• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.85-88
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• 2006

A fluidized bed reactor made of quartz with 0.055m I.D. and 1.0m in height was employed for the thermocatalytic decomposition of propane to produce $CO_2$-free hydrogen. The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. The propane decomposition rate used carbon black N33O as a catalyst. The propane decomposition reaction was carried out at the temperature range of $600{\sim}800^{\circ}C$, paropane gas velocity of $1.0 U_{mf}\;3.0U_{mf}$ and the operating pressure of 1.0 atm. Effect of operating parameters such as reaction temperature, gas velocity on the reaction rates was investigated. The carbon which was by-product of methane decomposition reaction was deposited on the catalyst surface that was observed by SEM. Resulting production in our experiment were not only hydrogen but also several by products such as methane, ethylene, ethane, and propylene.

• 대한환경공학회지
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• 제28권9호
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• pp.911-916
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• 2006

혐기성 미생물에 의한 수소 생산에 있어서 기질 농도와 HRT의 영향에 대하여 3계열로 구분하여 실험을 수행하였다. 계열 I는 HRT가 8시간에서 기질농도를 3에서 27 g-glucose/L로 증가시키면서 실험을 수행하였고, 계열 II는 HRT가 16시간, 계열 3은 HRT가 24시간으로 설정하여 실험을 수행하였다. 연구결과, 수소 생성 수율에 미치는 HRT와 기질 농도의 영향에 대하여 표면분석법에 의하여 분석하였다. 최대 수소 생성 수율은 기질농도 15.4 g/L 및 HRT 9.6시간에서 2.05 mol $H_2/mol$ 글루코오스의 값을 구할 수 있었다. 2 mol $H_2/mol$ 글루코오스의 수소 생성 수율을 얻기 위한 기질농도 및 HRT는 각각 $13{\sim}17$ g/L 및 $5{\sim}14$시간임을 알 수 있었다. 글루코오스의 소모에 따라 유기산의 농도는 증가하였고, 주요 대사산물은 아세트산과 부틸산이었다.

• 대한환경공학회지
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• 제31권6호
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• pp.434-441
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• 2009

황산염의 농도변화에 따른 연속 혐기성 수소 발효에 미치는 영향을 고찰하기 위해서 혼합균주를 사용한 완전 혼합형 반응조를 운전하였다. 기질은 글루코오스를 사용하였고, 수리학적 체류시간은 1, 0.5, 0.25 일로 각각 고정하였다. 황산염 농도는 0${\sim}$20,000 mg/L로 단계별 증가시켰고 pH 5.5로 운전하였다. 실험 결과 높은 황산염 농도에 관계없이 수소가 발생하였고, HRT 0.25일로 짧아짐에 따라 수소 발생이 높게 나타났다. HRT 1, 0.5, 0.25일 각 조건별 수소 생성량과 수소 수율은 2.9, 4.6, 9.4 L/day, 2.0, 1.8, 1.6 mol $H_2$/mol glucose로 나타났으며, 잔존 황산염 96${\sim}$98, 95${\sim}$97 94${\sim}$97%로 나타나 황산염 환원이 발생하지 않았다. FISH 결과 모든 조건에서 수소생성균의 분포는 나타났지만 황산염환원균의 분포는 나타나지 않았다.

• Environmental Engineering Research
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• 제19권4호
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• pp.387-393
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• 2014

The purpose of this study is to evaluate integrated anaerobic hydrogen fermentation and membrane bioreactor (MBR) for on-site domestic wastewater treatment and resource recovery. A synthetic wastewater (COD 17,000 mg/L) was used as artificial brown water which will be discharged from urine diversion toilet and fed into a continuous stirred tank reactor (CSTR) type anaerobic reactor with inclined plate. The effluent of anaerobic reactor mixed with real household grey water (COD 700 mg/L) was further treated by MBR for reuse. An optimum condition maintained in anaerobic reactor was HRT of 8 hrs, pH 5.5, SRT of 5 days and temperature of $37^{\circ}C$. COD removal of 98% was achieved from the overall system. Total gas production rate and hydrogen content was 4.6 L/day and 52.4% respectively. COD mass balance described the COD distribution in the system via reactor byproducts and effluent COD concentration. The results of this study asserts that, anaerobic hydrogen fermentation combined with MBR is a potent system in stabilizing waste strength and clean hydrogen recovery which could be implemented for onsite domestic wastewater treatment and reuse.

