• Title/Summary/Keyword: Carbon Conversion

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The Conversion of Methane with Oxygenated Gases using Atmospheric Dielectric Barrier Discharge (배리어방전을 이용한 메탄전환반응에서 함산소 가스가 전환율 및 생성물변화에 미치는 영향)

  • Lee Kwang-Sik;Yeo Yeong-Koo;Choi Jae-Wook;Lee Hwa-Ung;Song Hyung-Keun;Na Byung-Ki
    • Journal of Energy Engineering
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    • v.15 no.1 s.45
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    • pp.52-59
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    • 2006
  • This paper examined the conversion of methane to hydrogen and other higher hydrocarbons using dielectric barrier discharge with AC pulse power. Two metal electrodes of a coaxial-type plasma reactor were separated by gas gap and an alumina tube. The inner electrode was located inside the alumina tube. The alumina tube was located inside the stainless steel tube, which was used as the outer electrode. Effect of feed gas composition (methane, oxygen, argon, water and helium), flow rate, applied frequency, input volt-age on methane conversion and product distribution were studied. The major products of plasma chemical reactions were ethylene, ethane, propane, buthane, hydrogen, carbon monoxide and carbon dioxide. The increment of applied voltage and the usage of inert gas as the background (helium and argon) enhanced the selectivity of hydrocarbons and methane conversion. The addition of water in the feed stream enhanced the conversion of methane and yield of hydrogen. Higher voltage leads to higher yield of $C_2H_6,\;C_3H_8,\;C_4H_{10}$ and yield or $C_2H_2\;and\;C_2H_4$ appeared highly in lower voltage.

Optimization of C/N ratio for production of pullulan

  • Seo, Hyeong-Pil;Kim, Hyeon-Suk;Kim, Mi-Ryeong;Kim, Seong-Gu;Lee, Jin-U
    • 한국생물공학회:학술대회논문집
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    • 2000.04a
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    • pp.259-262
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    • 2000
  • The production of pullulan by Aureobasidium pullulans HP-2001 was investigated under various ratios of glucose as carbon source and yeast extract as the nitrogen source, Highest conversion rate (productivity) of glucose to pullulan was 40.0% when concentrations of glucose and yeast extract were 5% and 0.15%, respectively. Maximal production of pullulan was 29.3g/1 when the concentration of glucose was 8%(w/v) and that of yeast extract was 40:1. On basis of the result that production of pullulan was found in a medium which concentration of glucose as carbon source was up to 20%(w/v), Aureobasidium pullulans HP-2001 seemed to overcome the catabolite repression. Conversion rate of pullulan from 20%(w/v) of glucose was 11.1%.

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Gasification of Coal and Torrefied Biomass Mixture (석탄과 반탄화 바이오매스 혼합연료의 가스화)

  • OH, GUNUNG;JANG, JIN YOUNG;RA, HO WON;SEO, MYUNG WON;MUN, TAE YOUNG;LEE, JAE-GOO;YOON, SANG JUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.2
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    • pp.190-199
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    • 2017
  • Air-blown Gasification of coal and torrefied biomass mixture is conducted on fixed-bed gasifier. The various ratio (9:1, 8:2, 7:3) of coal and torrefied biomass mixture are used. The contents of $H_2$, CO in the syngas were increased with gasification temperature. Carbon conversion tend to increase with temperature and equivalence ratio (ER). However, cold gas efficiency showed maximum point in ER range of 0.26-0.36. The torrefied biomass showed highest cold gas efficiency of 67.5% at $934^{\circ}C$, ER 0.36. Gasification of 8:2 mixture showed the highest carbon conversion and cold gas efficiency and synergy effect.

Effects of La addition to Ni/$CeO_2$ Methane Partial Oxidation Catalysts (메탄 부분산화반응 Ni/$CeO_2$ 촉매에 LA 첨가의 영향)

  • Cheon, Han-Jin;Shin, Ki-Seok;Ahn, Sung-Hwan;Yoon, Cheol-Hun;Hahm, Hyun-Sik
    • Journal of the Korean Applied Science and Technology
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    • v.27 no.1
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    • pp.29-36
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    • 2010
  • The effects of La addition to Ni/$CeO_2$ methane partial oxidation catalysts were investigated. Catalysts were prepared by the impregnation and urea methods. In the preparation of catalysts, La content was changed from 1 wt% to 3wt%. Catalysts that contain 2wt% La showed the highest methane conversion of about 80% and CO selectivity of 84% and $H_2$ selectivity of 70%. This result may be stemmed from that, when La content is 2wt%, a fluorite oxide-type structure is well formed and carbon deposition is also decreased. Among the catalysts, 2.5wt% Ni/Ce(La)Ox showed the highest catalytic activity. From the experiment of changing reaction temperature with 2.5wt% Ni/Ce(La)Ox catalyst, it was found that the optimum reaction temperature is $750^{\circ}C$ and at this temperature methane conversion was about 90%, CO and $H_2$ selectivities were 94 and 80%, respectively.

