• Title/Summary/Keyword: Hydrogen Gas Consumption

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Experimental Study on Hydrogen Direct Reduction of Hematite in a Lab Scale Fluidized Bed Reactor by Estimating the Gas Consumption Rate

  • Hasolli, Naim;Jeon, Seong Min;Park, Young Ok;Kim, Yong Ha
    • Clean Technology
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    • v.21 no.2
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    • pp.96-101
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    • 2015
  • Hematite reduction using hydrogen was conducted and the various process parameters were closely observed. A lab scale fluidized bed unit was designed especially for this study. The optimal values of the gas velocity, reduction time and temperature were evaluated. The values which indicated the highest reduction rate were set as fixed parameters for the following tests starting with the reduction time of 30 minutes and 750 ℃ of temperature. Among these variables the one with the highest interest was the gas specific consumption. It will tell the amount of the gas which is required to achieve a reduction rate of over 90% at the optimal conditions. This parameter is important for the scale up of the lab scale unit. 1,500 Nm3/ton-ore was found to be the optimal specific gas consumption rate at which the reduction rates exhibit the highest values for hematite.

Design and Assessment of Reliquefaction System According to Boil Off Gas Reliquefaction Rate of Liquefied Hydrogen Carrier (액화수소 운반선의 증발가스 재액화 비율에 따른 재액화 시스템의 설계 및 평가)

  • Cho, Wook-Rae;Lee, Hyun-Yong;Ryu, Bo-Rim;Kang, Ho-Keun
    • Journal of Navigation and Port Research
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    • v.44 no.4
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    • pp.283-290
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    • 2020
  • BOG (Boil Off Gas) generation is unavoidable in the liquefied hydrogen carrier, and proper measures are necessary to prevent pressure problems inside the cargo tank. The BOG can be used as propulsion fuel for ships, and the remaining parts used for propulsion must be effectively managed, such as in the form of reliquefying or burning. This study proposes an BOG reliquefaction system optimized for a 160,000 m3 liquefied hydrogen carrier with a hydrogen propulsion system. The system comprises a hydrogen compression and helium refrigerant section, and increases the efficiency by effectively using the cold energy of the BOG discharged from the cargo tank. In this study, the system was evaluated through the exergy efficiency and SEC (Specific Energy Consumption) analysis according to the rate of the reliquefaction of the BOG while the hydrogen BOG with a supply temperature of -220℃ entered the reliquefaction system. As a result, it showed SEC of 4.11 kWh/kgLH2 and exergy efficiency of 60.1% at the rate of reliquefaction of 20%. And the parametric study of the effects of varying the hydrogen compression pressure, inlet temperature of the hydrogen expander, and the feed hydrogen temperature was conducted.

Technology Trend for Gas Hydrate Production Method by the Patent Analysis (특허 분석에 의한 가스 하이드레이트 제조 기술 동향)

  • Kang, Seong-Pil;Seo, Yu-Teak;Keum, Young-Sup;Ahn, Myung-Hee
    • Transactions of the Korean hydrogen and new energy society
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    • v.19 no.2
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    • pp.171-181
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    • 2008
  • There are several methods for the gas hydrate production such as spraying water with countercurrent gas flow, stirring water-gas mixture, and flowing water with micro-bubble, etc. These days it has been widely studied for the gas hydrate production method, having low energy consumption and high efficiency. In this paper, patents in the gas hydrate production method were gathered and analyzed. The search range was limited to the open patents of USA, European Union (EP), Japan (JP), and Korea (KR) from 1991 to 2007. Patents were gathered by using keywords searching and filtered by crucial criteria. The trends of the patents were analyzed by the years, countries, companies, and technologies.