• 한국수소및신에너지학회논문집
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• 제33권4호
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• pp.284-292
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• 2022

Hydrogen is promising a candidate for energy supporting the carbon neutrality policy for greenhouse gas reduction, which is being promoted in several countries, including Korea. Although challenging efforts-such as lowering the costs of green hydrogen production and fuel cells-remain, hydrogen fuel cell electric vehicles (FCEVs) are expected to play a significant role in the energy transition from fossil fuels to renewable energy. In line with this objective, the hydrogen FCEV working group in the International Organization for Standardization (ISO) compiled and revised international standards related to hydrogen refueling stations as of 2019. A well-established hydrogen quality management system based on the standard documents will increase the reliability of hydrogen charging stations and accelerate the use of FCEVs. In this study, among the published ISO standards and other references, the main requirements for managing charging stations and developing related techniques were summarized and explained. To respond preemptively to the growing FCEV market, a continuous hydrogen quality monitoring method suitable for use at hydrogen charging stations was proposed.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.761-764
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• 2009

The thermocatalytic decomposition of methane is an environmentally attractive approach to $CO_2$-free production of hydrogen. The fluidized bed was proposed for the continuous withdraw of product carbon from the reactor. The usage of carbon black was reported as stable catalyst for decomposition of methane. Therfore, carbon black (DCC-N330) is used as catalyst. A fluidized bed reactor made of quartz with 0.055 m I.D. and 1.0 m in height was selected for the thermo-catalytic decomposition. The porpane-containg methnae decomposition reaction was operated at the temperature range of 850-900 $^{\circ}C$ methane gas velocity of 1.0 $U_{mf}$ and the operating pressure of 1.0 atm. In this work, propane was added as reactant to make methane conversion higher. Therefore we compared with methane conversion and pre-experiment methane conversion that using only methane as reactant. The carbon black, after experiment, was measured in particle size and surface area and analyzed surface of the carbon black by TEM.

• KSBB Journal
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• 제20권6호
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• pp.458-463
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• 2005

Polyurethane foam이 충진된 trickle bed reactor에서 통성혐기성 미생물인 Citrobacter amalonaticus Y19을 이용하여 일산화탄소와 물로부터 연속적인 수소생산을 살펴보았다. C. amalonaticus Y19은 설탕을 탄소원으로 할 때 호기적 조건에서 13 g/L까지 성장하였고 혐기조건에서 CO 가스를 주입하였을 때 약 60시간만에 최대 수소 생산 활성을 나타내었다. TBR 반응기에서 유입가스의 CO의 분압이 증가할수록 혹은 기체 체류시간이 감소할수록 수소 생성속도가 증가하였으나 CO의 전환율은 반대로 감소하였다. 그러나 액상의 유속변화는 반응기 운전 결과에 큰 영향을 주지 못했다. 본 실험에서 얻은 최대 수소 생성속도는 기체 체류시간 25분, 유입 CO 압력 0.4 atm에서 16 mmol/L/hr(전환율 33%)이었다. 이 값은 비슷한 반응기에 대해 보고된 Cowger의 결과보다 약 2배 이상 높은 값으로 통성혐기성균주의 고농도 배양과 다공성 충진물의 사용에 의한 높은 기-액 물질 전달 속도가 그 원인으로 추정되었다.

