메탄올의 이산화탄소 흡수평형 추산에 대한 PC-SAFT모델식과 Two-model approach 모델식의 비교연구

노재현(Jaehyun Noh),박회경(Hoey Kyung Park),김동선(Dongsun Kim),조정호(Jungho Cho) 한국산학기술학회 2017 한국산학기술학회논문지 Vol.18 No.10

본 연구에서는 CO₂ 제거 용매로써 메탄올 수용액을 사용하는 Rectisol<SUP>Ⓡ</SUP>공정을 모델링하기 위한 열역학 모델식으로는 PC-SAFT(Perturebed-Chain Statistical Associating Fluid Theory) 상태방정식과 액체활동도계수 모델식을 기본으로 조합된 Two-model approach식{NRTL(Non Random Two Liquid) + Henry + Peng-Robinson}을 비교하였다. 또한 PC-SAFT 상태방정식의 이성분계 상호작용 매개변수와 Two-model approach식의 Henry 상수를 새롭게 결정하기 위해서 273.25K과 262.35K에서 CO₂와 메탄올 간의 흡수평형실험을 수행하고 회귀분석을 하였다. 그리고 새롭게 결정한 매개변수의 정확성은 실험 데이터의 추산결과를 통해 검증하였다. 이러한 모델식과 검증한 매개변수를 사용하여 CO₂ 제거공정을 모델링 하였다. 그 결과 Two-model approach식을 사용한 경우가 PC-SAFT EOS을 사용한 경우에 비해 CO2 99.00% 제거하기 위해 요구되는 메탄올 용매 유량이 약 43.72% 더 높게 추산되었으며, 증류탑에서의 냉각수 소모량은 39.22%정도, 스팀소모량은 43.09%정도 더 소요됨을 알 수 있었다. 결론적으로 고압에서 운전되는 Rectisol<SUP>Ⓡ</SUP>공정을 Henry관계식의 도움을 받는 액체활동도계수 모델식을 사용하여 모델링을 하는 경우 PC-SAFT 상태방정식을 사용한 경우에 비해서 크게 설계된 다는 것을 알 수 있었다. 이러한 이유는 액상에 대한 용해도가 낮은 가스성분이 일정한 온도에서 액상에 녹아드는 양은 기상의 분압에 비례하여 증가하는 것으로 계산되는 Henry 관계식의 특성 때문에 메탄올에 대해 용해도가 큰 CO₂의 경우 메탄올과 CO₂간의 흡수특성을 잘 예측하지 못하는 것을 알 수 있었다. The thermodynamic models, PC-SAFT (Perturbed-Chain Statistical Associated Fluid Theory) state equation and the Two-model approach liquid activity coefficient model NRTL (Non Random Two Liquid) + Henry + Peng-Robinson, for modeling the Rectisol process using methanol aqueous solution as the CO₂ removal solvent were compared. In addition, to determine the new binary interaction parameters of the PC-SAFT state equations and the Henry"s constant of the two-model approach, absorption equilibrium experiments between carbon dioxide and methanol at 273.25K and 262.35K were carried out and regression analysis was performed. The accuracy of the newly determined parameters was verified through the regression results of the experimental data. These model equations and validated parameters were used to model the carbon dioxide removal process.In the case of using the two-model approach, the methanol solvent flow rate required to remove 99.00% of CO₂ was estimated to be approximately 43.72% higher, the cooling water consumption in the distillation tower was 39.22% higher,and the steam consumption was 43.09% higher than that using PC-SAFT EOS. In conclusion, the Rectisol process operating under high pressure was designed to be larger than that using the PC-SAFT state equation when modeled using the liquid activity coefficient model equation with Henry"s relation. For this reason, if the quantity of low-solubility gas components dissolved in a liquid at a constant temperature is proportional to the partial pressure of the gas phase, the carbon dioxide with high solubility in methanol does not predict the absorption characteristics between methanol and carbon dioxide.

