Korean Journal of Chemical Engineering (v.28, #2)
Solid forms of pharmaceuticals: Polymorphs, salts and cocrystals by Bipul Sarma; Jie Chen; Huai-Ying Hsi; Allan S. Myerson (315-322).
Control and selection of the properties of active pharmaceutical ingredients is a crucial part of the drug development process. One major part of this process is the selection of an appropriate solid form. This review will discuss three major types of crystalline solids, polymorphs, salts and cocrystals and processes used to develop and find these forms.
Keywords: Solid Forms; Polymorphs; Pharmaceutical Salts; Cocrystals; Design; Screening; Scale-up
Risk assessment and drawing information system based change management by Jin Hwan Yoo; Heon Seok Lee; Jae Wook Ko (323-331).
Most process changes and modifications, which are caused by the process failure, the process life cycle and the economic environment, have been generated at industrial facilities. However, management of change (MOC) is based on basic process safety, such as change judgment, risk check with accurate technical references and risk assessment, and is difficult to carry out because of the lack of experience, knowledge, and process safety specialists. In this study, the MOC system was developed based on process safety technology and the drawing information system (DIS) oriented method. This study recommends the MOC system to industrial facilities as the setup of the obvious standard for the decision-making process, the MOC procedure based risk assessment, and the judgment and risk estimation of the process modification. The HIT and CAT modules were developed using the risk assessment checklist, HAZOP risk ranking, scenarios for consequence analysis and reporting automation. These two modules provide a clearcut view on the process risk. An effective risk-based MOC Review was performed by this new method. Additionally, this study suggests a new method for the MOC S/W system. This method was developed using a new technique which was based on the DIS system linking MOC system and the HIT and CAT Modules, including the process safety information. The goals of this method are to enhance the safety level and improve the performance efficiency.
Keywords: Management of Change; Drawing Information System; Process Safety Management System; Risk Assessment; Process Hazard Index; Process Safety Information Management
Simulation of mass exchange networks using modified genetic algorithms by Jutamart Thunyawart; Thongchai Srinophakun; Waranya Henwatthana (332-341).
The optimum water usage network leads to both a minimum of freshwater consumption and a minimum of generated wastewater. This work is to develop a mass-exchange networks (MENs) module for a minimum freshwater usage target. This module works as an interface to retrieve supplemental data of chemical processes from a process simulator and to communicate this to the genetic algorithm optimizer. A reuse system and a regeneration/recyclingsystem with a single contaminant are considered as approaches for freshwater minimization. In the formulated model, as mixed integer nonlinear programming (MINLP), all of the variables are divided into independent and dependent variables. The values of independent variables come from randomization, whereas the values of dependent variables come from simultaneous solutions of a set of equality constraints after assigning the values of independent variables. This method is applied to the steps of initialization, crossover and mutation. The MENs module is validated with a tricresylphosphate process consisting of five unit operations. Water is used to remove a fixed content of cresol. From the result, the module gives a reliable solution for freshwater minimization, which can satisfy mass balance and constraints. The results show that reuse and regeneration/recycling strategies can reduce freshwater consumption, including wastewater generated. Reuse cannot decrease the mass load of the contaminant, while regeneration/recycling can. In addition, regeneration requires less freshwater than the reuse process.
Keywords: Wastewater Minimization; Genetic Algorithm; Mixed Integer Nonlinear Programming
Third quadrant Nyquist point for the relay feedback autotuning of PI controllers by Jeonguk Byeon; Jin-Su Kim; Su Whan Sung; Won Ryoo; Jietae Lee (342-347).
The original relay feedback autotuning method of Astrom and Hagglund  is based on the Nyquist point at the phase angle of −π (the critical frequency). Recently, Friman and Waller  showed that the critical frequency is too high to tune PI controllers and proposed an autotuning method that finds a Nyquist point at the third quadrant through the two-channel relay. Here, the method to find Nyquist points in the third quadrant is revisited and adaptive relay feedback method which can be applied to noisy processes is proposed. It is shown that the bandwidths of PI control systems and the first-order plus time delay model identifications support the Nyquist point at the third quadrant. Nyquist points at the third quadrant can be obtained by introducing a filter and hysteresis to the relay feedback loop. However, the filter time constant and the size of hysteresis should be adjusted iteratively because their phase shifts are dependent on the resulting relay oscillation frequency. Simulations show that this adaptive relay feedback method finds a given Nyquist point at the third quadrant accurately under noisy environments and provides excellent PI control systems.
Keywords: Nyquist Points; Third Quadrant; PI Controller Tuning; Filters; Hysteresis
Study of the structural characteristics of a divided wall column using the sloppy distillation arrangement by Senug Hyun Lee; Mohammad Shamsuzzoha; Myungwan Han; Young Han Kim; Moonyong Lee (348-356).
An efficient design method is proposed for determining the optimal design structure of a dividing wall column (DWC). The internal section of the DWC is divided into four separate sections and matched to the sloppy arrangement with three conventional simple columns. The light and heavy key component mole-fractions are used as the design variables in each column. The structure that gives superior energy efficiency in the shortcut sloppy case also brings superior energy efficiency in the DWC, while the optimal internal flow distribution of the DWC is different from that obtained from the sloppy configuration. Based upon an extensive simulation study, a two-step approach is proposed for the DWC design: the optimal DWC structure is first determined by applying the shortcut method to the sloppy configuration; the optimal internal flow distribution is then found from the corresponding DWC configuration. The simulation study shows that the DWC designed by the proposed method gives a near-optimal structure.
Keywords: Divided Wall Column; Thermally Coupled Distillation Column; Optimal Structure Design; Energy Efficiency; Shortcut Design Method
Retention mechanism of some solutes using ionic liquids as mobile phase modifier in RP-high-performance liquid chromatography (HPLC) by Minglei Tian; Shengnan Li; Kyung Ho Row (357-363).
Two kinds of ionic liquid, 1-Hexyl-3-methylimidazolium tetrafluoroborate ([Hmim][BF4]) and 1-Methyl-3-octylimidazolium tetrafluoroborate ([Omim][BF4]), were used as additives in the linear solvation energy relationships (LSERs) model to investigate the fundamental chemical interactions governing the retention of nine aromatic compounds in acetonitrile/water mobile phases on a C18 column. The effects of the [Hmim][BF4] and [Omim][BF4] were compared and the ability of the LSERs to account for the chemical interactions underlying solute retention was shown. A comparison of predicted and experimental retention factors suggests that LSER formalism is able to reproduce adequately the experimental retention factors of the solutes studied in the different experimental conditions investigated.
Keywords: Ionic Liquid; Linear Solvation Energy Relationships (LSER); Retention; Modifier
Numerical simulation of bidisperse hard spheres settling in a fluid by Sangkyun Koo (364-369).
