Effect of hydrocarbon fractions, N2 and CO2 in feed gas on hydrogen production using sorption enhanced steam reforming: Thermodynamic analysis

Adiya, Zainab Ibrahim S G; Dupont, Valerie; Mahmud, Tariq

doi:10.1016/j.ijhydene.2017.06.169

Cited by 14 publications

(4 citation statements)

References 54 publications

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“…The CEA software was used to generate the equilibrium data [35,36]. This software is based on minimization of Gibbs free energy (G) [37,38]. The chemical equilibrium analysis was done by considering the gas species involved in the reactant and product streams, which are CH4, H2, CO, CO2, H2O, N2, CaO and CaCO3, using the option 'ONLY' in CEA.…”

Section: Resultsmentioning

confidence: 99%

Modelling of H2 production via sorption enhanced steam methane reforming at reduced pressures for small scale applications

Abbas

Dupont

Mahmud

2019

International Journal of Hydrogen Energy

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The production of H2 via sorption enhanced steam reforming (SE-SMR) of CH4 using 18 wt. % Ni/ Al2O3 catalyst and CaO as a CO2-sorbent was simulated for an adiabatic packed bed reactor at the reduced pressures typical of small and medium scale gas producers and H2 end users. To investigate the behaviour of reactor model along the axial direction, the mass, energy and momentum balance equations were incorporated in the gPROMS modelbuilder ®. The effect of operating conditions such as temperature, pressure, steam to carbon ration (S/C) and gas mass flow velocity (Gs) was studied under the low-pressure conditions (2-7 bar). Independent equilibrium based software, chemical equilibrium with application (CEA), was used to compare the simulation results with the equilibrium data. A good agreement was obtained in terms of CH4 conversion, H2 yield (wt. % of CH4 feed), purity of H2 and CO2 capture for the lowest (Gs) representing conditions close to equilibrium under a range of operating temperatures pressures, feed steam to carbon ratio. At Gs of 3.5 kg m-2 s-1 , 3 bar, 923 K and S/C of 3, CH4 conversion and H2 purity were up to 89% and 86% respectively compared to 44% and 63% in the conventional reforming process.

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Section: Resultsmentioning

confidence: 99%

Modelling of H2 production via sorption enhanced steam methane reforming at reduced pressures for small scale applications

Abbas

Dupont

Mahmud

2019

International Journal of Hydrogen Energy

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“…The latter (SE-CLSR process) also minimises the energy requirement of operating the system to a great extent by close-coupling the heat demand of H2 production with the heat released by the chemisorption of its CO2 by-product. Detail process description with schematics of the SE-SR and SE-CLSR process can be found in S G Adiya et al [9,43] and Ryden and Ramos [39].…”

Section: Introductionmentioning

confidence: 99%

Steam reforming of shale gas with nickel and calcium looping

Adiya

Dupont

Mahmud

2019

Fuel

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ReuseThis article is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs (CC BY-NC-ND) licence. This licence only allows you to download this work and share it with others as long as you credit the authors, but you can't change the article in any way or use it commercially. More information and the full terms of the licence here: https://creativecommons.org/licenses/ TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. AbstractsHigh purity H2 production from shale gas using sorption enhanced chemical looping steam reforming (SE-CLSR) was investigated at 1 bar, GHSV 0.498 hr -1 , feed molar steam to carbon ratio of 3 and 650 for 20 reduction-oxidation-calcination cycles using CaO and 18 wt. % NiO on Al2O3 as sorbent and catalyst/oxygen carrier (OC) respectively. The shale gas feedstock was able to cyclically reduce the oxygen carrier and subsequently reform with high H2 yield and purity. For example H2 yield of 31 wt. % of fuel feed and purity of 92 % were obtained in the 4 th cycle during the pre-breakthrough period (prior to cycles with low sorbent capacity). This was equivalent to 80 and 43 % enhancement compared to the conventional steam reforming process respectively.

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“…dioxide, and ammonia is also present in small amounts due to the presence of nitrogen in the feed stream. At lower temperatures, the equilibrium composition will contain more methane and water that did not react for the formation of hydrogen, considering that under these conditions the CO methanation reaction may occur more, evidently reducing the amount of hydrogen for the formation of hydrogen, methane and water [24]. Ayabe et al [20] also report that the methane conversion rate as a function of temperature begins to decrease at values above 773 K. Thus, the selectivity of hydrogen does not show a continuous increase with increasing temperature, following the behavior of the conversion at equilibrium.…”

Section: Gibbs Energy Minimization Methodology Validationmentioning

confidence: 99%

Autothermal Reforming of Methane: A Thermodynamic Study on the Use of Air and Pure Oxygen as Oxidizing Agents in Isothermal and Adiabatic Systems

Cavalcante,

Maccari Zelioli,

Guimarães Filho

et al. 2023

Methane

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In this paper, we analyze the autothermal reforming (ATR) of methane through Gibbs energy minimization and entropy maximization methods to analyze isothermic and adiabatic systems, respectively. The software GAMS® 23.9 and the CONOPT3 solver were used to conduct the simulations and thermodynamic analyses in order to determine the equilibrium compositions and equilibrium temperatures of this system. Simulations were performed covering different pressures in the range of 1 to 10 atm, temperatures between 873 and 1073 K, steam/methane ratio was varied in the range of 1.0/1.0 and 2.0/1.0 and oxygen/methane ratios in the feed stream, in the range of 0.5/1.0 to 2.0/1.0. The effect of using pure oxygen or air as oxidizer agent to perform the reaction was also studied. The simulations were carried out in order to maintain the same molar proportions of oxygen as in the simulated cases considering pure oxygen in the reactor feed. The results showed that the formation of hydrogen and synthesis gas increased with temperature, average composition of 71.9% and 56.0% using air and O2, respectively. These results are observed at low molar oxygen ratios (O2/CH4 = 0.5) in the feed. Higher pressures reduced the production of hydrogen and synthesis gas produced during ATR of methane. In general, reductions on the order of 19.7% using O2 and 14.0% using air were observed. It was also verified that the process has autothermicity in all conditions tested and the use of air in relation to pure oxygen favored the compounds of interest, mainly in conditions of higher pressure (10 atm). The mean reductions with increasing temperature in the percentage increase of H2 and syngas using air under 1.5 and 10 atm, at the different O2/CH4 ratios, were 5.3%, 13.8% and 16.5%, respectively. In the same order, these values with the increase of oxygen were 3.6%, 6.4% and 9.1%. The better conditions for the reaction include high temperatures, low pressures and low O2/CH4 ratios, a region in which there is no swelling in terms of the oxygen source used. In addition, with the introduction of air, the final temperature of the system was reduced by 5%, which can help to reduce the negative impacts of high temperatures in reactors during ATR reactions.

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Effect of hydrocarbon fractions, N2 and CO2 in feed gas on hydrogen production using sorption enhanced steam reforming: Thermodynamic analysis

Cited by 14 publications

References 54 publications

Modelling of H2 production via sorption enhanced steam methane reforming at reduced pressures for small scale applications

Modelling of H2 production via sorption enhanced steam methane reforming at reduced pressures for small scale applications

Steam reforming of shale gas with nickel and calcium looping

Autothermal Reforming of Methane: A Thermodynamic Study on the Use of Air and Pure Oxygen as Oxidizing Agents in Isothermal and Adiabatic Systems

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