• Title, Summary, Keyword: Hydrogen gas sensor

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Sensitivity Enhancement in Measurement of Hydrogen Gas Dissolved in Oil using Gas Collection Time (가스수집시간을 이용한 유중수소가스 측정감도 향상 연구)

  • Heo, Jong-Cheol;Sun, Jong-Ho;Kang, Dong-Sik;Jeong, Joo-Young;Park, Jung-Hoo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.3
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    • pp.539-543
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    • 2009
  • This paper describes the sensitivity enhancement in measurement of the hydrogen gas dissolved in oil using gas collection time. On-line gas measurement is a useful for continuous monitoring of power transformer. Recently many studies on hydrogen gas measurement, due to their simplicity and low price, have been done for transformer monitoring. In measurement of the hydrogen gas in oil, the suitable sensitivity and resolution in the desired ranges of the gas concentrations are needed for the reliable monitoring of power transformers. In this study, the sensor output trends were analyzed with the hydrogen gas collection time which means the time to collect the hydrogen gas before reaction of hydrogen gas sensor. It is indicated that the sensor outputs were increased with the increase of hydrogen gas collection times at the same hydrogen gas concentrations.

Measurement Technology of the Dissolved Hydrogen Gas Due to Partial Discharge in Oil using Gas Sensor (가스센서를 이용한 부분방전특성에 따른 유중수소가스 측정연구)

  • Heo, Jong-Cheol;Sun, Jong-Ho;Kang, Dong-Sik;Jeong, Joo-Young;Choo, Y.B.;Park, Jung-Hoo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.9
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    • pp.1784-1789
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    • 2009
  • This paper describes the measurement technology of the dissolved hydrogen gas due to partial discharge in oil using gas sensor. For higher resolution and less error in measurement of the dissolved hydrogen gas in oil, the sensor outputs with ambient temperature which affect the sensor output characteristics should be considered. The sensor output trends with ambient temperature and the properties of the dissolved hydrogen gas in oil with partial discharge characteristic were analyzed through the test results. It was indicated that the sensor peak and the base voltage with measuring time were affected by ambient temperature and the measurement errors of the sensor output by temperature were reduced by using the difference between the peak and the base voltage rather than just the peak voltage. In addition, the hydrogen gas sensor outputs were increased with the increase of partial discharge energy.

Implantation of portable hydrogen alarm system based on palladium coated single mode optical fiber sensor (팔라듐이 코팅된 단일모드 광섬유 센서를 이용한 수소 경보 시스템 구현)

  • Mun, Nam-Il;Yang, Byung-Cheol;Kim, Kwang-Taek;Kim, Tae-Un
    • Journal of Sensor Science and Technology
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    • v.18 no.4
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    • pp.269-273
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    • 2009
  • In this paper, a study on a portable hydrogen alarm system based on the palladium coated single mode fiber sensor has been reported. The fabricated hydrogen sensor exhibited 0.14 dB, 0.41 dB and 0.54 dB optical intensity variation when it was exposed by the nitrogen and hydrogen mixed gas containing 0.5 %, 1 % and 4 % of the hydrogen concentration, respectively. The fabricated sensor exhibited 20 second of response time and 120 second of recovery time for 4 % hydrogen containing gas. The fiber optics layout and software algorithm for detection of hydrogen leakage have been presented. The implanted portable hydrogen alarm system successfully generated an alarm signal when a 4 % hydrogen containing gas was leaked out.

An Experimental Study on the Transient Response of Hydrogen Sensors Dependent on Gas Temperature and Humidity (가스의 온도 및 습도 변화에 따른 수소 센서 응답 특성에 대한 실험적 연구)