Average settling velocity of non-uniform hard spheres in a viscous fluid is determined by using a large-scale numerical simulation that is carried out for over 103 spheres in a periodic unit cell which extends infinitely. An efficient calculation scheme is used for reducing the computation cost which steeply increases with the number of the spheres. The calculation scheme is based on a fast summation method for far-field hydrodynamic interaction among spheres. It is applied in the computation of hindered settling velocity of hard spheres with bidisperse size distribution in a viscous fluid. The simulation results are compared with the theoretical predictions by Batchelor  and Davis and Gecol . It is found that the prediction by Davis and Gecol reasonably agrees with the numerical results.
Keywords: Bidisperse Suspension; Hindered Settling Velocity; Fast Summation Algorithm; Stokes Flow Simulation; Multipole Expansion
Dehydrogenation of isobutane over Sn/Pt/Na-ZSM-5 catalysts: The effect of SiO2/Al2O3 ratio, amount and distribution of Pt nanoparticles on the catalytic behavior by Sedigheh Vaezifar; Hossein Faghihian; Mahdi Kamali (370-377).
Sn/Pt/Na-ZSM-5 was used as catalyst for the dehydrogenation of isobutane, and the effect of SiO2/Al2O3 ratio and the dispersion of Pt nanoparticles on the conversion and product selectivity were studied under atmospheric pressure at 848 K. The catalysts were characterized by various techniques such as H2 chemisorption, TEM, SEM, EDX, XRD, FT-IR, TG/DTG, elemental analysis by XRF and ICP techniques. Higher dispersion of Pt nanoparticles in the catalyst with SiO2/Al2O3 ratio of 40 resulted in higher selectivity for isobutene.
Keywords: Na-ZSM-5; SiO2/Al2O3 Ratio; Bimetallic Catalysts; Pt/Sn Nanoparticles; Dehydrogenation of Isobutane
Asymmetric reduction of 3-oxo-3-phenylpropionic acid ethyl ester by undifferentiated cells of white turnip in phosphate buffer/organic solvent by Zhimin Ou; Qingmei Chen; Gensheng Yang; Li Xu (378-382).
Ethyl (S)-3-hydroxy-3-phenylpropionate was synthesized by asymmetric reduction of 3-oxo-3-phenylpropionic acid ethyl ester with undifferentiated cells of white turnip in phosphate buffer/organic solvent. The conversion increased with the LogP oct of organic solvent increase. The phosphate buffer (0.2 mol/L, pH 7.0)/dodecane was selected as optimum medium for reduction. The optimal content of dodecane in medium is 10% (v). The conversion decreased with initial substrate concentration increase. Addition of more biomass of plant cells and 10% ethanol as co-substrate can improve conversion. The plant cells can be reused well for three times. The enantiomeric excess of ethyl (S)-3-hydroxy-3-phenylpropionate reached 100% with 1% allyl bromide as inhibitor.
Keywords: Ethyl (S)-3-hydroxy-3-phenylpropionate; Undifferentiated Cells of White Turnip; Phosphate Buffer/Organic Solvent; Asymmetric Reduction
Electronic density enrichment of Pt catalysts by coke in the propane dehydrogenation by Bao Khanh Vu; Myoung Bok Song; Sul-A Park; Youngil Lee; In Young Ahn; Young-Woong Suh; Dong Jin Suh; Won-Il Kim; Hyoung-Lim Koh; Young Gyo Choi; Eun Woo Shin (383-387).
We investigated the nature of coke generated in propane dehydrogenation over supported Pt catalysts by FTIR, NMR, and XPS. NMR and FTIR spectra proved that the coke produced in the reaction contained poly-aromatic rings, which was consistent with the previous result that pregraphite-like coke structure was formed. The XPS results indicated that the coke deposits consisted of sp2 hybridized carbon. All of the characterizations indicated that the pregraphite-like coke containing the poly-aromatic ring structure was generated over the catalysts during the propane dehydrogenation. Furthermore, the XPS measurement demonstrated that the coke deposits interacted with Pt and the electron density of Pt was enriched through the interaction.
Keywords: Electronic Density; Propane Dehydrogenation; Coke Deposition; Supported Pt Catalysts; Deactivation
Lumped-intermediates analysis in the photooxidation of Rhodamine 6G in the H2O2/UV system by Amaia Menendez; Jose I. Lombraña; Ana de Luis (388-395).
The combination of H2O2 with UV radiation was applied to study the degradation of Rhodamine 6G dye (Rh-6G). The lumped kinetic model proposed in this work is a reaction-system scheme to describe the degradation of dye using lumps of intermediate compounds grouped by their chemical and colorimetric behavior. Rate constants obtained by application of the model were shown to predict the progress of dye oxidation. The effects of pH and oxidant dosage on these rate constants were also analyzed. Finally, photodecoloration was studied considering the absorption at 528 nm (the maximum absorption wavelength of the dye) as the sum of all compounds absorbing at this wavelength: Rhodamine itself and the colored intermediates produced.
Keywords: Lumped Kinetic Model; H2O2/UV; Rhodamine 6G; Decoloration; Dye
Production of egg-like silica sphere in a carbon shell and their oxidation to produce egg-tray structures with high ammonia adsorption by Sayed Hasan Razi Abdi; Young Jin Kim; Yong-Ki Park; Songhun Yoon; Won Choon Choi; Hee Young Kim; Mijeong Han; Chul Wee Lee (396-401).
A simple synthesis protocol to prepare egg-like carbon-silica hybrids was developed where the size of a silica ball housed inside a carbon shell was tunable. An egg-tray type of carbon-silica hybrid was also made by the oxidation of egg-like carbon-silica hybrids. This oxidized hybrid has shown high ammonia adsorption capacity that is about 30 times more than the standard commercial adsorbent H-ZSM-5 (SiO2/Al2O3=128).
Keywords: Carbon-silica Hybrid; Porous Material; Egg-tray Morphology; Oxidative Chopping; Catalyst Support
Effects of La2O3 on ZrO2 supported Ni catalysts for autothermal reforming of CH4 by Sun Hee Park; Byung-Hee Chun; Sung Hyun Kim (402-408).
The effect of La2O3 content in Ni-La-Zr catalyst was investigated for the autothermal reforming (ATR) of CH4. The catalysts were prepared by the coprecipitation method and had a mesoporous structure. Temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS) indicated that a strong interaction developed between Ni species and the support with the addition of La2O3. Thermogravimetric analysis (TGA) and H2-pulse chemisorption showed that the addition of La2O3 led to well dispersed NiO molecules on the support. Ni-La-Zr catalysts gave much higher CH4 conversion than Ni-Zr catalyst. The Ni-La-Zr containing 3.2 wt% La2O3 showed the highest activity. The optimum conditions for maximal CH4 conversion and H2 yield were H2O/CH4=1.00, O2/CH4=0.75. Under these conditions, CH4 conversion of 83% was achieved at 700 °C. In excess O2 (O2/CH4>0.88), the catalytic activity was decreased due to sintering of the catalyst.
