• 한국응용과학기술학회지
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• 제13권1호
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• pp.67-74
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• 1996

This study was conducted to find a catalyst system which has high conversion and selectivity for the oxidative coupling of methane to produce ethane and ethylene. Various catalysts were tested in a fixed bed reactor ar $750^{\circ}C$, 1 atm, and the feed ratio($CH_4/O_2$) of 2/1. Under the reaction condition, 10wt%$PbSO_4/MgO$ catalyst showed the highest catalytic activity : methane conversion, $C_2$ selectivity and yield were 50, 40 and 20%, respectively. Catalysts containing sulfate compounds, 10wt%$PbSO_4/MgO$, 10wt%$MgSO_4/MgO$ and $Na_2SO_4/MgO$ revealed a moderate methane conversions such as 38, 50 and 50%, respectively and low $C_2$ selectivities such as 18, 5 and 9%, respectively. Catalysts containing carbonate compounds, 10wt%$PbCO_3/MgO$, 10wt%$Li_2CO_3/MgO$ and $NaCO_3/MgO$, also showed a moderate methane conversions such as 64, 44 and 51%, respectively and low $C_2$ selectivities such as 5, 6 and 2%, respectively. With the existence of chlorine and mercury, $C_2$ selectivity was decreased.

• 한국환경과학회지
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• 제2권4호
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• pp.311-316
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• 1993

3리터의 실험실 크기의 플러그 흐름의 혐기성 소화기를 사용하여 grain dust로부터 메탄가스를 생산하였다. 이 실험에서 사용한 소화기는 온도(35, 45, 55$^{\circ}C$), 체류 시간(6, 12일), 초기농도(7.8, 9.0% Total Solids)의 함수로 10가지 조건에서 실험이 행하여 졌는데, 실험 결과 55$^{\circ}C$, 6일 HRT, 7.8%TS 에서 가장 높은 메탄가스를 생산하였으며, 실험결과를 토대로 메탄가스생산 관계식을 제시하였다. 또한, 위의 실험의 조건에서는 thermophilic 의 경우가 mesophilic 경우보다 메탄가스 생성이 좋은 것으로 나타났다.

• 유기물자원화
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• 제23권4호
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• pp.11-20
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• 2015

원지반에서의 저품위 석탄층의 생물학적 메탄 생산을 위한 기초연구를 수행하였다. 인도네시아산 갈탄을 시료로 이용하였으며, 조건을 달리하여 BMP(Biochemical Methane Potential) 실험을 수행하였다. 갈탄에 영양물질과 혐기성 슬러지만 제공한 경우, 온도(23, $30^{\circ}C$)나 석탄의 입자크기는 메탄가스 생산에 영향을 주지 않았다. 이는 가용한 용해성 유기물질이 낮기 때문이다. 외부탄소원으로 볏짚을 갈탄에 첨가한 후 BMP 실험을 수행하였으며, 60일간의 BMP 실험 후 볏짚 첨가에 의한 메탄가스 발생량은 94.4~110.4 mL/g VS이었다. BMP 실험 후 갈탄의 발열량은 볏짚 첨가량이 증가할수록 감소하는 경향을 보였다. 이는 볏짚의 혐기성 분해와 함께 갈탄의 분해가 이루어졌음을 의미한다. 따라서 원지반에서의 저품위 석탄층의 생물학적 메탄 생산의 초기 운전 시에 볏짚을 탄소원으로 사용할 수 있다.

• 유기물자원화
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• 제31권1호
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• pp.27-34
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• 2023

본 연구에서는 버섯 폐배지의 혐기성소화 효율 향상을 위해 수열전처리를 실시하고, 리그노셀룰로오스계 물질의 고온 가수분해 과정에서 생성될 수 있는 중간산물이 기질의 생분해도와 바이오가스 전환 효율에 미치는 영향을 함께 판단하였다. 수열전처리 온도의 범위를 150, 180, 210℃로 설정하였으며, 모든 수열전처리 온도에서 기질의 가용화율이 향상되는 결과를 확인할 수 있었다. 추가적으로, 150℃로 버섯 폐배지를 전처리한 경우에는 혐기성소화 효율에 영향을 미칠 수 있는 C/N 비가 개선되는 효과를 함께 확인하였다. 다만 전처리 온도가 180, 210℃인 경우에는 오히려 150℃로 전처리를 수행한 경우에 비해 메탄 생성량이 저하되는 경향을 보였는데, 이는 리그노셀룰로오스 물질의 중간분해 산물인 퓨란유도체의 형성으로 인해 메탄생성균이 영향을 받은 것으로 판단된다. 결국, 수열전처리를 통해 리그노셀룰로오스계 바이오매스의 가용화율 향상을 통한 메탄 생성 향상을 기대할 수 있으나, 혐기성소화 효율을 저해할 수 있는 중간산물이 생성되지 않는 적정 전처리 온도의 확인과 적용이 중요할 것으로 판단된다.