PR 및 PC-SAFT 상태방정식을 이용한 메탄과 에탄의 기상과 액상의 밀도 추산 및 이성분계의 기-액 상평형 계산

박종기(Jong Kee Park),최건형(Kun Hyung Choi),이상규(Lee Sang Gyu),양영명(Young Myung Yang),조정호(Jung Ho Cho) 한국가스학회 2010 한국가스학회지 Vol.14 No.2

본 연구에서는 PC-SAFT 모델식을 활용하여 메탄과 에탄의 온도에 따른 증기압과 기상 및 액상에서의 밀도를 추산하였으며, 그 결과를 PR 상태방정식과 비교하였다. 기상의 밀도에 대해서는 두 모델이 모두 실험 데이터를 잘 추산하였으며, 액상의 밀도에 대해서는 PR 상태방정식보다 PC-SAFT 모델식이 좀 더 정확함을 알 수 있었다. 한편 메탄과 에탄 이성분계에 대한 기-액 상평형 실험 데이터에 대해서 두 모델식을 이용하여 추산하였는데 PC-SAFT 모델식이 PR 상태방정식보다 좀 더 우수함을 알 수 있었다. In this study, experimental vapor pressures and densities of vapor and liquid phases versus temperature were estimated using PC-SAFT equation. The estimated results were compared with those using PR equation of state. For the vapor phase densities, both equations well predicted the literature data. However, PC-SAFT equation showed better prediction capability for liquid phase densities. In the comparison of vapor-liquid equilibrium prediction capability for the binary systems of methane and ethane, PC-SAFT equation was better than the PR equation.

SAFT 상태 방정식과 회합성 유체 혼합물의 기액 상평형

장재언 ( Jaeeon Chang ) 한국화학공학회 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.5

We review SAFT equation of state (EOS) which is based on TPT theory and statistical-mechanical principles, and confirm that it can be used as a useful tool to predict vapor-liquid phase equilibria of associating fluid mixtures. We examine theoretical structure of PC-SAFT EOS in great detail, and then assess the applicability and performance of the EOS while applying it to various mixtures containing nonpolar components, polar components and associating components in a stage-wise manner. In contrast to the conventional engineering EOS, PC-SAFT EOS can accurately predict nonideal behaviors of those mixtures without using semi-empirical binary interaction parameter. This is because the SAFT theory is based on a rigorous theoretical framework at molecular level which effectively accounts for various intermolecular interactions, and it thus provides substantial benefits in applying the SAFT EOS to complex thermodynamic phenomena of multi-component mixtures.

DME 생산공정에서 메탄올을 이용한 이산화탄소 제거 공정 연구

조두희(Cho, Duhee),노재현(Rho, Jae-Hyun),김동선(Kim, Dong-Sun),조정호(Cho, Jung-Ho) 한국산학기술학회 2013 한국산학기술학회논문지 Vol.14 No.3

본 연구에서는 Dimethyl ether (DME) 생산 공정 중에 포함되어 있는 이산화탄소 제거를 위한 용매로써 메탄 올 수용액을 사용하는 공정에 대한 전산모사를 수행하였다. 공정모사를 위하여 Aspen tech 사의 Aspen Plus release 7.3을 사용하였으며, 열역학 모델식으로는 PC-SAFT 모델식을 사용하였다. PC-SAFT 모델식에서 필요한 이성분계 상 호작용 매개변수를 결정하기 위하여 실험 데이터를 수집하고 회귀분석을 통해 새롭게 결정하였으며, 결정한 매개변수 의 정확성은 실험 데이타와의 비교를 통해 검증하였다. 한편, 이러한 모델식과 검증한 매개변수를 사용하여 공정을 모델링 하였으며 최적 순환유량과 운전압력 그리고 원료 주입단 등을 결정하여 공정 최적화를 수행하였다. In this study, simulation works have been performed for the modeling of CO₂ removal process contained in the DME production process through an absorber-stripper system using methanol aqueous solution. Aspen Plus release 7.3 in AspenTech company was utilized as a simulation tool and PC-SAFT modeling equation of state was used as a thermodynamic model. Fitting parameters built-in PC-SAFT model was determined by regressing experimental data, predicted results using PC-SAFT model were compared with experimental data in order to verify the exactness of the thermodynamic model. Optimization works have been performed to reduce the utility consumptions using solvent circulation rate, column operating pressure and feed stage location as manipulated variables.

