• 한국습지학회지
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• 제23권1호
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• pp.54-59
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• 2021

폐수처리장에서 발생하는 바이오가스 중의 황화수소를 처리하기 위하여 습식스크러빙 장치가 적용되었다. 유입 H2S의 농도가 5,000mg/L이상에서 DIWS 장치에 물만을 사용할 경우 25%의 제거율을 나타내어 후속으로 소각처리 공정이 도입되어야만 98% 이상의 제거율을 나타냈다. 유입 H2S의 농도가 5,000mg/L일 때 CH4과 CO2는 각각 8.7%와 28.6% 감소하여 배출되었다. DIWS 장치에 중화약품으로 Na2CO3와 NaOH를 사용하였을 때 pH가 11.2~11.5를 유지하면서 H2S는 97.2% 제거되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제27권7호
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• pp.1050-1056
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• 2014

This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature ($^{\circ}C$) at a depth of 140 cm and 180 cm, biogas production and methane ($CH_4$) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank.

• Journal of Electrochemical Science and Technology
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• 제1권2호
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• pp.102-111
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• 2010

Molten carbonate fuel cell (MCFC) power plants are one of most attractive electricity generation systems for the use of biogas to generate high-efficiency ultra-clean power. However, MCFCs are considerably more expensive than comparable conventional electricity generation systems. The commercialization of MCFCs has been delayed more than expected. After being effective in the Kyoto protocol and considerably increasing the fossil price, the attention focused on $CO_2$ regression and renewable energy sources has increased dramatically. In particular, the commercialization and application of MCFC systems fed with biogas have been revived because of the characteristics of $CO_2$ collection and fuel variety of MCFCs. Better economic results of MCFC systems fed with biogas are expected because biogas is a relatively inexpensive fuel compared to liquefied natural gas (LNG). However, the pretreatment cost is added when using anaerobic digester gas (ADG), one of the biogases, as a fuel of MCFC systems because it contains high $H_2S$ and other contaminants, which are harmful sources to the MCFC stack in ADG. Thus, an accurate economic analysis and comparison between MCFCs fed with biogas and LNG are very necessary before the installation of an MCFC system fed with biogas in a plant. In this paper, the economic analysis of an MCFC fed with ADG was carried out for various conditions of electricity and fuel price and compared with the case of an MCFC fed with LNG.

• 열처리공학회지
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• 제36권3호
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• pp.153-160
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• 2023

The use of biogas is an industrially necessary means to achieve resource circulation. However, since biogas obtained from waste frequently causes corrosion in pipes, it is important to elucidate corrosion mechanisms of the pipes used for biogas transportation. Recently, corrosion failure occurred in a pipe which supplied for the biogas at the speed of 12.5 m/s. Pinholes and pits were found in a straight line along the seamline of the pipe. By using corrosion-damaged samples, residual thickness, microstructure, and composition of oxide film and inclusion were examined to analyze the cause of the failure. It was revealed that the thickness reduction of biogas pipe was ~0.11 mm per year. A thin sulfuric acid film was formed on the surface of the interior of a pipe due to moisture and hydrogen sulfide contained in a biogas. Near the seamline, microstructure was heterogeneous and manganese sulfide (MnS) was found. Pits were generated by micro-galvanic corrosion between the manganese sulfide and the matrix in the interior of the pipe along the seamline. In addition, microcracks formed along the grain boundaries beneath the pits revealed that hydrogen-induced cracking (HIC) also contributed to accelerating the pitting corrosion.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 추계학술발표논문집 1부
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• pp.503-503
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• 2010

국제협약에 따라 2012년부터 유기성폐기물의 해양배출이 금지됨에 따라 환경문제를 유발하는 축산분뇨, 음식물쓰레기, 농축산 폐기물 등의 처리가 곤란한 실정이다. 그러나 최근 저탄소 녹색성장으로 정부가 폐자원 에너지화에 관심을 기울이면서 위의 폐기물을 바이오가스로 전환하는 바이오가스 플랜트(Biogas Plant, BGP)의 이용이 보다 활성화 될 전망이다[1]. 이 바이오가스 처리방법에서 유기물은 메탄가스로 배출되고[2], 나머지 영양성분들(질소, 인산, 칼륨 등)은 모두 소화액에 남아있으므로[3] 이들은 친환경농업에서 필요한 액비로도 활용이 가능하며, 혐기소화 처리방법은 일반적인 가축분뇨 처리과정에서 발생되는 악취문제도 해결할 수 있는 장점 또한 가지고 있다. BGP는 유기성 폐기물에서 혐기성소화를 통해 바이오가스를 만드는 장점이 있는 반면, 가스를 만들고 남은 소화액은 액비로 활용이 가능하지만, 액비로 활용이 불가능할 경우 악성 폐수로 그 처리가 매우 까다로운 단점이 있다. 일반적인 생물학적인 폐수처리방법으로는 처리가 곤란하며, 환경기준을 맞추도록 처리하는데 많은 비용이 소요된다. 이러한 폐액처리를 위해 공정의 단순화와 높은 처리 효율[4]을 가지면서, 액비 또는 정화처리공정이 가능한 방법으로서 분리막공정이 바람직하나, BGP 발생폐액의 성상이 고농도의 오염물질을 함유하고 있어 적용이 쉽지 않다. 따라서 본 연구에서는 이를 보안할 수 있는 와류발생형 막모듈을 이용하여 Biogas Plant의 발생폐수에 대하여 분리막을 이용한 효과적인 처리공정을 개발하고 그에 따른 최적의 조건을 찾는 연구를 하고자 한다. 와류발생형 막모듈을 막과 막 사이에 와류를 발생시킴으로써 막에 전단력을 가하여 막의 가장 큰 단점인 막오염을 줄이는 방법으로 기존의 막모듈과 큰 차이가 있을 것으로 예상된다. 본 연구에서는 기존의 분리막 모듈[5]과 와류발생형 막모듈의 차이를 실험을 통해 확인하며, 막에 가해지는 압력, 막을 통과하는 유량 등의 차이를 두어 최적조건을 탐색하였다.

