Korean Journal of Chemical Engineering (v.26, #6)
A loss control management system for the petrochemical industry by Dong Ho Lim; Jin Hwan Yoo; Jae Wook Ko (1423-1428).
This study was performed to develop a system that can be used to manage safety and environmental issues efficiently in the petrochemical industry. The main objective of this study is to reduce loss in petrochemical industries using a loss control system (LCMCI; The Loss Control Management System for Continuous Improvement of the Petrochemical Industry), which can be used to improve safety and environmental management continuously in the petrochemical industries. To prevent loss by accident in this study, firstly, causes of accidents were analyzed according to frequency and severity of accidents that have occurred in domestic petrochemical industries for 30 years. Secondly, the requirements of several kinds of systems (PSM, RC, OHSAS18001, ISO14001, etc.) which were applied mandatorily/optionally in petrochemical industries were analyzed and, also, the merits/demerits of each system were compared. Thirdly, the best practices which were recommended basically as a loss control management system in the world were modified in accordance with the situation of domestic petrochemical industries. Lastly, the requirements of loss management were defined in accordance with a management structure and then LCMCI was developed by using distribution of scores as result of this study.
Keywords: LCIPI; PSM; Petrochemical Industry; Accidents Analysis
Development of a new automatic system for fault tree analysis for chemical process industries by Jiyong Kim; Jinkyung Kim; Younghee Lee; Il Moon (1429-1440).
The main purpose of this study was to develop a computer automated tool for fault tree analysis (FTA) in order to minimize the flaws of manual FTA. The automated FTA system developed in this study consists of two steps: 1) automatic fault tree conversion from a digraph, and 2) calculation of the probability of the occurrence of the top event and finding a minimal cut set of the top event. For the first step, we propose a new algorithm for automatic conversion of a digraph to a fault tree. The new digraph-FT conversion algorithm has eight FT generation rules to transform node information that is based on the node characteristics. Failures and faults are classified into three types to easily synthesize fault trees and analyze fault trees precisely. The automatic FTA system was then applied the analysis of real chemical processes to illustrate the effectiveness of the system.
Keywords: Fault Tree Analysis; Automatic FTA; Digraph; Hazard Assessment; Minimal Cut Set
Thermal instability of a fluid layer when cooled isothermally from above by Joo Hyung Moon; Kyung Hyun Ahn; Chang Kyun Choi; Min Chan Kim (1441-1446).
The onset of buoyancy-driven convection in an initially motionless isothermal fluid layer is analyzed numerically. The infinite horizontal fluid layer is suddenly cooled from above to relatively low temperature. The rigid lower boundary remains at the initial temperature. In the present transient system, when the Rayleigh number Ra exceeds 1101, thermal convection sets in due to buoyancy force. To trace the temporal growth rates of the mean temperature and its fluctuations we solve the Boussinesq equation by using the finite volume method. We suggest that the system begins to be unstable when the growth rate of temperature disturbances becomes equal to that of the conduction field. Three different characteristic times are classified to interpret numerical results clearly: the onset time of intrinsic instability, the detection time of manifest convection and the undershoot time in a plot of the cooling rate versus time. The present scenario is that the thermal instability sets in at the critical time, then grows super-exponentially up to near the undershoot time, and between these two times the first visible motion is detected. Numerical results are compared with available experimental data. It is found that the above scenario looks promising and the critical time increases with decreasing the Prandtl number Pr and also the Rayleigh number Ra.
Keywords: Buoyancy-driven Convection; Growth Rate; Thermal Instability; Rayleigh Number
Estimation method for determining surface film conductance during cooling of fish packages by Ibrahim Omer Mohamed; Kassim Ali Abass (1447-1452).
