• Title/Summary/Keyword: equilibrium temperature

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Thermal history of the Jecheon granite pluton in the Ogcheon Fold Belt, South Korea (남한의 옥천습곡대에 분포되어 있는 제천화강암체의 열역사)

  • Jin Myung-Shik;Kim Seong-Jae;Shin Seong-Cheon;Choo Seung-Hwan;Chi Se-Jung
    • The Journal of the Petrological Society of Korea
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    • v.1 no.1
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    • pp.49-57
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    • 1992
  • Whole rock and mineral ages for the Jecheon Granite distributed in the Ogcheon Fold Belt were dated by three radiometric methods, and its thermal history was elucidated as follows, on the basis of isotopic age data. Rb and Sr isotopic compositions of three whole rock and seven mineral concentrates made an isochron of 202.7${\pm}$ 1.9 Ma with a strontium initial ratio of 0.7140. Different age data of twelve mineral concentrates agree closely with the retention temperature of each mineral in K-Ar and Fission Track methods. The Jecheon granitic magma was generated by partial melting of crustal materials (S-type), or by mixins between mantle and crustal materials, intruded into the katazone or mesozone (7∼9 km) of the Ogcheon Fold Belt, at least in the Early Jurassic (about 203 Ma), and then crystallized and cooled down rapidly from about 600$^{\circ}C$ to 300$^{\circ}C$ (more than 20$^{\circ}C$/Ma), owing to thermal differences between the magma and the wall-rock. During the Middle to Late Jurassic (190∼140 Ma), the cooling of the granite was likely to stop and keep thermal equilibrium with the wall-rock. The severe tectonism associated with igneous activities and active weathering on the surface in Early to Late Cretaceous time (140∼70 Ma) might have accelerated the granite pluton to uplift rapidly (40∼60 m/Ma in average) up to 3∼4 km and cooled down from 300$^{\circ}C$ to 200$^{\circ}C$ (1.4 $^{\circ}C$/Ma). The granite pluton was likely to keep different uplifting and cooling rate of about 120 m/Ma and 5$^{\circ}C$/Ma in average from the Late Cretaceous to Early Tertiary (70∼50 Ma), and about 60 m/Ma and 2$^{\circ}C$/Ma in average from about 50 Ma up to the present, respectively.

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Pharmacological Studies of Cefoperazone(T-1551) (Cefoperazone(T-1551)의 약리학적 연구)

