• Title/Summary/Keyword: $CO_2$ 격리

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The Analysis of ECBM Efficiency about Sorption Rate between CH4 and CO2 (석탄층내 CH4과 CO2의 흡착거동에 의한 ECBM 효율성 분석)

  • Kim, Kihong;Sung, Wonmo;Han, Jeongmin
    • Journal of the Korean Institute of Gas
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    • v.17 no.2
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    • pp.36-43
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    • 2013
  • In order to asses gas production behavior for $CO_2$ ECBM, the sorption charcteristics on coal are considered to be a key factor. In this study, we have investigated the change of the sorption rate of adsorbed gas as a function of pressure and temperature below the appropriate depth for $CO_2$-ECBM. The experiment were carried out under four different temperatures varying from $15^{\circ}C$ to $45^{\circ}C$, while the coal pressure was varied from atmosphere to 1,400 psi for every temperature. From this results, the sorption rate both $CO_2$ and $CH_4$ increased with increasing the coal pressure. Otherwise, the sorption rate both $CH_4$ and $CO_2$ decreased linearly as the coal temperature increased. From the sensitivity studies on pressure and temperature change, it was experimentally identified that $CO_2$ sequestration rate and $CH_4$ production rate are better at deeper depths below a depth of 800 m in coal seams. However, the results showed continued decline in the increasing ratio of ECBM with formation depth.

Design and Implementation of a Internal Mobile Antenna for TDMB and KPCS (TDMB와 KPCS 대역을 지원하는 내장형 휴대폰 안테나의 설계 및 구현)

  • Park, Jun-Han;Lee, Chi-Woo;Yang, Myo-Geun;Seong, Won-Mo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.2
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    • pp.161-166
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    • 2009
  • In this paper, we propose the internal mobile antenna for TDMB and KPCS. The proposed antenna is made of different dielectric substrate and it has small size ($45{\times}8{\times}8\;mm$, about 2.8 cc) for mobile device. TDMB antenna is designed spiral structure that makes maximum current for each cell and KPCS antenna is PIFA that is usually used for internal antenna. In order to compensate length of resonance TDMB antenna has a large inductor above 100 nH. In this case, the inductor isolate KPCS signal at TDMB by cutting high frequency. Also the antenna has good isolation because TDMB radiator is parasitic element in KPCS band. We simulated the antenna by using CST microwave studio and measured performance of the antenna in anechoic chamber Proposed antenna has $-6{\sim}-14\;dBi$ gain for TDMB and $-3.5{\sim}-5\;dBi$ gain for KPCS.

Recent Research Trends of Catalytic Conversion of CO2 to High-value Chemicals (촉매 전환을 이용한 이산화탄소의 고부가 가치제품 생산에 대한 최근 연구 동향)

  • Song, Ki-Hun;Ryu, Jun-hyung;Chung, Jong-Sik
    • Korean Chemical Engineering Research
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    • v.47 no.5
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    • pp.519-530
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    • 2009
  • Reducing the emission of carbon dioxide, which is the main contributor to the green house effect, is becoming a global hot issue. Great attention has been thus given to utilization of carbon dioxide rather than just capturing and isolating it because it could convert carbon dioxide to high-value chemicals. In this paper, recent research trends are investigated on the catalytic conversion of carbon dioxide to syngas in the context of $CH_4$, dry-reforming, trireforming, and the electro-catalytic conversion of carbon dioxide through SOFC(Solid Oxide Fuel Cell) system. Research trends for utilizing syngas to high-value-added useful products, mainly fuel such as DME(Dimethyl Ether) are also discussed.

Implementation of Environmental Control System based on USN for Improving Comfort in Underground Space (지하공간의 쾌적도 향상을 위한 USN 기반의 환경제어시스템 구현)

  • Ryu, Jae-Bok;Kwon, Sook-Youn;Lim, Jae-Hyun
    • Proceedings of the Korea Information Processing Society Conference
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    • 2012.11a
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    • pp.1292-1295
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    • 2012
  • 인구 과밀화 및 급격한 도시 팽창은 지상공간에서 거주하는 인간 삶의 질을 위협하고 있다. 따라서 지상공간의 개발을 억제하여 환경을 보호하고 도시 공간 이용의 효율성을 최대화하기 위해 지하 공간을 개발하고자 하는 움직임이 활발하다. 자연환경으로부터 격리된 구조인 지하공간은 지상공간에 비해 실내 공기 질을 쾌적한 상태로 유지하기 어려운 밀폐된 환경이므로 오랜 시간동안 상주하는 거주자 및 한시적 이용자들의 건강에 영향을 미치는 온도, 습도, $CO_2$, 먼지 등의 환경을 제어하기 위한 기술 개발이 필요하다. 본 연구에서는 지하공간의 쾌적도 향상을 위해 온 습도 및 $CO_2$, 먼지센서를 이용한 통합 센서를 제작하여 현재 지하공간의 환경정보를 실시간 모니터링하고 실내공간의 쾌적 지표를 기반으로 환풍기, 송풍기 등의 디바이스를 제어하기 위한 USN 기반의 환경제어시스템을 구현한다. 제안한 시스템을 통해 지하공간의 환경을 개선할 뿐만 아니라 고가의 계측 장비로 인한 비용 절감 및 이동성과 확장성 등의 부가적인 효과를 기대한다.