This paper presents an alternative method for determining the surface film conductance of an infinite fish slab subjected to the cooling process. Many methods have been published, but their solutions have inherent appreciable inaccuracy and limitations. The present authors used the temperature histories of five locations within a slab sample of fish, obtained by the experimental investigation part of this work, along with the inverse heat conduction problem (IHCP) technique to develop a correlation for variable surface film conductance. When the above correlation was used for temperature predictions, the predicted and experimentally measured temperature distribution profiles were compared numerically. Better agreement than that implemented by other investigators was achieved. This revealed the accuracy and superiority of the present method, and the limitations of other methods are overcome in this method.
Keywords: Cooling; Fish; Surface Film Conductance; IHCP
Combined run-to-run and LQG control of a 12-inch RTP equipment by Wangyun Won; Woohyun Yun; Sang Hyun Ji; Byung-Cheol Na; Kwang Soon Lee (1453-1460).
A combined run-to-run (R2R) and LQG control method has been proposed for rapid thermal processing (RTP) equipment for run-wise improvement and real-time multivariable control of the temperature uniformity over the wafer surface. The standard LQG objective was modified to include a quadratic penalty term for input deviation from bias values which are updated by an R2R control law. The proposed method has been applied to commercial 12-inch rotating RTP equipment with four pyrometers and ten circular groups of tungsten-halogen lamps for measurements and manipulation of wafer temperatures. The performance of LQG control was evaluated under wafer rotation and found to show quite accurate tracking. For evaluation of the combined control technique, a wafer with seven thermocouples (TC’s) attached along the radial direction has been employed for the TC measurements to be used for R2R control, whereas the pyrometer measurements are fed back for real-time LQG control. It was observed that the temperature uniformity is improved as the run number increases.
Keywords: Rapid Thermal Processing; LQG Control; Run-to-run Control; QILC
Onset of marangoni convection in an initially quiescent spherical droplet subjected to the transient heat conduction by Min Chan Kim; Do-Young Yoon; Eunsu Cho (1461-1466).
The onset of Marangoni convection in an initially quiescent spherical droplet subjected to the impulsive change in boundary temperature is analyzed under the linear theory. For this system in which instabilities are driven by interface-tension gradients, a stability analysis on regular cell modes is conducted on the basis of the propagation theory we have developed. The present stability analysis predicts that τ c decreases with increasing Ma. For the limiting case of τ→0, the present study approaches the planar limit as expected.
Keywords: Marangoni Convection; Spherical Droplet; Propagation Theory
Two-level multiblock statistical monitoring for plant-wide processes by Zhiqiang Ge; Zhihuan Song (1467-1475).
Due to the complexity of plant-wide processes, many of the current multivariate statistical process monitoring techniques are lacking in interpretation of the detected fault, and fault identification also becomes difficult. A new two-level multiblock independent component analysis and principal component analysis (MBICA-PCA) method is proposed in this paper. Different from the conventional method, the new approach can incorporate block information into the high level for global process monitoring. Through the new method, the process monitoring task can be greatly reduced and the interpretation for the process can be made more quickly. When a fault is detected, a two-step fault identification method is proposed. The responsible sub-block is first identified by contribution plots, which is followed by fault reconstruction in the corresponding sub-block for advanced fault identification. A case study of the Tennessee Eastman (TE) process evaluates the feasibility and efficiency of the proposed method.
Keywords: Plant-wide Process Monitoring; Two-level Multiblock ICA-PCA; Fault Identification; Fault Reconstruction
A systematic approach towards accident analysis and prevention by Jamin Koo; Seunghyok Kim; Hyosuk Kim; Young-Hun Kim; En Sup Yoon (1476-1483).
A systematic approach towards accident analysis and prevention has been developed. It relies on system theory as an incident causation model, and adopts a hybrid model for identifying elements of the safety management system. PDCA (Plan-Do-Check-Act) process, commonly practiced in business for quality control, has been applied to defining components of the system. Using the experts’ judgment, accident data and their reported causes are correlated to the defined components, with RBI (risk-based inspection) defined consequence scores as weighting factors. The application of this approach allows users such as governments and companies to identify and prioritize among causes of accidents and near-misses in the petrochemical industry. A case study using the accident data of Yeosu petrochemical complex from 1990 to 2004 has been applied to illustrate insights readily obtainable by using the developed analysis technique. The results suggest comprehensive identification and ranking of accident causes for effective prevention of accidents in the future.