  • Lim J.K.;Hong S.A.;Park C.W.;Kim M.S.;Suh Y.H.;Shin S.G.;Kim Y.S.;Kim H.W.;Lee J.S.;Chang K.C.;Lee S.K.;Chang K.C.;Kim I.S.
    • The Korean Journal of Pharmacology
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    • v.16 no.2 s.27
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    • pp.55-70
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    • 1980
  • The pharmacological and microbiological studies of Cefoperazone (T-1551, Toyama Chemical Co., Japan) were conducted in vitro and in vivo. The studies included stability and physicochemical characteristics, antimicrobial activity, animal and human pharmacokinetics, animal pharmacodynamics and safety evaluation of Cefoperazone sodium for injection. 1) Stability and physicochemical characteristics. Sodium salt of cefoperazone for injection had a general appearance of white crystalline powder which contained 0.5% water, and of which melting point was $187.2^{\circ}C$. The pH's of 10% and 25% aqueous solutions were 5.03 ana 5.16 at $25^{\circ}C$. The preparations of cefoperazone did not contain any pyrogenic substances and did not liberate histamine in cats. The drug was highly compatible with common infusion solutions including 5% Dextrose solution and no significant potency decrease was observed in 5 hours after mixing. Powdered cefoperazone sodium contained in hermetically sealed and ligt-shielded container was highly stable at $4^circ}C{\sim}37^{\circ}C$ for 12 weeks. When stored at $4^{\circ}C$ the potency was retained almost completely for up to one year. 2) Antimicrobial activity against clinical isolates. Among the 230 clinical isolates included, Salmonella typhi was the most susceptible to cefoperazone, with 100% inhibition at MIC of ${\leq}0.5{\mu}g/ml$. Cefoperazone was also highly active against Streptococcus pyogenes(group A), Kletsiella pneumoniae, Staphylococcus aureus and Shigella flexneri, with 100% inhibition at $16{\mu}g/ml$ or less. More than 80% of Escherichia coli, Enterobacter aerogenes and Salmonella paratyphi was inhibited at ${\leq}16{\mu}/ml$, while Enterobacter cloaceae, Serratia marcescens and Pseudomonas aerogenosa were somewhat less sensitive to cefoperagone, with inhibitions of 60%, 55% and 35% respectively at the same MIC. 3) Animal pharmacokinetics Serum concentration, organ distritution and excretion of cefoperazone in rats were observed after single intramuscular injections at doses of 20 mg/kg and 50 mg/kg. The extent of protein binding to human plasma protein was also measured in vitro br equilibrium dialysis method. The mean Peak serum concentrations of $7.4{\mu}g/ml$ and $16.4{\mu}/ml$ were obtained at 30 min. after administration of cefoperazone at doses of 20 mg/kg and 50 mg/kg respectively. The tissue concentrations of cefoperazone measured at 30 and 60 min. were highest in kidney. And the concentrations of the drug in kidney, liver and small intestine were much higher than in blood. Urinary and fecal excretion over 24 hours after injetcion ranged form 12.5% to 15.0% in urine and from 19.6% to 25.0% in feces, indicating that the gastrointestinal system is more important than renal system for the excretion of cefoperazone. The extent of binding to human plasma protein measured by equilibrium dialysis was $76.3%{\sim}76.9%$, which was somewhat lower than the others utilizing centrifugal ultrafiltration method. 4) Animal pharmacodynamics Central nervous system : Effects of cefoperazone on the spontaneous movement and general behavioral patterns of rats, the pentobarbital sleeping time in mice and the body temperature in rabbits were observed. Single intraperitoneal injections at doses of $500{\sim}2,000mg/kg$ in rats did not affect the spontaneous movement ana the general behavioral patterns of the animal. Doses of $125{\sim}500mg/kg$ of cefoperazone injected intraperitonealy in mice neither increased nor decreased the pentobarbital-induced sleeping time. In rabbits the normal body temperature was maintained following the single intravenous injections of $125{\sim}2,000mg/kg$ dose. Respiratory and circulatory system: Respiration rate, blood pressure, heart rate and ECG of anesthetized