Keywords: Methane; Reforming; Autothermal; Lanthanum; Zirconium Oxide; Nickel Catalyst
Isopropylation of naphthalene over H-mordenite, H-Y, and H-beta zeolites: Roles of isopropylnaphthalene isomers by Yoshihiro Sugi; Yukio Hasegawa; Hiroshi Tamada; Kenichi Komura; Yoshihiro Kubota; Jong-Ho Kim (409-417).
Isopropylation of naphthalene (NP) was examined over H-mordenite (MOR), H-Y zeolite (FAU), and HBeta zeolite (BEA) in order to elucidate roles of isopropylnaphthalene (IPN) isomers during the catalysis. 2-IPN was the predominant isomer over MOR and works as a precursor for the selective formation of β,β-DIPN, particularly, 2,6-DIPN. In contrast, 1-IPN was predominant (with 2-IPN as a minor isomer) over FAU and BEA at low temperatures; dialkylation accompanied by the consumption of 1- and 2-IPN led to predominant formation of α,α- and α,β-DIPN. The formation of β,β-DIPN from 2-IPN was enhanced at higher temperatures. Bulky transition states of 1-IPN in IPN isomers and α,α- and α,β-DIPN among DIPN isomers were hindered by the interaction with MOR channels, resulting in the selective formation of β,β-DIPN, particularly 2,6-DIPN through the less bulky 2-IPN. FAU and BEA allow the formation of α,α- and α,β-DIPN from both of 1- and 2-IPN isomers because their channels are too large to exclude bulky transition states. The catalysis over FAU and BEA occurred under kinetic control at lower temperatures, and thermodynamic control also participates at higher temperatures.
Keywords: Isopropylation; Naphthalene; Isopropylnaphthalene; Diisopropylnaphthalene; Mordenite; Y Zeolite; Beta Zeolite
Catalytic process for decolorizing yellow plume by Jung Hoon Yang; Jung-Il Yang; Dong Hyun Chun; Hak-Joo Kim; Ho-Tae Lee; Heon Jung (418-423).
Yellow-colored exhaust gas streams from internal engines or gas turbines, frequently referred to as “yellow plume,” contain nitrogen dioxide (NO2) at concentrations as low as 15 ppm. The process developed in this work for decolorizing the yellow plume is based on reduction of NO2 to NO utilizing a combination of a Pt catalyst and a reducing agent. A stoichiometric excess of carbon monoxide, diesel oil, methanol or ethanol were used as reducing agents. Depending on the type of the reductant, the active temperature window of NO2 reduction was varied with methanol and CO being active at lower temperatures and ethanol and diesel oil at higher temperatures. By changing the Pt loading of the catalysts the active temperature window of NO2 reduction was also changed, higher loading Pt catalysts being active at lower temperatures. This scheme of NO2 reduction process was verified in a pilot-scale test with the real exhaust gas from the gas turbine power plant, showing 96% of NO2 reduction at the stack temperatures of 102–123 °C and at space velocities of 28,000–95,000 h−1 with inherent CO in the exhaust gas as the reducing agent.
Keywords: Yellow Plume; Decolorizing; NO2 Reduction; Pt Catalyst; Pilot Scale
Nelumbo nucifera extracts as whitening and anti-wrinkle cosmetic agent by Tagon Kim; Hee Jin Kim; Sung Ki Cho; Whan Yul Kang; Hyun Baek; Hye Young Jeon; Boyoung Kim; Donguk Kim (424-427).
Water extract from Nelumbo nucifera was tested for possible functional cosmetic agent. Whitening effect was measured by tyrosinase inhibition assay and DOPA-oxidase inhibition assay, and anti-wrinkle effect was checked by elastase inhibition assay. DOPA-oxidase inhibition effect (whitening effect) of Nelumbo nucifera’s leaf, seed and flower extract was 59%, 57% and 50%, respectively. Nelumbo nucifera’s leaf, seed and flower extract showed 56%, 49%, and 54% elastase inhibition (anti-wrinkle effect) at 200 μg/ml, while adenosine indicated 26% inhibition. Water cream including Nelumbo nucifera’s root, leaf, flower, stem extract did not cause significant skin irritation. Water cream including 4% Nelumbo nucifera extract was stable for 30 days under various temperature conditions. From the study, Nelumbo nucifera’s leaf, flower and seed extracts showed strong possibility for whitening and anti-wrinkle functional cosmetic agent.
Keywords: Nelumbo nucifera ; Cosmetics; Whitening; Anti-wrinkle; Safety
Electrospun nanofibers with application in nanocomposites by Mohammad Kanafchian; Masoomeh Valizadeh; Akbar Khodaparast Haghi (428-439).
The use of fine fiber has become an important design tool for filter media. Nanofibers-based filter media have some advantages such as lower energy consumption, longer filter life, high filtration capacity, easier maintenance, low weight rather than other filter media. The nanofibers-based filter media made up of fibers of diameter ranging from 100 to 1,000 nm can be conveniently produce by electrospinning technique. Common filter media have been prepared with a layer of fine fiber on typically forming the upstream or intake side of the media structure. The fine fiber increases the efficiency of filtration by trapping small particles, which increases the overall particulate filtration efficiency of the structure. Improved fine fiber structures have been developed in this study in which a controlled amount of fine fiber is placed on both sides of the media to result in an improvement in filter efficiency and a substantial improvement in lifetime. In the first part of this study, the production of electrospun nanofibers is investigated. In the second part, a different case studyis presented to show how they can be laminated for application as filter media. Response surface methodology (RSM) was used to obtain a quantitative relationship between selected electrospinning parameters and average fiber diameter and its distribution.
Keywords: Biopolymers; Scanning Electron Microscope; Morphology; Proteins; Nanofibers; Statistical Analysis
Synthesis of copper-poly tetrafluoro-ethylene composites by supercritical impregnation process by Eun-Bong Kim; Jung-Teag Kim; Si-Young Kim; Chang-Sik Ju (440-444).
This study attempted to develop a copper-PTFE composite consisting of copper nano-particles homogeneously distributed into PTFE using scCO2. The overall synthesis process consisted of impregnation of copper precursor and thermolytic reduction. The impregnation process was performed over a range of temperature from 40 to 160 °C and pressure from 120 to 200 bar. The reduction process was performed at 230 °C and 250 bar for 2 hours consecutively after impregnation. The changes in appearance, mass, and morphology of the PTFE composite were examined by precision balance, SEM, TEM, and EDS. The impregnation ratio increased with temperature up to 120 °C, but decreased above 120 °C. The impregnation ratio increased with the pressure. These results could be explained by dehydration reaction of Cu(hfa)2H2O and thermodynamical affinity difference of copper precursors for PTFE or scCO2. Copper nano-particles impregnated into the PTFE were identified from SEM, TEM and EDS analysis.
