The Experts below are selected from a list of 45267 Experts worldwide ranked by ideXlab platform
Makoto Sakurai - One of the best experts on this subject based on the ideXlab platform.
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investigation of 2 liquid phase separation characteristics on the iodine sulfur thermochemical Hydrogen Production Process
International Journal of Hydrogen Energy, 2000Co-Authors: Makoto SakuraiAbstract:Separation characteristics of 2 liquid phase, sulfuric acid phase and poly-hydriodic acid phase, in HI-H2SO4-I2 solution of the iodine–sulfur (IS) thermochemical Hydrogen Production Process were measured in the wide operation temperature range, from 273 to 368 K in order to establish the closed-cycle operation technology and to improve thermal efficiency of the Process. The effects of solution temperature and composition of initial solution on the separation characteristics were investigated. The effect of iodine concentration in the solution on the separation characteristics was also evaluated. The separation characteristics were found to improve with the increase in iodine concentration. Iodine concentration at the point where the solution starts to separate and at the point that iodine saturates, were determined by using measured data.
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experimental study on side reaction occurrence condition in the iodine sulfur thermochemical Hydrogen Production Process
International Journal of Hydrogen Energy, 2000Co-Authors: Makoto SakuraiAbstract:Abstract In iodine–sulfur thermochemical Hydrogen Production Process (IS Process), side-reactions from HI, H2SO4 and I2 mixture solution were investigated experimentally in operating temperature ranges, from 295 to 368 K. The effects of the reaction temperature, acid concentration, iodine concentration and the ratio of the amount of H2SO4 to that of HI on the sulfur formation are discussed. The quantitative reaction analysis was also conducted for certain experimental conditions. The results of mass balance during the reaction showed that the sulfur formation side-reaction appeared to predominate in comparison with the Hydrogen sulfide formation side-reaction. By using experimental data, the desirable closed cycle operation conditions for IS Process were clarified.
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preliminary Process analysis for the closed cycle operation of the iodine sulfur thermochemical Hydrogen Production Process
International Journal of Hydrogen Energy, 1999Co-Authors: Makoto SakuraiAbstract:Abstract In the iodine–sulfur thermochemical Hydrogen Production Process, a separation characteristic of 2-liquid phase (H2SO4 phase and HIx phase) in the separator at 0°C was measured. Two-phase separation began to occur at about 0.32 of I2 molar fraction and over. The separation characteristic became better with the increase in iodine concentration in the solution. The effect of flow rate variations of HI solution and I2 solution from the HIx distillation column on the Process was evaluated. The flow rate increase in HI solution from the distillation column did not have a large effect on the flow rate of HI solution fed to the distillation column from the separator. The decreasing flow rate of I2 solution from the distillation column decreased the flow rate of I2 solution fed to the distillation column from the separator. The variation of I2 molar fraction in the H2SO4 phase in the separator was sensitive to the variation in flow rate of both solutions from the distillation column. The tolerance level of the variation was investigated by considering I2 solubility, 2-liquid phase disappearance and SO2 reaction amount.
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Analysis of a reaction mechanism in the UT-3 thermochemical Hydrogen Production cycle
International Journal of Hydrogen Energy, 1996Co-Authors: Makoto Sakurai, N Miyake, Atsushi Tsutsumi, K. YoshidaAbstract:Abstract The UT-3 thermochemical Hydrogen Production Process consists of four gas-solid reactions, two Ca-compounds reactions and two Fe-compounds reactions. In this Process, it is important to obtain the solid reactant with high reactivity and durability. Bromination of CaO included in the UT-3 cycle was analyzed to clarify the mechanism of this reaction, and a reaction model was proposed. Simulated results showed a good agreement with observed data.
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test of one loop flow scheme for the ut 3 thermochemical Hydrogen Production Process
International Journal of Hydrogen Energy, 1992Co-Authors: Makoto Sakurai, N Miyake, Atsushi Tsutsumi, Masahiko Aihara, Kunio YoshidaAbstract:Abstract Reactivity of Ca compounds in the UT-3 thermochemical Hydrogen Production Process has been improved by introducing the alkoxide method. Also, the gas flow Process in the UT-3 Process has been improved to a one-loop flow scheme. In the one-loop flow scheme, it was found that during the bromination of CaO in the presence of steam, the reactivity can be well maintained above 863 K. Dependence of concentration of both gas reactant and solid reactant on the reaction rate of bromination of CaO above 863 K was measured and the rate equations were obtained for two temperature ranges, i.e. from 863 to 883 K and from 883 to 923 K. A bench-scale Hydrogen Production plant was operated continuously using the new flow scheme, and Hydrogen was produced smoothly during the operation of 11 cycles.