Evaluation on the Basic Properties of Phosphate Modified Portland Cement Paste for Potential Application of Geologic CO2 Sequestration (이산화탄소 지중 격리용 인산염 혼입 시멘트 페이스트에 관한 기초물성 평가)

  • Yoon, Ju-Han;Kim, Seong-Geun;Kim, Ji-Hyun;Lee, Jae-Yong;Chung, Chul-Woo
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.3
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    • pp.253-260
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    • 2017
  • As global warming became a worldwide issue, a significant effort has been made on the development of technology related to $CO_2$ capture and storage. Geologic sequestration of $CO_2$ is one of those technologies for safe disposal of $CO_2$. Geologic sequestration stores $CO_2$ in the form of supercritical fluid into the underground site surrounded by solid rock, and concrete is used for prevention of $CO_2$ leakage into the atmosphere. In such case, concrete may experience severe damage by attack of supercritical $CO_2$, and especially in contact with underground water, very aggressive form of carbonation can occur. In this work, to prevent such deterioration in concrete, calcium phosphates were added to the portland cement to produce hydroxyapatite, one of the most stable mineral in the world. Temperature rise, viscosity, set and stiffening, and strength development of cement paste incorporating three different types of calcium phosphates were investigated. According to the results, it was found that the addition of calcium phosphate increased apparent viscosity, but decreased maximum temperature rise and 28 day compressive strength. It was found that monocalcium phosphate was found to be inappropriate for portland cement based material. Applicability of dicalcium and tricalcium phosphates for portland cement needs to be evaluated with further investigation, including the long term compressive strength development.

A Real-Time Implementation of Isolated Word Recognition System Based on a Hardware-Efficient Viterbi Scorer (효율적인 하드웨어 구조의 Viterbi Scorer를 이용한 실시간 격리단어 인식 시스템의 구현)

  • Cho, Yun-Seok;Kim, Jin-Yul;Oh, Kwang-Sok;Lee, Hwang-Soo
    • The Journal of the Acoustical Society of Korea
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    • v.13 no.2E
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    • pp.58-67
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    • 1994
  • Hidden Markov Model (HMM)-based algorithms have been used successfully in many speech recognition systems, especially large vocabulary systems. Although general purpose processors can be employed for the system, they inevitably suffer from the computational complexity and enormous data. Therefore, it is essential for real-time speech recognition to develop specialized hardware to accelerate the recognition steps. This paper concerns with a real-time implementation of an isolated word recognition system based on HMM. The speech recognition system consists of a host computer (PC), a DSP board, and a prototype Viterbi scoring board. The DSP board extracts feature vectors of speech signal. The Viterbi scoring board has been implemented using three field-programmable gate array chips. It employs a hardware-efficient Viterbi scoring architecture and performs the Viterbi algorithm for HMM-based speech recognition. At the clock rate of 10 MHz, the system can update about 100,000 states within a single frame of 10ms.

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Mechanical Properties of Mortar Containing Bio-Char From Pyrolysis (바이오숯을 함유한 모르타르의 역학적 특성)

  • Choi, Won Chang;Yun, Hyun Do;Lee, Jae Yeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.3
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    • pp.67-74
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    • 2012
  • Bio-char, obtained from biomass as a by-product of the pyrolysis process, is used successfully as a soil amendment and carbon sequester in this limited study. Recent and active research from literatures has extended the application of bio-char in the industry to promote sustainability and help mitigate the negative environmental impacts caused by carbon emissions. This study aims to investigate the feasibility of high-carbon bio-char as a carbon sequester and/or admixture in mortar and concrete to improve the sustainability of concrete. This paper presents the experimental results of an initial attempt to develop a cement admixture using bio-char. In particular, the effects of the water retention capacity of bio-char in concrete are investigated. The chemical and mechanical properties (e.g., the chemical components, microstructure, concrete weight loss, compressive strength and mortar flow) are examined using sample mortar mixes with varying replacement rates of cement that contains hardwood bio-char. The experimental results also are compared with mortar mixes that contain fly ash as the cement substitute.

