• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.135-144
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• 2021

In this study, we investigated the characteristics of the process of hydrogen production using boil-of gas (BOG) generated from an LNG-fueled ship and the application of hydrogen fuel cell systems as auxiliary engines. In this study, the BOG steam reformer process was designed using the UniSim R410 program, and the reformer outlet temperature, pressure, and the fraction and consumption of the product according to the steam/carbon ratio (SCR) were calculated. According to the study, the conversion rate of methane was 100 % when the temperature of the reformer was 890 ℃, and maximum hydrogen production was observed. In addition, the lower the pressure, the higher is the reaction activity. However, higher temperatures have led to a decrease in hydrogen production owing to the preponderance of adverse reactions and increased amounts of water and carbon dioxide. As SCR increased, hydrogen production increased, but the required energy consumption also increased proportionally. Although the hydrogen fraction was the highest when the SCR was 1.8, it was confirmed that the optimal operation range was for SCR to operate at 3 to prevent cocking. In addition, the lower the pressure, the higher is the amount of carbon dioxide generated. Furthermore, 42.5 % of the LNG cold energy based on carbon dioxide generation was required for cooling and liquefaction.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.382-390
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• 2007

To check the feasibility of SMART(Steam Methane Advanced Reforming Technology) system, an experimental investigation was performed. A fluidized bed reactor of diameter 0.052m was operated cyclically up to 10th cycle, alternating between reforming and regeneration conditions. FCR-4 catalyst was used as the reforming catalyst and calcined limestone(domestic, from Danyang) was used as the $CO_2$ absorbent. Hydrogen concentration of 98.2% on a dry basis was reached at $650^{\circ}C$ for the first cycle. This value is much higher than $H_2$ concentration of 73.6% in the reformer of conventional SMR (steam methane reforming) condition. The hydrogen concentration decreased because the $CO_2$ capture capacity decreased as the number of cycles increased. However, the average hydrogen concentration at 10th cycle was 82.5% and this value is also higher than that of SMR. Based on these results, we could conclude that the SMART system can replace SMR system to generate pure hydrogen without HTS (high tempeature shift), LTS (low temperature shift) and $CO_2$ separation process.

• Journal of Energy Engineering
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• v.19 no.4
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• pp.240-245
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• 2010

In this study, characteristics of wood pellet gasification was studied using a Two Stage Gasifier which is consisted of pyrolysis reactor and ultra high temperature reformer. The average yields of $H_2$, $CH_4$, CO, $CO_2$ were 16.7, 11.3, 37.2, 26.6 L/mim, conversion rate from biomass to gas was 65% in pyrolysis reactor and gas yields in reformer were 55.4, 0.8, 120.8, 56.8 L/mim, respectively. The hydrogen flow rate from reformer is obtained 360.1 L/hr. The most of $CH_4$ was decomposed from 12.3 to 0.3 vol.% while $H_2$ is from 18.2 to 23.7 vol.% in reformer by methane dry reforming, Boudouard reaction, oxidation and/or steam reforming. The amount of $H_2O$ generated by hydration reaction from reformer was 1111.8 g, its accelerated conversion of $CH_4$ to other products. The conversion rate from $CH_4$ to other Compounds was 97.2%. Cold gas efficiency was 53.2%.

• 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.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.2
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• pp.135-143
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• 2016

Biogas is a renewable fuel from anaerobic digestion of organic matters such as sewage sludge, manure and food waste. Raw biogas consists mainly of methane, carbon dioxide, hydrogen sulfide, and water. Biogas may also contain other impurities such as siloxanes, halogenated hydrocarbons, aromatic hydrocarbons. Efficient power technologies such as fuel cell demand ultra-low concentration of containments in the biogas feed, imposing stringent requirements on fuel purification technology. Biogas is upgraded from pressure swing adsorption after biogas purification process which consists of water, $H_2S$ and siloxane removal. A polymer electrolyte membrane fuel cell power plant is designed to operate on reformate produced from upgraded biogas by steam reformer.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.12
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• pp.840-846
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• 2012