Keywords: Accident Analysis; Accident Prevention; PDCA; Petrochemical Industry; Quantitative Method
Optimization of district heating systems based on the demand forecast in the capital region by Tae Chang Park; Ui Sik Kim; Lae-Hyun Kim; Weon Ho Kim; Yeong Koo Yeo (1484-1496).
A district heating system (DHS) consists of energy suppliers and consumers, heat generation and storage facilities and power transmission lines in the region. DHS has taken charge of an increasingly important role as the energy cost increases recently. In this work, a model for operational optimization of the DHS in the metropolitan area is presented by incorporating forecast for demand from customers. In the model, production and demand of heat in the region of Suseo near Seoul, Korea, are taken into account as well as forecast for demand using the artificial neural network. The optimization problem is formulated as a mixed integer linear programming (MILP) problem where the objective is to minimize the overall operating cost of DHS. The solution gives the optimal amount of network transmission and supply cost. The optimization system coupled with forecast capability can be effectively used as design and longterm operation guidelines for regional energy policies.
Keywords: District Heating System; Optimal Operation; Demand Forecast; District Network; Mixed Integer Linear Programming
Macroscopic estimation method of the mixedness of Kenics type static mixer by Sunho You; Naotaka Higuchi; Toshihisa Ueda (1497-1503).
We investigated the mixing process of the Kenics type static mixer, in which the mixing is enhanced by both advective mixing and mixing due to molecular diffusion in order to propose an estimation method of the mixedness. The results show that the element divides, folds and stretches the mixing fluids and forms a lamellar structure with striation width l a . The value of l a decreases with an increase in the number of elements by l a -(2 n−1)−1, which represents the characteristics length of advective mixing. The characteristic length of mixing due to molecular diffusion l d can be estimated by solving the one-dimensional unsteady species conservation equation analytically. The macroscopic estimation and prediction method of mixedness is proposed as function of l a and l d . When l a >l d , the advective mixing is dominant, while, when l a <l d , the mixing due to molecular diffusion plays an important role.
Keywords: Mixedness; Advective Mixing; Molecular Diffusion; Kenics Static Mixer
Simulation and optimization of ethanol amine production plant by Gholamreza Zahedi; Saeideh Amraei; Mazda Biglari (1504-1511).
An industrial Ethanol Amine (EA) production plant was simulated and optimized. Due to lack of accurate reaction rate information, the first step involved obtaining reliable kinetic data from the SRI (Stanford Research Institute) industrial database and calculation using error minimization method. In the next step, by implementing the obtained reaction kinetics the whole plant was simulated using Hysys software. Simulation results were compared with the SRI data and showed that there is acceptable agreement between simulation and the measured industrial data. In the next step of study by applying the gradient search (GS) optimization technique the plant was optimized using: feeding ammonia to ethylene oxide (EO) molar ratio, water flow rate in the feed stream, and reactor temperature as optimization variables. Employing process profit as objective function the optimal operating conditions were found to be: ammonia to EO ratio of 5 (mol/mol), water flow rate of 52.59 kg mol/hr and reactor temperature of 85 °C.
Keywords: Simulation; Optimization; Ethanol Amine Production; Ethylene Oxide; Ammonia
Iterative learning controller synthesis using FIR models for batch processes by Junghui Chen; Kuo-Tong Chou (1512-1518).
