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Extraction of bitumen with sub- and supercritical water
박정훈,Sou Hwan Son 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.2
The sub- and supercritical water extractions of Athabasca oil sand bitumens were studied using a micro reactor. The experiments were carried out in the temperature range of 360-380 ℃, pressure 15-30 MPa and water density 0.07-0.65 g/cm^3 for 0-2 hrs. The extraction conversion of bitumens increased with solvent power and temperature. A maximum conversion of 24% was obtained after 90 min extraction at the supercritical condition. Hydrogen and carbon mono-oxide were not detected in sub-critical region but in the supercritical region. The supercritical condition was favorable to the hydrogen formation for bitumen extraction. The extraction products were upgraded relative to the original bitumens due to direct hydrolysis of low-energy linkage and H2 formed by water gas shift reaction in supercritical condition. 18% of initial sulfur in bitumen can be removed at maximum conversion condition. The asphaltene contents of the residue were significantly higher than that of original bitumen due to preferential extraction of aromatic compounds in supercritical condition.
Kim, Sou Hyun,Kwon, Do-young,Kwak, Jae-Hwan,Lee, Seunghyun,Lee, Yun-Hee,Yun, Jieun,Son, Tae Gen,Jung, Young-Suk MDPI 2018 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.19 No.12
<P>Endoplasmic reticulum (ER) stress is involved in non-alcoholic fatty liver disease (NAFLD), but the relationship between oxidative stress, another well-known risk factor of NAFLD, and ER stress has yet to be elucidated. In this study, we treated mice with tunicamycin (TM) (2 mg/kg body weight) for 48 h to induce ER stress in the liver and examined the metabolic pathway that synthesizes the endogenous antioxidant, glutathione (GSH). Tunicamycin (TM) treatment significantly increased mRNA levels of CHOP and GRP78, and induced lipid accumulation in the liver. Lipid peroxidation in the liver tissue also increased from TM treatment (CON vs. TM; 3.0 ± 1.8 vs. 11.1 ± 0.8 nmol MDA/g liver, <I>p</I> < 0.001), which reflects an imbalance between the generation of reactive substances and antioxidant capacity. To examine the involvement of GSH synthetic pathway, we determined the metabolomic changes of sulfur amino acids in the liver. TM significantly decreased hepatic S-adenosylmethionine concentration in the methionine cycle. The levels of cysteine in the liver were increased, while taurine concentration was maintained and GSH levels profoundly decreased (CON vs. TM; 8.7 ± 1.5 vs. 5.4 ± 0.9 µmol GSH/g liver, <I>p</I> < 0.001). These results suggest that abnormal cysteine metabolism by TM treatment resulted in a decrease in GSH, followed by an increase in oxidative stress in the liver. In HepG2 cells, decreased GSH levels were examined by TM treatment in a dose dependent manner. Furthermore, pretreatment with TM in HepG2 cells potentiated oxidative cell death, by exacerbating the effects of tert-butyl hydroperoxide. In conclusion, TM-induced ER stress was accompanied by oxidative stress by reducing the GSH synthesis, which made the liver more susceptible to oxidative stress.</P>
산소분리를 위한 Ba0.5Sr0.5Co0.8Fe0.2O3-δ 관형 분리막 제조 및 투과 특성
김종표 ( Jong Pyo Kim ),손수환 ( Sou Hwan Son ),박정훈 ( Jung Hoon Park ),이용택 ( Yong Taek Lee ) 한국화학공학회 2011 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.49 No.6
Ba0.5Sr0.5Co0.8Fe0.2O3-δ 조성의 관형 분리막을 압출 성형 방법으로 제조하였다. 압출성형 직후 분리막의 TGA 분석결과 3단계의 무게감소로 첨가제와 탄산염이 분해되었고, 건조 수축율은 68 h 경과 후 변화가 없었으며 외경이 큰 분리막에서 높게 나타났다. 소결 후 분리막의 XRD 및 SEM 분석결과, 분리막은 단일상의 페롭스카이트 구조를 갖는 치밀한 막을 보였고, EDS 분석을 통해 Ba0.5Sr0.5Co0.8Fe0.2O3-δ와 유사한 성분함량을 가짐을 확인하였다. 두께 0.95mm Ba0.5Sr0.5Co0.8Fe0.2O3-δ 관형 분리막의 압환강도(radial crushing strength)는 5.7 kgf/mm2이였으며, 950 ℃에서 산소투과량은 146.85 mL/min(Jo2=2.33 mL/min·cm2)를 나타냈었다. 투과 측의 진공펌프 사용이 쓸개 가스를 활용한 것보다 산소 투과량 증진에 효과가 있음을 알 수 있었다. Tubular Ba0.5Sr0.5Co0.8Fe0.2O3-δ membranes were prepared by extrusion. TGA results of green body membrane after extrusion showed three successive weight losses due to decomposition of organic additives and carbonate. Drying shrinkage rate of tubular Ba0.5Sr0.5Co0.8Fe0.2O3-δ membranes was no change after 68 h and higher in the membrane with large outer diameter. XRD and SEM results showed the sintered membranes were the single phase structure and dense. The stoichiometric molar ratio agreed well with composition ratio calculated by EDS results for Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane. Radial crushing strength of tubular Ba0.5Sr0.5Co0.8Fe0.2O3-δ membrane with 0.95 mm thickness was 5.7 kgf /mm2 and the oxygen permeation rate of same membrane was 146.85 mL/min (Jo2=2.33 mL/min·cm2) at 950 ℃. Therefore, it was known that use of vacuum pump was more effective than that of sweep gas to obtain higher oxygen permeation flux.