Global climate changes caused by $CO_2$ emissions are currently debated around the world; green sources of energy are being sought as alternatives to replace fossil fuels. The sustainable use of biogas for energy production does not contribute to $CO_2$ emission and has therefore a high potential to reduce them. Catalytic steam reforming of a model biogas ($CH_4:CO_2$ = 60%:40%) is investigated to produce $H_2$-rich synthesis gas. The biogas utilized 3D-IR matrix burner in which the surface combustion is applied. The ruthenium catalyst was used inside a reformer. Parametric screening studies were achieved as Steam/Carbon ratio, biogas component ratio, Space velocity and Reformer temperature. When the condition of Steam/Carbon ratio, $CH_4/CO_2$ ratio, Space velocity and Refomer temperature were 3.25, 60% : 40%, $14.7L/g{\cdot}hr$ and $550^{\circ}C$ respectively, the hydrogen concentration and methane conversion rate were showed maximum values. Under the condition mentioned above, $H_2$ yield, $H_2$/CO ratio, CO selectivity and energy efficiency were 0.65, 2.14, 0.59, 51.29%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.7
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• pp.558-565
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• 2008

Solid oxide fuel cell(SOFC) has a higher fuel flexibility than low temperature fuel cells, such as polymer electrolyte fuel cell(PEMFC) and phosphoric acid fuel cell(PAFC). SOFCs also use CO and $CH_4$ as a fuel, because SOFCs are hot enough to allow the CH4 steam reformation(SR) reaction and water-gas shift(WGS) reaction occur within the SOFC stack itself. Diesel is a good candidate for SOFC system fuel because diesel reformate gas include a higher degree of CO and $CH_4$ concentration than other hydrocarbon(methane, butane, etc.) reformate gas. Selection of catalyst for autothermalr reforming of diesel was performed in this paper, and characteristics of reforming performance between packed-bed and microchannel catalyst are compared for SOFC system. The mesh-typed microchannel catalyst also investigated for diesel ATR operation for 1kW-class SOFC system. 1kW-class diesel microchannel ATR was continuously operated about 30 hours and its reforming efficiency was achieved nearly 55%.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.37-42
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• 2006

In this study, $20Nm^3/hr$ scale compact hydrogen generator which can be apply to the hydrogen station was tested for hydrogen station application. $20Nm^3/hr$ scale compact hydrogen generator was developed by upgrading concept of stacking plate reactor from former $20Nm^3/hr$ scale plate hydrogen generator. concepts for improving system efficiency and performance include such as idea of heat recovery from the exhaust, exhaust duct which is especially design for plate type reactor reinforcement of insulation, enlargement of heat exchange area of reactor, introduction of desulphurizer reactor and PROX rector in a compact design, introduction of back fire protection structure of plate burner and so on, We can learn that final prototype of scale-up $20Nm^3/hr$ scale compact hydrogen generator can be operated steadily in 100% road at which over 94% of methane conversion(S/C=3.75) was obtained. In case of making up the weak point, we expect that it is possible to apply to hydrogen station by way of showing an example.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.1-8
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• 2020

In recent years, hydrogen has received much attention as an alternative energy source to fossil fuels. In order to ensure safety from the increasing number of hydrogen refueling stations, prevention methods have been required. In this regard, this study suggested an approach to reduce the risk of hydrogen refueling station by increasing Safety Integrity Level (SIL) for a Steam Methane Reformer (SMR) in On-Site Hydrogen Refueling Station. The worst scenario in the SMR was selected by HAZOP and the required SIL for the worst scenario was identified by LOPA. To verify the required SIL, the PFDavg.(1/RRF) of Safety Instrumented System (SIS) in SMR was calculated by using realistic failure rate data of SIS. Next, several conditions were tested by varying the sensor redundancy and proof test interval reduction and their effects on risk reduction factor were investigated. Consequently, an improved condition, which were the redundancy of two-out-of-three and the proof test interval of twelve months, achieved the tolerable risk resulting in the magnitude of risk reduction factor ten times greater than that of the baseline condition.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.56-62
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• 2014

The present study investigated numerically heat and mass transfer characteristics of a fixed bed reactor by using a computational fluid dynamics (CFD) code of Fluent (ver. 13.0). The temperature and species fraction were estimated for different porosities. For modeling of the catalyst in a fixed bed tube, catalysts were regarded as the porous material, and the empirical correlation of pressure drop based on the modified Eugun equation was used for simulation. In addition, the averaged porosities were taken as 0.545, 0.409, and 0.443 and compared with non-porous state. The predicted results showed that the temperature at the tube wall became higher than that estimated along the center line of tube, leading to higher hydrogen generation by the endothermic reaction and heat transfer. As the mean porosity increases, the hydrogen yield and the outlet temperature decreased because of the pressure drop inside the reformer tube.