rabbits were monitored for 3 hours following single intravenous injections of cefoperazone at doses of $125{\sim}2,000mg/kg$. The respiration rate decreased by $3{\sim}l7%$ at all the doses of cefoperazone administered. Blood pressure did not show any changes but slight decrease from 130/113 to 125/107 by the highest dose(2,000 mg/kg) injected in this experiment. The dosages of 1,000 and 2,000 mg/kg seemed to slightly decrease the heart rate, but it was not significantly different from the normal control. All the doses of cefoperazone injected were not associated with any abnormal changes in ECG findings throughout the monitering period. Autonomic nervous system and smooth muscle: Effects of cefoperazone on the automatic movement of rabbit isolated small intestine, large intestine, stomach and uterus were observed in vitro. The autonomic movement and tonus of intestinal smooth muscle increased at dose of $40{\mu}g/ml$ in small intestine and at 0.4 mg/ml in large intestine. However, in stomach and uterine smooth muscle the autonomic movement was slightly increased by the much higher doses of 5-10 mg/ml. Blood: In vitro osmotic fragility of rabbit RBC suspension was not affected by cefoperazone of $1{\sim}10mg/ml$. Doses of 7.5 and 10 mg/ml were associated with 11.8% and 15.3% prolongation of whole blood coagulation time. Liver and kidney function: When measured at 3 hours after single intravenous injections of cefoperaonze in rabbits, the values of serum GOT, GPT, Bilirubin, TTT, BUN and creatine were not significantly different from the normal control. 5) Safety evaluation Acute toxicity: The acute toxicity of cefoperazone was studied following intraperitoneal and intravenous injections to mice(A strain, 4 week old) and rats(Sprague-Dawler, 6 week old). The LD_(50)'s of intraperitonealy injected cefoperazone were 9.7g/kg in male mice, 9.6g/kg in female mice and over 15g/kg in both male and female rats. And when administered intravenously in rats, LD_(50)'s were 5.1g/kg in male and 5.0g/kg in female. Administrations of the high doses of the drug were associated with slight inhibition of spontaneous movement and convulsion. Atdominal transudate and intestinal hyperemia were observed in animals administered intraperitonealy. In rats receiving high doses of the drug intravenously rhinorrhea and pulmonary congestion and edema were also observed. Renal proximal tubular epithelial degeneration was found in animals dosing in high concentrations of cefoperazone. Subacute toxicity: Rats(Sprague-Dawley, 6 week old) dosing 0.5, 1.0 and 2.0 g/kg/day of cefoperazone intraperitonealy were observed for one month and sacrificed at 24 hours after the last dose. In animals with a high dose, slight inhibition of spontaneous movement was observed during the experimental period. Soft stool or diarrhea appeared at first or second week of the administration in rats receiving 2.0g/kg. Daily food consumption and weekly weight gain were similar to control during the administration. Urinalysis, blood chemistry and hematology after one month administration were not different from control either. Cecal enlargement, which is an expected effect of broad spectrum antibiotic altering the normal intestinal microbial flora, was observed. Intestinal or peritoneal congestion and peritonitis were found. These findings seemed to be attributed to the local irritation following prolonged intraperitoneal injections of hypertonic and acidic cefoperazone solution. Among the histopathologic findings renal proximal tubular epithelial degeneration was characteristic in rats receiving 1 and 2g/kg/day, which were 10 and 20 times higher than the maximal clinical dose (100 mg/kg) of the drug. 6) Human pharmacokinetics Serum concentrations and urinary excretion were determined following a single intravenous injection of 1g cefoperazone in eight healthy, male volunteers. Mean serum concentrations of 89.3, 61.3, 26.6, 12.3, 2.3, and $1.8{\mu}g/ml$ occured at 1,2,4,6,8 and 12 hours after injection respectively, and the biological half-life was 108 minutes. Urinary excretion over 24 hours after injection was up to 43.5% of administered dose.