Characteristics of Various Ranks of Coal Gasification with $CO_2$ by Gas Analysis (가스분석을 이용한 석탄 종류별 $CO_2$ 가스화 반응특성 연구)

  • Kim, Yong-Tack;Seo, Dong-Kyun;Hwang, Jung-Ho
    • Journal of the Korean Society of Combustion
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    • v.15 no.2
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    • pp.41-49
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    • 2010
  • Various coals from many countries around the world have been used for pulverized coal boiler in power plants in Korea. In this study, the gasification reactivities of various coal chars with $CO_2$ were investigated. Carbon conversion was measured using a real time gas analyzer with NDIR CO/$CO_2$ sensor. In a lab scale furnace, each coal sample was devolatilized at $950^{\circ}C$ in nitrogen atmosphere and became coal char and then further heated up to reach to a desired temperature. Each char was then gasified with $CO_2$ under isothermal conditions. The reactivities of coal chars were investigated at different temperatures. The shrinking core model (SCM) and volume reaction model(VRM) were used to interpret the experiment data. It was found that the SCM and VRM could describe well the experimental results within the carbon conversion of 0-0.98. The gasification rates for various coals were very different. The gasification rate for any coal increased as the volatile matter content increased.

Activity test of post-reforming catalyst for removing the ethylene in diesel ATR reformate (디젤 자열개질 가스 내 포함된 $C_2H_4$ 제거를 위한 후개질기 촉매 활성 실험)

  • Yoon, Sang-Ho;Bae, Joong-Myeon;Lee, Sang-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.218-221
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    • 2009
  • Solid oxide fuel cells (SOFCs), as high-temperature fuel cells, have various advantages. In some merits of SOFCs, high temperature operation can lead to the capability for internal reforming, providing fuel flexibility. SOFCs can directly use CH4 and CO as fuels with sufficient steam feeds. However, hydrocarbons heavier than CH4, such as ethylene, ethane, and propane, induce carbon deposition on the Ni-based anodes of SOFCs. In the case of the ethylene steam reforming reaction on a Ni-based catalyst, the rate of carbon deposition is faster than among other hydrocarbons, even aromatics. In the reformates of heavy hydrocarbons (diesel, gasoline, kerosene and JP-8), the concentration of ethylene is usually higher than other low hydrocarbons such as methane, propane and butane. It is importatnt that ethylene in the reformate is removed for stlable operation of SOFCs. A new methodology, termed post-reforming was introduced for removing low hydrocarbons from the reformate gas stream. In this work, activity tests of some post-reforming catalysts, such as CGO-Ru, CGO-Ni, and CGO-Pt, are investigated. CGO-Pt catalyst is not good for removing ethylene due to low conversion of ethylene and low selectivity of ethylene dehydrogenation. The other hand, CGO-Ru and CGO-Ni catalysts show good ethylene conversion, and CGO-Ni catalyst shows the best reaction selectivity of ethylene dehydrogenation.

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The Study of Steam Reforming for Model Bioigas using 3D-IR Matrix Burner Reformer (3D-IR Matrix 버너 개질기를 활용한 모사 바이오가스 수증기 개질 연구)

  • Lim, Mun-Sup;Chun, Young-Nam
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.1
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    • pp.100-108
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    • 2011
  • The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases, $CH_4$ and $CO_2$, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. This research if for the hydrogen production through the steam reforming of the biogas. The biogas utilized 3D-IR matrix burner in which the surface combustion is applied. The nickel catalyst was used inside a reformer. Parametric screening studies were achieved as Steam/Carbon ratio, biogas component ratio, Space velocity and Reformer temperature. When the condition of Steam/Carbon ratio, $CH_4/CO_2$ ratio, Space velocity and Refomer temperature were 3.25, 60%:40%, 19.32L/$g{\cdot}hr$ and $700^{\circ}C$ respectively, the hydrogen concentration and methane conversion rate were showed maximum values. Under the condition mentioned above, $H_2$ concentration was 73.9% and methane conversion rate was 98.9%.