Jianlong Wang - One of the best experts on this subject based on the ideXlab platform.
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fermentative Hydrogen Production from macroalgae laminaria japonica pretreated by microwave irradiation
International Journal of Hydrogen Energy, 2019Co-Authors: Yanan Yin, Jianlong WangAbstract:Abstract Pretreatment is an essential procedure to enhance the biodegradability when algae biomass is used as substrate for fermentative Hydrogen Production, In this study the potential of microwave pretreatment for enhancing the Hydrogen Production from macroalgae biomass Laminaria japonica was investigated. Microwave pretreatment at different temperatures (100–180 °C, 30 min) was explored, algae biomass disruption increased with increasing temperature, while highest Hydrogen yield of 15.8 mL/g TSadded was obtained from 160 °C microwave treated algae biomass. Hydrogen Production can be indicated by the deHydrogenase activity. After the microwave treatment, Hydrogen Production Process altered from butyrate-type to acetate-type fermentation. Maximum Hydrogen yield was enhanced by 1.9 fold compared with the control test. Indicating microwave treatment can be a good candidate in enhancing the Hydrogen Production from macroalgae biomass.
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pretreatment of macroalgal laminaria japonica by combined microwave acid method for bioHydrogen Production
Bioresource Technology, 2018Co-Authors: Jianlong WangAbstract:Abstract Suitable pretreatment can effectively enhance the fermentative Hydrogen Production from algae biomass. In this study, combined microwave-acid pretreatment was applied to disintegrate the biomass of macroalgae L. japonica , and dark fermentation in batch mode was conducted for Hydrogen Production. The results showed that combining microwave pretreatment at 140 °C and 2450 MHz with 1% H 2 SO 4 for 15 min could effectively disrupt macroalgal cells and release the organic matters, and soluble chemical oxygen demand (SCOD) concentration increased by 1.92-fold and achieved 5.12 g/L. During the fermentation Process, both polysaccharides and proteins were consumed. Hydrogen Production Process was dominated by acetate-type fermentation, and the dominance of genus Clostridium contributed to more efficient Hydrogen Production. After the pretreatment, Hydrogen yield increased from 15 mL/g TS added to 28 mL/g TS added , and energy conversion efficiency increased from 9.5% to 23.8%. Combined microwave-acid pretreatment is potential in enhancing Hydrogen Production from the biomass of L. japonica .
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changes in microbial community during bioHydrogen Production using gamma irradiated sludge as inoculum
Bioresource Technology, 2016Co-Authors: Yanan Yin, Jianlong WangAbstract:Abstract The changes in microbial community structures during fermentative Hydrogen Production Process were investigated by analyzing 16S rDNA gene sequences using gamma irradiated sludge as inoculum. The experimental results showed that the microbial community structure of untreated sludge was very rich in diversity. After gamma irradiation, lots of species were inhibited, and species with high survival rates under radiation conditions became dominant. After fermentation, Clostridium butyrium and a sequence closely related to Clostridium perfringens ATCC 13124 T (CP000246) became predominant, which were all common Hydrogen producers. Microbial distribution analysis indicated that gamma irradiation was a good pretreatment method for enriching Hydrogen-producing strains from digested sludge.
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kinetic models for fermentative Hydrogen Production a review
International Journal of Hydrogen Energy, 2009Co-Authors: Jianlong WangAbstract:Abstract The kinetic models were developed and applied for fermentative Hydrogen Production. They were used to describe the progress of a batch fermentative Hydrogen Production Process, to investigate the effects of substrate concentration, inhibitor concentration, temperatures, pH, and dilution rates on the Process of fermentative Hydrogen Production, and to establish the relationship among the substrate degradation rate, the Hydrogen-producing bacteria growth rate and the product formation rate. This review showed that the modified Gompertz model was widely used to describe the progress of a batch fermentative Hydrogen Production Process, while the Monod model was widely used to describe the effects of substrate concentration on the rates of substrate degradation, Hydrogen-producing bacteria growth and Hydrogen Production. Arrhenius model was used a lot to describe the effects of temperature on fermentative Hydrogen Production, while modified Han–Levenspiel model was used to describe the effects of inhibitor concentration on fermentative Hydrogen Production. The Andrew model was used to describe the effects of H + concentration on the specific Hydrogen Production rate, while the Luedeking–Piret model and its modified form were widely used to describe the relationship between the Hydrogen-producing bacteria growth rate and the product formation rate. Finally, some suggestions for future work with these kinetic models were proposed.
