• Korean Chemical Engineering Research
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• v.44 no.1
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• pp.16-22
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• 2006

Biological hydrogen production processes are more environment-friendly and less energy intensive than thermochemical and electrochemical processes. The biological process can be divided into two categories: photosynthetic hydrogen production and hydrogen production by dark fermentation. Photosynthetic process produces hydrogen mainly from water and reduces $CO_2$ simultaneously. Dark fermentation is a dark and anaerobic process that produces hydrogen by fermentative bacteria from organic carbon. The article presents a survey of biological hydrogen production processes.

• Proceedings of the Membrane Society of Korea Conference
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• 2005.11a
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• pp.119-123
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• 2005

The thermochemical splitting of water has been proposed as a clean method for hydrogen production. The IS process is one of the thermochemical water splitting processes using iodine and sulfur as reaction agents. HI decomposition procedure to obtain hydrogen is one of the key operations in the process, because equilibrium conversion of HI is low (22% at $450^{\circ}C$). The silica membranes prepared by CVD. method were applied to the decomposition reaction of HI vapor. The permeation characteristics of hydrogen and nitrogen belong to the Knudsen flow pattern.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.723-726
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• 2009

As a preliminary study of cost estimates for nuclear hydrogen systems, the hydrogen production costs of the nuclear energy sources benchmarking GT-MHR are estimated in the necessary input data on a Korean specific basis. G4-ECONS developed by EMWG of GIF in 2008 was appropriately modified to calculate the cost for hydrogen production of SI process with VHTR as a thermal energy source rather than the LUEC. The estimated costs presented in this paper show that hydrogen production by the VHTR could be competitive with current techniques of hydrogen production from fossil fuels if $CO_2$ capture and sequestration is required. Nuclear production of hydrogen would allow large-scale production of hydrogen at economic prices while avoiding the release of $CO_2$. Nuclear production of hydrogen could thus become the enabling technology for the hydrogen economy. The major factors that would affect the cost of hydrogen were also discussed.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.1
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• pp.12-25
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• 2007

Numerical simulation of the natural gas steam reforming process for on-site hydrogen production in a $H_2$ fueling station was conducted on the basis of process material and heat balances. The effects of reforming parameters on the process efficiency of hydrogen production were investigated, and set-point values of each of the parameters to minimize the sizes of unit process equipments and to secure a stable operability of the reforming process were suggested. S/C ratio of the reforming reactants was found to be a crucial parameter in the reforming process mostly governing both the hydrogen production efficiency and the stable operability of the process. The operation of the process was regarded to be stable if the feed water(WR) as a reforming reactant could evaporate completely to dry steam through HRSG. The optimum S/C ratio was 3.0 where the process efficiency of hydrogen production was maximized and the stable operability of the process was secured. The optimum feed rates of natural gas(NGR) and WR as reforming reactants and natural gas(NGB) as a burner fuel were also determined for the hydrogen production rate of $27\;Nm^3/h$.

• Journal of Institute of Convergence Technology
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• v.12 no.1
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• pp.19-23
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• 2022

Interest in hydrogen production to respond to climate change is increasing. Until now, hydrogen has been mainly produced through the SMR (Steam Methane Reforming) process using natural gas. A large amount of CO₂ is emitted in the hydrogen production process through SMR, and the gas flow including CO₂ generated in the SMR process has different characteristics for each emission source, so it is important to apply a suitable CO₂ capture process. In the case of PSA tail gas or synthesis gas, the applicability of an amine-based process has been confirmed or demonstrated close to a commercial level. However, in the case of the flue gas generated from the reformer, it is still difficult to apply the conventional amine-based process because the partial pressure of CO₂ is relatively low. Energy-saving innovative absorbents such as phase separation absorbents can be a solution to these difficulties.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.3
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• pp.267-273
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• 2023

As the impacts of global climate change become increasingly apparent, the reduction of carbon emissions has emerged as a critical subject of discussion. Nuclear power has garnered attention as a potential carbon-free energy source; however, the rapidity of load following in nuclear power generation poses challenges in comparison to fossil-fueled methods. Consequently, power-to-gas systems, which integrate nuclear power and hydrogen, have attracted growing interest. This study presents a preliminary design of a very high temperature reactor (VHTR) integrated blue hydrogen production process utilizing DWSIM, an open-source process simulator. The blue hydrogen production process is estimated to supply the necessary calorific value for carbon capture through tail gas combustion heat. Moreover, a thermodynamic assessment of the main recuperator is performed as a function of the helium flow rate from the VHTR system to the blue hydrogen production system.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.467-475
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• 2007

This study was conducted to examine temperature effects on hydrogen production in anaerobic fermentation. 18 batch reactors were operated at mesophilic ($35^{\circ}C$) and thermophilic conditions ($55^{\circ}C$) to achieve maximum hydrogen production in anaerobic fermentation. Optimum hydrogen production conditions were also investigated at each temperature. Different trends were observed regarding pH effects on hydrogen production. This effect was not significant for mesophilic fermentation ($35^{\circ}C$). In this case, pH may not drop to interfere hydrogen production during the test. However, hydrogen production decreased without pH control for thermophilic condition ($55^{\circ}C$). Effects of heat treatment were observed for both fermentation process. Hydrogen production with heat treatment was higher than hydrogen production without heat treatment for both fermentation processes. The amount of produced hydrogen for each substrate concentration with temperature changes showed that more hydrogen was produced at $35^{\circ}C$ than at $55^{\circ}C$.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.310-311
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• 2005

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.3
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• pp.235-242
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• 2018

Hydrogen can be produced by reforming reaction of natural gas (NG) and biogas, or by water electrolysis. In this study, hydrogen production through water-electrolysis needs superheated steam above $700^{\circ}C$ for high efficiency. The production method of hydrogen like this was recommended for the 4-type processes for superheated steam ($700^{\circ}C$, 3 atm) by Bio-SRF combustion furnace. The 4-type processes to produce superheated steam at $700^{\circ}C$ from the heat source of SRF combustion furnace was simulated using PRO II. The optimum process was selected through exergy analysis. The difference of process 1 and 2 is to the order of depressure and heating process to change $180^{\circ}C$ and 7 atm to $700^{\circ}C$ and 3 atm. Process 3 and 4 is to utilize 25% of steam to generate superheated steam and remaining to use for the power generation by steam generator.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.25-33
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• 2003

It summarized about the application of the membrane technology in thermochemical water-splitting iodine-sulfur process that was hydrogen production using the nuclear heat from the High Temperature Gas-Cooled Reactor (HTGR). Thermochemical water-splitting hydrogen production method using the high temperater nuclear thermal energy could be realized and remained to be solved the investigation subject. And, it is possible for mass-production of hydrogen such as one of the clean energy in future.