Selective separation of solvent from deasphalted oil using CO₂ for heavy oil upgrading process based on solvent deasphalting

Im, Soo Ik,Shin, Sangcheol,Park, Jun Woo,Yoon, Hyung Jin,Go, Kang Seok,Nho, Nam Sun,Lee, Ki Bong Elsevier 2018 Chemical Engineering Journal Vol.331 No.-

<P><B>Abstract</B></P> <P>The solvent deasphalting (SDA) process is a heavy oil upgrading process in which deasphalted oil (DAO) is extracted from heavy oil feedstock by precipitating asphaltene using an excess amount of alkane solvent (C3-C6). After the extraction, solvent recovery should be carried out for separating the solvent from the DAO in order to recycle the expensive solvent. In the conventional solvent recovery method, the mixture of solvent and DAO is heated to evaporate the solvent, which requires massive heat energy, resulting in reduced process efficiency. In this study, CO<SUB>2</SUB> is applied for the first time to selectively separate solvent from DAO at a relatively low temperature. The experimental results in a batch separator indicate that the temperature required for high solvent recovery of over 80% decreases from 200°C to 40°C when using CO<SUB>2</SUB> compared to the conventional method. The theoretical approach using Hansen distance calculation based on the Hansen solubility parameter (HSP) was used to verify the mechanism of solvent separation using CO<SUB>2</SUB>. The results suggest that the increase in the interaction between CO<SUB>2</SUB> and solvent causes the separation of solvent from DAO, leading to an increase in solvent recovery. Also, numerical simulation results show the possibility of continuous operation for solvent recovery using CO<SUB>2</SUB>.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Solvent recovery using CO<SUB>2</SUB> was newly developed for solvent deasphalting process. </LI> <LI> High solvent recovery was achieved at relatively low temperature. </LI> <LI> CO<SUB>2</SUB> acts as an anti-solvent to separate the solvent from DAO. </LI> <LI> Numerical simulation confirmed the possibility of a new solvent recovery operation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

만성유기용제 폭로에 의한 정신신경학적 이상소견의 현장진단방법 개발에 관한 연구

조수헌,김선민,권호장,임용현,임현술,Cho, Soo-Hun,Kim, Sun-Min,Kwon, Ho-Jang,Yim, Yong-Hyun,Lim, Hyun-Sul 대한예방의학회 1993 Journal of Preventive Medicine and Public Health Vol.26 No.1

A study has been conducted on developing questionnaires to serve as on site diagnostic tools for the early detection of neuropsychiatric impairment among workers chronically exposed to low-level organic solvents. Two drafts of tentative questionnaires have been developed as follows; several question items were selected from questionnaires which were administered to workers exposed to organic solvents in previous studios and were grouped into each symptom category based on the presence of its association using Guttman scaling method, then these selected items were reviewed by neuropsychiatry specialists. The final draft of the questionnaire (total symptom score=36) was developed by selecting 33 question items which had more than a 0.88 Guttman coefficient of reproducibility in each symptom category from a pilot study in which these tentative questionnaires were administered to workers manufacturing soles. Three plants using organic solvents and one plant never using organic solvents as a control group were selected to test the reliability and validity of the developed questionnaires. The major organic solvent in the workplace environment detected by a personal air sampler and GC/MSD nab toluene. The concentration of toluene in air from the department using organic solvent was statistically different from that of the department never using organic solvent. The concentration of toluene from almost all of the workplace did not exceed the allowable level. There was no statistically significant difference between the concentration of urinary hippuric acid from the workers of the department using organic solvent and that of the department never using it. Total symptom score of the plant never using organic solvents was 9.8 and those of the three plants using organic solvents were 15.6, 14.7, and 13,7 respectively. In order to evaluate the validity of the questionnaires, the workers from two different departments of the plant in which usage of organic solvents are totally dofferemt were compared. The total symptom score was 17.8 for workers of the department using organic solvent and 13.5 for the department never using organic solvent and scores of each symptom group between exposure and non-exposure group also showed statistically significant difference. The finding that total symptom score of the exposure group increased as the duration of employment increased indirectly suggests the usefulness of the developed questionnaire to assess the health effects of chronic exposure to organic solvents. The correlation coefficient, which was calculated to evaluate the test-retest reliability, was 0.581 (p=0.001). The coefficient of Crohnbach which reflects the internal consistency of the questionnaire was 0.91. In conclusion, the reliabilty of the questionnaire was well maintained over the time lapse between the two administrations of the questionnaire and despite the seasonal difference.