Adaptive iterative learning control based on the measured input-output data is proposed to solve the traditional iterative learning control problem in the batch process. It produces a control law with self-tuning capability by combining a batch-to-batch model estimation procedure with the control design technique. To build the unknown batch operation system, the finite impulse response (FIR) model with the lifted system is constructed for easy construction of a recursive least squares algorithm. It can identify the pattern of the current operation batch. The proposed model reference control method is applied to feedback control of the lifted system. It finds an appropriate control input so that the desired performance of the batch output can track the prescribed finite-time trajectory by iterative trials. Furthermore, on-line tracking control is developed to explore the possible adjustments of the future input trajectories within a batch. This can remove the disturbances in the current batch rather than the next batch trial and keep the product specifications consistent at the end of each batch. To validate the theoretical findings of the proposed strategies, two simulation problems are investigated.
Keywords: Batch Process; Iterative Learning Control; Model Reference Control
Optimal design of multi-nozzle etching process for shadow mask by Minkyo Seo; Jin Soo Park; Sangdae Park; Jae Hak Jung (1519-1527).
This paper presents a new design approach of a multi-nozzle etching process which is the core system for the production of a shadow mask. The shadow mask, which is a thin metal plate with a huge number of small holes in regular patterns, is a key component of televisions and computer monitors. The shadow mask plays an important role in controlling the definition, color and distinction of televisions and computer monitors. Thus, the development of a rigorous and systematic design method for a multi-nozzle etching process to manufacture the shadow mask is beneficial particularly from the viewpoint of increasing efficiency and improving productivity. The proposed design method is based on simulating the complex spraying pattern using a Monte-Carlo method, whereas a stochastic method, so-called genetic algorithm, is used for an optimization tool. In such a highly complex solution space, the genetic algorithm searches optimal solutions efficiently and effectively. The simulation of spraying pattern for the multi-nozzle system and the genetic algorithm are coded by C language, while the graphic representations are attained by MATLAB graphic tools.
Keywords: Multi-nozzle; Etching Process; GA; MATLAB
Influence of operating conditions, Si/Al ratio and doping of zinc on Pt-Sn/ZSM-5 catalyst for propane dehydrogenation to propene by Zeeshan Nawaz; Tang Xiaoping; Wei Fei (1528-1532).
The direct catalytic dehydrogenation of propane to propene is an important route to enhance propene production. In the present experimentation the focus was to investigate the influence of incipient operating conditions, Si/Al ratio of zeolite support and effect of zinc doping on Pt-Sn/ZSM-5 catalyst performance. The catalysts were extensively investigated by reaction tests in a continuous plug-flow quartz micro-reactor. The experimental data shows that the manipulation of operating parameters significantly improves the reaction performance, while huge dynamicity is observed in product distribution. Reaction temperature, 600 °C is found to be most suitable, while increasing the weight hourly space velocity (WHSV), propene selectivity improves at the expense of lower conversion. The OPE was drawn to observe overall reaction network. It was found that the acidity of zeolitic support plays a more important role in achieving desired product selectivity than additional metallic content. Accordingly, the Si/Al ratio of the ZSM-5 zeolite the pro- pene selectivity was enhanced, leading to remarkable improvement in the total olefins selectivity which was remarkably improved owing to a suppression of secondary reactions. At Si/Al ratio 300, the selectivity of propene and total olefins becomes stable at 73% and 90% respectively. The doping of Zn on Pt-Sn/ZSM-5 improves only propene selectivity, but is severely affected by quick deactivation.
Keywords: Propene; Direct Dehydrogenation; ZSM-5 Zeolite; Support; Selectivity
Hydrogenation of CO on supported cobalt γ-Al2O3 catalyst in fixed bed and slurry bubble column reactors by Suk-Hwan Kang; Kwang-Jae Woo; Ki-Won Jun; Yong Kang (1533-1538).