A Study on PSA Controll Strategy for Part Load Operation of a Hydrogen Generator (수소추출기의 부분부하 운전을 위한 PSA 제어전략에 대한 연구)

  • SANGHO LEE;SEONYEOB KIM;YOUNG CHOI
    • Transactions of the Korean hydrogen and new energy society
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    • v.33 no.6
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    • pp.819-826
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    • 2022
  • Fuel cell systems are being supplied to households and buildings to reduce greenhouse gases. The fuel cell systems have problems of high cost and slow startup due to fuel processors. Greenhouse gas reduction of the fuel cell systems is also limited by using natural gas. The problems can be solved by using a hydrogen generator consisting of a reformer and pressure swing adsorption (PSA). However, part load operation of the hydrogen generator is required depending on the hydrogen consumption. In this paper, PSA operation strategies are investigated for part load of the hydrogen generator. Adsorption and purge time were changed in the range of part load ratio between from 0.5 to 1.0. As adsorption time increased, hydrogen recovery increased from 29.09% to 48.34% at 0.5 of part load ratio. Hydrogen recovery and hydrogen purity were also improved by increasing adsorption and purge time. However, hydrogen recovery dramatically decreased to 35.01% at 0.5 of part load ratio.

An Economic Analysis on Slush Hydrogen Containing Liquid and Solid Phase for Long-Term and Large-Scale Storage (장주기/대용량 수소저장을 위한 액체/고체기반 Slush 수소의 저장 비용 분석)

  • PARK, SUNGHO;LEE, CHANGHYEONG;RYU, JUYEOL;HWANG, SEONGHYEON
    • Transactions of the Korean hydrogen and new energy society
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    • v.33 no.3
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    • pp.247-254
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    • 2022
  • Slush hydrogen containing liquid and solid hydrogen is expected to achieve zero boil-off by suppressing boil-off gas because heat of fusion for solid absorbe the heat ingress from atmosphere. In this paper, quantitative analysis on storage cost considering specific energy consumption between 1,000 m3 class liquid hydrogen storage system with re-liquefaction and slush hydrogen storage system during equivalent zero boil off period. Even though approximately 50% of total storage capacity should be converted into solid phase during the initial cargo bunkering, total energy consumption to convert into slush hydrogen is relatively 25% less than re-liquefaction energy for boil off hydrogen during zero boil off period. That's because energy consumption of slush phase change take up only 1.8% of liquefaction energy. moreover, annual revenue requirement including CAPEX, OPEX and electric cost for slush hydrogen storage could be more reduced approximately 32.5% than those of liquid hydrogen storage and specific energy storage cost ($/kg-H2) could also be lowered by about 41.7% compared with liquid hydrogen storage.

An Evaluation of Net-zero Contribution by Introducing Clean Hydrogen Production Using Life Cycle Assessment (청정수소 생산 방식 도입에 따른 LCA 기반 탄소중립 기여도 평가)

  • SO JEONG JANG;DAE WOONG JUNG;JEONG YEOL KIM;YONG WOO HWANG;HEE KYUNG AN
    • Transactions of the Korean hydrogen and new energy society
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    • v.35 no.2
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    • pp.175-184
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    • 2024
  • This study focuses on investigating the importance of managing greenhouse gas emissions from global energy consumption, specifically examining domestic targets for clean hydrogen production. Using life cycle assessment, we evaluated reductions in global warming potential and assessed the carbon neutrality contribution of the domestic hydrogen sector. Transitioning from brown or grey hydrogen to blue or green hydrogen can significantly reduce emissions, potentially lowering CO2 equivalent levels by 2030 and 2050. These research findings underscore the effectiveness of clean hydrogen as an energy management strategy and offer valuable insights for technology development.

