• Title/Summary/Keyword: Carbon neutral methane

Search Result 14, Processing Time 0.022 seconds

Performance Analysis of Adiabatic Reactor in Thermochemical Carbon Dioxide Methanation Process for Carbon Neutral Methane Production (탄소중립 메탄 생산을 위한 열화학적 이산화탄소 메탄화 공정의 단열 반응기 성능 분석)

  • JINWOO KIM;YOUNGDON YOO;MINHYE SEO;JONGMIN BAEK;SUHYUN KIM
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.34 no.3
    • /
    • pp.316-326
    • /
    • 2023
  • Development of carbon-neutral fuel production technologies to solve climate change issues is progressing worldwide. Among them, methane can be produced through the synthesis of hydrogen produced by renewable energy and carbon dioxide captured through a CO2 methanation reaction, and the fuel produced in this way is called synthetic methane or e-methane. The CO2 methanation reaction can be conducted via biological or thermochemical methods. In this study, a 30 Nm3/h thermochemical CO2 methanation process consisting of an isothermal reactor and an adiabatic reactor was used. The CO2 conversion rate and methane concentration according to the temperature measurement results at the center and outside of the adiabatic reactor were analyzed. The gas flow into the adiabatic reactor was found to reach equilibrium after about 1.10 seconds or more by evaluating the residence time. Furthermore, experimental and analysis results were compared to evaluate performance of the reactor.

The Parameter Analysis of Methane Production in Anaerobic Fermenter (혐기소화조에서 메탄 발생에 영향을 미치는 인자 분석)

  • 최광근;신종철;전현희;김상용;이진원
    • KSBB Journal
    • /
    • v.18 no.6
    • /
    • pp.473-478
    • /
    • 2003
  • The purpose of this study is to look for the optimal conditions of methane production. The conditions tested for methane production enhancement were temperature, pH, carbon source, nitrogen source, and inhibitor which can affects methane production. As a result, optimal conditions for methane production were 30$^{\circ}C$, neutral pH, methanol as a carbon source, NH$_4$Cl as a nitrogen source. 2-Bromoethanesulfonic acid was used as an inhibitor which can affects methane production. Existence in broth less than 10mM, inhibited methane production. Organic acid measurements revealed that formic acid exists in broth as majority.

Enrichment of Hydrogenotrophic Methanogens in Coupling with Methane Production Using Electrochemical Bioreactor

  • Jeon, Bo-Young;Kim, Sung-Yong;Park, Yong-Keun;Park, Doo-Hyun
    • Journal of Microbiology and Biotechnology
    • /
    • v.19 no.12
    • /
    • pp.1665-1671
    • /
    • 2009
  • Anaerobic digestion sludge was cultivated in an electrochemical bioreactor (ECB) to enrich the hydrogenotrophic methanogens. A modified graphite felt cathode with neutral red (NR-cathode) was charged with electrochemical reducing power generated from a solar cell. The methane and carbon dioxide collected in a Teflon bag from the ECB were more than 80 ml/l of reactant/day and less than 20 ml/l of reactant/day, respectively, whereas the methane and carbon dioxide collected from a conventional bioreactor (CB) was around 40 ml/l of reactant/day, respectively. Moreover, the maximal volume ratios of methane to carbon dioxide (M/C ratio) collected in the Teflon bag from the ECB and CB were 7 and 1, respectively. The most predominant methanogens isolated from the CB on the $20^{th}$, $80^{th}$, and $150^{th}$ days of incubation were hydrogenotrophs. The methanogenic diversity analyzed by temperature gradient gel electrophoresis (TGGE) of the 16S rDNA variable region was higher in the ECB than in the CB. The DNA extracted from the TGGE bands was more than 95% homologous with hydrogenotrophic methanogens in the ECB, but was an aceticlastic methanogen in the CB. In conclusion, the ECB was demonstrated as a useful system for enriching hydrogenotrophic methanogens and increasing the M/C ratio of the gas product.

