In this study, numerical analysis was performed for the purpose of analyzing the flow characteristics and performance according to the change in the inflow hydrogen temperature and differential pressure of the receptacle of the hydrogen charging system. The pressure distribution and turbulent kinetic energy in the filter area were analyzed by changing the outlet pressure condition under the inlet hydrogen temperature condition, and the flow velocity change at the outlet was compared and analyzed. As a result of the analysis, as the differential pressure decreased, the flow rate at the outlet of the receptacle decreased by up to about 70% at the 2.86 MPa condition compared to the 1.86 MPa condition, and the mass flow rate decreased by about 56.5% at the maximum. It was found that the standard CV performance was not satisfied when the differential pressure at the inlet and outlet was 1.12 MPa or less under the 363K temperature condition.

Hydrogen is considered as one of the most promising future energy carriers due to its noteworthy advantages of renewable and high calorific value. The long-term storage of liquid hydrogen with low heat leakage is essential for future deep space exploration. Because of low critical temperature and volatility, liquid hydrogen tank poses severe requirements to multi-layer insulation (MLI). In order to reduce heat leak into tank, vapor cooled shield (VCS) was set up to cool MLI by retrieving the heat of discharged cryogenic gas hydrogen. This paper presents an parametric study on insulation system in liquid hydrogen storage vessel with MLI and VCS. Thermal model was developed, and heat transfer analysis by varying VCS position was conducted. Temperature and heat flux distributions along time passing were derived, and effect of VCS position on insulation performance was investigated.

본 연구에서는 중공사형 지지체막을 폴리술폰(polysulfone, PSf) 고분자를 이용하여 비용매 상분리법(non solvent induced phase separation, NIPS)에 의해 제조하였다. 제조된 중공사 지지체막을 PDMS와 Pebax를 코팅하여 중공사형 복합막 을 제조하고 CO2, H2, O2 그리고 N2에 대한 순수 투과도(permeance)와 선택도를 측정하였다. 제조된 복합막 모듈 중에서 선 택도(CO2/H2)가 가장 높은 모듈을 선정하여 모사가스를 사용하여 스테이지컷(stage cut, SC)의 변화에 따라 분리성능을 측정 하였다. 이때 사용된 모사가스는 PSA에서 버려지는 off gas의 농도인 CO2 70% : H2 30%인 것을 사용하였다. 1단 실험에서 는 H2 농도 약 60%, H2 회수율 12%의 값을 얻을 수 있었다. 낮은 H2 농도와 회수율을 극복하기 위해 2단 직렬 테스트를 수 행하였으며, 이를 통해 H2 농도 약 70%, H2 회수율 70%를 달성할 수 있었으며, 이를 통해 CO2/H2 분리에 대하여 분리 공정 구성을 도출할 수 있었다.

본 총설은 탄소중립 및 에너지순환을 실현하기 위한 재생에너지로부터 그린수소 생산 전략 중 하나인 바이오수소 생산 및 정제법에 관해 소개하고자 한다. 바이오수소는 생물질과 미생물과 같은 재생에너지원을 이용하며, 상온 및 상압 등의 마일드한 실험조건에서 작동하여 에너지소비 및 공정비용이 적게 드는 친환경 공정으로 알려져 있다. 하지만, 이러한 바이오 수소를 상업적으로 이용하기 위해서는 해결해야 할 중요한 도전적인 과제가 존재한다. 특히, 바이오수소는 생물반응기내의 복합한 화학반응으로 합성되어, 낮은 수소생산 속도 및 반응기내 다양한 혼합물이 존재하여, 바이오수소 고순도화를 위해서 연속공정 형태의 분리 및 정제 기술이 반드시 필요하다. 이를 위해, 저온 증류법, 압력 흡착법, 분리막법 등을 비롯한 다양한 분리 및 정제 기술이 고순도 바이오수소를 얻기 위해 제안되었다. 본 총설에서는 바이오수소 생산 및 정제 연계화를 위한 비 다공성 고분자 분리막의 가능성에 대해 소개하고자 한다.

The influence of specimen geometry and notch on the hydrogen embrittlement of an SA372 steel for pressure vessels was investigated in this study. A slow strain-rate tensile (SSRT) test after the electrochemical hydrogen charging method was conducted on four types of tensile specimens with different directions, shapes (plate, round), and notches. The plate-type specimen showed a significant decrease in hydrogen embrittlement resistance owing to its large surface-to-volume ratio, compared to the round-type specimen. It is well established that most of the hydrogen distributes over the specimen surface when it is electrochemically charged. For the round-type specimens, the notched specimen showed increased hydrogen susceptibility compared with the unnotched one. A notch causes stress concentration and thus generates lots of dislocations in the locally deformed regions during the SSRT test. The solute hydrogen weakens the interactions between these dislocations by promoting the shielding effect of stress fields, which is called hydrogen-enhanced localized plasticity mechanisms. These results provide crucial insights into the relationship between specimen geometry and hydrogen embrittlement resistance.