Lu, Hui,Kim, Jong Pyo,Son, Sou Hwan,Park, Jung Hoon Elsevier 2010 Materials science and engineering B. Advanced Func Vol.166 No.2
<P><B>Abstract</B></P><P>The perovskite La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>M<SUB>0.3</SUB>Fe<SUB>0.7</SUB>O<SUB>3−<I>δ</I></SUB> (M=Co, Ti) powders have been synthesized by the citrate gel method. The structural and chemical stability of the La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>M<SUB>0.3</SUB>Fe<SUB>0.7</SUB>O<SUB>3−<I>δ</I></SUB> (M=Co, Ti) oxides were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. The electrical conductivities of the sintered La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>M<SUB>0.3</SUB>Fe<SUB>0.7</SUB>O<SUB>3−<I>δ</I></SUB> (M=Co, Ti) ceramics were measured. The results demonstrate the chemical stability in H<SUB>2</SUB>/helium (He) atmosphere of the La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>Ti<SUB>0.3</SUB>Fe<SUB>0.7</SUB>O<SUB>3−<I>δ</I></SUB> oxide is improved significantly compared to that of the La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>Co<SUB>0.3</SUB>Fe<SUB>0.7</SUB>O<SUB>3−<I>δ</I></SUB> oxide. The incorporation of Ti<SUP>3+/4+</SUP> ions in the perovskite structure can significantly stabilize the neighboring oxygen octahedral due to the stronger bonding strength, leading to the enhanced structural and chemical stability of the La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>Ti<SUB>0.3</SUB>Fe<SUB>0.7</SUB>O<SUB>3−<I>δ</I></SUB>. In addition, the perovskite La<SUB>0.6</SUB>Sr<SUB>0.4</SUB>M<SUB>0.3</SUB>Fe<SUB>0.7</SUB>O<SUB>3−<I>δ</I></SUB> (M=Co, Ti) oxides possess much higher chemical stability in CO<SUB>2</SUB>/He atmosphere than that of Ba<SUB>0.5</SUB>Sr<SUB>0.5</SUB>Co<SUB>0.8</SUB>Fe<SUB>0.2</SUB>O<SUB>3−<I>δ</I></SUB> oxide, in which the perovskite structure is destroyed completely in a flowing CO<SUB>2</SUB>-containing atmosphere.</P>
Kim, Ki-Young,Park, Jung-Hoon,Kim, Jong-Pyo,Son, Sou-Hwan,Park, Sang-Do The Membrane Society of Korea 2007 Korean Membrane Journal Vol.9 No.1
A perovskite-type ($La_{0.6}Sr_{0.4}Ti_{0.2}Fe_{0.8}O_{3-{\delta}}$) dense ceramic membrane was prepared by polymerized complex method, using citric acid as a chelating agent and ethylene glycol as an organic stabilizer. Effect of Ti addition on lanthanum-strontium ferrite mixed conductor was investigated by evaluating the thermal expansion coefficient, the oxygen flux, the electrical conductivity, and the phase stability. The thermal expansion coefficient in air was $21.19\;{\times}\;10^{-6}/K$ at 473 to 1,223 K. At the oxygen partial pressure of 0.21 atm ($20%\;O_2$), the electrical conductivity increased with temperature and then decreased after 973 K. The decrement in electrical conductivity at high temperatures was explained by a loss of the lattice oxygen. The oxygen flux increased with temperature and was $0.17\;mL/cm^2{\cdot}min$ at 1,223 K. From the temperature-dependent oxygen flux data, the activation energy of oxygen ion conduction was calculated and was 80.5 kJ/mol at 1,073 to 1,223 K. Also, the Ti-added lanthanum-strontium ferrite mixed conductor was structurally and chemically stable after 450 hours long-term test at 1,173 K.