Comparison of three different types of cilostazol-loaded solid dispersion: Physicochemical characterization and pharmacokinetics in rats

Mustapha, Omer,Kim, Kyung Soo,Shafique, Shumaila,Kim, Dong Shik,Jin, Sung Giu,Seo, Youn Gee,Youn, Yu Seok,Oh, Kyung Taek,Yong, Chul Soon,Kim, Jong Oh,Choi, Han-Gon Elsevier 2017 Colloids and surfaces Biointerfaces Vol.154 No.-

<P><B>Abstract</B></P> <P>The aim of this research was to compare three different types of cilostazol-loaded solid dispersion system including solvent-evaporated, solvent-wetted and surface-attached solid dispersion. The effect of polymers and surfactants on the aqueous solubility of cilostazol was investigated, leading to the selection of polyvinylpyrrolidone (PVP) and sodium lauryl sulphate (SLS). Employing a spray-drying technique, numerous surface-attached, solvent-evaporated and solvent-wetted solid dispersions were prepared with various amounts PVP and SLS using water, 90% ethanol and acetone, respectively. Their physicochemical properties, solubility, dissolution and oral bioavailability in rats were assessed compared to the drug powder. Among each solid dispersion system tested, the surface-attached, solvent-evaporated and solvent-wetted solid dispersions composed of cilostazol, PVP and SLS at weight ratios of 3.0 : 0.75 : 1.5, 3.0 : 3.0 : 1.5 and 3.0 : 3.0 : 1.5, respectively, provided the highest drug solubility and dissolution. The solvent-evaporated solid dispersion gave homogeneous and very small spherical particles, in which the drug was changed to an amorphous state. In the solvent-wetted solid dispersion, the amorphous drug was attached to the polymer surface. Conversely, in the surface-attached solid dispersion, the carriers were adhered onto the surface of the unchanged crystalline drug. The solubility, dissolution and oral bioavailability were significantly increased in the order of solvent-evaporated>solvent-wetted>surface-attached>drug powder. Thus, the type of solid dispersion considerably affected the physicochemical properties, aqueous solubility and oral bioavailability. Furthermore, the cilostazol-loaded solvent-evaporated solid dispersion with the highest oral bioavailability would be actively recommended as a practical oral pharmaceutical product.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cilostazol-loaded three different types of cilostazol-loaded solid dispersions were prepared. </LI> <LI> They were prepared with PVP, sodium laurylsulfate and different solvents using spray-drying techniques. </LI> <LI> The solvent-evaporated solid dispersion gave higher drug solubility and bioavailability than the others. </LI> <LI> These different types affected the physicochemical properties and oral bioavailability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

유기용매 내성 세균과 이용가능성

주우홍(Woo Hong Joo) 한국생명과학회 2015 생명과학회지 Vol.25 No.12

유기용매 내성 세균의 첫 분리 보고 이후 다수의 유기용매 내성 세균들이 토양 폐수 심지어 심해 등 모든 환경에서 분리 보고되고 있다. 대부분의 유기용매 내성 세균은 그람음성세균으로 이는 그람음성 세균이 그람양성 세균 보다 유전적으로 더 내성을 보이기 때문이다. 유기용매 내성 기전은 유기용매 내성 그람음성 세균을 주로 사용하여 집중적으로 구명되어왔다. 유기용매 내성 그람양성 세균의 유기용매 내성 기전은 비교적 최근 연구에서 발견되고 있다. 유기용매는 용매에 따라 다른 독성을 보이며 유기용매 내성세균의 유기용매 내성 수준은 종과 균주에 의존적으로 매우 변화가 심하다. 그러므로 유기용매 내성세균은 다양한 변인과 다유전자에 의한 적응 전략에 의하여 용매독성과 싸우며 용매 스트레스에 적응할 수 있다. 그들은 세포형태 및 세포 행동에서의 변화, 세포표층의 수식, 세포막 적응, 용매 배출 펌프, 샤페론 그리고 항산화 반응 등의 기전을 통하여 유기용매의 과량의 농도에서도 생존할 수 있다. 본 총설에서는 대표적인 유기용매 내성 세균, 유기용매 내성 세균에서의 유기용매에의 적응 및 내성 전략들 나아가 그들의 산업적 및 환경공학적인 잠재적인 영향에 대하여 개관하고자 한다. Many organic solvent-tolerant bacteria have been isolated from all environments such as soil, wastewater, even deep sea after first isolation report of organic solvent-tolerant bacterium. Most organic solvent- tolerant isolates have been determined to be Gram-negative bacteria, because Gram-negative bacteria have inherent tolerance property toward hostile organic solvents more than Gram-positive bacteria. The mechanisms of organic solvent tolerance have been elucidated extensively using mainly organic solvent-tolerant Gram-negative bacteria. The solvent-tolerance mechanisms in Gram-positive bacteria can be found in comparatively recent research. Organic solvents exhibited different toxicity depending on the solvent, and the tolerance levels of organic solvent-tolerant bacteria toward organic solvents were also highly changeable among species and strains. Therefore, organic solvent-tolerant bacteria could coped with solvent toxicity and adapted to solvent stress through the multifactorial and multigenic adaptative strategies. They could be survived even in the hyper concentrations of organic solvents by mechanisms which include: changes in cell morphology and cell behaviour, cell surface modifications, cell membrane adaptations, solvent excretion pumps, chaperones and anti-oxidative response. The aim of this work is to review the representative solvent tolerant bacteria and the adaptative and tolerance strategies toward organic solvents in organic solvent-tolerant bacteria, and their potential industrial and environmental impact.