  • Kim, Young-Doo;Chung, Tae-Yong;Shin, Dong-Hoon;Nam, Jin-Hyun;Kim, Young-Gyu;Lee, Jung-Woon
    • Journal of the Korean Institute of Gas
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    • v.13 no.5
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    • pp.15-19
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    • 2009
  • In this study, the transient responses of hydrogen sensor against abrupt hydrogen release was experimentally studied for three most common types of hydrogen sensors, i.e. the semiconductor type, electrochemical type, and catalytic combustion type. The experimental study was conducted using a 1% hydrogen - 99% nitrogen mixture gas as the standard gas, while the temperature and relative humidity (RH) of the mixture gas was varied from $25^{\circ}C$ to $50^{\circ}C$ and from 50% to 100%, respectively. The temperature of the mixture gas was found to influence the output signal levels of hydrogen sensors, especially the catalytic combustion type. However, the effect of RH on the sensor response was not noticeable in the present experimental study. Thus, the signal levels of hydrogen sensors, in case of catalytic gas sensor need to be calibrated dependent on gas temperature, when the accurate determination of hydrogen concentration is important.

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A Study on Pattern Analysis of Odorous Substances with a Single Gas Sensor

  • Kim, Han-Soo;Choi, Il-Hwan;Kim, Sun-Tae
    • Journal of Sensor Science and Technology
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    • v.25 no.6
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    • pp.423-430
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    • 2016
  • This study used a single metal oxide semiconductor (MOS) sensor to classify the major odorous gases hydrogen sulfide ($H_2S$), ammonia ($NH_3$) and toluene ($C_6H_5CH_3$). In order to classify these odorous substances, the voltage on the MOS sensor heater was gradually reduced in 0.5 V steps 5.0 V to examine the changes to the response by the cooling effect on the sensor as the voltage decreased. The hydrogen sulfide gas showed the highest sensitivity compared to odorless air under approximately 2.5 V and the ammonia and toluene gases showed the highest sensitivity under approximately 5.0 V. In other words, the hydrogen sulfide gas reacted better in the low temperature range of the MOS sensor, and the ammonia and toluene gases reacted better in the high-temperature range. In order to analyze the response characteristics of the MOS sensor by temperature in a pattern, a two-dimensional (2D) x-y pattern analysis was introduced to clearly classify the hydrogen sulfide, ammonia, and toluene gases. The hydrogen sulfide gas was identified by a straight line with a slope of 1.73, whereas the ammonia gas had a slope of 0.05 and the toluene gas had a slope of 0.52. Therefore, the 2D x-y pattern analysis is suggested as a new way to classify these odorous substances.

Sensing Properties of Hydrogen Gas for the MWCNT Thin Film Sprayed on the Glass Substrate Cured with Plasma and Nitrocellulose (플라즈마 및 니트로셀롤로우스로 처리된 유리기판을 사용한 MWCNT 스프레이 박막의 수소가스 검출특성)

  • Jang, Kyung-Uk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.4
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    • pp.290-296
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    • 2011
  • Carbon nanotubes (CNTs) have excellent electrical, chemical stability, mechanical and thermal properties. In this paper, networks of Multi-walled carbon nanotube (MWCNT) materials were investigated as a resistive gas sensors for the $H_2$ gas detection. Sensor films were fabricated by the air spray method using the multi-walled CNTs dispersion solution on the glass substrates cured with plasma and nitrocellulose. Sensors were characterized by the resistance measurements in the self-fabricated oven in order to find the optimum detection properties for the hydrogen gas molecular. The sensitivity and the linearity of the MWVNT sensors using the glass substrate cured with plasma for the $H_2$ gas concentration of 0.06~0.6 ppm are 0.013~0.097%/sec and 0.131~0.959%FS, respectively. The MWCNT film was excellent in the response for the hydrogen gas moleculars and its reaction speed was very fast, which could be using as hydrogen gas sensor. The resistance of the fabricated sensors decreases when the sensors are exposed to $H_2$ gas.