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optimization of fermentative Hydrogen Production Process using genetic algorithm based on neural network and response surface methodology
International Journal of Hydrogen Energy, 2009Co-Authors: Jianlong WangAbstract:Abstract A central composite design was carried out to investigate the effect of temperature, initial pH and glucose concentration on fermentative Hydrogen Production by mixed cultures in batch test. The modeling abilities of the response surface methodology model and neural network model, as well as the optimizing abilities of response surface methodology and the genetic algorithm based on a neural network model were compared. The results showed that the root mean square error and the standard error of prediction for the neural network model were much smaller than those for the response surface methodology model, indicting that the neural network model had a much higher modeling ability than the response surface methodology model. The maximum Hydrogen yield of 289.8 mL/g glucose identified by response surface methodology was a little lower than that of 360.5 mL/g glucose identified by the genetic algorithm based on a neural network model, indicating that the genetic algorithm based on a neural network model had a much higher optimizing ability than the response surface methodology. Thus, the genetic algorithm based on a neural network model is a better optimization method than response surface methodology and is recommended to be used during the optimization of fermentative Hydrogen Production Process.
Atsushi Tsutsumi - One of the best experts on this subject based on the ideXlab platform.
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optimization of steam methane reforming coupled with pressure swing adsorption Hydrogen Production Process by heat integration
Applied Energy, 2015Co-Authors: Chunfeng Song, Na Ji, Yasuki Kansha, Atsushi TsutsumiAbstract:Hydrogen has been widely researched as a promising alternative fuel. Steam methane reforming (SMR) coupled with pressure swing adsorption (PSA) is one of the most dominant Processes for Hydrogen Production. In order to reduce the energy consumption, a novel energy saving SMR–PSA H2 Production Process by combining heat integration technology has been put forward. In SMR section, the waste heat of reformer and water–gas-shift (WGS) reactors is recovered to pre-heat feed gas and H2O. In the view of exergy, a compressor is used to achieve a well heat pairing of sensible and latent heat between hot and cold streams. In PSA section, the generated adsorption heat is recovered by heat pump and reused for regeneration of sorbent. In the total Process, optimal heat coupling between hot and cold streams is realized. The simulation results indicated that the SMR and PSA sections in the optimized Hydrogen Production Process can save 55.77kJ/mol H2 and 6.01kJ/mol H2, respectively. The total energy consumption of the novel SMR–PSA Process can be reduced to 39.5% that of the conventional Process.
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Analysis of a reaction mechanism in the UT-3 thermochemical Hydrogen Production cycle
International Journal of Hydrogen Energy, 1996Co-Authors: Makoto Sakurai, N Miyake, Atsushi Tsutsumi, K. YoshidaAbstract:Abstract The UT-3 thermochemical Hydrogen Production Process consists of four gas-solid reactions, two Ca-compounds reactions and two Fe-compounds reactions. In this Process, it is important to obtain the solid reactant with high reactivity and durability. Bromination of CaO included in the UT-3 cycle was analyzed to clarify the mechanism of this reaction, and a reaction model was proposed. Simulated results showed a good agreement with observed data.
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test of one loop flow scheme for the ut 3 thermochemical Hydrogen Production Process
International Journal of Hydrogen Energy, 1992Co-Authors: Makoto Sakurai, N Miyake, Atsushi Tsutsumi, Masahiko Aihara, Kunio YoshidaAbstract:Abstract Reactivity of Ca compounds in the UT-3 thermochemical Hydrogen Production Process has been improved by introducing the alkoxide method. Also, the gas flow Process in the UT-3 Process has been improved to a one-loop flow scheme. In the one-loop flow scheme, it was found that during the bromination of CaO in the presence of steam, the reactivity can be well maintained above 863 K. Dependence of concentration of both gas reactant and solid reactant on the reaction rate of bromination of CaO above 863 K was measured and the rate equations were obtained for two temperature ranges, i.e. from 863 to 883 K and from 883 to 923 K. A bench-scale Hydrogen Production plant was operated continuously using the new flow scheme, and Hydrogen was produced smoothly during the operation of 11 cycles.
Chang Feng - One of the best experts on this subject based on the ideXlab platform.
