variation of CO and CO2 at different H2O/C, as well as the analysis of fuel conversion profile, leads to the finding of effective approaches for suppression of coke formation.

Assay of NF Ethylene by Gas Chromatography

1972 ◽  
Vol 55 (5) ◽  
pp. 1067-1069
Author(s):  
N Aubrey Carson
Keyword(s):  
Atmospheric Pressure ◽  
Chromatographic Method ◽  
Collaborative Study ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Thermal Conductivity Detector ◽  
Gas Chromatograph ◽  
Gas Sampling ◽  
Gas Chromatographic Method ◽  
Standard Gas

Abstract A gas chromatographic method, utilizing a 6′ × 1/4″ Poropak R column and a thermal conductivity detector, was developed for the analysis of NF ethylene. The sample was introduced into the gas chromatograph at atmospheric pressure, using a gas sampling valve with calibrated loop. A high purity standard gas was used for comparison. With the instrument set for optimum operating conditions the precision for multiple injections of standard gas was excellent. The assay value of a sample was found to be 99.7%, when determined on 3 separate days. A collaborative study of the method is recommended.

Taguchi Approach and ANOVA in Optimization of the Dissolution of Colemanite in CO2 and SO2- Water Systems

2020 ◽  
Vol 10 (2) ◽  
pp. 88-97
Author(s):  
Zafer Ekinci ◽  
Esref Kurdal ◽  
Meltem Kizilca Coruh
Keyword(s):  
Particle Size ◽  
Reaction Time ◽  
Reaction Temperature ◽  
Gas Flow ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Process Conditions ◽  
Liquid Ratio ◽  
Positive Effects ◽  
Controllable Factors

Background: Turkey is approximately 72% of the world’s boron sources. Colemanite, tincal, ulexite and pandermite are among the most significant in Turkey. Boron compounds and minerals are widely used in many industrial fields. Objective: The main purpose of this study was to investigate the control of impurities in the boric acid production process using colemanite by carrying out the reaction with a mixture of CO2 and SO2 - water, and determining the appropriate process conditions to develop a new process as an alternative to the use of sulfuric acid. Due to worrying environmental problems, intensive studies are being carried out globally to reduce the amount of CO2 and SO2 gases released to the atmosphere. Methods: The Taguchi method is an experimental design method that minimizes the product and process variability by selecting the most appropriate combination of the levels of controllable factors compared to uncontrollable factors. Results: It was evaluated the effects of parameters such as reaction temperature, solid-to liquid ratio, SO2/CO2 gas flow rate, particle size, stirring speed and reaction time. The optimum conditions determined to be reaction temperature of 45°C; a solid–liquid ratio of 0.083 g.mL−1; an SO2/CO2 ratio of 2/2 mL.s−1; a particle size of -0.354+0 .210 mm; a mixing speed of 750 rpm and a reaction time of 20 min. Conclusion: Under optimum operating conditions, 96.8% of colemanite was dissolved. It is thought that the industrial application of this study will have positive effects on the greenhouse effect by contributing to the reduction of CO2 and SO2 emissions that cause global warming.

Solid Oxide Fuel Cell Integrated with Supercritical Water Fueled by Methanol

2016 ◽  
Vol 689 ◽  
pp. 133-137
Author(s):  
Anuchart Srisiriwat ◽  
Nawadee Srisiriwat
Keyword(s):  
Power Generation ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Reaction Temperature ◽  
Supercritical Water ◽  
High Efficiency ◽  
Solid Oxide ◽  
Molar Ratio ◽  
Hydrogen Yield ◽  
Oxide Fuel

A solid oxide fuel cell (SOFC) is known as an interesting energy conversion device because of its fuel flexibility and high efficiency. The hydrogen-rich stream is used as fuel carrier converting to generate electrical energy. A non-stoichiometric thermodynamic model based on minimum free energy was performed to predict the amount of hydrogen production via the methanol reforming under supercritical water (SCW) condition. The effects of SCW reaction temperature and water-to-methanol molar ratio on the SOFC power generation integrated with SCW reforming from methanol were investigated. The hydrogen yield, the required heat duty for a feed preheater and a SCW reactor and the SOFC power generation increase with increasing the SCW reaction temperature and the amount of water fed in SCW reactor. Under operating parameters of SCW reformer based on 1 mole/sec of methanol fed at the high temperature of 1273 K and water-to-methanol molar ratio of 5, the SOFC electrical power of 246 kW was produced with the maximum fuel utilization of 0.7.

