• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.283-291
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• 2019

Fermentation of food waste in the presence of different concentrations of salt ($Na^+$) and ammonia was conducted to investigate the interrelation of $Na^+$ and ammonia content in bio-hydrogen production. Analysis of the experimental results showed that peak hydrogen production differed according to the ammonia and $Na^+$ concentration. The peak hydrogen production levels achieved were (97.60, 91.94, and 49.31) ml/g COD at (291.41, 768.75, and 1,037.89) mg-N/L of ammonia and (600, 1,000, and 4,000) $mg-Na^+/L$ of salt concentration, respectively. At peak hydrogen production, the ammonia concentration increased along with increasing salt concentration in the medium. This means that for peak hydrogen production, the C/N ratio decreased with increasing salt content in the medium. The butyrate/acetate (B/A) ratio was higher in proportion to the bio-hydrogen production (r-square: 0.71, p-value: 0.0006). Different concentrations of $Na^+$ and ammonia in the medium also produced diverse microbial communities. Klebsiella sp., Enterobacter sp., and Clostridium sp. were predominant with high bio-hydrogen production, while Lactococcus sp. was found with low bio-hydrogen production.

• 한국수소및신에너지학회논문집
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• 제34권6호
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• pp.581-586
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• 2023

As the development of alternative energy is required due to the depletion of fossil fuels, interest in the use of hydrogen energy is increasing. Hydrogen is a promising clean energy source with high energy density and can lead to the application of environmentally friendly technologies. However, due to difficulties in production, storage, and transportation that prevent the application of hydrogen-based eco-friendly technology, research on reforming reactions using dimethyl ether (DME) is being conducted. Unlike other hydrocarbons, DME is attracting attention as a hydrogen carrier because it has excellent storage stability and transportability, and there is no C-C bond in the molecule. The reaction between DME and steam is one of the reforming processes with the highest hydrogen yield in theory at a temperature lower than that of other hydrocarbons. In this study, a hydrogen reforming device using DME was developed and a catalyst prepared by supporting Cu in alumina was put into a reactor to find optimal hydrogen production conditions for supplying hydrogen to fuel cells while changing reaction temperature (300-500℃), pressure (5-10 bar), and steam/carbon ratio (3:1 to 5:1).

• 한국수소및신에너지학회논문집
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• 제22권2호
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• pp.257-264
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• 2011

This study discribes performance of DEFC (Direct Ethanol Fuel Cell) utilized bio-ethanol based on fruit wastes. To produce the bio-ethanol, fruit wastes were treated at temperature $120^{\circ}C$ and 90minutes in acid pre-treatment. After pre-treatment was done, alcohol fermentation process was running. Initial alcohol concentration was 5%. Using the multi coloumn distillation system, more than 95% ethanol was distilled and each component of bio-ethanol was analyzed. In DEFC performance test, it was revealed that cell performance was much higher than that of ethanol. Comparing ethanol with mixed fuel (bio-ethanol (10%) + ethanol (90%)), the performance of ethanol was higher than that of mixed fuel. Even though the bio-ethanol from the fruit wastes is corresponded with transport ethanol standards, it thought that organic matter in bio-ethanol could be negative effect on fuel cell.

• 설비공학논문집
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• 제29권5호
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• pp.259-268
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• 2017

This paper proposes a hydrogen-based social economy derived from fuel cells capable of replacing fossil fuels and resolving global warming, It thus provides an entry for developing economically feasible social configurations to make use of bio-hydrogen production systems. Bio-hydrogen production works from the principle that microorganisms decompose water in the process of converting CO to $CO_2$, thereby producing hydrogen. This study parts from an analysis of an existing 157-ton class NA1 bio-hydrogen reactor that identifies the state of feedstock and reactor conditions. Based on this analysis, we designed a 1-ton class bio-hydrogen reactor process simulator. We carried out thermal analyses of biological heat reactions, sensible heat, and heat radiation in order to calculate the thermal load of each system element. The reactor temperature changes were determined by modeling the feed mixing tank capacity, heat exchange, and heat storage tank. An analysis was carried out to confirm the condition of the feed mixing tank, heat exchanger, heat storage tank capacity as well as the operating conditions of the system so as to maintain the target reactor temperature.