• Advances in environmental research
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• 제7권2호
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• pp.73-85
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• 2018

The anaerobically digestion and agricultural application of organic wastes was conducted using food wastes and cow dung. Twenty kilograms each of the feed stocks was added into two 30 liters-capacity batch digesters. The anaerobic digestion was carried out within a temperature range of $25-31^{\circ}C$ for a retention time of 51 days. The results showed a cumulative gas yield of 5.0 bars for food waste and no gas production for cow dung within the retention time. Bacteria such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris and Clostridium sp were isolated. Fungi isolated included Aspergillus niger, Aspergillus nidulan, Trichophyton rubrum and Epidermophyton flocossum. The non-dispersive infrared (NDIR) analysis of the biogas produced confirmed that the gas consisted of $CH_4$, $CO_2$ and $H_2$. Statistical analysis revealed there was no significant correlation between temperature and biogas produced from the organic wastes (r= 0.177, p = 0.483).The organic wastes from the biogas production process stimulated maize growth when compared to control (soil without organic waste) and indicated maximum height. The study therefore reveals that food waste as potential substrates for biogas production has a moderate bio-fertilizer potential for improving plant growth and yield when added to soil.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.260-263
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• 2008

KEPCO(Korea Electric Power Corporation) is performing the nation's first biogas-MGT project as an effort to encourage the utilization of wasted biogas which contains useful CH4. The goals of this project are to develop the Pretreatment system of Livestock bio-gas and set up the biogas-MGT co-generation system. The project will not only utilze flared biogas as precious energy but also improve the economics of the plant a lot. The pretreatment system mainly consists of sulfur removal tower, biogas compressor and many filtering systems. A computational fluid dynamics study in the bio gas sulfur removal tower and sulfur absorption filter was carried out. Understanding of the flow in the sulfur removal tower and sulfur adsorption filter obtained by this study can be used to identify the problems in the sulfur removal tower and to improve the sulfur removal efficiency of the sulfur removal tower. Resistance material modeling is used to simulate the sulfur adsorption filter, and the resistance coefficient was adjusted to reflect the experimental pressure loss value. And the pressure loss change with the flowrate is predicted

• 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.

• 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.

• 한국환경농학회지
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• 제26권1호
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• pp.1-6
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• 2007

본 연구에서는 바이오가스의 연소엔진을 이용한 에너지 전환시에 발생되는 $NO_x$와 CO의 배출특성을 분석하고 나아가 배출계수를 산정하고자 하였다. 바이오가스의 주성분인 메탄을 70%로 한 합성가스를 이용하여 실험한 결과 연소엔진의 표준상태에서 $NO_x$와 CO가 각각 4 ppm과 100 ppm의 배출농도를 나타내었고, 이는 1.29g/MMBtu와 30.86 g/MMBtu의 배출계수 값을 산정할 수 있었다. 바이오가스의 주성분인 메탄을 60%로 한 약간의 과잉공기의 상태에서는 $NO_x$와 CO가 각각 2 ppm과 200 ppm의 배출농도를 나타내었고, 이는 정격 조건에 비해 투입열량이 적어져 연소온도의 저하로 인하여 열적 반응에 의해 생성되는 $NO_x$는 줄고, CO는 증가함을 알 수 있었다. 미국 EPA의 배출계수를 비교하기 위하여 투입된 연료의 열량을 기준으로 비교해 볼 때 본 연구의 결과가 $NO_x$의 경우 근사한 값을 보여 주었고, 이는 국내 바이오 가스 연소시의 오염배출계수로 잘 적용 가능함을 보여 주었다. 본 연구에서 사용한 가스엔진이 오염배출 측면에서 대기 환경보전법상의 배출 허용기준 내에서 가동됨을 알 수 있었고, 가동조건에 따라 연소온도를 증가시킴으로서 CO의 발생을 저감시킬 수 있으리라 사료된다.