• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.77-83
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• 2023

Energy consumption is increased by rapid industrialization. As a result, climate change is accelerating due to the increase in CO₂ concentration in the atmosphere. Therefore, a shift in the energy paradigm is required. Hydrogen is in the spotlight as a part of that. Currently 95% of hydrogen is fossil fuel-based reforming hydrogen which is accompanied by CO₂ emissions. This is called gray hydrogen, if the CO₂ is captured and emission of CO₂ is reduced, it can be converted into blue hydrogen. There are 3 technologies to capture CO₂: absorption, adsorption and membrane technology. In order to select CO₂ capture technology, the analysis of the exhaust gas should be carried out. The concentration of CO₂ in the flue gas from the hydrogen production process is higher than 20%if water is removed as well as the emission scale is classified as small and medium. So, the application of the membrane technology is more advantageous than the absorption. In addition, if LNG cold energy can be used for low temperature CO₂ capture system, the CO₂/N₂ selectivity of the membrane is higher than room temperature CO₂ capture and enabling an efficient CO₂ capture process. In this study, we will analyze the flue gas from hydrogen production process and discuss suitable CO₂ capture technology for it.

• Food Science and Preservation
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• v.19 no.4
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• pp.532-538
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• 2012

Seven rice varieties (Dasan, Keunseon, Goami, Baekjinju, Seolgaeng, Hangangchal and Heukseol) were used to study the physicochemical properties of dry milled (200-mesh) rice flour species. The moisture and crude protein contents of rice were 15.00-15.10% and 6.09-8.21%, respectively. The crude lipid and crude ash of rice were 0.21-1.02% and 0.37-1.62%, respectively. As for the Hunter's color value, the L value was highest in the Dasan flour (96.47); the a value was highest in the Heukseol flour (5.03); and the b value was highest in the Baekjinju flour (3.36). The water aborption index was highest in the Goami flour (1.45), and the water solubility index was highest in the Hangangchal flour (9.16%). The amylose contents of the rice flour species were highest in the Goami (26.42%) rice flour, followed by the Dasan (19.39%), Seolgaeng (19.24%), Keunseon (18.06%), Heukseol (15.52%), Baekjinju (9.16%), and Hangangchal (0.84%) rice flour. In the X-raydiffractin patterns of the diverse species, seven tice varieties showed A-type crystallinity. As for the amylogram properties, the initial pasting temperature was 58.00-$69.03^{\circ}C$. The maximum viscosity was highest in the Dasan flour. The Heukseol flour had the lowest maximum viscosity, breakdown, and setback. In terms of the thermal properties of the differential scanning calorimeter (DSC), the onset temperature was 59.03-$66.84^{\circ}C$; the peak temperature, 66-70-$72.82^{\circ}C$; and the end temperature, 74.06-$78.66^{\circ}C$. The enthalpy (${\Delta}H$) was lowest in the Heukseol flour (7.59 J/g) and highest in the Seolgaeng flour (11.36J/g).

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.499-505
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• 2010

In this study, hydrodynamics and reaction characteristic of K-based solid sorbents for $CO_2$ capture were investigated using a continuous system composed of two bubbling fluidized-bed reactors(1.2 m tall bed with 0.11 m i.d.). Potassium-based dry sorbents manufactured by the Korea Electric Power Research Institute were used, which were composed of $K_2CO_3$ of 35% for $CO_2$ absorption and supporters of 65% for mechanical strength. The continuous system consists of two bubbling fluidized-bed reactors, solid injection nozzle, riser, chiller, analyzer and heater for regeneration reaction. The minimum fluidizing velocity of the continuous system was 0.0088 m/s and the solid circulation rate measured was $10.3kg/m^2{\cdot}s$ at 1.05 m/s velocity of the solid injection nozzle. The $CO_2$ concentration of the simulated gas was about 10 vol% in dry basis. Reaction temperature in carbonator and regenerator were maintained about $70^{\circ}C$ and $200^{\circ}C$, respectively. Differential pressures, which were maintained in carbonator and regenerator, were about $415mmH_2O$ and $350mmH_2O$, respectively. In order to find out reaction characteristics of dry sorbents, several experiments were performed according to various experimental conditions such as $H_2O$ content(7.28~19.66%) in feed gas, velocity (0.053~0.103 m/s) of simulated gas, temperature($60{\sim}80^{\circ}C$) of a carbonator, temperature($150{\sim}200^{\circ}C$) of a regenerator and solid circulation rate($7.0{\sim}10.3kg/m^2{\cdot}s$). The respective data of operating variables were saved and analyzed after maintaining one hour in a stable manner. As a result of continuous operation, $CO_2$ removal tended to increase by increasing $H_2O$ content in feed gas, temperature of a regenerator and solid circulation rate and to decrease by increasing temperature of a carbonator and gas velocity in a carbonator.

• The Korean Journal of Blood Transfusion
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• v.29 no.3
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• pp.301-309
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• 2018

Background: If donors who were deferred due to the reactivity or grey zone in HBV surface antigen (HBsAg) assay want to donate blood again, they need to pass reentry tests. On the other hand, approximately half of the donors who are subject to the reentry tests cannot be reentered. This study examined the association between the sample to cutoff (S/Co) value of the HBsAg assay and the final results of the reentry test. Methods: This study analyzed the S/Co values of the HBsAg assay and the final results of the reentry tests for the 3,947 donors from January 2008 to December 2017 using the database of Blood Information Management System of the Korean Red Cross. Results: 1,767 donors (44.8%) were not reentered among 3,947 deferred donors. Among 1,585 donors showing ${\geq}10$ of the S/Co value in the HBsAg screening test, 1,542 donors (97.3%) were not reentered. The additional reentry tests were performed on 120 donors who were not reentered in the first reentry test; 98 donors (81.7%) were still not reentered. Overall, 4.6% of the donors showing a grey zone in the HBsAg assay were not reentered. Conclusion: The reentry test needs to be restricted for the deferred donors showing a more than 10 S/Co value. The application of the grey zone of current HBsAg assay will need to be continued to enhance the HBV-related blood safety.