Application of PC-SAFT EoS for calculating gas solubility and viscosity of ammonium- based ionic liquids

Alireza Afsharpour,Seyyed Hamid Esmaeli 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.6

The well-known perturbed-chain-statistical-association-fluid-theory (PC-SAFT) EoS was employed tomodel CO2 and H2S absorption in some protic ammonium-based ionic liquids, including Methyl-diethanol-ammoniumFormate, Methyl-diethanol-ammonium Acetate, Dimethyl-ethanol-ammonium Formate, and Dimethyl-ethanolammoniumAcetate. In this way, all the acidic gases and the ILs were considered as associative compounds so that theycan establish hydrogen bonding by their own or other molecules. Accordingly, 4C, 2B, and 1A association schemeswere assumed for H2S, the ILs, and CO2, respectively. Moreover, to estimate the liquid phase concentrations, a complexformation reaction (CFR) approach was followed. In this concept, acidic gases are supposed to form chemical complexeswith the ILs. To show the importance of the reactions, the solubilities were calculated with and without usingthem, and the achieved results were compared. As the outputs show, considering the reactions, the excellent overallAADs% equal to 1.38 and 0.17 were obtained for H2S and CO2 absorption, respectively. While without them, these valueswere about 5.05 and 8.57. In the second part of the work, the viscosity of the used ILs was estimated through a newapproach that combines the free-volume-theory (FVT) and the PC-SAFT, CPA, and mSRK EoSs. Accordingly, the densityof the ILs computed using the EoSs, and then FVT was applied to estimate the dynamic viscosity. Based on theoutputs, all the EoSs illustrate good ability to calculate viscosities, precisely, so that all the models present AAD% ofabout 2.5. This is because of the high ability of the FVT to obtain a precise estimation of viscosity using a rough estimationof the density.

산성가스 처리공정 설계에 적합한 PC-SAFT 모델식

박종기 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

통계역학에 기반한 상태방정식인 Purturbed Chain Statistical Associating Fluid Theory(PC-SAFT) 모델에 아민용액에서 산성가스인 이산화탄소와 황화수소의 존재로 인한 반응부분이 추가되고 화합하는 항과 극성 항을 추가할 경우 산성가스 처리용 흡수공정에 관여된 성분을 포함하는 계의 기액 상평형, 엔탈피, 그리고 기상 및 액상의 밀도를 정확히 예측할 수 있다. 산성가스 처리공정에 적용할 수 있는 최근의 PC-SAFT 모델에 기반한 것을 소개하고 열역학적 물성 실험결과와 예측결과를 비교하였다.

Study on the activity coefficients and solubilities of amino acids in aqueous solutions with perturbed-chain statistical associating fluid theory

이봉섭,김기창 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.1

Perturbed-chain statistical associating fluid theory (PC-SAFT) was applied for modeling the thermodynamic properties of aqueous amino acid solutions. To account for the association phenomena of amino acids occurring in the aqueous solution, the zwitterionic forms of amino acids are assumed to be associating species with proton donor and acceptor sites. Also, in order to reduce the number of adjustable parameters of PC-SAFT equation of state (EoS)for amino acids from five to three, it is assumed that segment numbers of amino acids are linearly related with the molecular weight of amino acids, and the association volume parameters of amino acids can be set to a fixed value. Thus,3-parameters of PC-SAFT EoS for amino acids were estimated by simultaneously fitting the activity coefficients of amino acid and densities data in the aqueous amino acid solutions. The PC-SAFT EoS with estimated 3-parameters of amino acid is found to well describe activity coefficients of amino acid and densities of the aqueous amino acid solutions. Also, this equation was used for predicting solubilities of amino acids as well as the water activities and osmotic coefficients in the aqueous amino acid solutions. The predicted values of these properties are in good agreement with the experimental data.

