• Title/Summary/Keyword: Biogas

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Economic Feasibility Study for Molten Carbonate Fuel Cells Fed with Biogas

  • Song, Shin-Ae;Han, Jong-Hee;Yoon, Sung-Pil;Nam, Suk-Woo;Oh, In-Hwan;Choi, Dae-Ki
    • Journal of Electrochemical Science and Technology
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    • v.1 no.2
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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.

An Experimental Study on the Possibility of Biogas Reforming using the Waste Heat of a Small-Sized Gas Engine Generator (소형 가스엔진 발전기의 배기가스 폐열을 이용한 바이오가스 개질 가능성에 관한 실험적 연구)

  • Cha, Hyo-Seok;Kim, Tae-Soo;Eom, Tae-Jun;Jung, Choong-Soo;Chun, Kwang-Min;Song, Soon-Ho
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.3
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    • pp.236-242
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    • 2012
  • This study has been carried out the experiment for the possibility of biogas reforming using waste heat. The source of this waste heat is the exhaust gas from a small-sized gas engine generator. For recovering the waste heat, Two-stage heat exchanger is manufactured. The two-stage heat exchanger is composed of a heat exchanger for the exhaust gas and a heat exchanger for the water. This two-stage heat exchanger is used for reforming the biogas by means of on-site hydrogen production at the small-sized gas engine generator. The two-stage heat exchanger is coupled with the biogas reformer which is a kind of catalytic reformer. To confirm a heat recovery efficiency of the two-stage heat exchanger, temperature differences of inlet and outlet locations are measured. Also, the variations of syngas concentrations with various biogas flow rates are investigated. As a result using manufactured two-stage heat exchanger, the biogas can be reformed from waste heat recovery. This experiment suggests that the exhaust gas heat exchanger is available for reforming the biogas.

Resourcing of Methane in the Biogas Using Membrane Process (분리막을 이용한 바이오가스의 메탄 자원화)

  • Park, Young G.;Yang, Youngsun
    • Clean Technology
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    • v.20 no.4
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    • pp.406-414
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    • 2014
  • Biogas is a gaseous mixture produced from microbial digestion of organic materials in the absence of oxygen. Raw biogas, depending upon organic materials, digestion time and process conditions, contains about 45-75% methane, 30-50% carbon dioxide, 0.3% of hydrogen sulfide gas and fraction of water vapor. To achieve the standard composition of the biogas the treatment techniques like absorption or membrane separation was performed for the resourcing of biogas. In this paper the experimental results of the methane purification in simulated biogas mixture consisted of methane, carbon dioxide and hydrogen sulfide were presented. The composite membrane is manufactured within polysulfone in order to increase the separation performances for the gaseous mixtures of $CO_2$ and $CH_4$ which are main components of the biogas. The effects of feed pressures and mixed gas on the separation of $CO_2-CH_4$ by membrane are investigated. Chelate chemical was utilized to treat the purification of methane from the $H_2S$ concentration of 0.3%.

Corrosion Failure Analysis of a Biogas Pipe (바이오가스 배관의 부식 파손 원인 분석)

  • Min Ji Song;Woo Cheol Kim;Heesan Kim;Jung-Gu Kim;Soo Yeol Lee
    • Journal of the Korean Society for Heat Treatment
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    • v.36 no.3
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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.

Operating Characteristics Study of a Small Gas/Steam Turbine Combined System Using Biogas (바이오가스 연료를 사용하는 소형 가스/증기터빈 복합 발전 시스템의 성능특성 해석)

  • Kang, Do-Won;Shin, Hyun-Dong;Kim, Tong-Seop;Hur, Kwang-Beom;Park, Jung-Keuk
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.3
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    • pp.51-56
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    • 2012
  • This study analyzed the influence of firing biogas on the performance and operation of a gas/steam turbine combined system. A reference gas/steam turbine combined system, designed with biogas fuel(57% volumetric methane) was set up and off-design simulation was made to investigate operating characteristics when a couple of operating schemes to mitigate turbine blade overheating were applied. Performance at base-load operation using each scheme was compared and part load operation using the variable inlet guide vane was analysed. Also, differences in operating characteristics and performance caused by changes in the methane content of biogas and ambient temperature were examined.