Fischer-Tropsch synthesis for the production of C5+ hydrocarbons from syngas was carried out in a tubular fixed bed reactor (TFBR) and in a slurry bubble column reactor (SBCR). The Co-based catalysts for FTS were prepared by the conventional wet-impregnation of γ-Al2O3. Effects of operating conditions such as GHSV (1,000–4,000 ml/g·hr), reaction temperature (220–250°C) and pressure (0.5–3.0MPa) on the CO conversion and product selectivity of Co/γ-Al2O3 catalyst were examined in the TFBR and SBCR. The C5+ selectivity and olefin selectivity in an SBCR were found to be higher than that in a TFBR, whereas C2–C4 selectivity showed a reverse trend. The CO conversion and product distribution in an SBCR were less sensitive than that in a TFBR with variations of reaction conditions.
Keywords: Fischer-Tropsch Synthesis; Tubular Fixed Bed Reactor; Slurry Bubble Column Reactor; Co Catalyst
Regeneration of H3PW12O40 catalyst in the direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas by Sun Ho Song; Sang Hee Lee; Dong Ryul Park; Heesoo Kim; Sung Yul Woo; Won Seob Song; Myong Suk Kwon; In Kyu Song (1539-1544).
Methods for regenerating H3PW12O40 catalyst in the solvent-free direct preparation of dichloropropanol (DCP) from glycerol and hydrochloric acid gas were investigated. Regenerated H3PW12O40 catalyst was then applied to the solvent-free direct preparation of DCP. In the solvent-free direct preparation of DCP, selectivity for DCP over H3PW12O40 catalyst regenerated by method I (recovery of solid H3PW12O40 catalyst by evaporating homogeneous liquidphase product solution) significantly decreased with increasing recycling run, while that over H3PW12O40 catalyst regenerated by method II (regeneration of H3PW12O40 catalyst by oxidative calcination of solid product recovered by method I) was slightly decreased with no significant catalyst deactivation with respect to recycling run. On the other hand, selectivity for DCP over H3PW12O40 catalyst regenerated by method III (regeneration of H3PW12O40 catalyst by recrystallization and subsequent oxidative calcination of solid product recovered by method II) was the same as that over fresh catalyst without any catalyst deactivation with respect to recycling run. Thus, method III was found to be the most efficient method for the regeneration of H3PW12O40 catalyst.
Keywords: Dichloropropanol; Glycerol; Hydrochloric Acid Gas; Heteropolyacid Catalyst; Regeneration Method
Effects of promoters on biomass gasification using nickel/dolomite catalyst by Pattaraporn Chaiprasert; Tharapong Vitidsant (1545-1549).
Metallic nickel has been selected as a catalyst for biomass gasification because of its activity in biomass steam gasification and tar reduction. The effects of types of promoters such as platinum, cobalt, and iron on biomass gasification were evaluated. The area of interest was the effects of preparation methods, which were impregnation and coprecipitation. Catalyst preparation by the impregnation method showed superior performance. The conclusion can be drawn from the experiments that the platinum promoter enhanced the reforming reaction, iron promoted a water-gas shift reaction, and the cobalt promoter favored a methanation reaction. Moreover, the addition of noble metal reduced carbon deposition on Ni/dolomite.
Keywords: Promoter; Biomass; Gasification; Ni/Dolomite; Coconut Shell
Scratch resistance and oxygen barrier properties of acrylate-based hybrid coatings on polycarbonate substrate by Sungkoo Lee; Kyeong Keun Oh; Sunyoung Park; Jun-Seok Kim; Hyunjoon Kim (1550-1555).
Organic/inorganic hybrid coating materials were synthesized using acrylate end-capped polyester, 1,6-hexanediolacrylate, tetraethoxysilane (TEOS), and 3-trimethoxysilylpropylmethacrylate (TMSPM). The hybrid materials were cast onto a polycarbonate (PC) substrate and cured by UV irradiation to give a hybrid film with covalent linkage between the inorganic and the organic networks. The coating layer was characterized by FT-IR and 29Si-NMR, and pencil hardness and oxygen permeation rate of coated films were investigated. The pencil hardness of all samples examined in this study was higher than 1H, whereas that of uncoated PC substrate was 6B. The hardness enhancement after coating may due to incorporation of organic acrylate resin. The oxygen permeability coefficient of the film coated with hybrid material on 3-aminopropyltriethoxysilane (APTEOS) pretreated polycarbonate substrate was 1.67×10−3 GPU, the lowest value in this work, whereas that of uncoated PC substrate was 8.07×10−3 GPU. The lower oxygen permeation rates of these films are attributed to the good adhesion between organic/inorganic hybrid coating layer and PC substrate and a dense structure induced by an increase of network density.
