• Korean Chemical Engineering Research
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• 제55권2호
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• pp.230-236
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• 2017

약 303 K로부터 약 343 K의 온도 범위와 약 50 bar까지의 압력 범위에서 poly(ethylene glycol) dimethyl ether(PEGDME)에 녹는 이산화탄소($CO_2$)의 용해도를 측정하였다. 가변부피 투시창이 장착된 고압용 상평형 장치를 사용하여 온도를 변화시키면서 여러 가지 조성을 갖는 $CO_2+PEGDME$ 혼합물의 기포점 압력을 측정함으로써 PEGDME에서의 고압 $CO_2$의 용해도를 결정하였다. PEGDME의 분자량이 $CO_2$ 용해도에 미치는 영향을 관찰하기 위하여, 두 가지 종류의 분자량을 가진 PEGDME 시료에 대한 $CO_2$ 용해도를 비교하였다. 압력이 증가함에 따라 PEGDME에 대한 $CO_2$ 용해도는 증가하였으며 온도가 증가함에 따라 용해도는 감소하였다. 같은 온도와 압력에서 비교할 때, 분자량이 더 큰 PEGDME는 질량분율과 몰랄농도 기준으로 더 작은 $CO_2$ 용해도를 주었으나, 몰분율 기준으로는 더 큰 $CO_2$ 용해도를 주었다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제3권2호
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• pp.137-142
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• 1999

One of the most important parameters required to model the absorption of CO2 into aqueous alkanolamine solutions is physical solubility. However, since CO2 reacts in amine solutions, its physical solubility cannot be measured directly. As a result, a nonreacting gas which is similar to CO2 has to be used such as N2O. The solubility of nitrous oxide (N2O) in aqueous solutions of 0wt%-50wt% MDEA, 0wt%-30wt% DEA, and 50wt % total amine with DEA/MDEA molar ratios of 0.05, 0.25, 0.5 and 0.67 was measured using a modified Zipperclave reactor over a temperature range of 293-353 K with near atmospheric partial pressures of N2O. the solubility data from this work were K with near atmospheric partial pressures of N2O. The solubility data from this work were found to be in good agreement with previously reported data where available.

• 한국대기환경학회지
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• 제17권5호
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• pp.407-414
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• 2001

In this study, the absorption kinetics of $CO_2$onto a mixture of AMP (2-amino-2-methyl-1-propanol) MEA (monoethanolamine) water were investigated at 30 and 4$0^{\circ}C$ using a packed absorption tower. Solubility and absorption rate of $CO_2$into alkanolamine solutions and optimal condition of $CO_2$absorption process were investigated. The experimental conditions are as follows; temperature of 30 and 4$0^{\circ}C$, gas flow rate of 3ι/min for the absorption tower, and liquid flow rate of 0.1ι/min. Feed gas was a mixture of 85% $N_2$and 15% $CO_2$. The experimental results showed that AMP had greater solubilities and faster absorption rates than MEA and DEA. In addition, MEA had the fastest initial reaction rate. To improve the properties of AMP which have low initial reaction rate and high cost, AMP was used with MEA. The mixing ratio was also changed in constant total molarity of 1,2,3 and 4. The experimental results can be summarized as follows: (1) in solubility experiment, the addition of MEA in constant total polarity decreased the solubility of $CO_2$in AMP/MEA mixture. (2) from 0 to about 0.3 in mixing ratio, the solubility of $CO_2$in AMP/MEA mixture had little differences compared with the sum of solubility of AMP only and solubility of MEA only . (3) mixing ratio of 0.3 was found to be an optimal point with the fastest $CO_2$absorption rate.