• 공업화학
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• 제9권1호
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• pp.94-100
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• 1998

천연가스의 주성분인 메탄의 마이크로웨이브 플라즈마 촉매반응에 의한 C2+ 탄화수소로의 전환반응을 고찰하였다. 플라즈마 출력의 증가(40~120 watt)와 유량이 감소(40~5mL/min)함에 따라서 메탄의 C2+ 생성물로의 전환율을 29.2%에서 42.2%로 향상되었으며, 촉매를 플라즈마와 함계 사용하여 에틸렌과 아세틸렌의 선택도를 향상시키는 동시에 높은 전환율을 유지할 수 있다. 실험에 사용한 여러 촉매중에는 Fe계의 촉매가 가장 높은 에틸렌의 선택도(30%)를 나타내었다. 실제 천연가스의 전환실험에서는 C2+ 생성물의 수율이 33.3%에서 46%의 범위를 보였다. 순수한 메탄이 원료였을 때 보다 높은 C2+ 수율이 얻어진 것은 천연가스가 메탄 보다 반응성이 높은 성분인 에탄과 프로판등을 함유하고 있기 때문으로 생각된다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.101-101
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• 2010

Anaerobic digestion(AD) is the most promising method for treating and recycling of different organic wastes, such as organic fraction of municipal solid waste, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. organic materials are decomposed by anaerobic forming bacteria and fina1ly converted to excellent fertilizer and biogas which is a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to produce renewable energy and to reduce $CO_2$ and other green-house gas(GHG) emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. Currently some 80% of the world's overall energy supply of about 400 EJ per year in derived from fossil fuels. Nevertheless roughly 10~15% of this demand is covered by biomass resources, making biomass by far the most important renewable energy source used to date. The representative biofuels produced from the biomass are bioethanol, biodiesel and biogas, and currently biogas plays a smaller than other biofuels but steadily growing role. Traditionally anaerobic digestion applied for different biowaste e.g. sewage sludge, manure, other organic wastes treatment and stabilization, biogas has become a well established energy resource. However, the biowaste are fairly limited in respect to the production and utilization as renewable source, but the plant biomass, the so called "energy crops" are used for more biogas production in EU countries and the investigation on the biomethane potential of different crops and plant materials have been carried out. In Korea, with steadily increasing oil prices and improved environmental regulations, since 2005 anaerobic digestion was again stimulated, especially on the biogasification of different biowastes and agro-industrial biomass including "energy crops". This study have been carried out to investigate anaerobic biodegradability by the biochemical methane potential(BMP) test of animal manures, different forage crops i.e. "energy crops", plant and industrial organic wastes in the condition of thermophilic temperature, The biodegradability of animal manure were 63.2% and 58.2% with $315m^3CH_4/tonVS$ of cattle slurry and $370m^3CH_4/tonVS$ of pig slurry in ultimate methane yields. Those of winter forage crops were the range 75% to 87% with ultimate methane yield of $378m^3CH_4/tonVS$ to $450m^3CH_4/tonVS$ and those of summer forage crops were the range 81% to 85% with ultimate methane yield of $392m^3CH_4/tonVS$ to $415m^3CH_4/tonVS$. The forge crops as "energy crops" could be used as good renewable energy source to increase methane production and to improve biodegradability in co-digestion with animal manure or only energy crop digestion.

• 유기물자원화
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• 제24권3호
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• pp.75-82
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• 2016

본 연구의 목적은 농업에서 발생하는 식물체 잔사 종류별 투입비율에 따른 메탄 잠재 발생량을 예측하는 것이다. 바이오가스를 생산하기 위하여 보릿짚 및 유채대 등의 식물체 잔사를 다양한 투입율로 사용하여 세륨병에서 실험을 수행하였다. 표면 방법론의 운동방법을 통하여 메탄 생산은 Gomperz 수식에 적합한 것으로 나타났다. 중온소화 시 식물체 잔사별 바이오가스 생산에 있어, 최대생산량은 보릿짚 및 유채대 투입율 1%로 혐기소화 후 각각 6.8일에 37.2 mL/g과 7.5일에 28.0 mL/g로 나타났다. 중온소화 시 메탄 함량은 보릿짚 및 유채대 투입율 5%로 혐기소화 후 각각 5.5일에 61.7%와 3.4일에 75.0%로 가장 높게 관측되었다. 중온 소화시 최대 메탄 잠재발생량은 1% 보릿짚 투입율에서 159.59 mL/g 와 3% 유채대 투입율에서 156.62 mL/g로 산정되었다. 전반적으로 중온소화 시 바이오매스 투입율은 유채대 3% 및 보릿짚 1%를 투입하는 것이 적정 비율인 것으로 나타났다.