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Mineralogy and Geochemistry of the Jeonheung and Oksan Pb-Zn-Cu Deposits, Euiseong Area (의성(義城)지역 전흥(田興) 및 옥산(玉山) 열수(熱水) 연(鉛)-아연(亞鉛)-동(銅) 광상(鑛床)에 관한 광물학적(鑛物學的)·지화학적(地化學的) 연구(硏究))

  • Choi, Seon-Gyu;Lee, Jae-Ho;Yun, Seong-Taek;So, Chil-Sup
    • Economic and Environmental Geology
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    • v.25 no.4
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    • pp.417-433
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    • 1992
  • Lead-zinc-copper deposits of the Jeonheung and the Oksan mines around Euiseong area occur as hydrothermal quartz and calcite veins that crosscut Cretaceous sedimentary rocks of the Gyeongsang Basin. The mineralization occurred in three distinct stages (I, II, and III): (I) quartz-sulfides-sulfosalts-hematite mineralization stage; (II) barren quartz-fluorite stage; and (III) barren calcite stage. Stage I ore minerals comprise pyrite, chalcopyrite, sphalerite, galena and Pb-Ag-Bi-Sb sulfosalts. Mineralogies of the two mines are different, and arsenopyrite, pyrrhotite, tetrahedrite and iron-rich (up to 21 mole % FeS) sphalerite are restricted to the Oksan mine. A K-Ar radiometric dating for sericite indicates that the Pb-Zn-Cu deposits of the Euiseong area were formed during late Cretaceous age ($62.3{\pm}2.8Ma$), likely associated with a subvolcanic activity related to the volcanic complex in the nearby Geumseongsan Caldera and the ubiquitous felsite dykes. Stage I mineralization occurred at temperatures between > $380^{\circ}C$ and $240^{\circ}C$ from fluids with salinities between 6.3 and 0.7 equiv. wt. % NaCl. The chalcopyrite deposition occurred mostly at higher temperatures of > $300^{\circ}C$. Fluid inclusion data indicate that the Pb-Zn-Cu ore mineralization resulted from a complex history of boiling, cooling and dilution of ore fluids. The mineralization at Jeonheung resulted mainly from cooling and dilution by an influx of cooler meteoric waters, whereas the mineralization at Oksan was largely due to fluid boiling. Evidence of fluid boiling suggests that pressures decreased from about 210 bars to 80 bars. This corresponds to a depth of about 900 m in a hydrothermal system that changed from lithostatic (closed) toward hydrostatic (open) conditions. Sulfur isotope compositions of sulfide minerals (${\delta}^{34}S=2.9{\sim}9.6$ per mil) indicate that the ${\delta}^{34}S_{{\Sigma}S}$ value of ore fluids was ${\approx}8.6$ per mil. This ${\delta}^{34}S_{{\Sigma}S}$ value is likely consistent with an igneous sulfur mixed with sulfates (?) in surrounding sedimentary rocks. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values. Equilibrium thermodynamic interpretation indicates that the temperature versus $fs_2$ variation of stage I ore fluids differed between the two mines as follows: the $fs_2$ of ore fluids at Jeonheung changed with decreasing temperature constantly near the pyrite-hematite-magnetite sulfidation curve, whereas those at Oksan changed from the pyrite-pyrrhotite sulfidation state towards the pyrite-hematite-magnetite state. The shift in minerals precipitated during stage I also reflects a concomitant $fo_2$ increase, probably due to mixing of ore fluids with cooler, more oxidizing meteoric waters. Thermodynamic consideration of copper solubility suggests that the ore-forming fluids cooled through boiling at Oksan and mixing with less-evolved meteoric waters at Jeonheung, and that this cooling was the main cause of copper deposition through destabilization of copper chloride complexes.

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Characteristics of Coal Slurry Gasification under Partial Slagging Operating Condition (부분 용융 운전 조건에서 석탄슬러리 가스화 운전 특성)

  • Lee, Jin Wook;Chung, Seok Woo;Lee, Seung Jong;Jung, Woohyun;Byun, Yong Soo;Hwang, Sang Yeon;Jeon, Dong Hwan;Ryu, Sang Oh;Lee, Ji Eun;Jeong, Ki Jin;Kim, Jin Ho;Yun, Yongseung
    • Korean Chemical Engineering Research
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    • v.52 no.5
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    • pp.657-666
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    • 2014
  • Coal gasification technology is considered as next generation clean coal technology even though it uses coal as fuel which releases huge amount of greenhouse gas because it has many advantages for carbon capture. Coal or pet-coke slurry gasification is very attractive technology at present and in the future because of its low construction cost and flexibility of slurry feeding system in spite of lower efficiency compared to dry feeding technology. In this study, we carried out gasification experiment using bituminous coal slurry sample by integrating coal slurry feeding facility and slurry burner into existing dry feeding compact gasifier. Especially, our experiment was conducted under fairly lower operation temperature than that of existing entrained-bed gasifier, resulting in partial slagging operation mode in which only part of ash was converted to slag and the rest of ash was released as fly ash. Carbon conversion rate was calculated from data analysis of collected slag and ash, and then cold gas efficiency, which is the most important indicator of gasifier performance, was estimated by carbon mass balance method. Fairly high performance considering pilot-scale experiment, 98.5% of carbon conversion and 60.4% of cold gas efficiency, was achieved. In addition, soundness of experimental result was verified from the comparison with chemical equilibrium composition and energy balance calculations.