• 분석과학
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• 제27권2호
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• pp.79-91
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• 2014

1-Butyl-3-methylpiperidinium bis(trifluoromethylsulfonyl)imide ($[bmpip][Tf_2N]$) 이온성 액체를 대상으로 약 303 K로부터 약 343 K의 온도 범위와 약 30 MPa까지의 압력 범위에서 이온성 액체에 녹는 이산화탄소 ($CO_2$)의 용해도를 측정하였다. 우리가 아는 한, $[bmpip][Tf_2N]$에 대한 $CO_2$의 용해도 데이터는 다른 연구자들에 의해 지금까지 문헌에 발표된 바가 없다. 가변부피투시창 (variable-volume view cell)이 장착된 고압용 상평형 장치를 사용하여 온도를 변화시키면서 여러 가지 조성을 갖는 $CO_2+[bmpip][Tf_2N]$ 혼합물의 기포점 또는 구름점 압력을 측정함으로써 $[bmpip][Tf_2N]$에서의 고압 $CO_2$의 용해도를 결정하였다. 이온성 액체가 가지고 있는 양이온이 $CO_2$ 용해도에 미치는 영향을 관찰하기 위하여, 본 연구에서 사용한 $[bmpip][Tf_2N]$에 대한 $CO_2$ 용해도 데이터를 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide($[bmim][Tf_2N]$)에 대한 $CO_2$ 용해도 데이터와 비교하였다. 압력이 증가함에 따라 $[bmpip][Tf_2N]$에 대한 $CO_2$ 용해도는 급격히 증가하였으며 온도가 증가함에 따라 용해도는 감소하였다. $[bmpip][Tf_2N]$와 $[bmim][Tf_2N]$ 두 이온성 액체에 대하여 $CO_2$의 용해도는 몰분율 기준으로 온도 및 압력 조건에 관계없이 거의 같았다. Peng-Robinson 상태 방정식을 사용하여 $CO_2+[bmpip][Tf_2N]$ 혼합물 시스템에 대한 상평형 모델링을 수행하였다.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2454-2458
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• 2007

Exploring the basic concepts for the design of CO2-philic molecules is important due to the possibility for “green” chemistry in supercritical CO2 as substitute solvent systems. The Lewis acid-base interactions and C?H…O weak hydrogen bonding were suggested as two key factors for the solubility of CO2-philic molecules. We have performed high level quantum mechanical calculations for the van der Waals complexes of CO2 with trimethylphosphate and trimethylphosphine oxide, which have long been used for metal extractants in supercritical CO2 fluid. Structures and energies were calculated using the MP2/6-31+G(d) and recently developed multilevel methods. These studies indicate that the Lewis acid-base interactions have larger impact on the stability of structure than the C?H…O weak hydrogen bonding. The weak hydrogen bonds in trimethylphosphine oxide have an important role to the large supercritical CO2 solubility when a metal is bound to the oxygen atom of the P=O group. Trimethylphosphate has many Lewis acid-base interaction sites so that it can be dissolved into supercritical CO2 easily even when it has metal ion on the oxygen atom of the P=O group, which is indispensable for a good extractant.

• Journal of Mechanical Science and Technology
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• 제19권5호
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• pp.1216-1225
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• 2005

$CO_{2}$ ocean sequestration is one of the promising options to reduce $CO_{2}$ concentration in the atmosphere because the ocean has vast capacity for $CO_{2}$ absorption. Therefore, in the present investigation, calculations for solubility and dissolution behavior of liquid $CO_{2}$ droplets released at 1000 m and 1500 m deep in the ocean from a moving ship and a fixed pipeline have been carried out in order to estimate the $CO_{2}$ dissolution characteristics in the ocean. The results show liquid $CO_{2}$ becomes bubble at around 500 m in depth, and the solubility of seawater is about $5{\%}$ less than of pure water. Also, it is shown that the injection of liquid from a moving ship is a more effective method for dissolution than from a fixed pipeline, and the presence of hydrate on liquid $CO_{2}$ acts as a resistant layer in dissolving liquid $CO_{2}$.

• 한국정밀공학회지
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• 제17권3호
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• pp.108-113
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• 2000

An important process for making a new class of polymeric material is called microcellular plastics invented at the Massachusetts Institute of Technology. Many researches for microcellular plastics have been done in various ways and fields. But a research for the polymer which has previous history has not been tried yet. In this paper, weight gain of $CO_2$ was measured in a polymer matrix which had previous history and no history. In each case, experimental data for solubility and diffusivity was shown. A model for $CO_2$ solution process in molecular range was made. The conclusion of this paper is that the previous history has an effect on diffusivity but not solubility and the previous history made by $CO_2$ in supercritical state makes diffusivity of $CO_2$ larger.