Keywords: Supercritical; Impregnation; PTFE; Copper Bis(Trifluoroacetylacetonate); Nano-particle
A study on the effects of laminating temperature on the polymeric nanofiber web by Mohammad Kanafchian; Masoomeh Valizadeh; Akbar khodaparast Haghi (445-448).
The purpose of this study is to consider the influence of laminating temperature on nanofiber/laminate properties. Hot-press laminating was carried out at five different temperatures and nanofiber web morphology was observed under an optical microscope. Also, air permeability experiments were performed to examine the effect of laminating temperature on breathability of multilayer fabric. Optical microscope images showed that the nanofiber web began to damage when laminating temperature was selected above the melting point of adhesive layer. Air permeability decreased with increasing laminating temperature. It is also observed that the adhesive force between layers was increased by increasing laminating temperature.
Keywords: Nanoscaled Polymeric Fiber; Laminating; Protective Clothing
Circulating flow reactor for recycling of carbon fiber from carbon fiber reinforced epoxy composite by Seok-Ho Lee; Hwan-Oh Choi; Jung-Seok Kim; Cheul-Kyu Lee; Yong-Ki Kim; Chang-Sik Ju (449-454).
For the purpose of development of a chemical recycling process for carbon fiber from carbon fiber reinforced epoxy composite, a new chemical recycling system using nitric acid aqueous solution has been proposed. The recycling system is composed of hexahedral circulating flow reactor made of quartz, Teflon supporter, acid resistance pump and auxiliaries. Epoxy matrix in the composite was effectively decomposed by nitric acid aqueous solution in the circulating flow reactor and carbon fiber could be recycled without any tangle or disturbance. Optimum conditions for the recycling process have been experimentally established. Tensile strength loss of recycled carbon fiber and composition of liquid phase decomposition products were analyzed.
Keywords: Recycling; Carbon Fiber; Epoxy Composite; Circulating Flow Reactor; Nitric Acid; Decomposition
Extraction of bitumen with sub- and supercritical water by Jung Hoon Park; Sou Hwan Son (455-460).
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 °C, pressure 15–30 MPa and water density 0.07–0.65 g/cm3 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.
Keywords: Bitumen; Supercritical Water; Sulfur Removal; Asphaltenes; Upgrading
Premixed filtration combustion of micron and sub-micron particles in inert porous media: A theoretical analysis by Mehdi Bidabadi; Jalil Fereidooni; Reza Tavakoli; Majid Mafi (461-469).
An analytical model for one-dimensional premixed filtration combustion of volatile fuel particles-air mixture is presented. It is presumed that fuel particles first vaporize and a gaseous fuel with definite chemical structure is formed, which is subsequently oxidized in the gas phase. Flame structure is considered in the three zones. In the preheating vaporization zone, the mixture is heated until it reaches ignition temperature. In the reaction zone, the combustible mixture burns and the post flame zone is occupied by the combustion products. The temperature and mass fraction profiles are obtained of gaseous fuel in these three zones at a semi-infinite inert porous media. Thereafter, the effects of various parameters such as gas velocity, porosity, fuel particles diameter, number density of fuel particles, and heat of chemical reaction on the temperature and mass fraction profiles are investigated.
Keywords: Fuel Particles Combustion; Inert Porous Medium; Analytical Solution
Analytical study on the optimum design of producing well to increase oil production at severe cold regions by Wonmo Sung; Sunil Kwon; Sangjin Kim; Hyemin Park; Youngsoo Lee; Inhang Yoo (470-479).
This paper presents a simulation study of fluid flow in the tubing on a reservoir system formed in a severe cold region. The thickness of the permafrost and specific gravity of the oil were applied by field survey. Then, flowing improvement techniques for oil production such as progressive cavity pump (PCP), insulated casing, electric trace heater and gas lifting were applied. For the reservoir located at 1,000 m depth in the Arctic region, the thicker the permafrost layer was, the more the mobility of oil in the tubing declined. By applying the flowing improvement techniques to this reservoir, the effect of the heater increased with the oil containing heavier components, and it was found that the production rate was improved as the heater installation interval became deeper. Despite the gas lifting method showing better productivity compared to other methods, there was an optimal injection rate at which the production rate became maximum. Moreover, it was shown that increasing the temperature of injection gas had little effect on enhancing the oil flow in tubing. Based on these results, flowing improvement techniques were applied to the oil wells in the Ada field. The productivity by PCP of Bashenkol_1X well, which contained comparatively light oil, increased 3.75 times more than natural state. Also, additional installation of insulated casing could yield better production. In the case of Bashenkol_3X in which 19.2° API of heavy oil was reserved, oil production was impossible without flowing improvement methods. This well was able to produce 158 BOPD of oil by installing PCP with insulated casing and additional installation of heater increased production rate to 267 BOPD. Meanwhile, although the gas lifting method can greatly improve productivity, the applicability and cost should be considered prior to its being applied.
Keywords: Permafrost; Heavy Oil; Pumping; Heater; Gas Lifting
The effect of relative humidity on CO2 capture capacity of potassium-based sorbents by Soo Chool Lee; Ho Jin Chae; Bo Yun Choi; Suk Yong Jung; Chun Yong Ryu; Jung Je Park; Jeom-In Baek; Chong Kul Ryu; Jae Chang Kim (480-486).
Potassium-based sorbent was prepared by impregnation with potassium carbonate on activated carbon. The role of water and its effects on pretreatment and CO2 absorption was investigated in a fixed bed reactor. K2CO3 could be easily converted into K2CO3·1.5H2O working as an active species by the absorption of water vapor as the following reaction: K2CO3+3/2 H2O→K2CO3·1.5H2O. One mole of K2CO3·1.5H2O absorbed one mole of CO2 as the following reaction: K2CO3·1.5H2O+CO2ai2KHCO3+0.5 H2O. The K2CO3·1.5H2O phase, however, was easily transformed to the K2CO3 phase by thermal desorption even at low temperature under low relative humidity. To enhance CO2 capture capacity and CO2 absorption rate, it is very important to maintain the K2CO3·1.5H2O phase worked as an active species, as well as to convert the entire K2CO3 to the K2CO3·1.5H2O phase during CO2 absorption at a temperature range between 50 °C and 70 °C. As a result, the relative humidity plays a very important role in preventing the transformation from K2CO3·1.5H2O to the original phase (K2CO3) as well as in producing the K2CO3·1.5H2O from K2CO3, during CO2 absorption between 50 °C and 70 °C.
Keywords: CO2 ; Absorption; Pretreatment; K2CO3 ; K2CO3·1.5H2O
Pinhole formation in PEMFC membrane after electrochemical degradation and wet/dry cycling test by Ho Lee; Taehee Kim; Woojong Sim; Saehoon Kim; Byungki Ahn; Taewon Lim; Kwonpil Park (487-491).