Characteristics of Bunsen Reaction using Ultrasonic Irradiation in Sulfur-iodine Hydrogen Production Process (황-요오드 수소 제조 공정에서 초음파 조사를 이용한 분젠 반응의 특성)

  • Kim, Hyo Sub;Lee, Dong Hee;Lee, Jong Gyu;Park, Chu Sik;Kim, Young Ho
    • Applied Chemistry for Engineering
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    • v.29 no.1
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    • pp.56-61
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    • 2018
  • In Bunsen reaction section for the integrated operation of sulfur-iodine (SI) process, $I_2$ and $H_2O$ reactants are supplied as dissolved species in an $HI_x$ solution. Most of the $H_2SO_4$ product is found in the $HI_x$ phase when Bunsen reaction is performed using the $HI_x$ solution and $SO_2$ feed, so that the volume ratio of the $H_2SO_4$ phase to the $HI_x$ phase is very low. In this study, we investigated the effects of ultrasound irradiation on Bunsen reaction using the $HI_x$ solution to improve its phase separation performance. With ultrasound irradiation, the amount of $H_2SO_4$ moved to the $H_2SO_4$ phase from the $HI_x$ phase increased by up to 58.0 mol% and the volume of $H_2SO_4$ phase also increased by up to 13.1 vol%. In particular, the effect of ultrasound irradiation on the phase separation was improved with decreasing operating temperature, $I_2$ and $H_2O$ feed concentrations. The ultrasound irradiation induces the formation of additional $H_2O$ molecules by shifting microscopically the reaction equilibrium in the $HI_x$ phase. Afterward, the additionally generated $H_2O$ and isolated $H_2SO_4$ molecules form more $H_2SO_4{\cdot}xH_2O$ (x = 5-6) clusters that can be moved to the $H_2SO_4$ phase.

Major, Trace and Rare Earth Element Geochemistry, and Oxygen-Isotope Systematics of Illite/smectite in the Reindeer D-27 Well, Beaufort-Mackenzie Basin, Arctic Canada (카나다 보포트-맥켄지 분지의 일라이트/스멕타이트의 원소 지화학 및 산소동위원소 연구)

  • Ko, J.;Hesse, R.;Longstaffe, F.J.
    • Economic and Environmental Geology
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    • v.28 no.4
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    • pp.351-367
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    • 1995
  • The elemental geochemistry and oxygen isotopes of illite/smectite (I/S) have been studied in relationship to the mineralogical trend in the Reindeer D-27 well, Beaufort-Mackenzie Basin. The increase in concentrations of $K_2O$, Rb and rare earth elements (REE), the decrease in concentrations of tetrahedral elements such as Mg, Ti, Sc, Zn and Zr, and the increase in concentrations of tetrahedral elements such as Be and V can be related to I/S compositions that vary systematically with depth. Layer formulae of S- and I-layers are estimated as $[Al_{1.57}Fe_{.19}Mg_{.31}Ti_{.07}][Si_{3.84}Al_{.16}]O_{10}(OH)_2$ and $[Al_{1.84}Mg_{.16}][Si_{3.33}Al_{.67}]O_{10}(OH)_2$, respectively. The mobilization of REE appears to occur during illitization. The increase in concentrations of REE, especially La and Ce, with depth is probably linked to incorporation of ions with high valency (e.g. $V^{5+}$) in tetrahedral sites. The excess valency due to V is partly counter-balanced by ions with low valency (e.g. $Be^{2+}$) and, in turn, the local valency deficiency caused by $Be^{2+}$ could be compensated by high-charge interlayer cations such as REE (+3). ${\delta}^{18}O$ values of I/S range from 2.91 to 15.72‰ (SMOW), and increase with depth, contrasting to trends observed in the Gulf Coast and elsewhere. The increase in ${\delta}^{18}O$ of I/S results from the rapid increase in ${\delta}^{18}O$ of pore water that overcomes the decrease in temperature-dependent fractionation values with increasing burial depth (${\delta}^{18}O_{pore\;water}>-d{\Delta}/_{I/S-water};\;d{\delta}^{18}O_{I/S}>0$). Calculated ${\delta}^{18}O$ values of pore water in equilibrium with I/S suggest that the original water was probably meteoric water. The stratification of pore water is postulated from the presence of an isotopically light interval, about 450m thick. The depth range of the isotopically light zone overlaps, but does not coincide with the interval of lowered I-content and $K_2O$ concentrations, suggesting that oxygens may have been exchanged independently of mineralogical and geochemical reactions.

