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Comparative CFD modeling of foam and conventional pellet catalysts in glycerol steam reforming
(2025-07-15)
Simasatitkul, Lida
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Phitchayakorn, Chattharika
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Amornraksa, Suksun
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Anantpinijwatna, Amata
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Assabumrungrat, Suttichai
A novel approach to glycerol valorization via steam reforming was investigated through computational fluid dynamics (CFD) modelling. The performance characteristics of conventional pellet catalysts were compared with foam catalysts in a 6-inch diameter packed bed reactor. A two-dimensional pseudo-homogeneous steady-state model was employed to evaluate catalyst configurations ranging from 10 to 30 pores per inch (PPI). The foam catalyst structures exhibited superior performance across key metrics, achieving maximum hydrogen yield (60 %) at one-third of the reactor length whilst reducing pressure drop by 95 % compared to conventional pellets. Within the foam configurations, the 10PPI variant demonstrated optimal performance characteristics, with an 80 % reduction in normalized pressure drop compared to 30PPI, whilst maintaining comparable product yields. The enhanced performance was attributed to the open-cell architecture, which facilitated improved mass transfer and reduced diffusion limitations. These findings suggest that foam catalysts represent a promising alternative to conventional pellet configurations for glycerol steam reforming processes.
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Performance Analysis of Biomass Gasification with Biogas Co-Feeding for Hydrogen Production
(2025-01-01)
Saebea, Dang
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Patcharavorachot, Yaneeporn
To improve the hydrogen yield in biomass gasification, the addition of biogas for co-feeding with biomass in gasification was proposed in this work. The gasification model developed in Aspen Plus software was validated with experimental data. The performance of biomass gasification with biogas co-feeding using steam as a gasifying agent was investigated. The effect of the steam-to-fuel ratio on the gasification of mixed biomass and biogas was studied. The results show that the simulation results of biomass gasification were consistent with experimental data. Biomass gasification with biogas co-feeding can raise the amount of hydrogen and carbon monoxide in gas products by 22.12% and 18.44%, respectively. Moreover, the increase in the steam-to-fuel ratio enhances hydrogen in syngas. However, the system efficiency decreases with increasing steam-to-fuel ratio.
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Thermodynamic analysis of a proton conducting SOFC integrated system fuelled by different renewable fuels
(2021-03-19)
Saebea, Dang
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Arpornwichanop, Amornchai
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Patcharavorachot, Yaneeporn
This work proposes a power generation system consisting of steam reformer and SOFC–H+ fuelled by different types of fuel, i.e., ethanol, glycerol and biogas. The performance analysis of integrated system is performed based on thermodynamic calculation through Aspen Plus simulator. The total of the Gibbs free energy minimization is used to determine product composition at equilibrium. The electrochemical model not only considers all voltage losses but also includes the effect of current leakage as a result from the electrolyte used. Considering the operating condition of steam reformer, it is found that the gas product contains the highest amount of hydrogen without the carbon formation when reformer is operated at 973 K with steam to carbon ratio of 1. In addition, the simulation results show that the SOFC–H+ operated at 973 K and 1 A/cm2 can provide a suitable compromise between system performances and exhaust gas composition. The use of glycerol reformate has the highest cell and system efficiencies and fuel utilization compared to the others. In addition, the integrated system fuelled by glycerol can release low CO amount whereas there is more heat provided to the surrounding. Therefore, it can be concluded that glycerol is suitable renewable fuel for SOFC–H+ integrated system.
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Ba0·5Sr0·5(Co0·8Fe0.2)1-xTaxO3-δ perovskite anode in solid oxide electrolysis cell for hydrogen production from high-temperature steam electrolysis
(2021-02-08)
Prasopchokkul, P.
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Seeharaj, P.
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Kim-Lohsoontorn, P.