유용성 도료와 수용성 도료의 유해성 비교에 관한 연구 : 자동차 보수용 도료를 중심으로

권은혜,김광식,오정룡,최정근,정윤석,이유진,김은아,송세욱,정호근 한국산업위생학회 2001 한국산업보건학회지 Vol.11 No.1

The purpose of this study is to substitute water-based painting materials for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters. This study assessed the exposure of organic solvents to the painters using water-based and solvent-based painting materials and compared compositions, painting processes and the health hazards of the application of these alternative painting materials. The results of this study are as follows. 1. solvent-based painting materials used in motor-repairing process consist of various organic solvents, which consist primarily of toluene, xylene, ethyl benzene, ethyl methyl bezene, trimethyl bezene, ethyl acetate, butyl acetate, methyl isobutyl ketone, 2-ethoxy ethanol, 2-ethoxy ethyl acetate and toluene-2.4-diisocianate and the others. These organic solvents are know as health-hazardous substances. But water-based painting materials are high-solid, low-solvent ones and consist of such two organic solvents as 2-butoxy ethanol and 2-heptanone and the others. 2. The painters using solvent-based painting materials in motor-repairing process are exposed to various organic acetate, methyl isobutyl ketone, trimethyl benzene, 2-ethoxy ethanol, and 2-ethoxy ethyl acetate. But the painters using solvent-based ones are only exposed to 2-butoxy ethanol and 2-heptanone. 3. By using water-based painting materials in stead of solvent-based painting materials containing health-hazardous organic solvents, the exposure of such organic solvents in the painter's breathing zone can be largely prevented. 4. This study recommends water-based painting materials as substitutes for the current solvent-based ones used in motor-repairing process to minimize the exposure of organic solvents to the painters.