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Adsorption Removal of Sr by Barium Impregnated 4A Zeolite (BaA) From High Radioactive Seawater Waste (Barium이 함침된 4A 제올라이트 (BaA)에 의한 고방사성해수폐액에서 Sr의 흡착 제거)

  • Lee, Eil-Hee;Lee, Keun-Young;Kim, Kwang-Wook;Kim, Ik-Soo;Chung, Dong-Yong;Moon, Jei-Kwon;Choi, Jong-Won
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.14 no.2
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    • pp.101-112
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    • 2016
  • This study investigated the removal of Sr, which was one of the high radioactive nuclides, by adsorption with Barium (Ba) impregnated 4A zeolite (BaA) from high-radioactive seawater waste (HSW). Adsorption of Sr by BaA (BaA-Sr), in the impregnated Ba concentration of above 20.2wt%, was decreased by increasing the impregnated Ba concentration, and the impregnated Ba concentration was suitable at 20.2wt%. The BaA-Sr adsorption was added to the co-precipitation of Sr with $BaSO_4$ precipitation in the adsorption of Sr by 4A (4A-Sr) within BaA. Thus, it was possible to remove Sr more than 99% at m/V (adsorbent weight/solution volume)=5 g/L for BaA and m/V >20 g/L for 4A, respectively, in the Sr concentration of less than 0.2 mg/L (actual concentration level of Sr in HSW). It shows that BaA-Sr adsorption is better than 4A-Sr adsorption in for the removal capacity of Sr per unit gram of adsorbent, and the reduction of the secondary solid waste generation (spent adsorbent etc.). Also, BaA-Sr adsorption was more excellent removal capacity of Sr in the seawater waste than distilled water. Therefore, it seems to be effective for the direct removal of Sr from HSW. On the other hand, the adsorption of Cs by BaA (BaA-Cs) was mainly performed by 4A within BaA. Accordingly, it seems to be little effect of impregnated Ba into BaA. Meanwhile, BaA-Sr adsorption kinetics could be expressed the pseudo-second order rate equation. By increasing the initial Sr concentrations and the ratios of V/m, the adsorption rate constants ($k_2$) were decreased, but the equilibrium adsorption capacities ($q_e$) were increasing. However, with increasing the temperature of solution, $k_2$ was conversely increased, and $q_e$ was decreased. The activation energy of BaA-Sr adsorption was 38 kJ/mol. Thus, the chemical adsorption seems to be dominant rather than physical adsorption, although it is not a chemisorption with strong bonding form.

Studies on Food Preservation by Controlling Water Activity III. Quality Changes of Fish Meat during Drying and Storage (식품보장과 수분활성에 관한 연구 3. 어육의 건조 및 저장중의 품질)

  • HAN Bong-Ho;LEE Jong-Gab;BAE Tae-Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.16 no.3
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    • pp.181-189
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    • 1983
  • A study on the qualify changes of fish meat during drying and storage has been carried out with filefish meat. Filefish meat was dried in a forced air dryer at 40 and $55\%$ for 20 hours with an air velocity of 0.4 m/sec under different conditions of relative air humidities in the range of 10 to $50\%$. The dried fish meat was stored at $30^{\circ}C$ in chambers with constant relative humidities controlled by the use of conditioned air stream passing through the saturated salt solutions. The qualify of filefish meat was evaluated with the brown color densities developed by lipid oxidation and Maillard reaction. Changes of viable cell count during drying and storage were also discussed. The predominant reaction for the brown color developed during the study period was the lipid oxidation. The lipid oxidation rate during drying at constant temperature was appreciably affected by water activities at the drying surfaces of filefish meat during the falling drying rate period. The lipid oxidation rate was the slowest under the condition of the relative air humidity of around $30\%$. In samples stored at water activity of 0.33, the lipid oxidation rate was retarded remarkably in comparison with the samples with lower or higher water activities. The addition of $1\%$ table salt, $1.5\%$ D-sorbitol and $6\%$ sucrose slightly lowered the water activity with the slowest lipid oxidation rate. Such additives resulted the increase of the water soluble brown color densities, which seemed due to the increase of mobility of the water soluble substances by the result of the increase of equilibrium water content. Microflora of the samples immediately after drying consisted of ca. $30\%$ of coccus types, ca. $65\%$ of rod types and ca. $5\%$ of molds and yeasts. During the storage of the samples with a water activity of 0.76, the ratio of the coccus types to the total microflora was increased remarkably while that of the Gram negative non-spore rod types was decreased. The ratios of the Gram positive rod types, molds and yeasts during the storage were nearly constant.