Among perovskite anodes in solid oxide electrolysis cell (SOEC), Ba<inf>0·5</inf>Sr<inf>0·5</inf>Co<inf>0·8</inf>Fe<inf>0·2</inf>O<inf>3-δ</inf> (BSCF) has gained much attention due to its dominantly high performance. However, the BSCF still suffers from chemical instability. In this study, the B-site of BSCF is partially substituted by a higher valence Ta5+ (5, 10, 15 and 20 mol%) to improve its structural stability - Ba<inf>0·5</inf>Sr<inf>0·5</inf>(Co<inf>0·8</inf>Fe<inf>0.2</inf>)<inf>1-x</inf>Ta<inf>x</inf>O<inf>3-δ</inf> (BSCFTax, 0 ≤ x ≤ 0.20). It is found that doping with higher valence Ta5+ increases both chemical stability and electrochemical performance of BSCF. Although the BSCFTa0.10 shows the lowest oxygen vacancies indicating by the ratio of adsorbed oxygen vacancies (O<inf>adsorbed</inf>) to lattice oxygen (O<inf>lattice</inf>), the electrochemical performance increases. The decrease in Co3+/Co4+ ratio results in increasing electronic conductivity in the anode. It is likely that proper amount of Ta5+ doping provide a balance between ionic and electronic conductivity in the anode and improved electrochemical performance. The symmetrical half-cells with electrolyte support (BSCFTa/YSZ/BSCFTa) are fabricated to determine the area specific resistance (ASR) and activation energy of conduction - BSCFTa0.10 shows the best performance. Cathode-supported Ni-YSZ/YSZ/BSCFTa0.10 also shows higher durability than Ni-YSZ/YSZ/BSCF (operating at current density −0.45 A cm−2 in electrolysis mode, 80 h, 800 °C and H<inf>2</inf>O to H<inf>2</inf> ratio of 70:30).
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Factors affecting hydrogen production by unicellular green alga chlamydomonas reinhardtii cc-125
(2021-01-01)
Sereetrakul, Kodchaporn
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Phunpruch, Saranya
In this study, factors affecting H<inf>2</inf> production by the unicellular green alga Chlamydomonas reinhardtii CC-125 were investigated. It was found that the cell density, O<inf>2</inf> concentration and nutrient deprivation in media play important roles in H<inf>2</inf> production by C. reinhardtii CC-125. C. reinhardtii CC-125 at a cell age of 36 hours with an optical density at 750 nm of 0.8 shows the highest H<inf>2</inf> production rate. Similar to other microorganisms, higher O<inf>2</inf> concentrations decrease H<inf>2</inf> production. However, hydrogenase activity in C. reinhardtii CC-125 seems to show high O<inf>2</inf> tolerance, with an O<inf>2</inf>I<inf>50</inf> of 16.87 ± 0.81%. Under atmospheric air, maximum H<inf>2</inf> production of 100.90 ± 7.92 and 107.47 ± 3.72 mL L-1 was found in cells incubated in sulfur-deprived and sulfur-nitrogen-deprived media, respectively, after 7 days of incubation. The deprivation of both sulfur and nitrogen prolongs H<inf>2</inf> production in this algal strain.
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Compact heat integrated reactor system of steam reformer, shift reactor and combustor for hydrogen production from ethanol
(2020-06-01)
Khaodee, Watcharapong
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Jiwanuruk, Tara
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Ountaksinkul, Khunnawat
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Charojrochkul, Sumittra
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Charoensuk, Jarruwat
A compact heat integrated reactor system (CHIRS) of a steam reformer, a water gas shift reactor, and a combustor were designed for stationary hydrogen production from ethanol. Different reactor integration concepts were firstly studied using Aspen Plus. The sequential steam reformer and shift reactor (SRSR) was considered as a conventional system. The efficiency of the SRSR could be improved by more than 12% by splitting water addition to the shift reactor (SRSR-WS). Two compact heat integrated reactor systems (CHIRS) were proposed and simulated by using COMSOL Multiphysics software. Although the overall efficiency of the CHIRS was quite a bit lower than the SRSR-WS, the compact systems were properly designed for portable use. CHIRS (I) design, combining the reactors in a radial direction, was large in reactor volume and provided poor temperature control. As a result, the ethanol steam reforming and water gas shift reactions were suppressed, leading to lower hydrogen selectivity. On the other hand, CHIRS (II) design, combining the process in a vertical direction, provided better temperature control. The reactions performed efficiently, resulting in higher hydrogen selectivity. Therefore, the high performance CHIRS (II) design is recommended as a suitable stationary system for hydrogen production from ethanol.
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Optimization of hydrogen production from three reforming approaches of glycerol via using supercritical water with in situ CO2 separation
(2019-01-22)
Patcharavorachot, Yaneeporn
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Chatrattanawet, Narissara
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Arpornwichanop, Amornchai
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Assabumrungrat, Suttichai
A pathway for hydrogen production from supercritical water reforming of glycerol integrated with in situ CO<inf>2</inf> removal was proposed and analyzed. The thermodynamic analysis carried out by the minimizing Gibbs free energy method of three glycerol reforming processes for hydrogen production was investigated in terms of equilibrium compositions and energy consumption using AspenPlus™ simulator. The effect of operating condition, i.e., temperature, pressure, steam to glycerol (S/G) ratio, calcium oxide to glycerol (CaO/G) ratio, air to glycerol (A/G) ratio, and nickel oxide to glycerol (NiO/G) ratio on the hydrogen production was investigated. The optimum operating conditions under maximum H<inf>2</inf> production were predicted at 450 °C (only steam reforming), 400 °C (for autothermal reforming and chemical looping reforming), 240 atm, S/G ratio of 40, CaO/G ratio of 2.5, A/G ratio of 1 (for autothermal reforming), and NiO/G ratio of 1 (for chemical looping reforming). Compared to three reforming processes, the steam reforming obtained the highest hydrogen purity and yield. Moreover, it was found that only autothermal reforming and chemical looping reforming were possible to operate under the thermal self-sufficient condition, which the hydrogen purity of chemical looping reforming (92.14%) was higher than that of autothermal reforming (52.98%). Under both the maximum H<inf>2</inf> production and thermal self-sufficient conditions, the amount of CO was found below 50 ppm for all reforming processes.