유기용매 내성 리파아제와 그 이용가능성

주우홍(Woo Hong Joo) 한국생명과학회 2017 생명과학회지 Vol.27 No.11

본 총설에서는 유기용매 내성 리파아제와 그들의 산업, 생물공학 및 환경에서의 잠재적인 영향에 대하여 서술하고자 한다. 유기용매 내성 리파아제는 유기용매 내성 세균에서 처음 보고되었으나, 많은 유기용매 내성 리파아제들이 유기용매 내성 세균 뿐만 아니라 잘 알려진 Bacillus, Pseudomonas, Streptomyce 그리고 Aspergillus sp. 균주같은 유기용매 비내성 세균 그리고 균류 균주들에서도 보고되고 있다. 이들 리파아제들은 유기용매에서 쉽게 불활성화되지 않기 때문에 유기용매에 의한 효소 불활성화를 방지하기 위하여 별도로 그들을 고정화할 필요가 없다. 그러므로 다수의 생물공정 및 생물변환 공정에서 이용될 수 있는 잠재적인 유용성을 가지고 있다. 이들 유기용매 내성 리파아제들을 사용하면, 유기용매계 또는 비수계에서 다수의 불용성 기질들의 용해도가 증가하며, 수계에서는 불가능한 다양한 화학반응들이 일어나고, 가수분해 대신에 합성반응이 일어나며, 물에 의한 부반응이 억제되며, 화학, 위치 그리고 엔안티오(대칭) 선택성(chemo, regio and enantioselective) 변환반응의 가능성이 증가한다. 나아가 고정화하지 않아도 효소의 회수와 재이용이 가능하며, 유기용매계와 비수계에서는 리파아제의 안정성이 더 좋아지는 경향도 있다. 그러므로 유기용매 내성 리파아제는 유기용매계와 비수계를 이용한 생물변환공정에 생물촉매로써 그들을 이용가능하다는 점에서 많은 주목을 받고 있다. This review described solvent-tolerant lipases and their potential industrial, biotechnological and environmental impacts. Although organic solvent-tolerant lipase was first reported in organic solvent-tolerant bacterium, many organic solvent-tolerant lipases are in not only solvent-tolerant bacteria but also solvent-intolerant bacterial and fungal strains, such as the well-known Bacillus, Pseudomonas, Streptomyces and Aspergillus strains. As these lipases are not easily inactivated in organic solvents, there is no need to immobilize them in order to prevent an enzyme inactivation by solvents. Therefore, the solvent-tolerant lipases have the potential to be used in many biotechnological and biotransformation processes. With the solvent-tolerant lipases, a large number insoluble substrates become soluble, various chemical reactions that are initially impossible in water systems become practical, synthesis reactions (instead of hydrolysis) are possible, side reactions caused by water are suppressed, and the possibility of chemoselective, regioselective and enantioselective transformations in solvent and non-aqueous systems is increased. Furthermore, the recovery and reuse of enzymes is possible without immobilization, and the stabilities of the lipases improve in solvent and non-aqueous systems. Therefore, lipases with organic-solvent tolerances have attracted much attention in regards to applying them as biocatalysts to biotransformation processes using solvent and non-aqueous systems.

The Gas Liquid Partition Coefficients of Eleven Normal, Branched and Cyclic Alkanes in Sixty Nine Common Organic Liquids II: The Effect of Solvent Structure

Cheong, Won-Jo Korean Chemical Society 2003 Bulletin of the Korean Chemical Society Vol.24 No.8

The effect of solvent structure on the slope in the plot of ln K vs. solute carbon number was examined. It was found that the free energy of methylene group transfer from the gas phase into a solvent was always negative and that the absolute magnitude of interaction free energy between the methylene group and the solvent was always larger than the absolute magnitude of cavity formation free energy of the methylene group in the solvent. Thus, the slope in the plot of ln K vs. solute carbon number was always positive and its value decreases with increase of solvent polarity since the cavity formation energy of the CH₂ unit increases with increase of solvent polarity while the dispersive interaction energy of the CH₂ unit is virtually invariant. We also examined the effect of sequential addition of CH₂ unit to a solvent molecule upon ln K for three homologous series of solvents: n-alkanes, n-alcohols, and n-nitriles. Characteristic trends in the plots of ln K vs. solvent carbon number were observed for individual solvent groups. A decrease of ln K with solvent carbon number was observed for n-alkanes. An abrupt increase in ln K followed by levelling off was observed for n-alcohols while a final slight decrease in ln K after an abrupt increase followed by rapid levelling off was noted for n-nitriles. All of theses phenomena were found related to variation in cavity formation energy. It was clearly shown that a structural change of a polar solvent by sequential addition of CH₂ units causes an abrupt polarity decrease initially, then gradual levelling off, and finally, conversion to a virtually nonpolar solvent if enough CH₂ units are added.