• 설비공학논문집
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• 제19권12호
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• pp.842-849
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• 2007

For a $CO_2$ two-stage twin rotary compressor used for heat pump water heater system, changes of $CO_2$ solubility in PAG oil were investigated along the gas passages from the first stage suction to final discharge. Only slight changes in solubility took place in suction chambers for both of the first and second stages, but for compression chambers, solubility variation ranged from 0.115 to 0.136, and from 0.133 to 0.182, respectively for the first and second stages. Calculation of gas flashing in parts of leakage oil flows and of oil contained in control volumes due to solubility changes was conducted and included in gas pressure calculation. For the second stage, gas flashing amounts to around $5%\sim6%$ for most leakage flows. Cooling capacity, compressor input, and COP obtained by calculation were well compared to the experimental results. Effects of operation speed on the compressor performance was also studied: as the shaft speed increased, adiabatic efficiency decreased rapidly due to increased over-compression loss.

• Nuclear Engineering and Technology
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• 제42권5호
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• pp.552-561
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• 2010

This study investigates the solubility of neptunium (Np) in the deep natural groundwater of the Korea Atomic Energy Research Institute Underground Research Tunnel (KURT). According to a Pourbaix diagram (pH-$E_h$ diagram) that was calculated using the geochemical modeling program PHREEQC 2.0, the redox potential and the carbonate ion concentration both control the solubility of neptunium. The carbonate effect becomes pronounced when the total carbonate concentration is higher than $1.5\;{\times}\;10^{-2}$ M at $E_h$ = -200 mV and the pH value is 10. Given the assumption that the solubility-limiting stable solid phase is $Np(OH)_4(am)$ under the reducing condition relevant to KURT, the soluble neptunium concentrations were in the range of $1\;{\times}\;10^{-9}$ M to $3\;{\times}\;10^{-9}$ M under natural groundwater conditions. However, the solubility of neptunium, which was calculated with the formation constants of neptunium complexes selected in an OECD-NEA TDB review, strongly deviates from the value measured in natural groundwater. Thus, it is highly recommended that a prediction of neptunium solubility is based on the formation constants of ternary Np(IV) hydroxo-carbonato complexes, even though the presence of those complexes is deficient in terms of the characterization of neptunium species. Based on a comparison of the measurements and calculations of geochemical modeling, the formation constants for the "upper limit" of the Np(IV) hydroxo-carbonato complexes, namely $Np(OH)_y(CO_3)_z^{4-y-2z}$, were appraised as follows: log $K^{\circ}_{122}\;=\;-3.0{\pm}0.5$ for $Np(OH)_2(CO_3)_2^{2-}$, log $K^{\circ}_{131}\;=\;-5.0{\pm}0.5$ for $Np(OH)_3(CO_3)^-$, and log $K^{\circ}_{141}\;=\;-6.0{\pm}0.5$ for $Np(OH)_4(CO_3)^{2-}$.

• Fisheries and Aquatic Sciences
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• 제17권1호
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• pp.59-65
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• 2014

We measured the reductions in size and solubility of mackerel muscle that was freeze-dried, deoiled by supercritical carbon dioxide (SC-$CO_2$), or roasted. The percent size reduction and solubility were high in SC-$CO_2$-treated muscle compared with freeze-dried and roasted muscle. We used oil-free residues to test for heavy metals and determine microbial safety. The SC-$CO_2$, hexane, and ethanol were used to separate oil from muscle. The concentrations of cadmium (Cd) in all treated muscles were less than the values reported in the literature, as were the concentrations of lead in SC-$CO_2$- and hexane- treated muscle. In contrast, concentrations of arsenic and mercury in muscles were greater than the reported values regardless of treatment. Zinc and iron, which are beneficial for health, were found in high levels after all treatments of muscle tissue. After 6 months of storage at different temperatures, SC-$CO_2$-and ethanol-treated muscle showed few bacterial colonies, and none were found after 4 months of storage at $-20^{\circ}C$. These results will be useful to food-processing industries for maintaining high-quality, safe mackerel muscle.