Fuel Consumption and CO2 Characteristics of HCNG Bus (HCNG 버스의 연비와 CO2 배출특성)

  • Han, JO;Kim, YC;Lee, YC
    • Journal of the Korean Institute of Gas
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    • v.21 no.2
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    • pp.20-25
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    • 2017
  • For the HCNG bus using fuel which is the mixture gas of hydrogen and natural gas, the fuel efficiency and $CO_2$ emission characteristics were analyzed based on the WHVC test results and compared with that of the CNG and diesel buses. $CO_2$ emission characteristics were also analyzed by contribution effects such as carbon emission factor and fuel consumption. As a result, the fuel economy of HCNG bus was evaluated to be 11.5% improvement compared to CNG bus, and it was also showed equivalent to diesel bus. In addition, the $CO_2$ emission of HCNG bus was reduced 20.4% and 34.5% compared to CNG bus and diesel bus respectively. It was concluded that the $CO_2$ emission characteristics were influenced by the carbon emission factor depending on fuel composition and the fuel consumption according to the engine performance.

A Theoretical Study on Boil-off Gas Generated from Cooling Process for Cryogenic Components Using Liquid Hydrogen (액체 수소를 활용한 극저온 부품의 냉각 과정에서 발생하는 BOG에 관한 이론적 연구)

  • DONG WOO HA;HYUN WOO NOH;YOUNG MIN SEO;TAE HYUNG KOO;ROCK KIL KO
    • Transactions of the Korean hydrogen and new energy society
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    • v.34 no.6
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    • pp.615-622
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    • 2023
  • In this study, the theoretical analysis focused on the quantity of liquid hydrogen required for cooling down to 20 K, as well as the generation of boil-off gas (BOG) from the cooling process of the cryogenic components. The study involved calculating the amount of liquid hydrogen needed to achieve the desired temperature for the cryogenic components and subsequently determining the resulting BOG production at various reference temperatures. It was shown that it was important to efficiently lower the temperature of cryogenic parts through preliminary cooling. As a result, the reference temperature and pressure had an influence on the BOG generation on the cooling of cryogenic components using liquid hydrogen.

Design and Analysis for Hydrogen Liquefaction Process Using LNG Cold Energy (LNG냉열이용 수소액화 공정해석 및 설계)

  • Yun, Sang-Kook
    • Journal of the Korean Institute of Gas
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    • v.15 no.3
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    • pp.1-5
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    • 2011
  • For the hydrogen liquefaction, the large amount of energy is consumed, because precooling, liquefaction and ortho/para conversion heats should be eliminated. In this paper the basic design and thermal analysis are carried out to reduce the energy consumption by using LNG cold energy for precooling process in hydrogen liquefaction processes. The LNG cold energy utilization for hydrogen precooling enables not only to get energy saving for liquefaction, but to recover the wasted cold energy to sea water at the LNG terminal. The results show that the energy saving rate for liquefaction using LNG cold energy is almost 75% of current industrial hydrogen liquefaction plant. The demand flow-rate of LNG is only 15T/D for 1T/D hydrogen liquefaction.

A Study on Safety Performance Evaluation of NG Blower for 5 kW Class Stationary Fuel Cell Systems (5 kW급 건물용 연료전지 시스템 연료승압 블로워 안전 성능 평가에 관한 연구)

  • BAEK, JAE-HOON;LEE, EUN-KYUNG;LEE, JUNG-WOON;LEE, SEUNG-KUK;MOON, JONG-SAM;KIM, KYU-HYUNG;PARK, HAN-WOO;KIM, DONG-CHEOL;LEE, JIN-HEE
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.6
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    • pp.675-682
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    • 2017
  • New government, the market for stationary fuel cell systems in domestic is expected to expand in line with the policy for expanding new and renewable energy. In order to promote and expand the domestic market for stationary fuel cell systems, it is required to do research and develop for cost reduction and efficiency improvement technologies through the localization of BOP. In this study, the safety performance including the power consumption, flow rate, noise and air-tightness of the domestic fuel booster blower and the foreign fuel booster blower was evaluated and the performance improvement of the domestic blower was confirmed. As a result of the power consumption measurement and the flow rate according to the back pressure of the A company 2nd prototype and B company, the values were 73 W, 27 LPM, and 55 W, 25 LPM. These results are attributed to the improvement of performance through design changes such as CAM angle and diaphragm material.