During the operation of a PEMFC, the polymer membrane is degraded by electrochemical reactions and mechanical stresses. We investigated the effects of repeated electrochemical and mechanical degradations in a membrane. For mechanical degradation, the membrane and MEA were repeatedly subjected to wet/dry cycles; for electrochemical degradation, the cell was operated under open-circuit voltage (OCV)/low-humidity conditions. The repeated wet/dry cycles led to a decrease in the mechanical strength of the membrane. When the MEA was degraded electrochemically, repeated wet/dry cycling resulted in the formation of pinholes in the membrane. In the case of different MEAs that were first degraded electrochemically, the extents of their hydrogen crossover currents increased due to repeated wet/dry cycling being different. Therefore, these results indicated that the membrane durability could be evaluated by these methods of repeated electrochemical degradation and wet/dry cycles.
Keywords: Polymer Electrolyte Membrane Fuel Cell; Durability; Membrane Degradation; Mechanical Degradation; Wet/Dry Cycling
Preparation and performance of cobalt-doped carbon aerogel for supercapacitor by Yoon Jae Lee; Ji Chul Jung; Sunyoung Park; Jeong Gil Seo; Sung-Hyeon Baeck; Jung Rag Yoon; Jongheop Yi; In Kyu Song (492-496).
Carbon aerogels were prepared by polycondensation of resorcinol with formaldehyde in ambient conditions. The effect of resorcinol-to-catalyst ratio (R/C ratio) on volume shrinkage, BET surface area, and electrochemical property was investigated by changing R/C ratio from 50 to 2000. Carbon aerogel prepared at R/C ratio of 500 showed less than 2% of volume shrinkage and the highest BET surface area (706 m2/g). Specific capacitance of carbon aerogel prepared at R/C ratio of 500 was found to be 81 F/g in 1M H2SO4 electrolyte. Cobalt-doped carbon aerogels were then prepared by an impregnation method with a variation of cobalt content, and their performance was investigated. Among the samples prepared, 7 wt% cobalt-doped carbon aerogel showed the highest capacitance (100 F/g) and the most stable cyclability. The enhanced capacitance of cobalt-doped carbon aerogel was attributed to the faradaic redox reactions of cobalt oxide.
Keywords: Carbon; Aerogel; Doping; Electrochemical Properties
Copyrolysis of block polypropylene with waste wood chip by Mi-Jin Jeon; Suek Joo Choi; Kyung-Seun Yoo; Changkook Ryu; Sung Hoon Park; Jong Min Lee; Jong-Ki Jeon; Young-Kwon Park; Seungdo Kim (497-501).
In this study, the copyrolysis of waste wood chip (WC) and block polypropylene (PP) was studied to investigate how the characteristics of bio-oils are affected by copyrolysis. The thermogravimetric analysis performed with a temperature rise of 20 °C/min, from room temperature to 600 °C, showed that the decomposition temperature of PP was a little higher via copyrolysis than the single-component pyrolysis. This result suggests that the characteristics of the pyrolysis of PP were affected by the pyrolysis products of WC. The Py-GC/MS analysis of the copyrolysis products detected some new compounds that had not been detected in the single-component pyrolysis products, indicating interactions between the products of WC and PP pyrolyses. The results of the experiments using a fixed bed reactor showed improved properties of the bio-oil obtained from the copyrolysis compared to those of the bio-oil obtained from the single-component pyrolysis: increased carbon and hydrogen contents, decreased water content and a significantly increased heating value.
Keywords: Copyrolysis; Waste Wood Chip; Block Polypropylene; Interaction; Bio-oil
Mass transfer and shear rate in baffled surface aerator by Bimlesh Kumar; Ajey Kumar Patel; Achanta Ramakrishna Rao (502-506).
The scale up or scale down of the process variables in a surface aerator requires information about the shear rate prevailing in the system. In fact, the performance of surface aerator depends upon the shear rate. Shear rate affects the mass transfer operation needed by the surface aerator. Theoretical analysis of shear rate suggests a nonlinear behavior with rotational speed of the impeller, which has been shown in the present work. Present work also shows that in a geometrically similar system of baffled surface aerator, shear rate can be used as a governing parameter for scaling up or down the mass transfer phenomena.
Keywords: Mass Transfer Rate; Mixing; Power Number; Shear Rate; Surface Aeration
The effect of pressure on removal of carbon monoxide in biofilter by Morteza Hosseini (507-510).
Solubility of carbon monoxide in water is very important for its biological oxidation or removal process of gaseous pollutants. Present research shows the effect of pressure on solubility of carbon monoxide in liquid phase and its removal process by a biofilter. The results are considered as laboratory research on carbon monoxide elimination. In this method a pressurized trickle-bed biofilter was used to increase pressure in the reactor. The biofilter was filled with Leca-stones and inoculated with microorganisms. When the system’s pressure is increased, the solubility of carbon monoxide will be increased, respectively, and it causes a better reaction of the microorganisms for removing of gaseous pollutants. The efficiency was improved significantly by increasing the pressure in the reactor.
Keywords: Carbon Monoxide; Biofilter; Bioreactor; Pressurized Biofilter
Positive and negative effects of excessive water reuse to be considered in water network synthesis by Seong-Rin Lim; Jong Moon Park (511-518).
Water network synthesis has focused on maximizing water reuse to minimize freshwater consumption, even though the adverse effect of water use has not been examined until now. This study evaluates and analyzes the positive and negative effects of excessive water reuse on the environmental and economic performance of a water network system. Life cycle assessment and life cycle costing are used to evaluate the environmental impacts and economic costs of the three water systems with the different levels of water reuse. Networking for low water reuse enhances both environmental and economic performance of a water system. However, networking for excessive water reuse deteriorates the economic performance of the water system, even though this networking enhances its environmental performance. Therefore, the positive and negative effects of excessive water reuse should be taken into account in developing new pinch analysis methodologies and mathematical optimization models for water network synthesis.
Keywords: Environmental and Economic Performance; Life Cycle Assessment; Life Cycle Costing; Water Network Synthesis; Water Reuse
Examining the effects of velocity ratio of the pressurized flow to the main inlet flow on coagulants dispersion in pump diffusion mixer by No-Suk Park; Seong-Su Kim; Kwan-Yeop Kim; Sangyoung Park (519-526).
This study was conducted to evaluate the ratio of the pressurized flow to the main inlet flow, which has been considered one of the most important parameters for operating the pump diffusion mixer (PDM). Computational fluid dynamics (CFD) simulation was employed to evaluate the conventional operation rule of PDM and to propose a supplementary operating parameter and criterion. Test simulation of CFD was carried out for the 21 cases of flow ratio in a full scale PDM. The values of local velocity gradient were calculated in each case to analyze the simulation results in more detail. A wet test was conducted to verify CFD simulation results, which measures the factual coagulant dispersion distribution at a distance of 5.4 m from deflector. From results of both CFD simulation and wet test, the flow ratio was adequate as an operating parameter or criterion; also, the velocity ratio (dimensionless) of the pressurized flow to the main inlet was useful in predicting the performance of PDM. In addition, the injected coagulant could be dispersed evenly in overall cross section on the condition that the velocity ratio is at least over 20.