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Synergistic effect of hierarchical structure and Z-scheme heterojunction constructed by CdS nanoparticles and nanoflower-structured Co9S8 with significantly enhanced photocatalytic Hydrogen Production performance
Journal of Photochemistry and Photobiology A: Chemistry, 2021Co-Authors: Chang Feng, Zhuoyuan Chen, Jiangping Jing, Mengmeng Sun, Jing Han, Ke FangAbstract:Abstract Hierarchical structure can significantly increase the reactive sites and provide advantages for heterojunction engineering in the field of photocatalysis. However, it is still a great challenge to realize efficient photocatalytic Hydrogen Production by controlling the band structure and constructing Z-scheme heterojunction system based on the hierarchical photocatalyst. In this paper, a CdS/Co9S8 Z-scheme heterojunction system was prepared by depositing CdS nanoparticles on nanoflower-structured Co9S8 hierarchical photocatalyst, which showed enhanced photocatalytic Hydrogen Production performance. The photocatalytic Hydrogen Production rate of the CdS/Co9S8 Z-scheme heterojunction system is 11.60 mmol g−1 h−1, which is 13.6 and 55.2 times that of CdS and Co9S8, respectively. The synergistic effect of the hierarchical structure and the Z-scheme heterojunction makes the photogenerated charge carriers quickly and efficiently transfer to the surface of the photocatalyst, which accelerates the photocatalytic Hydrogen Production Process.
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effectively enhanced photocatalytic Hydrogen Production performance of one pot synthesized mos2 clusters cds nanorod heterojunction material under visible light
Chemical Engineering Journal, 2018Co-Authors: Chang Feng, Zhuoyuan Chen, Jian Hou, Mingxian Sun, Rongchang ZengAbstract:Abstract In the present work, the MoS2 clusters/CdS (CMo/CdS) nanorod (NR) heterojunction photocatalysts were prepared through a simple one-pot solvothermal method under lower temperature. The cluster-structured MoS2 is uniformly dispersed on the surface of CdS NRs, and the MoS2 modification does not change the crystal structure and morphology of CdS NRs. The modification of MoS2 can significantly enhance the photocatalytic Hydrogen Production performance of CdS NRs. When the molar ratio of MoS2 to CdS NRs is 3%, the CMo/CdS NRs has the highest photocatalytic Hydrogen evolution rate, 12.38 mmol·g−1·h−1, which is 17.4 times that of CdS NRs. The enhanced photocatalytic Hydrogen Production performance can be attributed to the co-catalytic action of MoS2, which can accelerate the photocatalytic Hydrogen Production Process of CdS NRs. Meanwhile, MoS2 can reduce the surface resistance of CdS NRs and improve the transmission of the photogenerated electrons to the surface of CdS NRs, resulting in the significant decrease of the recombination rate of the photogenerated electrons and holes, and thus promoting the photocatalytic Hydrogen Production performance of CdS NRs.
P N Sarma - One of the best experts on this subject based on the ideXlab platform.
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valorization of fatty acid waste for bioplastics Production using bacillus tequilensis integration with dark fermentative Hydrogen Production Process
International Journal of Hydrogen Energy, 2014Co-Authors: Venkateswar M Reddy, P N Sarma, K Amulya, M V Rohit, Venkata S MohanAbstract:Abstract Synthesis of bioplastics (polyhydroxyalkanoates (PHA)) using Bacillus tequilensis, a newly isolated strain was investigated under aerobic condition using designed wastewater with synthetic acids (SA) and acidogenic fermented food waste (AFW) collected from bioHydrogen (H2) producing anaerobic bioreactors as substrates. The isolate showed the ability to grow and accumulate PHA in both the substrates, with simultaneous waste remediation. Higher PHA synthesis was observed with SA (59% dry cell weight) compared to AFW (36% dry cell weight) with good substrate removal (SA, 87%; AFW, 59%). The PHA composition showed presence of co-polymer [P(3HB-co-3HV)] with varying contents of hydroxy butyrate (HB, 80–90%) and hydroxy valerate (HV, 10–15%) in both the substrates. High deHydrogenase activity was observed which leads to the formation of considerable quantity of PHA. AFW from H2 producing reactor as substrate contributes in reducing the Production cost of both H2 as well as PHA embedded with waste valorization.
