• Journal of Energy Engineering
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• v.25 no.4
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• pp.141-151
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• 2016

Recently, technology for energy recovery from waste has been increasing interest globally including the Korea. In Korea, we have interested in using biogas generated from the sewage treatment process. As one alternative, there are operating biogas combined heat and power plant. The generation amount of the Sewage Sludge are expected to grow in the future. For this reason, total processing cost of Sewage Sludge will increase. To solve this problem, it seems will be invested with the expansion of facilities that use biogas as energy. Therefore, quantitative information on such facilities is required. Thus, this study attempts to economic feasibility analysis for Seonam Biogas Combined Heat and Power Plant. Meanwhile, as the benefit items for economic feasibility analysis consider electricity supply benefit except for heat supply benefit. The average prices of electricity use were residence 123.69, commercial 130.46, and industry 102.59 won per kWh for the year 2015, In addition, the economic benefit are calculated to be residence 310.21, commercial 378.49, and industry 222.87 won per kWh. The results of economic feasibility analysis is NPV 72.18 billion won, B/C 1.90, IRR 37%, shows that economic validity of Seonam Biogas Combined Heat and Power Plant.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.43-52
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• 2020

As the membrane gas separation technology grows, various models were developed by numerous researchers to describe the separation process. In this work, the counter-current model was compared thoroughly with experimental data. Experimentally, hollow fiber membrane using CA module was prepared for the separation of biogas. The pure gas permeation properties of membrane module for methane, nitrogen, oxygen, and carbon dioxide were measured. The permeance of CO2 and CH4 were 25.82 GPU and 0.65 GPU, respectively. The high CO2/CH4 selectivity of 39.7 was obtained. the separation test for three different simulated mixed gases were carried out after pure gas test, and the gas concentration of the permeate at various stage-cut were measured from CA membrane module. Results showed that the experimental data agreed with the numerical simulation. A mathematical model has implemented in this study for the separation of biogas using a membrane module. The finite difference method (FDM) is applied to calculate the membrane biogas separation behaviors. Futhermore, the counter-current model can be considered as a convenient model for biogas separation process.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.6
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• pp.586-593
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• 2014

Limited sources of fossil fuels and also global climate changes caused by $CO_2$ emissions are currently discussed around the world. As a renewable, carbon neutral and widely available energy source, biogas is regarded as a promising alternative to fossil fuels. In this study, a plasma dump reformer was proposed to produce $H_2$-rich synthesis gas by a model biogas. The three-phase gliding arc plasma and dump combustor were combined. Screening studies were carried out with the parameter of a dump injector flow rate, water feeding flow rate, air ratio, biogas component ratio and input power. As the results, methane conversion rate, carbon dioxide conversion rate, hydrogen selectivity, carbon monoxide yield at the optimum conditions were achieved to 98%, 69%, 42%, 24.7%, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.315-322
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• 2007

The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a granule of two-phase anaerobic process applied UASB. BMP test was conducted as simple means to monitor relative biodegradability of substrate and to determine methane production of an organic material. The two-phase anaerobic process is consisted of a continuous flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. A stable maximum biogas production rate was 400mL. The methane contents ranged from 73 to 80% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

• Environmental Engineering Research
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• v.22 no.4
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• pp.432-438
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• 2017

Slum settlement, a direct result of the rapid worldwide urbanization is a common site in most developing countries. Uganda is among the top African countries with high number of slums. The status of Katanga slum located in the low-lands between Mulago national hospital and Makerere University is a typical of many other slums within Uganda. This project proposal seeks to tackle urbanization challenges by specializing in slum upgrading as a sustainable way of curbing the menace. An integrated toilet, biogas, poultry and backyard gardening project is proposed as a channel of boosting the Katanga slum dwellers' economic, sanitation and domestic energy status. Designed to serve up to 30 households, the project will utilize residual wastes from poultry houses and toilets to produce biogas and slurry. The biogas yield will provide clean cooking fuel and energy for lighting, while the slurry used as organic fertilizers to improve vegetable yields. The social, economic and environmental impacts of the project will empower the vulnerable women and children within the slums and reduce water pollution and land degradation. This affordable project can be applied in developing countries experiencing slum settlement challenges as a strategy for reducing urbanization pressure.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.1
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• pp.72-79
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• 2010

This paper is studying the selective separation of methane and carbon dioxide which are the main ingredients of biogas. Adsorption performance of molecular sieve 13x for carbon dioxide seems to be reasonable. In this experiments carbon dioxide contains about 3~5 ppm of methane and it is impossible to obtain high purity carbon dioxide. Applying the low temperature technique, it is possible to separate methane and carbon dioxide from bio gas. PRO II simulation shows results a small change of liquefaction temperatures and no difference with the used thermodynamic models. Applying low temperature technique, It is possible to separate carbon dioxide and methane from biogas.