Room Temperature Hydrogen Sensor

  • Cho, Hyoung Jin;Zhang, Peng;Seal, Sudipta
    • 한국신재생에너지학회:학술대회논문집
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    • pp.51.3-51.3
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    • 2010
  • Due to the recent public awareness of global warming and sustainable economic growth, there has been a growing interest in alternative clean energy sources. Hydrogen is considered as a clean fuel for the next generation. One of the technical challenges related to the use of hydrogen is safe monitoring of the hydrogen leak during separation, purification and transportation. For detecting various gases, chemiresistor-type gas sensors have been widely studied and used due to their well-established detection scheme and low cost. However, it is known that many of them have the limited sensitivity and slow response time, when used at low temperature conditions. In our work, a sensor based on Schottky barriers at the electrode/sensing material interface showed promising results that can be utilized for developing fast and highly sensitive gas sensors. Our hydrogen sensor was designed and fabricated based on indium oxide (In2O3)-doped tin oxide (SnO2) semiconductor nanoparticles with platinum (Pt) nanoclusters in combination with interdigitated electrodes. The sensor showed the sensitivity as high as $10^7%$ (Rair/Rgas) and the detection limit as low as 30 ppm. The sensor characteristics could be obtained via optimized materials synthesis route and sensor electrode design. Not only the contribution of electrical resistance from the film itself but also the interfacial effect was identified as an important factor that contribute significantly to the overall sensor characteristics. This promises the applicability of the developed sensor for monitoring hydrogen leak at room temperature.

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A Study on Characteristics of Hydrogen Leakage in Hydrogen Town Governor Room (수소타운 정압기실 내 수소 누출 특성 연구)

  • NAM, TAE-HO;KIM, DONG-HWAN;LEE, JUNG-WOON;LEE, SEUNG-KUK;LEE, YEON-JAE
    • Transactions of the Korean hydrogen and new energy society
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    • v.27 no.6
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    • pp.685-692
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    • 2016
  • Hydrogen will be a future eco-friendly energy source that can replace current fossil fuels However when hydrogen gas leaks and people inhale a lot of hydrogen gases, they can have fatal effects fell into comas. Therefore, we need to develop a safety technology and related guidelines for reducing risks of hydrogen leakage. In this regard, we carried out demonstration tests assuming a situation of hydrogen leakage. Before the experiments, we analyze the standards for governor facilities to check vent positions and sensor positions. Then, we select four types of ventilation structures and proceeds with the experiments of hydrogen leakage at 1 LPM and 1.5 LPM. Based on the experimental results, we propose the direction on optimization of vent positions and sensor positions in the hydrogen leakage situation.

Capacitive-type Hydrogen Gas Sensor Using Ta2O5 as Sensitive Layer (감지막으로 Ta2O5를 이용한 정전용량형 수소 가스센서)

  • Choi, Je-Hoon;Kim, Seong-Jeen
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.12
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    • pp.882-887
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    • 2013
  • We investigated a SiC-based hydrogen gas sensor with metal-insulator-semiconductor (MIS) structure for high temperature process monitoring and leak detection applications. The sensor was fabricated by Pd/$Ta_2O_5$/SiC structure, and a thin tantalum oxide ($Ta_2O_5$) layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature as well as high permeability for hydrogen gas. In the experiment, dependence of I-V characteristics and capacitance response properties on hydrogen gas concentrations from 0 to 2,000 ppm was analyzed at room temperature to $500^{\circ}C$. As the result, our sensor exploiting a $Ta_2O_5$ dielectric layer showed possibilities with regard to use in hydrogen gas sensors for high-temperature applications.

Pt-AlGaN/GaN HEMT-based hydrogen gas sensors with and without SiNx post-passivation

  • Vuong, Tuan Anh;Kim, Hyungtak
    • Journal of IKEEE
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    • v.23 no.3
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    • pp.1033-1037
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    • 2019
  • GaN-based sensors have been widely investigated thanks to its potential in detecting the presence of hydrogen. In this study, we fabricated hydrogen gas sensors with AlGaN/GaN heterojunction and investigated how the sensing performance to be affected by SiN surface passivation. The gas sensor employed a high electron mobility transistors (HEMTs) with 30 nm platinum catalyst as a gate to detect the hydrogen presence. SiN layer was deposited by inductively-coupled chemical vapor deposition as post-passivation. The sensors with SiN passivation exhibited hydrogen sensing characteristics with various gas flow rates and concentrations of hydrogen in inert background gas at $200^{\circ}C$ similar to the ones without passivation. Aside from quick response time for both sensors, there are differences in sensitivity and recovery time because of the existence of the passivation layer. The results also confirmed the dependence of sensing performance on gas flow rate and gas concentration.