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regulatory influence of co2 supplementation on fermentative Hydrogen Production Process
International Journal of Hydrogen Energy, 2010Co-Authors: Prathima M Devi, Venkata S Mohan, G Mohanakrishna, P N SarmaAbstract:This study presents an approach to enhance fermentative bioHydrogen (H2) Production by improving the system buffering capacity through utilization of CO2 generated from syngas. The experimental data substantiates the positive impact of CO2 sparging on H2 Production Process. Various CO2 sparging times viz., 30, 60 and 120 s were evaluated on H2 Production and substrate degradation. Based on the optimum sparging time (60 s), experiments were further performed to study the influence of pH microenvironment (5, 6 and 7) on the Process efficiency. Further the influence of periodic CO2 sparging was also evaluated. Experimental data visualized a marked improvement on the overall Process performance based on H2 Production and substrate degradation after sparging CO2. Carbonic acid upon association/dissociation forms bicarbonates in the system. Alkaline condition helps to build up buffering nature, which resist fluctuations in pH even at higher VFA concentrations. Substrate degradation was effective during intermittent sparging at neutral conditions. CO2 sparging directly effecting the bulk liquid environment of the system improves buffering nature which indirectly helps to maintain favorable microenvironment for bioHydrogen Production Process.
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utilizing acid rich effluents of fermentative Hydrogen Production Process as substrate for harnessing bioelectricity an integrative approach
International Journal of Hydrogen Energy, 2010Co-Authors: G Mohanakrishna, Venkata S Mohan, P N SarmaAbstract:Abstract Lower substrate degradation is one of the limiting factors associated with fermentative Hydrogen Production Process. To overcome this, an attempt was made to integrate microbial fuel cell (MFC) as a secondary energy generating Process with the fermentative Hydrogen (H2) Production. The acid-rich effluents generated from the acidogenic sequential batch biofilm reactor (AcSBBR) producing H2 by fermenting vegetable waste was subsequently used as substrate for bioelectricity generation in single chambered MFC (air cathode; non-catalyzed electrodes). AcSBBR was operated at 70.4 kg COD/m3-day and the outlet was fed to the MFC at three variable organic loading rates. The final outlet from AcSBBR was composed of fermentative soluble acid intermediates along with residual carbon source. Experimental data illustrated the feasibility of utilizing acid-rich effluents by MFC for both additional energy generation and wastewater treatment. Higher power output (111.76 mW/m2) was observed at lower substrate loading condition. MFC also illustrated its function as wastewater treatment unit by removing COD (80%), volatile fatty acids (79%), carbohydrates (78%) and turbidity (65.38%) effectively. Fermented form of vegetable wastewater exhibited higher improvement (94%) in power compared to unfermented wastewater. The performance of MFC was characterized with respect to polarization behavior, cell potentials, cyclic voltammetry and sustainable power. This integration approach enhanced wastewater treatment efficiency (COD removal, 84.6%) along with additional energy generation demonstrating both environmental and economic sustainability of the Process.
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bio electrochemical evaluation of fermentative Hydrogen Production Process with the function of feeding ph
International Journal of Hydrogen Energy, 2008Co-Authors: Venkata S Mohan, Lalit V Babu, S Srikanth, P N SarmaAbstract:Abstract Fermentative Hydrogen (H2) Production Process in concurrence with feeding pH [aciodophilic (pH 6.0) and neutral (pH 7.0)] and reactor operation mode (continuous and fed-batch) was evaluated in a biofilm configured reactor [upflow mode; retention time, 24 h; operating temperature, 28 ± 2 °C; organic loading rate, 3.4 kg COD/m3 day] using anaerobic mixed consortia. Acidophilic pH showed relatively effective performance with respect to H2 Production compared to neutral operation. Neutral pH illustrated effective substrate removal efficiency over the corresponding acidophilic operation. Fed-batch mode of operation with acidophilic pH showed highest H2 Production among the studied experimental variations. The pattern of soluble metabolites distribution showed the persistence of acid-forming metabolic flow associated with acidogenesis which may be considered as optimum microenvironment for effective H2 Production. Bio-electrochemical behavior of mixed anaerobic consortia (whole cell) during H2 Production Process was evaluated employing cyclic voltammetry (CV) in electrochemical cell [platinum as working electrode; Ag/AgCl as reference electrode; graphite rod as counter electrode; wastewater as electrolyte] to gain insight into the possible mechanism based on intracellular electron transfer involved in the fermentative metabolic Process. Voltammogram profiles visualized well defined redox pairs in forward and reverse scans at both pH conditions and the signals corresponded to intracellular electron carrier, NADH/NAD+ (E0′, −0.32 V). Relatively higher energy output was observed in acidophilic operation which might be attributed to the possibility of efficient proton (H+) transfer between metabolic intermediates.