• Environmental Engineering Research
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• v.17 no.1
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• pp.41-46
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• 2012

In this study, the performance of new digestion system (NDS) for the treatment of food waste leachate was evaluated. The food waste leachate was fed intermittently to an anaerobic reactor at increasing steps of 3.3 L/day (hydraulic retention time [HRT] = 30 day), 5 L/day (HRT = 20 day), and finally 10 L/day (HRT = 10 day). In the anaerobic reactor, the pH and alkalinity were maintained at 7.6 to 8.2 and 8,940-14,400 mg/L, respectively. Maximum methane yield determined to be 0.686L $CH_4$/g volatile solids (VS) containing HRT over 20 day. In the digester, 102,328 mg chemical oxygen demand (COD)/L was removed to produce 350 L/day (70% of the total) of biogas, but in the digested sludge reduction (DSR) unit, only 3,471 mg COD/L was removed with a biogas production of 158 L/day. Without adding any chemicals, 25% of total nitrogen (TN) and 31% of total phosphorus (TP) were removed after the DSR, while only 48% of TN and 32% of TP were removed in the nitrogen, phosphorus, and heavy metals (NPHM) removal unit. Total removal of TN was 73% and total removal of TP was 63%.

• Journal of Science and Technology Studies
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• v.11 no.1
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• pp.1-29
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• 2011

The purpose of this study is to develop a theoretical framework to analyze the social processes of embedding new technologies, among others, green technologies, in society, and based on this, to identify problems and challenges in introducing and assimilating biogas technologies in local communities in Korea. Chapter Two strives to develop a framework to analyze the social processes of embedding new technologies in society. A couple of key concepts such as technology community, technology learning and technology politics are introduced and discussed. Chapter Three and Four examine the problems arising from the social processes of embedding biogas plant technologies in local communities in Korea and tries to suggest policy options to tackle these problems.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.6
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• pp.811-817
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• 2013

A two-stage bioreactor system using sulfur-oxidizing bacteria was studied to abate high strength hydrogen sulfide ($H_2S$) from biogas. The two-stage bioreactor consisted of a $H_2S$ absorption column (0.5 L) and a microbial oxidation column (1 L) in series, and the liquid medium was continuously recirculated through the columns. The objectives of this study were to determine the feasibility of the bioreactor for biogas desulfurization and to investigate the effect of the medium circulation rate on the system performance. An averaged concentration of $H_2S$ introduced to the bioreactor was 530 ppm, corresponding to an overall loading rate of $44.4g/m^3/hr$. During the initial 20 days period at the medium recirculation rate of 8 reactor volumes per hour (12 L/hr), the dissolved oxygen (DO) concentration in the oxidation column was 6 mg/L, while the DO in the absorption column was 0.5 mg/L showing that the oxygen contents of the biogas stream was not altered. Because of the biological oxidation of $H_2S$ in the oxidation column, the sulfate concentration increased from 200 mg/L to 5,600 mg/L in the liquid medium. The removal efficiency of $H_2S$ was greater than 99% in the initial operation period. After the initial period, the medium recirculation rate between the two columns was stepwise changed eight times from 1.0 to 40 vol/hr (1.5~60 L/hr). At the recirculation rate of faster than 4 vol/hr, the $H_2S$ removal efficiencies were found to be high, but the efficiency declined at the lower recirculation rates than the threshold.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.4
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• pp.393-402
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• 2017

In this study, greenhouse gas (GHG) reductions from bioenergy (biogas, biomass) have been estimated in Korea, 2015. This study for construction of reduction inventories as direct and indirect reduction sources was derived from IPCC 2006 guidelines for national greenhouse gas inventories, guidelines for local government greenhouse inventories published in 2016, also purchased electricity and steam indirect emission factors obtained from KPX, GIR respectively. As a result, the annual GHG reductions were estimated as $1,860,000tonCO_{2eq}$ accounting for 76.8% of direct reduction (scope 1) and 23.2% of indirect reduction (scope 2). Estimation of individual greenhouse gases (GHGs) from biogas appeared that $CO_2$, $CH_4$, $N_2O$ were $90,000tonCO_2$ (5.5%), $55,000tonCH_4$ (94.5%), $0.3tonN_2O$ (0.004%), respectively. In addition, biomass was $250,000tonCO_2$ (107%), $-300tonCH_4$ (-3.2%), $-33tonN_2O$ (-3.9%). For understanding the values of estimation method levels, field data (this study) appeared to be approximately 85.47% compared to installed capacity. In details, biogas and biomass resulting from field data showed to be 76%, 74% compared to installed capacity, respectively. In the comparison of this study and CDM project with GHG reduction unit per year installed capacity, this study showed as 42% level versus CDM project. Scenario analysis of GHG reductions potential from bioenergy was analyzed that generation efficiency, availability and cumulative distribution were significantly effective on reducing GHG.