Phase behaviors for the poly(2-phenylethyl methacrylate) in supercritical fluid solvents: Experiment and PC-SAFT EoS

Lee, Bong-Seop,Byun, Hun-Soo THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2018 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.59 No.-

<P><B>Abstract</B></P> <P>In this work, the experimental cloud-points in the binary and ternary mixtures for poly(2-phenylethyl methacrylate) [P(2-PEMA)] solutions containing supercritical solvents (i.e., carbon dioxide, propylene, 1-butene, dimethyl ether (DME)) are carried out up to 473K and 224MPa. According to the amount of cosolvent (i.e., DME), the cloud-point curves for ternary mixtures of P(2-PEMA) in supercritical solvents (i.e., carbon dioxide, propylene, 1-butene) show the changes from upper critical solution temperature (UCST) behavior to lower critical solution temperature (LCST) behavior. The PC-SAFT equation of state is applied to correlate the phase behaviors of all experimental systems, and the calculated results are shown as a reasonable agreement with experimental data. According to the amount of DME (i.e., cosolvent), the UCST- and LCST-type phase behaviors are described exactly by PC-SAFT EoS with one adjustable binary interaction parameter on which the effect of temperature and/or cosolvent amount is not considered.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The cloud-point curves for P(2-PEMA) in various supercritical fluids are measured. </LI> <LI> The phase behavior for P(2-PEMA) in gases except for DME shows UCST-type. </LI> <LI> According to the increase of DME concentration, P(2-PEMA) became more soluble in SCF /DME mixtures. </LI> <LI> PC-SAFT equation of state described well the phase behaviors for binary and ternary systems. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Phase behaviors for the poly(2-phenylethyl methacrylate) in supercritical fluid solvents: Experiment and PC-SAFT EoS

이봉섭,변헌수 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.59 No.-

In this work, the experimental cloud-points in the binary and ternary mixtures for poly(2-phenylethyl methacrylate) [P(2-PEMA)] solutions containing supercritical solvents (i.e., carbon dioxide, propylene, 1-butene, dimethyl ether (DME)) are carried out up to 473 K and 224 MPa. According to the amount of cosolvent (i.e., DME), the cloud-point curves for ternary mixtures of P(2-PEMA) in supercritical solvents (i.e., carbon dioxide, propylene, 1-butene) show the changes from upper critical solution temperature (UCST) behavior to lower critical solution temperature (LCST) behavior. The PC-SAFT equation of state is applied to correlate the phase behaviors of all experimental systems, and the calculated results are shown as a reasonable agreement with experimental data. According to the amount of DME (i.e., cosolvent), the UCST- and LCST-type phase behaviors are described exactly by PC-SAFT EoS with one adjustable binary interaction parameter on which the effect of temperature and/or cosolvent amount is not considered.

Poly(4-vinylphenol)/Ketone 용액계의 상평형

김미경 ( Mi Kyung Kim ),김기창 ( Ki Chang Kim ) 한국화학공학회 2005 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.43 No.5

Phase separations of Poly (4-vinylphenol) (PVPh)/acetone and PVPh/methyl ethyl ketone solutions were measured using the thermal optical analysis (TOA) method, The phase separations of these system showed the behaviors of LCST-type (lower critical solution temperature). The measured cloud temperatures were lowered with increasing molecular weight of PVPh, and cloud temperatures of PVPh/MEK solutions shifted to higher temperature regions, compared to the PVPh/acetone solutions. Phase equilibria of PVPh/ketone solutions were described with taking account of self-associations of PVPh and cross-associations between PVPh and solvent, by using the PC-SAFT equation of state. PC-SAFT EoS parameters of PVPh and cross-association parameters were determined by simultaneously fitting liquid density data of PVPh and VLE data of the PVPh/acetone system. The estimated parameters of PVPh and cross-association parameters were utilized to calculations of the binodal and spinodal curves, and the calculated binodal curves were in good agreements with the experimental cloud temperatures.