혐기소화조에서 메탄 발생에 영향을 미치는 인자 분석

  • Choe, Gwang-Geun;Mun, Sun-Sik;Lee, Sang-Hun;Kim, Sang-Yong;Lee, Jin-Won
    • 한국생물공학회:학술대회논문집
    • /
    • 2001.11a
    • /
    • pp.525-528
    • /
    • 2001
  • The purpose of this study is to looking for the optimal condition of methane production enhancement. The conditions tested for increasing methane production were temperature. pH. and various carbon sources including methanol. formic acid. sodium acetate. succinic acid. and glucose. As a result, optimal temperature was 55 .C and optimal pH was around neutral condition. And methanol seemed to be best carbon source which can drastically increase methane production.

  • PDF

Methane Fermentation of Pit in Pond System for Ecological Treatment and Recycling of Animal Excreta (생태적 축산폐수 처리 및 재활용 연못시스템의 Pit 메탄발효)

  • Yang, Hong-Mo
    • Korean Journal of Environmental Agriculture
    • /
    • v.18 no.2
    • /
    • pp.191-195
    • /
    • 1999
  • An integrated wastewater treatment pond system is developed for treatment and recycling of excreta from dairy cattle. It is composed of three ponds in series. A pit with a capacity of $10m^3$, 2-day hydraulic residence time, and overflow velocity of $1.5m^3m^{-2}day^{-1}$ is located internally in primary pond. It is designed for efficient sludge sedimentation and effective methane fermentation. It receives $5m^3/day$ of diluted cattle excreta by the water used for clearing stalls. A submerged gays collector for the recovery of methane is installed on the top of the pit. The average BOD_5 concentration of influent is 398.7mg/l. That of the effluent from primary pond is 49.2mg/l. About 88% of BOD_5 are removed in primary pond. It is assumed that about 60% of the influent BOD_5 is removed in the pit and that almost all of the carbon of the removed BOD_5 in the pit is converted to methane and carbon dioxide. Methane fermentation of the pit is well established at $16^{\circ}C$. This phenomena results from temperature stability, complete anaerobic condition, and neutral pH of the pit. Gas from the collector is almost 90% methane, less than 9% nitrogen, and less than 1% carbon dioxide. Thus a purified methane is produced, which can be used as energy source.

  • PDF

Technology Trends of Fuel Cell Power Plant Based on Biogas Fuel (바이오가스 연료기반 연료전지발전 기술동향)

  • Lee, Jong-Gyu;Jeon, Jae-Ho;Lee, Jong-Yeon
    • New & Renewable Energy
    • /
    • v.4 no.3
    • /
    • pp.5-14
    • /
    • 2008
  • The target for the reduction of $CO_2$ emissions, as specified in the Kyoto Protocol, can only be achieved by an extended use of renewable fuels and the increasing of the energy efficiency. The energy generation from waste gases with a reasonable content of methane like biogas can significantly contribute to reach this target. A further reduction of greenhouse gas emissions is possible by increasing the electrical efficiency using progressive technologies. Fuel cells can be highly energy conversion devices. Utilizing biogas as the fuel for fuel cell systems offers an option that is technically feasible, potentially economically attractive and greenhouse gas neutral. High temperature fuel cells that are able to operate with carbon monoxide in the feed are well suited to these applications. Furthermore, because they do not require noble metal catalysts, the cost of high-temperature fuel cells has the greatest potential to become competitive in the near future compared to other types of fuel cells.

  • PDF

Microbial Diversity in Three-Stage Methane Production Process Using Food Waste (음식물 쓰레기를 이용한 3단계 메탄생산 공정의 미생물 다양성)

