• Transactions of the Korean hydrogen and new energy society
• /
• v.18 no.4
• /
• pp.464-480
• /
• 2007

There are several methods for the hydrogen production such as steam reforming of natural gas, photochemical method, biological method, electrolysis and thermochemical method, etc. These days it has been widely studied for the hydrogen production method having low hydrogen production cost and high efficiency. In this paper, patents in the hydrogen production by steam reforming of natural gas were gathered and analyzed. The search range was limited in the open patents of USA(US), European Union(EP), Japan(JP), and Korea(KR) from 1996 to 2006. Patents were gathered by using key-words searching and extracted by filtering criteria. The trends of the patents was analyzed by the years, countries, companies, and technologies.

• Asian Journal of Atmospheric Environment
• /
• v.2 no.2
• /
• pp.116-124
• /
• 2008

In this study, the Tier 2 method recommended by the Intergovernmental Panel on Climate Change (IPCC) was used to predict the methane generation rate at two landfill sites, designated as Y and C for purposes of this study, in South Korea. Factors such as the average annual waste disposal, methane emissions ($L_0$) and methane gas generation rate constant (k) were estimated by analyses of waste and the historical data for the landfills. The value of k was estimated by field experiments and then the changes in the methane generation rate were predicted through the year 2050, based on the value of k. The Y landfill site, which was in operation until the year 2008, will generate a total of 17, 198.7 tons by the end of 2018, according to our estimations. At the C landfill site, which will not be closed until the end of 2011, the amount of methane gas generated in 2011 will be 3,316 tons and the total amount of gas generated by 2029 will be 61,200 tons. The total production rate of methane gas at the C landfill is higher than that of the Y landfill. This indicates that the capacity of a landfill site affects the production rate of methane gas. However, the interrelation between the generation rate of methane and the value of k is weak. In addition, the generation of methane gas does not cease even when the operations at a landfill site come to a close and the methane gas production rate is at its highest at end of the operating life of a landfill site.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.3
• /
• pp.270-274
• /
• 2005

A reactor-scale hydrogen (H2) production via the water-gas shift reaction of carbon monoxide (CO) and water was studied using the purple nonsulfur bacterium, Rhodopseudomonas palustris P4. The experiment was conducted in a two-step process: an aerobic/chemoheterotrophic cell growth step and a subsequent anaerobic $H_2$ production step. Important parameters investigated included the agitation speed. inlet CO concentration and gas retention time. P4 showed a stable $H_2$ production capability with a maximum activity of 41 mmol $H_2$ g $cell^{-1}h^{-1}$ during the continuous reactor operation of 400 h. The maximal volumetric H2 production rate was estimated to be 41 mmol $H_2 L^{-1}h^{-1}$, which was about nine-fold and fifteen-fold higher than the rates reported for the photosynthetic bacteria Rhodospirillum rubrum and Rubrivivax gelatinosus, respectively. This is mainly attributed to the ability of P4 to grow to a high cell density with a high specific $H_2$ production activity. This study indicates that P4 has an outstanding potential for a continuous H2 production via the water-gas shift reaction once a proper bioreactor system that provides a high rate of gas-liquid mass transfer is developed.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.5
• /
• pp.708-714
• /
• 1999

Fermentation of legume fodder tree leaves by rumen microorganisms was evaluated. The substrates were sun-dried, ground leaves. Gas and volatile fatty acid (VFAs) production were estimated. Using gas production as an index of fermentation at 12 h, the leaves tested ranked as follows; Chamaecytisus palmensis>Gliricidia sepium>Sebania sesban>Tephrosia bracteolate>Leucaena pallida>Vernonia amygdalina>Acacia sieberiana>Sesbania goetzei>Acacia angustissima. Using VFA production, the ranking was a follows; G. sepium>S. sesban>S. goetzei>L. pallida>C. palmensis/V. amygdalina>T. bracteolate> A. sieberiana>A. angustissima. Absolute gas or VFA production rates, were also used to rank the leaves. Extracts (70% acetone) of A. angustissima inhibited the growth of Ruminococcus albus 8, R. flavefaciens FD-1, Prevotella ruminicola D3ID and Streptococcus bovis JBI while the trowth of Selenomonas ruminantium D was depressed when 0.6 ml exracts were added. C. palmensis water extracts enhanced cellulose hydrolysis by R. flavefaciens FD-1. All extracts reduced celluloysis by R. albus 8. R. flavefaciens FD-1 hydrolyzed more (p<0.001) cellulose than R. albus 8.

• Korean Chemical Engineering Research
• /
• v.43 no.3
• /
• pp.344-351
• /
• 2005

Hydrogen energy will be considered one of the most important energy carries for the future not only as raw material of petroleum chemical industry but also as the fuel of the fuel cell. The hydrogen production based upon the water electrolysis system combined renewable energy or atomic power energy is being watched as long-term hydrogen sources. Hydrogen from fossil fuel, especially natural gas steam reforming, is the economical mass production method at this time. But the cost of $CO_2$ reduction is added in the economic analysis of hydrogen production processes. Therefore many different results are suggested from these analyses about old processes, and modified schemes are studying for the efficient development. In this review, status for the technology of hydrogen production from natural gas are summarized.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.398-401
• /
• 2000

The effect of volatile components on cell growth and polysaccharide production in suspension cultures of Aloe saponaria was investigated using an intelligent on-line gas control system which enabled to control the concentrations of oxygen, carbon dioxide and ethylene simultaneously. Aloe production was enhanced in the presence of exogenous ethylene in the concentration range of 5ppm and 15ppm. Maintaining high tension of carbon dioxide (5% v/v) was found to enhance polysaccharide production significantly.