Numerical Study on Operating Parameters and Shapes of a Steam Reformer for Hydrogen Production from Methane (천연가스로부터 수소를 생산하기 위한 수증기 개질기의 작동조건과 형상에 대한 수치해석 연구)

  • Park, Joong-Uen;Lee, Shin-Ku;Lim, Sung-Kwang;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.1
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    • pp.60-68
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    • 2009
  • The steam reformer for hydrogen production from methane is studied by a numerical method. Langmuir- Hinshelwood model is incorporated for catalytic surface reactions, and the pseudo-homogeneous model is used to take into account local equilibrium phenomena between a catalyst and bulk gas. Dominant chemical reactions are Steam Reforming (SR) reaction, Water-Gas Shift (WGS) reaction, and Direct Steam Reforming (DSR) reaction. The numerical results are validated with experimental results at the same operating conditions. Using the validated code, parametric study has been numerically performed in view of the steam reformer performance. As increasing a wall temperature, the fuel conversion increases due to the high heat transfer rate. When Steam to Carbon Ratio (SCR) increases, the concentration of carbon monoxide decreases since WGS reaction becomes more active. When increasing Gas Hourly Space Velocity (GHSV), the fuel conversion decreases due to the heat transfer limitation and the low residence time. The reactor shape effects are also investigated. The length and radius of cylindrical reactors are changed at the same catalyst volume. The longer steam reformer is, the better steam reformer performs. However, system energy efficiency decreases due to the large pressure drop.

Numerical Study on Correlation between Operating Parameters and Reforming Efficiency for a Methane Autothermal Reformer (천연가스 자열개질기를 위한 작동조건과 개질효율의 상관관계에 대한 수치해석 연구)

  • Park, Joon-Guen;Lee, Shin-Ku;Lim, Sung-Kwang;Bae, Joong-Myeon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.8
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    • pp.636-644
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    • 2008
  • The objective of this paper is to investigate characteristics of an autothermal reformer at various operating conditions. Numerical method has been used, and simulation model has been developed for the analysis. Pseudo-homogeneous model is incorporated because the reactor is filled with catalysts of a packed-bed type. Dominant chemical reactions are Full Combustion reaction, Steam Reforming(SR) reaction, Water-Gas Shift(WGS) reaction, and Direct Steam Reforming(DSR) reaction. Simulation results are compared with experimental results for code validation. Operating parameters of the autothermal reformer are inlet temperature, Oxygen to Carbon Ratio(OCR), Steam to Carbon Ratio(SCR), and Gas Hourly Space Velocity(GHSV). Temperature at the reactor center, fuel conversion, species at the reformer outlet, and reforming efficiency are shown as simulation results. SR reaction rate is improved by increased inlet temperature. Reforming efficiency and fuel conversion reached the maximum at 0.7 of OCR. SR reaction and WGS reaction are activated as SCR increases. When GHSV is increased, reforming efficiency increases but pressure drop from the increased GHSV may decrease the system efficiency.

Study of Pore Development Model in Low Rank Solid Fuel Using FERPM (FERPM을 적용한 저등급 고체연료의 기공발달 모델 특성 연구)

  • PARK, KYUNG-WON;KIM, GYEONG-MIN;JEON, CHUNG-HWAN
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.2
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    • pp.178-187
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    • 2019
  • Due to the increasing demand of high rank coal, the use of low rank coal, which has economically advantage, is rising in various industries using carbonaceous solid fuels. In addition, the severe disaster of global warming caused by greenhouse gas emissions is becoming more serious. The Republic of Korea set a goal to reduce greenhouse gas emissions by supporting the use of biomass from the Paris International Climate Change Conference and the 8th Basic Plan for Electricity Supply and Demand. In line with these worldwide trends, this paper focuses on investigating the combustibility of high rank coal Carboone, low rank coal Adaro from Indonesia, Baganuur from Mongolia and, In biomass, wood pellet and herbaceous type Kenaf were simulated as kinetic reactivity model. The accuracy of the pore development model were compared with experimental result and analyzed using carbon conversion and tau with grain model, random pore model, and flexibility-enhanced random pore model. In row lank coal and biomass, FERPM is well-matched kinetic model than GM and RPM to using numerical simulations.