• Title/Summary/Keyword: Hydrogen liquefaction

Search Result 73, Processing Time 0.019 seconds

Effectiveness Measurement of a Double-Tube Heat Exchanger for a Hydrogen Liquefaction System (수소액화 시스템용 이중관 열교환기의 유용도 측정)

  • Choi, H.J.;Baik, J.H.;Kang, B.H.;Choi, Y.D.
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.10 no.1
    • /
    • pp.19-26
    • /
    • 1999
  • The effectiveness of a double-tube heat exchanger has been investigated experimentally. This problem is of particular interest in the design of the heat exchanger in a hydrogen liquefaction system. Temperature, pressure, and mass flow rate for hydrogen were measured both in inner tube and in annulus of a double-tube heat exchanger. The effectiveness could be evaluated from the measured temperature and mass flow rate. It is found that the effectiveness increases with an increase in the heat transfer area of a double-tube heat exchanger and with a decrease of the heat capacity ratio. But the increase rate of the effectiveness decreased with a decrease of the heat capacity ratio. Therefore, it is presented that a criterion for selecting the heat exchanger length and heat capacity ratio to obtain the effectiveness required in a hydrogen liquefaction system.

  • PDF

Operating Conditions of Hydrogen Liquefaction Systems using Two-Stage GM Refrigerator (2단 GM냉동기를 이용한 수소액화 시스템의 운전조건)

  • 박대종;장호명;강병하
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
    • /
    • 1999.02a
    • /
    • pp.194-197
    • /
    • 1999
  • Thermodynamic cycle analysis has been performed to maximize the liquid amount for two hydrogen liquefaction systems using two-stage GM(Gifford-McMahon) refrigerator. the optimal operating conditions have been analytically sought with real properties of normal hydrogen for the two-stage GM direct contact system and the two-stage GM precooled L-H (Linde-Hampson) system. In the precooled system, there existed optimal values for compressed mass flow and compressed pressure to maximize the liquefied mass. It was recommended to use a cryocooler, which had a large precooling capacity between 70 and 100K.

  • PDF

Study on the Synthesis of HoN Nanoparticles and Magnetocaloric Effect as Magnetic Refrigerant for Hydrogen Re-Liquefaction (수소재액화를 위한 자기냉매용 HoN 나노분말 합성 및 자기열량효과 연구)

  • Kim, Dongsoo;Ahn, Jongbin;Jang, Sehoon;Chung, Kookchae;Kim, Jongwoo;Choi, Chuljin
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.25 no.6
    • /
    • pp.594-601
    • /
    • 2014
  • Rare-earth (RE) nitrides can be used as magnetocaloric materials in low temperature. They exhibit ferromagnetism and have Curie temperature in the region from 6 to 70 K. In this study, Holmium nitride (HoN) nano particles were prepared through plasma arc discharge technique and their magnetocaloric properties were studied. Nitrogen gas ($N_2$) was employed as an active element for arc discharge between two electrodes maintained at a constant current. Also, it played an important role not only as a reducing agent but also as an inevitable source of excited nitrogen molecules and nitrogen ions for the formation of HoN phase. Partial pressure of $N_2$ was systematically varied from 0 to 28,000 Pa in order to obtain single phase of HoN with minimal impurities. Magnetic entropy change (${\Delta}S_m$) was calculated with data set measured by PPMS (Physical Property Measurement System). The as-synthesized HoN particles have shown a magnetic entropy change ${\Delta}S_m$) of 27.5 J/kgK in applied field of 50,000 Oe at 14.2 K thereby demonstrating its ability to be applied as an effective magnetic refrigerant towards the re-liquefaction of hydrogen.

Study on Cool-down Analysis Technology for Large Scale Liquid Hydrogen Receiving Terminal (대용량 액체수소 인수기지 쿨다운 해석 기술 연구)

  • CHANG-WON PARK;DONG-HYUK KIM;YEONG-BEOM LEE;HEUNG-SEOK SEO;YOUNG-SOO KWON
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.35 no.1
    • /
    • pp.34-39
    • /
    • 2024
  • Korea government is trying to supply liquid hydrogen from another country to domestic The research for liquid hydrogen transportation and liquefaction plant of hydrogen underway for several years, and empirical research is also planned in the future. Along with the development of liquid hydrogen transport ship/liquefaction plant technology, the development of liquid hydrogen reception base technology must be carried out. In this study, a concept level liquid hydrogen receiving terminal is constructed based on the process of the LNG receiving terminal. Based on this, a study is conducted on the development of analysis technology for the amount of BOG (pipe, tank) generated during cooldown and unloading in the liquid hydrogen unloading line (loading arm to storage tank). The research results are intended to be used as basic data for the design and liquid hydrogen receiving terminal in the future.

Comparative Research on the Carbon Dioxide Liquefaction Using Several Refrigerants (몇 가지 냉매를 사용한 이산화탄소 액화에 대한 비교 연구)

  • ILSU PARK;PHILSUNG HWANG;KICHEOL JUNG;JUNESHU ANH;JUNGHO CHO
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.34 no.2
    • /
    • pp.226-233
    • /
    • 2023
  • In this study, we compared the performance of several refrigeration cycles using different refrigerants and utilizing the cold heat of liquefied natural gas (LNG) for the liquefaction of carbon dioxide. The final conditions for the liquefied CO2 were set to -20℃ and 20 bar. The refrigerants used included R404a, ammonia, propane, and propylene using a vapor recompression refrigeration cycle. For the refrigeration cycle, the CO2 at room temperature and pressure was compressed in a two-stage compression process with an intermediate cooling stage using a refrigeration unit. To compare with the liquefaction process using refrigeration, we compressed the CO2 to 8 bar in a single compression stage and cooled it to around -50℃ using the cold heat of the LNG before liquefying it. Results showed that using ammonia as the refrigerant required the least amount of compressor power for the liquefaction process, and the heat transfer area of the evaporator was the smallest when using propylene as the refrigerant. Using the cold heat of LNG instead of refrigeration using R404a resulted in approximately 69% less energy consumption.