• Journal of Animal Science and Technology
• /
• v.45 no.2
• /
• pp.241-250
• /
• 2003

Accurate and rapid evaluation of the nutritional quality of Korean straws is important because of the recent increase in the use of these feedstuffs in Korean. The aim of the study was to establish with relationships between ruminal fermentation of Korean straws and in vitro gas production using a pressure transducer. The pressure transducer system includes pressure censors, AD board, LED monitor, and the computer with real-time graphics. Both gas production and DM digestibility data were fitted into the exponential equation P = a + b (1-e-$1-e^{-ct}$). The initial rate of gas production was highest for rice straw, followed by barley straw and wheat straw. The gas production rate of constant (c) in gas production for rice straw, wheat straw, and barley straw were 3.8, 2.5, and 2.5 $%h^{－1}$, respectively. Total VFA concentration (mM) produced after 72h incubation was similar among three Korean straws, even though was variable during the early (12h) fermentation. Volume of gas production was related (P> 0.05: r = 0.76 to 0.83) to DM disappearance and also strongly related (p< 0.05: r = 0.91 to 0.98) to VFA concentration at all incubation times. Linear correlation showed between gas production and DM disappearance and VFA by in vitro will be matched in in vivo digestibility.

• Journal of the Korean Institute of Gas
• /
• v.22 no.4
• /
• pp.39-48
• /
• 2018

This study presents optimal design of gas lift considering composition of reservoir oil and injected gas which can affect gas lift performance in offshore oil reservoir. Reservoir simulation was conducted by using reservoir models which were built in accordance with API gravity of oil. The results of simulation reveal that oil production rate is considerably increased by gas lift when the reservoir productivity decrease. As a results of response curve analysis for gas lift using well models, gas injection rate to improve the production rate increases as the API gravity of oil decreases and the specific gravity of injected gas increases. The optimal design of gas lift was carried out using multiple lift valves. Consequently, gas lift can be operated at relatively low injection pressure because of decrease in injection depth in comparison to the single lift valve design. The improved oil production rates were analyzed by coupling between reservoir model and well model. As a results of the coupling, it is expected that natural gas injection in the heavy oil reservoir is the most efficient method for improving oil production by gas lift.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.1
• /
• pp.51-61
• /
• 2016

In order to provide recommendations on the most useful forage species to smallholder farmers, eleven grass and eleven legume forages grown in Abomey-Calavi in Republic of Benin were investigated for nutritive value (i.e. chemical composition and energy content) and fermentation characteristics (i.e. gas and volatile fatty acid production, organic matter degradability). The in vitro gas production technique was used, incubating the forages for 120 h under anaerobic condition with buffalo rumen fluid. Compared to legume, tropical grass forages showed lower energy (8.07 vs 10.57 MJ/kg dry matter [DM]) and crude protein level (16.10% vs 19.91% DM) and higher cell wall content (neutral detergent fiber: 63.8% vs 40.45% DM), respectively. In grass forages, the chemical composition showed a quite high crude protein content; the in vitro degradability was slightly lower than the range of tropical pasture. The woody legumes were richer in protein and energy and lower in structural carbohydrates than herbaceous plants, however, their in vitro results are influenced by the presence of complex compounds (i.e. tannins). Significant correlations were found between chemical composition and in vitro fermentation characteristics. The in vitro gas production method appears to be a suitable technique for the evaluation of the nutritive value of forages in developing countries.

• Environmental Engineering Research
• /
• v.24 no.3
• /
• pp.521-528
• /
• 2019

Electrochemical method was used for the fracturing flow-back fluid treatment in Guangyuan oilfield. After performing electrolysis, we found that the amount of $H_2$ gas produced by electrode was closely related to the combination mode of electrodes and electrode materials. Using an aluminium electrode resulted in a large $H_2$ production of each electrode combination, whereas inert anode and cathode materials resulted in low $H_2$ production. Then, the relationship between the gas production of $H_2$ and the treatment efficiency of fracturing flow-back fluid in Guangyuan oilfield was studied. Results showed that the turbidity removal and decolourisation rates of fracturing flow-back fluid were high when $H_2$ production was high. If the $H_2$ production of inert electrode was large, the energy consumption of this inert electrode was also high. However, energy consumption when an aluminium anode material was used was lower than that when the inert electrode was used, whereas the corresponding electrode combination production of $H_2$ was larger than that of the inert electrode combination. When the inert electrode was used as anode, the gas production type was mainly $O_2$, and $Cl_2$ was also produced and dissolved in water to form $ClO^-$. $H_2$ production at the cathode was reduced because $ClO^-$ obtained electrons.