• 대한환경공학회지
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• 제30권9호
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• pp.933-938
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• 2008

유기성 폐기물을 이용하여 생산된 수소를 환원제로 활용하여 이산화탄소를 유용한 에너지원인 메탄으로 전환시키고자 하였다. 3 개월 동안 혐기성 미생물을 이산화탄소와 수소만을 이용하여 배양하였으며, 그 결과 acetogenotrophs의 영향에 의한 메탄의 생성은 없었고, 이산화탄소를 8 mL/min으로 주입하였을 때 이산화탄소와 수소의 주입비가 1:5에서 메탄의 생성량이 2.2 m$^3$/m$^3$ day로 가장 많았으며, 이때의 이산환탄소 저감률 또한 92%로 가장 우수하였다. 회분형태로 수소 생산과 메탄발효조와의 연계실험을 통하여, 연속적으로 수소를 생산하면서 이산화탄소를 같이 메탄발효조에 주입하여, 이산화탄소의 메탄으로의 전환을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권1호
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• pp.90-95
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• 2005

Lactic acid bacteria were isolated from silage, which produce high level of hydrogen peroxide in cell culture supernatant. The 16S rDNA sequences of the isolate matched perfectly with that of Lactobacillus fermentum (99.9%), examined by a 16S rDNA gene sequence analysis and similarity search using the GenBank database, thus named L. fermentum CS12-1. L. fermentum CS12-1 showed resistance to low pH and bile acid. The production of hydrogen peroxide by L. fermentum CS12-1 was confirmed by catalase treatment and high-performance liquid chromatography. L. fermentum CS12-1 accumulated hydrogen peroxide in culture broth as cells grew, and the highest concentration of hydrogen peroxide reached 3.5 mM at the late stationary growth phase. The cell-free supernatant of L. fermentum CS12-1 both before and after neutralization inhibited the growth of enterotoxigenic Escherichia coli K88 that causes diarrhea in piglets.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2001-2006
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• 2005

Glycoproteins and glycolipids play key roles in intracellular reactions between cells and their environments at the membrane surface. For better understanding of the nature of these events, it is necessary to know threedimensional structures of those carbohydrates, involved in them. Since carbohydrates contain many hydroxyl groups which can serve both as hydrogen bond donors and acceptors, hydrogen bond is an important factor stabilizing the structure of carbohydrate. DMSO is an aprotic solvent frequently used for the study of carbohydrates because it gives detailed insight into the intramolecular hydrogen bond network. In this study, conformational properties and the hydrogen bonds in $\beta$-lactose in DMSO are investigated by NMR spectroscopy and molecular dynamics simulations. NOEs, temperature coefficients, deuterium isotope effect, and molecular dynamics simulations proved that there is a strong intramolecular hydrogen bond between O3 and HO2' in $\beta$-lactose and also OH3 in $\beta$-lactose may form an intermolecular hydrogen bond with DMSO.

• 한국막학회:학술대회논문집
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• 한국막학회 2005년도 추계 총회 및 학술발표회
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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.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3090-3093
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• 2011

Curcumin is a natural product with antioxidant, anti-inflammatory, antiviral and antifungal functions. As it is known that the excited state intramolecular hydrogen transfer of curcumin are related to its medicinal antioxidant mechanism, we investigated its excited state dynamics by using femtosecond transient absorption spectroscopy in an effort to understand the molecule's therapeutic effect in terms of its photophysics and photochemistry. We found that stronger intermolecular hydrogen bonding with solvents weakens the intramolecular hydrogen bonding and decelerates the dynamical process of the enolic hydrogen. Exceptions are found in methanol and ethylene glycol due to their nature as simultaneous hydrogen bonding donor-acceptor and high viscosity solvent, respectively.

• 한국수소및신에너지학회논문집
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• 제31권2호
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• pp.223-233
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• 2020

Fast pyrolysis is one of the most promising technologies for converting biomass to liquid fuels. Pyrolysis bio-oil can replace petroleum-based fuels used in various thermal conversion devices. However, pyrolysis bio-oil is completely different from petroleum fuels. Therefore, in order to successfully use pyrolysis bio-oil, it is necessary to understand the fuel characteristics of pyrolysis bio-oil. This paper focuses on fuel characteristics and upgrading methods of pyrolysis bio-oil and discusses how these fuel characteristics can be applied to the use of pyrolysis bio-oils. In addition, the fuel quality standards of fast pyrolysis bio-oil were examined.