Keywords: Pump Diffusion Mixer; Flow Ratio; Velocity Ratio; Computational Fluid Dynamics; Wet Test
Performance evaluation of an electrometer system for ion and aerosol charge measurements by Panich Intra; Nakorn Tippayawong (527-530).
An aerosol electrometer system for measuring ion and aerosol charge using electrostatic detection technique was developed and presented. It consists of a size-selective inlet, a particle charger, an ion trap, a Faraday cup, an electrometer, and a data acquisition and processing system. In this system, an aerosol sample first passes through the size-selective inlet to remove particles outside the measurement size range based on their aerodynamic diameter, and then passes through the unipolar corona charger that sets a charge on the particles and enters the ion trap to remove the free ions. After the ion trap, the charged particles then enter the Faraday cup electrometer for measuring ultra low current of about 1 pA induced by ion and aerosol charge collected on the filter in Faraday cup corresponding to the number concentration of ion and aerosol. Signal current is then recorded and processed by a data acquisition system. Finally, the detailed description of the operating principle of the system as well as the preliminary experimental testing results of ion and aerosol charge measurements were also introduced and discussed.
Keywords: Aerosol; Ion; Faraday Cup; Electrometer
Statistical optimization of process conditions for photocatalytic degradation of phenol with immobilization of nano TiO2 on perlite granules by Narges Keshavarz Jafarzadeh; Shahram Sharifnia; Seyed Nezam Hosseini; Farshad Rahimpour (531-538).
Response surface methodology (RSM) using D-optimal design was applied to optimization of photocatalytic degradation of phenol by new composite nano-catalyst (TiO2/Perlite). Effects of seven factors (initial pH, initial phenol concentration, reaction temperature, UV irradiation time, UV light intensity, catalyst calcination temperature, and dosage of TiO2/perlite) on phenol conversion efficiency were studied and optimized by using the statistical software MODDE 8.02. On statistical analysis of the results from the experimental studies, the optimum process conditions were as follows: initial pH, 10.7; initial phenol concentration, 0.5 mM; reaction temperature, 27 °C; UV irradiation time, 6.5 h; UV light intensity, 250 W; catalyst calcination temperature, 600 °C; and TiO2/perlite dosage, 6 g/L. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) of 91.8%.
Keywords: Photocatalyst; Phenol; TiO2 ; Perlite; Experimental Design
Naphthalene destruction performance from tar model compound using a gliding arc plasma reformer by Yoon Cheol Yang; Young Nam Chun (539-543).
Recycling of various wastes such as sewage sludge requires an energy conversion process like thermal pyrolysis/gasification. During the process, tar and syngas are produced, but the tar brings trouble in pipelines and creates operating problems for the facility. In this study, to investigate naphthalene destruction in a gliding arc plasma reformer, parametric experiments were achieved in the variables that can affect the destruction efficiency. And through the parametric studies, the optimal operating conditions and the results were taken. For the parametric studies, steam input amount (steam/carbon ratio), input discharged power SEI (specific energy input), total feed gas amount, input naphthalene concentration, and electrode length were selected for experiments. Optimal conditions were 2.5 of S/C ratio, 1 kWh/m3 of SEI, 18.4 L/min of total gas amount, 1% of input naphthalene concentration, and 95 mm of electrode length. The corresponding maximum destruction efficiency of naphthalene was 79%, and energy efficiency showed 47 g/kWh.
Keywords: Tar Model Compound; Gliding Arc Plasma; Reformer; Thermal Destruction; Pyrolysis/Gasification
Mutation breeding of nuclease p1 production in Penicillium citrinum by low-energy ion beam implantation by Qinting He; Nan Li; Xiaochun Chen; Qi Ye; Jianxin Bai; Jian Xiong; Hanjie Ying (544-549).
Nuclease p1 is an important enzyme in the nucleotide industry that is used to hydrolyze nucleic acid into nucleotides. To improve enzyme activity, Penicillium citrinum, a nuclease p1 producing strain, was mutated by low-energy Nitrogen ion beam implantation at an energy level of 15 keV and a dose ranging from 1×1015–1×1016 ions/cm2. The mutant strain designated as N409 was obtained with a high yield of nuclease p1. The activity of nuclease p1 was 421 U/mL from the mutant strain N409, which was increased by 86% compared with the control. The fermentation kinetics of nuclease p1 by the mutant strain N409 was studied in a 30 L external airlifting bioreactor. A model was proposed using the logistic equation for microbial growth, the Luedeking-Piret equation for product formation and a Luedeking-Piret-like equation for substrate uptake. The results predicted from the model were in good agreement with the experimental observations.
Keywords: Ion Beam Implantation; Mutation; Penicillium citrinum ; Nuclease p1; Kinetic Model
Effect of calcium carbonate in waste office paper on enzymatic hydrolysis efficiency and enhancement procedures by Xiusheng Wang; Andong Song; Liping Li; Xiaohong Li; Rui Zhang; Jie Bao (550-556).
Hydrolysis of waste office paper (WOP) into fermentable sugars is an important option of WOP utilization. In this work, the effect of major chemicals in WOP on its hydrolysis using industrial cellulase Accellerase 1000 (Genencor, Rochester, NY, USA) was investigated, and calcium carbonate (CaCO3) was found to be the key parameter affecting the enzymatic hydrolysis efficiency of WOP. The pretreatment methods, acid washing and acid presoaking, were tested for the removal of CaCO3 from WOP. It was found that the presoaking of sulfuric acid (H2SO4) in WOP was an effective way. The pretreating parameters of WOP were studied on maximizing the hydrolysis efficiency. The conversion yield of cellulose to glucose and cellobiose using the pretreated WOP reached 73.3% after 96 hours hydrolysis at the optimal conditions. The results provided the WOP utilization with a practical enzymatic hydrolysis method with industrial application potential.
Keywords: Waste Office Paper (WOP); Calcium Carbonate (CaCO3); Hydrolysis; Pretreatment; Presoaking
Rare earth elements leaching from Chadormalu apatite concentrate: Laboratory studies and regression predictions by Esmaeil Jorjani; Amir Hossein Bagherieh; Saeed Chehreh Chelgani (557-562).