Application of Taguchi Optimization Method in Improving the Selectivity of Dihydroxystearic Acid

2015 ◽  
Vol 1113 ◽  
pp. 703-709 ◽  
Author(s):  
Siti Khatijah Jamaludin ◽  
Ku Halim Ku Hamid ◽  
Hazimah Abu Hassan ◽  
Ayub Md Som ◽  
Zulina Maurad ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oleic Acid ◽  
Taguchi Method ◽  
Formic Acid ◽  
Reaction Temperature ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Dihydroxystearic Acid ◽  
Catalyst Loading ◽  
Taguchi Optimization

Dihydroxystearic acid (DHSA) is perceived to be of significant value to various types of industries, especially the oleochemical industry. It is produced by reacting palm-based crude oleic acid (OA) with formic acid and hydrogen peroxide through thein situepoxidation-dihydroxylation, a multistep reaction process. Optimization of the reaction’s operating conditions with respect to the selectivity of DHSA was conducted via the Taguchi method of optimization. The selectivity of DHSA was determined based on gas chromatography (GC) analysis. The signal-to-noise (S/N) ratio analysis procedure in Taguchi method revealed that the optimum operating conditions for the production of crude DHSA with respect to its selectivity were found to be: catalyst (sulphuric acid) loading at 0.5 gm, formic acid-to-oleic acid unsaturation mole ratio of 1:1, hydrogen peroxide-to-oleic acid unsaturation mole ratio of 0.75:1 and reaction temperature: 85°C. ANOVA tested at 90% confidence level revealed that reaction temperature and catalyst loading highly affect the selectivity of DHSA. The selectivity of DHSA was improved to 97.2% by applying the optimum operating conditions as obtained by Taguchi method.

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 Effect of Different Inoculum Combination on Biohydrogen Production from Melon Fruit Waste

2018 ◽  
Vol 7 (2) ◽  
pp. 101-109 ◽  
Author(s):  
Yumechris Amekan ◽  
Dyah Sekar A P Wangi ◽  
Muhammad Nur Cahyanto ◽  
Sarto Sarto ◽  
Jaka Widada
Keyword(s):  
Hydrogen Production ◽  
Operating Conditions ◽  
Production Performance ◽  
Biohydrogen Production ◽  
Cow Dung ◽  
Strictly Anaerobic ◽  
Hydrogen Yield ◽  
Production Type ◽  
Fruit Waste ◽  
Melon Fruit

The natural microbial consortium from many sources widely used for hydrogen production. Type of substrate and operating conditions applied on the biodigesters of the natural consortium used as inoculum impact the variation of species and number of microbes that induce biogas formation, so this study examined the effect of different inoculum source and its combination of biohydrogen production performance. The hydrogen producing bacteria from fruit waste digester (FW), cow dung digester (CD), and tofu waste digester (TW) enriched under strictly anaerobic conditions at 37OC. Inoculums from 3 different digesters (FW, CD, and TW) and its combination (FW-CD, CD-TW, FW-TW, and FW-CD-TW) were used to test the hydrogen production from melon waste with volatile solids (VS) concentration of 9.65 g/L, 37°C and initial pH 7.05 ± 0.05. The results showed that individual and combined inoculum produced the gas comprising hydrogen and carbon dioxide without any detectable methane. The highest cumulative hydrogen production of 743 mL (yield 207.56 mL/gVS) and 1,132 mL (yield 231.02 mL/gVS) was shown by FW and FW-CD-TW, respectively. Butyric, acetate, formic and propionic were the primary soluble metabolites produced by all the cultures, and the result proves that higher production of propionic acid can decrease hydrogen yield. Clostridium perfringens and Clostridium baratii prominently seen in all single and combination inoculum. Experimental evidence suggests that the inoculum from different biodigesters able to adapt well to the environmental conditions and the new substrate after a combination process as a result of metabolic flexibility derived from the microbial diversity in the community to produce hydrogen. Therefore, inoculum combination could be used as a strategy to improve systems for on-farm energy recovery from animal and plant waste to processing of food and municipal waste.Article History: Received February 5th 2018; Received in revised form May 7th 2018; Accepted June 2nd 2018; Available onlineHow to Cite This Article: Amekan, Y., Wangi, D.S.A.P., Cahyanto, M.N., Sarto and Widada, J. (2018) Effect of Different Inoculum Combination on Biohydrogen Production from Melon Fruit Waste. Int. Journal of Renewable Energy Development, 7(2), 101-109.https://doi.org/10.14710/ijred.7.2.101-10

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