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Effect of cell density and nutrient deprivation on hydrogen production by unicellular green alga Scenedesmus sp. KMITL-OVG1
(2019-01-01)
Warichanan, Kittiphat
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Phunpruch, Saranya
Hydrogen is considered as one of the energy carriers for the near future. H2 production by green algae is catalyzed by hydrogenase activity using electrons from photosynthetic process under the light and from accumulated carbohydrate catabolism in the dark. This research aimed to investigate the effect of cell density and nutrient deprivation on H<inf>2</inf> production by Scenedesmus sp. KMITL-OVG1 isolated in Thailand. The result showed that cell culture with the optical density at 750 nm of 0.8 gave the highest H2 production rate. Interestingly, the highest H2 production rate of 1.957 ± 0.100 mL L-1 h-1 and hydrogenase activity of 0.031 ± 0.001 ml L-1 min-1 were found in cells incubated under potassium deprivation. H<inf>2</inf> production rate was approximately 3 folds higher than that of cells incubated in normal TAP medium. The increased H2 production rate and hydrogenase activity might be involved in the reduction of starch accumulation. Moreover, the deprivation of potassium combined with other nutrients did not enhance H<inf>2</inf> production rate by Scenedesmus sp. KMITL-OVG1.
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Effect of light intensity and light pattern on hydrogen production by unicellular green alga chlorella sp. LSD-W2
(2019-01-01)
Puangplub, Amornrat
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Phunpruch, Saranya
Green microalgae can use solar energy and water to produce H2 via hydrogenase enzyme activity. The unicellular green alga Chlorella sp. LSD-W2 has been previously shown to produce high H2 under nitrogen deprivation. This research aimed to examine the effects of light intensity and light pattern on H2 production by Chlorella sp. LSD-W2 under nitrogen deprivation. The result showed that H<inf>2</inf> production rate was significantly enhanced when light intensities were increased. The cells could hardly produce H2 in the dark. The highest H2 production rate with 0.956 ± 0.015 mL L-1 h-1 was obtained in cells incubated in TAP-N medium in a 120-mL glass bottle under light intensity of 60 μmol photons m-2 s-1. H<inf>2</inf> production by cells incubated under light/dark or dark/light cycles was lower than that under continuous light illumination. In order to reduce O2 which is an inhibitor of hydrogenase enzyme, the PSII inhibitor, 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) was added to the Chlorella sp. LSD-W2 cell cultures. It was found that O<inf>2</inf> was obviously decreased in cells treated with 10 μM DCMU. Unexpectedly, DCMU caused the reduction of H<inf>2</inf> production by Chlorella sp. LSD-W2.
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Performance comparison of solid oxide steam electrolysis cells with/without the addition of methane
(2016-07-15)
Patcharavorachot, Yaneeporn
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Thongdee, Sirapa
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Saebea, Dang
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Authayanun, Suthida
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Arpornwichanop, Amornchai
Hydrogen is considered a clean energy carrier for the future. At present, the production of hydrogen via a solid oxide electrolysis cell is of interest because water is the only reactant used; however, hydrogen production through electrolysis technology is still costly due to high electrical energy consumption. To reduce this energy demand, an addition of methane to the anode side of the solid oxide electrolysis cell, where it behaves like the anode side of the solid oxide fuel cell and generates heat and electricity to accomplish the electrolysis process, is one interesting method. In this study, modeling of the solid oxide fuel-assisted electrolysis cell is performed based on an electrochemical model to analyze the performance of the electrolyzer with/without the addition of methane in terms of the power input and the energy efficiency. In addition, the effect on the electrolyzer cell by key operating parameters, such as current density, steam fraction, steam-to-carbon ratio, temperature, pressure, steam utilization and fuel utilization, is presented. The simulation analysis shows that the performance of the solid oxide fuel-assisted electrolysis cell is higher than that of conventional solid oxide electrolysis cell, as it requires a lower power input. Furthermore, it is possible to run the solid oxide fuel-assisted electrolysis cell without an external electrical energy input.

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