The extraction of rare earth elements from apatite concentrate of Chadormalu plant of Iran was studied with the dissolution of ore in nitric acid. The parameters of acidity: 60%, solid to liquid ratio: 30%, leaching time: 30 minute, agitation rate: 200 rpm, temperature: 60 °C and particle size (d80): 50 microns were determined as the optimum operational conditions. The recoveries of lanthanum, cerium, neodymium and yttrium were achieved at 74, 59, 72 and 73%, respectively, in the optimized conditions. Multivariable regression was used to predict La, Ce, Nd, Y and total REEs (Y+Nd+Ce+La) leaching recoveries, using experimental data from laboratory studies. It was achieved quite satisfactory correlations of 0.93, 0.98, 0.99, 0.97 and 0.99 for the prediction of Y, Nd, Ce, La and total REEs recoveries, respectively. It was shown that the proposed equations accurately reproduce the effects of operational variables on the different REEs recoveries, and can be used to optimize the REEs leaching plant.
Keywords: Leaching; Apatite; Rare Earth Elements; Regression
Oxygen removal from nitrogen using YBaCo2O5+δ adsorbent by Haoshan Hao; Bojun Chen; Limin Zhao; Xing Hu (563-566).
The oxygen intake/release behavior of YBaCo2O5+δ and its application as a medium-temperature (100–600 °C) adsorbent to oxygen removal in nitrogen purification was investigated. The oxygen content in YBaCo2O5+δ was varied between 5.46 and 5.0 with the change of the temperature and oxygen partial pressure. This oxygen nonstoichiometry showed good reversibility and the crystal structure of YBaCo2O5+δ remained stable in the oxygen intake/release process. Results of nitrogen purification experiment show that YBaCo2O5+δ material is a promising candidate to remove trace oxygen from nitrogen. After being deoxidized at 600 °C in nitrogen, 1 kg YBaCo2O5+δ adsorbent can purify 310 L nitrogen of 98.1% to high-purity nitrogen of over 99.9999% in one cycle.
Keywords: YBaCo2O5+δ ; Oxygen Intake/Release; Adsorbent; Nitrogen Purification
Chemical absorption of carbon dioxide into oxirane solution containing ID-CP-MS41 catalyst by Kwang-Joong Oh; Seong-Man Mun; Seong-Soo Kim; Sang-Wook Park (567-574).
CP-MS41 was synthesized by hydrolysis of tetraorthosilicate, as a silicon source, with 3-chloropropyltriethoxysilane as an organosilane using cetyltrimethylammonium bromide as a template. ID-CP-MS41 was synthesized by immobilization of imidazole on the CP-MS41 and was dispersed in organic liquid as a mesoporous catalyst for the reaction between carbon dioxide and oxirane. Phenyl glycidyl ether and glycidyl methacrylate were used as oxiranes. Carbon dioxide was absorbed into the oxirane solution in a stirred batch tank with a planar gas-liquid interface within a range of 0–2.0 kmol/m3 of oxirane and 333–363 K at 101.3 kPa. The measured values of absorption rate were analyzed to obtain the reaction kinetics using the mass transfer mechanism associated with the chemical reactions based on the film theory. The overall reaction of CO2 with oxirane, which is assumed to consist of two steps-i) a reversible reaction between oxirane (B) and catalyst of ID-CP-MS41 (QX) to form an intermediate complex (C1), and ii) irreversible reaction between C1 and CO2 to form QX and five-membered cyclic carbonate (C)-was used to obtain the reaction kinetics through the pseudo-first-order reaction model. Polar solvents such as N, N-dimethylacetamide, Nmethyl-2-pyrrolidinone, and dimethyl sulfoxide affected the reaction rate constants.
Keywords: Absorption; Carbon Dioxide; Oxirane; Imidazole; MCM-41
Desalination of fish meat extract by electrodialysis and characterization of membrane fouling by Shaoyuan Shi; Seung-Hee Cho; Yong-Hee Lee; Sung-Hyun Yun; Jung-Je Woo; Seung-Hyeon Moon (575-582).
Fish meat extract (FME) desalination via electrodialysis (ED) was performed and the changes of important parameters such as membrane stack potential, brix, pH, and electrical conductivity were examined for a quantitative evaluation. The change of electrical conductivity in diluted or concentrated solutions showed that the mineral ions contained in the FME could be effectively removed. The characterization of membrane fouling indicated that the organic/ inorganic components deposited, respectively, on the surfaces of anion/cation exchange membrane and resulted in the increase of membrane electrical resistance. Ion chromatograph (IC) analysis showed that the main mineral ions, such as Na+ and Cl+ ions contained in the FME, were removed about 82.3% at an average current efficiency of around 77.9% via ED. By considering the removal rate of mineral ions and current efficiency, the feasibility of FME desalination via ED was proved.
Keywords: Fish Meat Extract; Electrodialysis; Desalination; Membrane Fouling
Adsorption dynamics and effects of carbon to zeolite ratio of layered beds for multicomponent gas adsorption by Seong-Cheol Jang; Se-Il Yang; Seong-Geun Oh; Dae-Ki Choi (583-590).
To optimize the performance of an adsorption bed, layered beds of activated carbon and zeolite 5A are used for multicomponent gas separation (H2: 72.2%, CO2: 21.6%, CO: 2.03%, CH4: 4.17%). The adsorption dynamic characteristics were studied experimentally and theoretically using layered beds of activated carbon and zeolite 5A at 8 atm adsorption pressure and 16.67 L/min feed rate. Non-isothermal and non-adiabatic models, based on a linear driving force model and Dual-Site Langmuir adsorption isotherm model, were used. As the carbon ratio increased, the average velocity of CH4 wavefront became slow, and wavefronts of CO and CO2 propagated quickly on average.
Keywords: Adsorption Dynamic; Layered Bed; Carbon to Zeolite Ratio; Hydrogen; Dual-Site Langmuir
Separation of tetrahydrofuran and water using pressure swing distillation: Modeling and optimization by Jihwan Lee; Jungho Cho; Dong Min Kim; Sangjin Park (591-596).
Computer simulations were performed to obtain highly pure tetrahydrofuran (THF) with over 99.9 mole% from the mixture of THF and water. Pressure swing distillation (PSD) was used since the azeotropic point between tetrahydrofuran and water can be varied with pressure. A commercial process simulator, PRO/II with PROVISION release 8.3, was used for the simulation studies. The Wilson liquid activity coefficient model was used to simulate the low pressure column, and the Peng-Robinson equation of state model was added to correct the vapor phase non-idealities for the modeling of the high pressure column. The most optimal reflux ratios and the most optimal feed stage locations that could minimize the total reboiler heat duties were determined.
Keywords: Pressure Swing Distillation; Tetrahydrofuran; Computer Simulation; Liquid Activity Coefficient Mode; Equation of State
Expanded ensemble Monte Carlo simulations for the chemical potentials of supercritical carbon dioxide and hydrocarbon solutes by Jaeeon Chang (597-601).