노출기준 적용을 위한 세탁소용 석유계 솔벤트 특성규명

정지연,이광용,이나루,전홍진,김성진,이인섭,김광종 한국산업위생학회 2003 한국산업보건학회지 Vol.13 No.1

Although in the U.S perchloroethylene is the most commonly used in commercial dry cleaning shops, petroleum based dry cleaning solvent is the most frequently used in Korea. The solvent is a mixture of hydrocarbons, straight or branched chain aprraffins, naphthenes, and aromatic hydrocarbons. Exposure assessment at the cleaning shop was mainly focused on highly toxic substances, especially benzene, toluene, xylene, ethylbenzene, and 2-butoxyethanol in the solvents. However the contents of the toxic substances in the solvents are very small. Not only the exposure assessment for highly toxic substances is important, but also exposure for the petroleum based solvent itself is more important in dry cleaning shop. The specific aim of the present study was to identify the physical and the chemical properties of petroleum based dry cleaning solvents and to investigate the possivility of using occupational exposure standard of stoddard solvent for overall expostreassessment of petroleum based solvent. Four different petroleum based solvent(solvent A~solvent D). commonly used in Korda were analyzed and investigated for identifying the phtsical and chemical properties of those solvents. Molecula species of those solvents were C8~C12, and predominant molecular species were C10~C11 for solvent A, solvent C, solvent D. C9~C10 for solvent B. The proportion of paraffin, aromatic, naphthenic,and olefin compounds in dry cleaning solvents was 45.5~54.5%, 16.0~21.4%, 7.9%~15.8%, and 0.8%~1.0%, respectively. The range of boiling point, specific grabity, flash point found in material safety and data sheet made by the solvent manufacturing company was 150 ~210˚C. 0.76~0.79, and 30~44˚C., respectively. We conclude that petroleum based solvents used in dry cleaning shop is almost similar to stoddard solvent defined by ACGIH and NIOSH, and the occupational exposure standard of stoddrd solvent could be used in total exposure assessment of those solvents.

Controlling organization of conjugated polymer films from binary solvent mixtures for high performance organic field-effect transistors

Opoku, Henry,Nketia-Yawson, Benjamin,Shin, Eun Sol,Noh, Yong-Young Elsevier 2017 Organic electronics Vol.41 No.-

<P><B>Abstract</B></P> <P>We investigate the effect of a binary solvent blend as a solvent for poly{[<I>N</I>,<I>N</I>′-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} P(NDI2OD-T2) on the characteristics of n-channel organic field-effect transistors (OFETs). To make the binary solvent blend, the low-boiling-point non-solvent propylene glycol methyl ether acetate (PGMEA, b.p ∼146 °C) is added to the high-boiling-point good solvent 1,2-dichlorobenzene (O-DCB, b.p ∼180 °C) at various mixing ratio from 0 to 40 v%. UV–vis spectra of P(NDI2OD-T2) solution dissolved in the binary solvent clearly show the formation of polymer aggregates through a gradual red shift of the intramolecular charge transfer band with the addition of high concentrations of non-solvent PGMEA. Higher edge-on oriented crystallinity is observed for P(NDI2OD-T2) films spin-coated from the binary solvent with 5–10 v% PGMEA by out-of-order x-ray diffraction. P(NDI2OD-T2) films are applied as the active layer in top-gate/bottom-contact OFETs. Improved n-type field-effect mobility of the P(NDI2OD-T2) semiconducting layer up to 0.59 cm<SUP>2</SUP>/Vs was achieved for on-center spin coated films compared to 1.03 cm<SUP>2</SUP>/Vs for off-center (parallel alignment) spin-coated films respectively employing the binary solvent with 10 v% PGMEA.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Investigate the binary solvent effect on characteristics of organic transistors. </LI> <LI> Low-boiling-point non-solvent and the high-boiling-point good solvent is optimized. </LI> <LI> P(NDI2OD-T2) OFETs show an improved mobility of 1.03 cm<SUP>2</SUP>/Vs by binary solvent. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Solvent screening for the separation of ethylbenzene and p-xylene by extractive distillation

주영환,설용건,전유권,Sung wook Row,이기천,Sang-Sun Park,Young-Jong Seo 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.10

Extractive distillation is one of the most effective processes for the separation of ethylbenzene and p-xylene. The goal was to find single solvents or combinations of multi-solvents with good properties while minimizing the ratioof solvent to feed. The distillations were performed at equilibrium to determine the relative volatility of ethylbenzeneto p-xylene with the extractive solvents under isothermal condition. For a single extraction solvent, 1,2,4-trichlo-robenzene had the highest relative volatility at 1.123. In some cases, combinations of two or three solvents were usedas well as different ratios of solvent to feed to investigate the synergy effect of the mixture solvents. The binary solventmixture of 1,2,4-trichlorobenzene and maleic anhydride (2 : 1) had the best performance with a relative volatility of1.228 at the solvent/feed ratio of 1 : 1. Some of the solvents were further studied at different solvent/feed (S/F) ratios. Selected solvents generally tended to have higher relative volatilities at high S/F ratios, but the operation cost will in-crease. Therefore, it is important to find the proper conditions to optimize the S/F ratio for extractive distillation fromthe industrial point of view.