Design of Broadband Polarization Diversity Antenna for Mobile Base Stations (이동 통신 기지국용 광대역 편파 다이버시티 안테나 설계)

  • Seo, In-Jong;Cho, In-Ho;Lee, Cheon-Hee;Jung, Jin-Woo;Lee, Hyeon-Jin;Lim, Yeong-Seog
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.9
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    • pp.1023-1029
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    • 2010
  • In this paper, we proposed the broadband polarization diversity antenna operating in the PCS, WCDMA and WiBro band for mobile base station. We designed the antenna using the dipole antenna of the square loop type and microstrip feeding structure. Additionally, we used the choke box to remove the distortion of radiation patterns by the reflector structure when operating broadband. The simulation was performed using MWS in a commercial tool of CST company and the antenna was fabricated on a teflon substrate with 3.33 of the relative permittivity. The proposed antenna has the bandwidth of 640 MHz(from 1.75 to 2.39 GHz) when VSWR is below 1.5. At the operating bands, the interisolation between the cross-pair radiators is less than -25 dB and the maximum gains for PCS, WCDMA and WiBro band are 8.9, 8.2 and 8.6 dBi, respectively.

Monitoring of Fracture Occurrence During Carbon Dioxide Injection at the Meruap Oil Reservoir, Indonesia (인도네시아 머루압 유전에 이산화탄소 주입 시 균열대 생성 여부 모니터링)

  • Kim, Dowan;Byun, Joongmoo;Kim, Kiseog;Ahn, Taewoong
    • Geophysics and Geophysical Exploration
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    • v.19 no.1
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    • pp.37-44
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    • 2016
  • $CO_2$-EOR (Carbon Dioxide-Enhanced Oil Recovery), one of the enhanced oil recovery methods, helps to not only enhance the production of oil, but also store carbon dioxide in underground. However, if micro fractures occur when during the injection of $CO_2$, it is difficult to make permanent storage of $CO_2$ in reservoir and can cause contamination of groundwater and soil. Therefore, in this study, we performed microseismic monitoring to investigate the occurrence of fractures during the $CO_2$ injection at the Meruap oil reservoir, Indonesia. To pick the first arrivals of microseismic events, Improved MER (Modified Energy Ratio) method was used. After picking the first arrivals, hodogram analysis was carried out by using the data recorded at three component geophones to calculate the back azimuth of events. Finally, locations of microseismic events were decided by using the results of first arrival picking and hodogram analysis. Estimated locations showed that all microseismic events were occurred at surface and any fracture did not occur around the reservoir. Moreover, by analyzing noise characteristic, we confirmed that almost of picked first arrivals were due to the repetitive mechanical noise.

Influence of the Increase of Dissolved $CO_2$ Concentration on the Marine Organisms and Ecosystems (해수중 용존 $CO_2$ 농도 증가가 해양생물 및 해양생태계에 미치는 영향: 국내외 사례 연구)

  • Lee, Jung-Suk;Lee, Kyu-Tae;Kim, Chan-Kook;Park, Gun-Ho;Lee, Jong-Hyeon;Park, Young-Gyu;Gang, Seong-Gil
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.4
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    • pp.243-252
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    • 2006
  • Influence of the increasing carbon dioxide concentration in seawater on various marine organisms is assessed in this article with regard to the impacts of anthropogenic $CO_2$ introduced into surface or deep oceans. Recent proposals to sequester $CO_2$ in deep oceans arouse the concerns of adverse effects of increased $CO_2$ concentration on deep-sea organisms. Atmospheric introduction of $CO_2$ into the ocean can also acidify the surface water, thereby the population of some sensitive organisms including coral reefs, cocolithophorids and sea urchins will be reduced considerably in near future (e.g. in 2100 unless the increasing trend of $CO_2$ emission is actively regulated). We exposed bioluminescent bacteria and benthic amphipods to varying concentrations of $CO_2$ and also pH for a short period. The ${\sim}l.5$ unit decrease of pH adversely affected test organisms. However, amphipods were not influenced by decreasing pH when HCl was used for the seawater acidification. In this article, we reviewed the biological adverse effects of $CO_2$ on various marine organisms studied so for. Theses results will be useful to predict the potential risks of the increase of $CO_2$ concentrations in seawater due to the increase of atmospheric $CO_2$ emission and/or sequestration of $CO_2$ in deep oceans.

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