We carry out expanded ensemble Monte Carlo simulations in order to calculate the chemical potentials of carbon dioxide as solvent and those of hydrocarbons as solutes at supercritical conditions. Recently developed adaptive method is employed to find weight factors during the simulation, which is crucial to achieving high accuracy for free energy calculation. The present simulation method enables us to obtain chemical potentials of large solute molecules dissolved in compressed phase from a single run of simulation. Simulation results for the excess chemical potentials of pure carbon dioxide at 300, 325 and 350 K are compared with experimental data and values predicted by the Peng-Robinson equation of state. A good agreement is found for high pressures up to 500 bar. The chemical potentials of hydrocarbon solutes dissolved in carbon dioxide at infinite dilution are predicted by simulation. Less than eight intermediate subensembles are required to gradually insert (or delete) hydrocarbon solute molecules from methane to noctane into dense CO2 phase of approximately 1.0 g cm−3.
Keywords: Molecular Simulation; Monte Carlo; Expanded Ensemble; Chemical Potential; Carbon Dioxide
High catalytic performance of CuO nanocrystals with largest defects by Chunfang Zhang; Yunxiang Bai; Yanqi Yin; Jin Gu; Yuping Sun (602-607).
To improve the calalytic performance of CuO, nanometer-sized CuO particles were prepared with ultrafiltration surface contact method (UMSCM). X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the crystal structure and morphology of the particles made with UMSCM, hydrothermal method, grounding method as well as a commercial one. SEM results illustrate that UMSCM prepared CuO particles mainly show the form of orthorhombic sliced crystals with the largest amounts of defects compared to CuO particles made by the other three methods. In the oxidation of cumene, CuO prepared with UMSCM also shows better catalytic performance than the other three particles, which can be ascribed to its smaller particle sizes and larger defects so as to accelerate the surface adsorption rate of O2 molecules and the diffusion of ions and atoms, thus improving the catalytic activity.
Keywords: Ultrafiltration; Membrane; Nano-sized CuO; Reaction of Cumene Oxidation; Catalytic Performance
Impact of electrolyte additives (alkali metal salts) on the capacitive behavior of NiO-based capacitors by Yong Zhang; Lizhen Wang; Aiqin Zhang; Yanhua Song; Xiaofeng Li; Xingbing Wu; Peipei Du; Lv Yan (608-612).
To improve the specific capacitance and energy density of electrochemical capacitor, nanostructured NiO was prepared by high temperature solid-state method as electrode material. The crystal structure and morphology of as-parepared NiO samples were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Cyclic voltammetry (CV) measurement was applied to investigate the specific capacitance of the NiO electrode. Furthermore, a novel mixed electrolyte consisting of NaOH, KOH, LiOH and Li2CO3 was prepared for the NiO capacitor, and the component and concentration of the four different electrolytes was examined by orthogonal test. The results showed that the NiO sample has cubic structure with nano-size particles, and the optimal composition of the electrolyte was: NaOH 2 mol L−1, KOH 3 mol L−1, LiOH 0.05 mol L−1, and Li2CO3 0.05 mol L−1. At a scan rate of 10 mV s−1, the fabricated capacitor exhibits excellent electrochemical capacitive performance, while the specific capacitance and the energy density were 239 F g−1 and 85 Wh kg−1, which was higher than one-component electrolyte.
Keywords: Mixed Electrolyte; Nickel Oxide; Orthogonal Test; Optimal Composition
Influence of pulsing-air injection distance on pressure drop in a coke dust bagfilter by Jeong-Min Suh; Young-Il Lim; John Zhu (613-619).
The effect of the pulsing-air injection distance between the nozzle and venturi on total pressure drop was investigated in a pilot-scale pulse-jet bagfilter for coke dust of a steel mill factory. Theoretical and empirical models were used to predict the pressure drop. The empirical model contains two parameters—dust cake resistance and exponent of areal mass density—to be estimated by experiment. The optimum injection distance for minimizing the total pressure drop was evaluated by 64 experimental data at a fixed filtration velocity and pulse pressure in the practical ranges of dust concentration and pulse interval time. The dust cake resistance shows a minimum value at the optimum injection distance. The empirical model is in good agreement with the experimental data, showing a correlation coefficient of 0.952.
Keywords: Pulse-jet Bagfilter; Coke Dust; Pressure Drop; Modeling; Nozzle Injection Distance
Polylactic acid/epoxidized palm oil/fatty nitrogen compounds modified clay nanocomposites: Preparation and characterization by Emad Abbas Jaffar Al-Mulla (620-626).
Clay modification was carried out by treatment of fatty nitrogen compounds (FNCs); fatty hydrazide (FH), hydroxy methyl fattyamide (HMFA), and difatty acyl thiourea (DFAT) were synthesized from vegetable oils with a sodium montmorillonite (MMT) as natural clay. This process was accomplished by stirring the clay particles in an aqueous solution of FH, HMFA, and DFAT, by which the clay layer thickness increased from 1.23 to 2.69, 2.89 and 3.21 nm, respectively. The modified clay was then used in the preparation of the polylactic acid/epoxidized palm oil (PLA/ EPO) blend nanocomposites. The interaction of the modifier in the clay layer was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR). Elemental analysis was used to estimate the presence of FNCs in the clay. The nanocomposites were synthesized by solution casting of the modified clay and a PLA/EPO blend at the weight ratio of 80/20, which has the highest elongation at break. The nanocomposites were then characterized using XRD, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and tensile properties measurements. Improvement in mechanical properties of the FH-MMT, HMFA-MMT, and DFAT-MMT nanocomposites was obtained when 2% of the DFAT-MMT and 3% of both FH-MMT and HMFA-MMT loadings were used. PLA/EPO modified clay nanocomposites show higher thermal stability in comparison with those of the PLA/EPO blend. The XRD and TEM results confirmed the production of nanocomposites.
Keywords: Nanocomposites; Montmorillonite; FNCs; Epoxidized Palm Oil
Synthesis of polyethylene glycol-polystyrene core-shell structure particles in a plasma-fluidized bed reactor by Lee-Hwa Song; Soung Hee Park; Soon Hwa Jung; Sang Done Kim; Seung Bin Park (627-632).
Particles with core-shell structure with polystyrene (PS) core and polyethylene glycol (PEG) grafted on the surface were synthesized in a plasma-fluidized bed reactor. The virgin, plasma-treated, and grafted powders were characterized by the DPPH method, UV-vis spectrophotometer, NMR, FT-IR and SEM. The plasma-treated PS powders have well formed peroxide on the surface. By PEG grafting polymerization, PEG is well grafted and dispersed on the surface of the plasma-treated PS powders. The PEG-g-PS powder exhibits the core shell structure in the cross-sectional SEM image, and it can be claimed that well dispersed PEG grafting polymerization on PS surface can be achieved in the plasma fluidized bed reactor.
Keywords: Fluidized Bed; Plasma; Surface Treatment; Polyethylene Glycol; Polystyrene