• Environmental Engineering Research
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• 제10권4호
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• pp.181-190
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• 2005

Severe loss or hydrogen occurred in most anaerobic hydrogen fermentation reactors. Several selected methods were applied to suppress the consumption of hydrogen and increase the potential of production. As the first trial, pH shock was applied. The pH of reactor was dropped nearly to 3.0 by stopping alkalinity supply and on]y feeding glucose (5 g/L-d). As the pH was increase to $4.8{\pm}0.2,$ the degradation pathway was derived to solventogenesis resulting in disappearance of hydrogen in the headspace. In the aspect of bacterial community, methanogens weren't detected after 22 and 35 day, respectively. Even though, however, there was no methanogenic bacterium detected with fluorescence in-situ hybridization (FISH) method, hydrogen loss still occurred in the reactor showing a continuous increase of acetate when the pH was increased to $5.5{\pm}0.2$. This result was suggesting the possibility of the survival of spore fanning acetogenic bacteria enduring the severely acidic pH. As an alternative and additive method, nitrate was added in a batch experiment. It resulted in the increase of maximum hydrogen fraction from 29 (blank) to 61 % $(500\;mg\;NO_3/L)$. However, unfortunately, the loss of hydrogen occurred right after the depletion of nitrate by denitrification. In order to prevent the loss entangled with acetate formation, $CO_2$ scavenging in the headspace was applied to the hydrogen fermentation with heat-treated sludge since it was the primer of acetogenesis. As the $CO_2$ scavenging was applied, the maximum fraction of hydrogen was enhanced from 68 % to 87 %. And the loss of hydrogen could be protected effectively.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.765-771
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• 2011

This study was conducted to investigate the effect of heat treatment on the start-up performance for anaerobic hydrogen fermentation of food waste. The result showed that hydrogen production was $0.61{\pm}0.31$ mol $H_2$/mol hexose with heat-treatment of food waste at $70^{\circ}C$ for 60 min whereas it was $0.36{\pm}0.31$ mol $H_2$/mol hexose without heat-treatment of one. The heat treatment of food waste enhanced hydrogen yield due probably to the increase of hydrolysis as well as the decrease of non-hydrogen fermentation microorganisms. The removal efficiency of carbohydrate in reactors regardless of heat treatment of food waste maintained over 90%. The hydrogen conversion efficiency from food waste was 1.7-6.3% with heat-treatment whereas it was 0.7-4.5% without heat-treatment. At the time of switchover from batch to continuous operation, lactate concentration was high compared to the n-butyrate concentration in anaerobic hydrogen fermentation reactor without heat-treatment. Anaerobic hydrogen fermentation of food waste with heat treatment was stable in start-up periods because lactate concentration could be maintained at a relatively low compared to n-butyrate concentration due to the decrease of non-hydrogen fermentation microorganisms.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권5호
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• pp.49-55
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• 2012

A 1.28 L-batch reactor and continuous-flow stirred tank reactor (CFSTR) fed with formate and trichloroethene (TCE) were operated for 120 days and 56 days, respectively, to study the effect of formate as electron donor on anaerobic reductive dechlorination (ARD) of TCE to cis-1,2-dichloroethylene (c-DCE), vinyl chloride (VC), and ethylene (ETH). In batch reactor, injected 60 ${\mu}mol$ TCE was completely degraded in the presence of 20% hydrogen gas ($H_2$) in less than 8 days by anaerobic dechlorination mixed-culture (300 mg-soluble protein), Evanite Culture with ability to completely degrade tetrachloroethene (PCE) and -TCE to ETH under anaerobic conditions. Once the formate was used as electron donor instead of hydrogen gas in batch or chemostat system, the TCE-dechlorination rate decreased and acetate production rate increased. It indicates that the concentration of hydrogen produced in both systems is possibly more close to threshold for homoacetogenesis process. Soluble protein concentration of Evanite culture during the batch test increased from 300 mg to 688 mg for 120 days. Through the protein monitoring, we confirmed an increase of microbial population during the reactor operation. In CFSTR test, TCE was fed continuously at 9.9 ppm (75.38 ${\mu}mol/L$) and the influent formate feed concentration increased stepwise from 1.3 mmol/L to 14.3 mmol/L. Injected TCE was accumulated at 18 days of HRT, but TCE was completely degraded at 36 days of HRT without accumulation of the injected-TCE during the left of experiment period, getting $H_2$ from fermentative hydrogen production of injected formate. Although c-DCE was also accumulated for 23 days after beginning of CFSTR operation, it reached steady-state in the presence of excessive formate. We also evaluated microbial dynamic of the culture at different chemical state in the reactor by DGGE (denaturing gradient gel electrophoresis).