  • Nam, Ji-Hyun;Kim, Si-Wouk;Lee, Dong-Hun
    • Korean Journal of Microbiology
    • /
    • v.48 no.2
    • /
    • pp.125-133
    • /
    • 2012
  • Anaerobic digestion is an alternative method to digest food wastes and to produce methane that can be used as a renewable energy source. We investigated bacterial and archaeal community structures in a three-stage methane production process using food wastes with concomitant wastewater treatment. The three-stage methane process is composed of semianaerobic hydrolysis/acidogenic, anaerobic acidogenic, and strictly anaerobic methane production steps in which food wastes are converted methane and carbon dioxide. The microbial diversity was determined by the nucleotide sequences of 16S rRNA gene library and quantitative real-time PCR. The major eubacterial population of the three-stage methane process was belonging to VFA-oxidizing bacteria. The archaeal community consisted mainly of two species of hydrogenotrophic methanogen (Methanoculleus). Family Picrophilaceae (Order Thermoplasmatales) was also observed as a minor population. The predominance of hydrogenotrophic methanogen suggests that the main degradation pathway of this process is different from the classical methane production systems that have the pathway based on acetogenesis. The domination of hydrogenotrophic methanogen (Methanoculleus) may be caused by mesophilic digestion, neutral pH, high concentration of ammonia, short HRT, and interaction with VFA-oxidizing bacteria (Tepidanaerobacter etc.).

Development of a Plasma-Dump Reformer for Syngas Production (합성가스 생산을 위한 플라즈마-덤프 개질기 개발)

  • Lim, Mun Sup;Kim, Eun Hyuk;Chun, Young Nam
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.25 no.6
    • /
    • pp.586-593
    • /
    • 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.

Numerical Study of Methane-hydrogen Flameless Combustion with Variation of Recirculation Rate and Hydrogen Content using 1D Opposed-flow Diffusion Flame Model of Chemkin (Chemkin 기반의 1차원 대향류 확산 화염 모델을 활용한 재순환율 및 수소 함량에 따른 메탄-수소 무화염 연소 특성 해석 연구)

  • Yu, Jiho;Park, Jinje;Lee, Yongwoon;Hong, Jongsup;Lee, Youngjae
    • Clean Technology
    • /
    • v.28 no.3
    • /
    • pp.238-248
    • /
    • 2022
  • The world is striving to transition to a carbon-neutral society. It is expected that using hydrogen instead of hydrocarbon fuel will contribute to this carbon neutrality. However, there is a need for combustion technology that controls the increased NOx emissions caused by hydrogen co-firing. Flameless combustion is one of the alternative technologies that resolves this problem. In this study, a numerical analysis was performed using the 1D opposed-flow diffusion flame model of Chemkin to analyze the characteristics of flameless combustion and the chemical reaction of methane-hydrogen fuel according to its hydrogen content and flue gas recirculation rate. In methane combustion, as the recirculation rate (Kv) increased, the temperature and heat release rate decreased due to an increase in inert gases. Also, increasing Kv from 2 to 3 achieved flameless combustion in which there was no endothermic region of heat release and the region of maximum heat release rate merged into one. In H2 100% at Kv 3, flameless combustion was achieved in terms of heat release, but it was difficult to determine whether flameless combustion was achieved in terms of flame structure. However, since the NOx formation of hydrogen flameless combustion was predicted to be similar to that of methane flameless combustion, complex considerations of flame structure, heat release, and NOx formation are needed to define hydrogen flameless combustion.

Decomposition of Chlorinated Methane by Thermal Plasma (열플라즈마에 의한 클로로메탄의 분해)

  • Kim, Zhen Shu;Park, Dong Wha
    • Applied Chemistry for Engineering
    • /
    • v.18 no.2
    • /
    • pp.136-141
    • /
    • 2007
  • The decomposition of chlorinated methanes including $CCl_4$, $CCl_3H$, and $CCl_2H_2$ was carried out using a thermal plasma process and the characteristics of the process were investigated. The thermal equilibrium composition was analyzed with temperature by Fcatsage program. The decomposition rates at various process parameters including the concentration of reactants, flow rate of carrier gas, and quenching rate, were evaluated, where sufficiently high conversion over 92% was achieved. The generation of main products was strongly influenced by the reaction atmosphere; carbon, chlorine, and hydrogen chloride at neutral condition; carbon dioxide, chlorine, and hydrogen chloride at oxidative condition. The decomposition mechanism was speculated considering the results from Factsage and the identification of generated radicals and ionic species. The main decomposition pathways were found to be dissociative electron attachment and oxidative by radicals formed in a plasma state.