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The Effect of the Surfactant on the Migration and Distribution of Immiscible Fluids in Pore Network (계면활성제가 공극 구조 내 비혼성 유체의 거동과 분포에 미치는 영향)

  • Park, Gyuryeong;Kim, Seon-Ok;Wang, Sookyun
    • Economic and Environmental Geology
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    • v.54 no.1
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    • pp.105-115
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    • 2021
  • The geological CO2 sequestration in underground geological formation such as deep saline aquifers and depleted hydrocarbon reservoirs is one of the most promising options for reducing the atmospheric CO2 emissions. The process in geological CO2 sequestration involves injection of supercritical CO2 (scCO2) into porous media saturated with pore water and initiates CO2 flooding with immiscible displacement. The CO2 migration and distribution, and, consequently, the displacement efficiency is governed by the interaction of fluids. Especially, the viscous force and capillary force are controlled by geological formation conditions and injection conditions. This study aimed to estimate the effects of surfactant on interfacial tension between the immiscible fluids, scCO2 and porewater, under high pressure and high temperature conditions by using a pair of proxy fluids under standard conditions through pendant drop method. It also aimed to observe migration and distribution patterns of the immiscible fluids and estimate the effects of surfactant concentrations on the displacement efficiency of scCO2. Micromodel experiments were conducted by applying n-hexane and deionized water as proxy fluids for scCO2 and porewater. In order to quantitatively analyze the immiscible displacement phenomena by n-hexane injection in pore network, the images of migration and distribution pattern of the two fluids are acquired through a imaging system. The experimental results revealed that the addition of surfactants sharply reduces the interfacial tension between hexane and deionized water at low concentrations and approaches a constant value as the concentration increases. Also it was found that, by directly affecting the flow path of the flooding fluid at the pore scale in the porous medium, the surfactant showed the identical effect on the displacement efficiency of n-hexane at equilibrium state. The experimental observation results could provide important fundamental information on immiscible displacement of fluids in porous media and suggest the potential to improve the displacement efficiency of scCO2 by using surfactants.

Improvement of Oxygen Isotope Analysis in Seawater samples with Stable Isotope Mass Spectrometer (질량분석기를 이용한 해수 중 산소안정동위원소 분석법의 개선)

  • Park, Mi-Kyung;Kang, Dong-Jin;Kim, Kyung-Ryul
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.13 no.4
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    • pp.348-353
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    • 2008
  • Oxygen isotope has not been used actively in water mass studies because of difficulties on the analysis though it has advantages as a water mass tracer. The most popular method to analysis the oxygen isotope ratio in water samples is equilibration method: isotopic equilibrium of water with $CO_2$ at constant temperature. The precision of oxygen isotope analysis using commercial automatic $H_2O/CO_2$ equilibrator is ${\pm}0.1%o$. This value is not sufficient for studies in open ocean. The object of this study is to improve the analytical precision enough to apply open ocean studies by modification of the instrument. When sample gas is transferred by the pressure difference, the fractionation which is preferential transportation of light isotope can be occurred since the long transportation path between the equilibrator and mass spectrometer. And the The biggest source of error during the analysis is long distance and large volume of the pathway of sample gas between. Therefore, liquid nitrogen trap and high vacuum system are introduced to the system. The precisions of 14 time analysis of same seawater sample are ${\pm}0.081%o$ and ${\pm}0.021%o$ by built-in system and by modified system in this study, respectively.