• Journal of Animal Science and Technology
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• 제62권1호
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• pp.1-13
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• 2020

This study was designed to evaluate the in vitro and in vivo effects of reductive acetogens isolated from ruminants on methane mitigation, and milk performance, respectively. Four acetogens, Proteiniphilum acetatigenes DA02, P. acetatigenes GA01, Alkaliphilus crotonatoxidans GA02, and P. acetatigenes GA03 strains were isolated from ruminants and used in in vitro experiment. A control (without acetogen) and a positive group (with Eubacterium limosum ATCC 8486) were also included in in vitro experiment. Based on higher acetate as well as lower methane producing ability in in vitro trial, P. acetatigenes GA03 was used as inoculum for in vivo experiment. Holstein dairy cows (n = 14) were divided into two groups viz. control (without) and GA03 group (diet supplied with P. acetatigenes GA03 at a feed rate of 1% supplementation). Milk performance and blood parameters were checked for both groups. In in vitro, the total volatile fatty acids and acetate production were higher (p < 0.05) in all 4 isolated acetogens than the control and positive treatment. Also, all acetogens significantly lowered (p < 0.05) methane production in comparison to positive and control groups however, GA03 had the lowest (p < 0.05) methane production among 4 isolates. In in vivo, the rate of milk yield reduction was higher (p < 0.05) in the control than GA03 treated group (5.07 vs 2.4 kg). Similarly, the decrease in milk fat was also higher in control (0.14% vs 0.09%) than treatment. The somatic cell counts (SCC; ×10³/mL) was decreased from 128.43 to 107.00 in acetogen treated group however, increased in control from 138.14 to 395.71. In addition, GA03 increased blood glucose and decreased non-esterified fatty acids. Our results suggest that the isolated acetogens have the potential for in vitro methane reduction and P. acetatigenes GA03 strain could be a candidate probiotic strain for improving milk yield and milk fat in lactating cows with lowering SCCs.

• Asian-Australasian Journal of Animal Sciences
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• 제28권2호
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• pp.280-289
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• 2015

Anaerobic digestion is an efficient and renewable energy technology that can produce biogas from a variety of biomasses such as animal manure, food waste and plant residues. In developing countries this technology is widely used for the production of biogas using local biomasses, but there is little information about the value of these biomasses for energy production. This study was therefore carried out with the objective of estimating the biogas production potential of typical Vietnamese biomasses such as animal manure, slaughterhouse waste and plant residues, and developing a model that relates methane ($CH_4$) production to the chemical characteristics of the biomass. The biochemical methane potential (BMP) and biomass characteristics were measured. Results showed that piglet manure produced the highest $CH_4$ yield of 443 normal litter (NL) $CH_4kg^{-1}$ volatile solids (VS) compared to 222 from cows, 177 from sows, 172 from rabbits, 169 from goats and 153 from buffaloes. Methane production from duckweed (Spirodela polyrrhiza) was higher than from lawn grass and water spinach at 340, 220, and 110.6 NL $CH_4kg^{-1}$ VS, respectively. The BMP experiment also demonstrated that the $CH_4$ production was inhibited with chicken manure, slaughterhouse waste, cassava residue and shoe-making waste. Statistical analysis showed that lipid and lignin are the most significant predictors of BMP. The model was developed from knowledge that the BMP was related to biomass content of lipid, lignin and protein from manure and plant residues as a percentage of VS with coefficient of determination (R-square) at 0.95.This model was applied to calculate the $CH_4$ yield for a household with 17 fattening pigs in the highlands and lowlands of northern Vietnam.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.109-112
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• 2000

Long chain fatty acids (LCFA) are potential inhibitors of bacteria involved in anaerobic digestion because of their surface activity. Precipitation of long-chain fatty acids with iron can improve the anaerobic degradation due to their precipitation and reducing surface properties. Degradation of stearic acid was improved in the presence of iron (II). The methane production was increased 1.6 times as compared to control. Iron-containing soil was applied for degradation of vegetable oil as model case. The methane production was increased 1.5 times as compared to control. Yield of methane production was 0.09 and 0.06L/g COD in experiment and control respectively. Optimum COD/Fe ratio was found 20 mg/mg. Iron (II) can be produced in the treatment system from iron (III) hydroxide or iron containing minerals.