Pre-feasibility Study in Mongolia Tavan Tolgoi Coal Bed Methane (Tavan Tolgoi Coal Bed Methane에 대한 몽골에서의 타당성 조사)

  • CHO, WONJUN;YU, HYEJIN;LEE, JESEOL;LEE, HYUN CHAN;JU, WOO SUNG;LIM, OCKTAEK
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.29 no.1
    • /
    • pp.124-129
    • /
    • 2018
  • Methane is the cleanest fuel and supplies by many distributed type: liquefaction natural gas (LNG), compressed natural gas (CNG), and pipeline natural gas (PNG). Natural gas is mainly composed by methane and has been discovered in the oil and gas fields. Coal bed methane (CBM) is also one of them which reserved in coalbed. This significant new energy sources has emerge to convert an energy source, hydrogen and hydrogen-driven chemicals. For this CBM, this paper was written to analyze the geological analysis and reserves in Mongolian Tavan Tolgoi CBM coal mine and to examine the application field. This paper is mainly a preliminary feasibility report analyzing the business of Tavan Tolgoi CBM and its exploitable gas.

Analysis of Cool-down Operation of Liquid Hydrogen Tank (액체수소 저장탱크의 냉각 방법 분석)

  • HWALONG YOU;BYUNGIL CHOI;KYUHYUNG DO;TAEHOON KIM;CHANGHYUN KIM;MINCHANG KIM;YONGSHIK HAN
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.34 no.6
    • /
    • pp.641-649
    • /
    • 2023
  • This study analyzes the cool-down process of liquid hydrogen storage tanks, which have advantages in terms of large-capacity transfer, storage, and utilization as hydrogen demand increases. A hydrogen liquefaction plant is selected for analysis and an efficient tank cooling method is sought by comparing the time required for the cool-down process with the gas consumption in connection with the gassing-up process required for the operation of the liquid hydrogen storage tank. The results of this study can be referred to in the operation process after the initial start-up and maintenance of the hydrogen liquefaction plant.

Study on the Improvement of Efficiency in Dehydration Process of LNG Liquefaction Plant Using Molecular Sieve (분자체를 이용한 LNG 액화 플랜트 탈수 공정의 효율성 향상에 관한 연구)

  • JONGHWA PARK;DONSANG YU;DAEMYEONG CHO
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.35 no.1
    • /
    • pp.105-113
    • /
    • 2024
  • The natural gas dehydration process plays a central role in liquefying LNG. This study proposes two natural gas dehydration process systems applicable to liquefied natural gas (LNG) liquefaction plants, and compares and analyzes energy optimization measures through simulation. The fuel gas from feed stream (FFF) case, which requires additional equipment for gas circulation, disadvantages are design capacity and increased energy. On the other hand, the end flash gas (EFG) case has advantages such as low initial investment costs and no need for compressors, but has downsides such as increased power energy and the use of gas with different components. According to the process simulation results, the required energy is 33.22 MW for the FFF case and 32.86 MW for the EFG case, confirming 1.1% energy savings per unit time in the EFG case. Therefore, in terms of design pressure, capacity, device configuration, and required energy, the EFG case is relatively advantageous. However, further research is needed on the impact of changes in the composition of regenerated gas on the liquefaction process and the fuel gas system.

Estimation of the Amount of Electric Power Saved in the Carbon Dioxide Liquefaction Process using LNG Cold Heat (LNG 냉열을 활용한 이산화탄소 액화공정에서 절감되는 전력량의 산출)

  • LEE, JIHWAN;CHO, JUNGHO
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.31 no.2
    • /
    • pp.259-264
    • /
    • 2020
  • In this study, comparison study has been performed between two-stage compression and a vapor-recompression refrigeration cycle and a liquefaction using LNG cold heat. When using a first method using two-stage compression and a refrigeration cycle, at least three compressors are required, however when using LNG cold heat, no compressor is required since carbon dioxide can be pumped after condensing with the heat exchange with -160℃ of LNG. Through this study, we can save more than one hundred million KRW annually by using LNG cold heat instead of using gas compression and refrigeration cycle.

Characteristics of Hydrogen and Considerations as a Rocket Propellant (수소의 특성 및 로켓 추진제로서의 고려사항)

  • Lim, Ha-Young;Cho, In-Hyun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2009.11a
    • /
    • pp.23-26
    • /
    • 2009
  • General characteristics of hydrogen and the ratio change of the two forms of hydrogen(ortho-hydrogen and para-hydrogen) as a function of the temperature were introduced. The unique characteristics of hydrogen, such as a wide range of flammability limits, low minimum ignition energy, low maximum inverse temperature, and hydrogen embrittlement were introduced. The process of producing the liquid hydrogen using pre-cooling and expansion engine and ortho-para conversion using the catalyst were introduced. Finally, the characteristics and the considerations as a propellant for liquid rocket were reviewed.

  • PDF