DEVELOPMENT OF HIGH EFFICIENCY COGENERATION SYSTEM USING BIOGAS FOR THE LOWER POLLUTION OF THE ENVIRONMENTAL

  • Park, J.S.;Ishii, K.;Terao, H.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2000.11c
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    • pp.670-675
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    • 2000
  • The purpose of the study is development and investigation about basic performance of the system operation on a dual fueled cogeneration system(CGS), which is operated with biogas and gas oil. As often seen in dual fueled CGS performance, the electric generating efficiency was obtained about 26□. Methane contained in the biogas could not bum completely at lower load, and it was discharged into exhaust gas. Considerable amount of the methane burned in the exhaust pipe, and the heat recovery ratio was 42□ on heat balance. As a result, the total heat efficiency, which is a summation of generating efficiency and heat recovery efficiency reached to about 70□. The supply of biogas into the engine reduces smoke density and NOx concentration in exhaust gas. At lower load, methane burned slowly and large portion of it was discharged without burning. Therefore the measures are desirable that promotes combustion of methane at lower load.

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State-of-the-art of Production and Utilization of Biogas in Germany (독일의 농업부산물을 이용한 바이오가스 생산시스템)

  • Oechsner, Hans
    • Proceedings of the Korean Society of Organic Agriculture Conference
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    • 2009.07a
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    • pp.343-366
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    • 2009
  • Biogas can be generated out of a variety of organic substances and is suitable for different utilizations. It is very efficient in technical application and has a good balance between energy input and output (1 : 7). Moreover there is a great reduction of carbon dioxide (6 - 7 t $CO_2$/ ha). By means of biogas energy can be produced locally and allows maximum energy utilization. Therefore in the next years biogas will become more important in Germany, also for the scientific research area. In the future we have to deal with questions about the improvement of efficiency of the biogas process intensified.

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To develop the classification method of Agricultural by-productions for biogas production

  • Kim, Minjee;Kim, Sanghun
    • International Journal of Internet, Broadcasting and Communication
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    • v.7 no.2
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    • pp.155-160
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    • 2015
  • The objective of this study was to develop the classification method of various organic wastes. Specifically, the effects of proximate composition on the biogas production and degradation rates of agricultural by-production was investigated and a new standards for mixture of various organic wastes based on proximate composition combination was developed. Agricultural by-products (ABPs) with medium total carbohydrate, medium crude protein and low fat contents demonstrated the single step digestion process. ABPs with low total carbohydrate, high crude protein and high fat contents demonstrated the two step digestion process of Diauxic growth. The single ABP (Class No. 15) and the mixed ABPs (Class No. 12+18, 6+12+22, 9+12+18) after 10days showed the similar biogas yield pattern. We can use the classification method for the more ABPs and organic wastes from factory and municipal waste treatment plant for the high efficient biogas production.

Performance evaluation of a steam injected gas turbine CHP system using biogas as fuel (바이오 가스를 연료로 사용하는 증기분사 가스터빈 열병합발전 시스템의 성능분석)

  • Kang, Do-Won;Kang, Soo-Young;Kim, Tong-Seop;Hur, Kwang-Beom
    • The KSFM Journal of Fluid Machinery
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    • v.13 no.6
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    • pp.57-62
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    • 2010
  • MW-class gas turbines are suitable for distributed generation systems such as community energy systems(CES). Recently, biogas is acknowledged as an alternative energy source, and its use in gas turbines is expected to increase. Steam injection is an effective way to improve performance of gas turbines. This study intended to examine the influence of injecting steam and using biogas as the fuel on the operation and performance a gas turbine combined heat and power (CHP) system. A commercial gas turbine of 6 MW class was used for this study. The primary concern of this study is a comparative analysis of system performance in a wide biogas composition range. In addition, the effect of steam temperature and injected steam rate on gas turbine and CHP performance was investigated.

Water Scrubbing of Carbon Dioxide for Improving Calorific Values of Biogass (수세정에 의한 바이오가스 중 이산화탄소의 제거 효율)

  • Shim, Jae-Hoon;Hong, Seong-Gu;Kwun, Soon-Kuk
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2005.10a
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    • pp.598-603
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    • 2005
  • Biogas produced from anaerobic digestion processes has about 60% of methane and about 40% of carbon dioxide. Raw biogas can be used in internal combustion engines either spark ignition or diesel engines. Since the gas has relatively low calorific values, engine power also is lower than rated power values. Modified engines or biogas-specific engines have been utilized in order to increase efficiency. Another option is gas cleansing for increasing its calorific values. A couple of European countries adopted this approach in using biogas for one of transportation fuels, such as $CO_2$ scrubbing with water or special solutions. This study reports the results of water scrubbing for reducing $CO_2$ concentration. In 2.5m-high PVC pipe accepting water, $CO_2$ reduction rates were investigated. When flow rate of $CO_2$ and air mixture was about 5 LPM, $CO_2$ concentration was decreased up to 70%. Higher calorific biogas through water scrubbing is expected to be applied to various commercial engines without costly modification.

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