Keywords: Oxygen Permeation; Hardness; TMSPM; Polycarbonate
Characteristics and photocatalytic degradation of methyl orange on Ti-RH-MCM-41 and TiO2/RH-MCM-41 by Surachai Artkla; Kitirote Wantala; Bang-orn Srinameb; Nurak Grisdanurak; Wantana Klysubun; Jatuporn Wittayakun (1556-1562).
Our purpose was to synthesize, characterize and test photodegradation of methyl orange on two catalysts containing 10 wt% titanium supported on mesoporous MCM-41 synthesized with rice husk silica. The first catalyst was Ti-RH-MCM-41 prepared by adding tetrabutyl orthotitanate (TBOT) in a synthetic gel of RH-MCM-41, and the second catalyst was TiO2/RH-MCM-41 prepared by grafting TBOT on the preformed RH-MCM-41. The mesoporous structures were observed on both catalysts and they had surface area of 1,073 and 1,006 m2/g. The Ti in Ti-RH-MCM-41 was in the form of Ti(IV) with tetrahedral geometry residing in the mesoporous structure. This form was less active for photodegradation of methyl orange than the other one. The Ti in TiO2/RH-MCM-41 was anatase titania with octahedral geometry located outside the mesoporous framework. This form was more an active phase for the photodegradation and the reaction parameters on this catalyst were further investigated. The optimum catalyst weight to methyl orange volume ratio was 5 g/L and the optimum initial concentration of the dye was 2.0 ppm. The degradation rate obeyed pseudo-first order and the adsorption of methyl orange on TiO2/RH-MCM-41 obeyed Langmuir isotherm.
Keywords: Photocatalysis; RH-MCM-41; TiO2 ; Methyl Orange; Photodegradation
Alkylation of anthracene to 2-isopropylanthracene catalyzed by Lewis acid ionic liquids by Min Chen; Ying Luo; Guofang Li; Minqiang He; Jimin Xie; Huamin Li; Xinhua Yuan (1563-1567).
Alkylation of anthracene with 2-chloropropane to 2-isopropylanthracene catalyzed by various Lewis acidic ionic liquids (ILs), such as [Emim]Cl-AlCl3, [Emim]Cl-FeCl3, [Emim]Cl-ZnCl2, [Bmim]Cl-AlCl3, and [Omim]Cl-AlCl3 ([Emim]+=1-ethyl-3-methylimidazolium cation, [Bmim]+=1-butyl-3-methylimidazolium cation, [Omim]+=1-octyl-3-methylimidazolium cation,), was investigated. [Emim]C1-A1C13 ionic liquid was found to be the most active catalyst in the alkylation. The yield of 2-isopropylanthracene was up to 74.5% and the selectivity of 2-isopropylanthracene was up to 82.9%. The [Emim]C1-A1C13 ionic liquid catalyst showed good catalytic activity after running for 6 times. Ease of product separation and the recycling performance of the ionic liquid catalyst is expected to contribute to the development of clean and environmentally friendly strategy for the synthesis of 2-isopropylanthracene.
Keywords: Lewis Acidic Ionic Liquid; Alkylation; 2-Isopropylanthracene; Anthracene; 2-Chloropropane
Catalytic activity of Cu/MgO in liquid phase oxidation of cumene by Shuai Xu; Chongpin Huang; Jie Zhang; Biaohua Chen (1568-1573).
Cumene was oxidized with air as the oxidant and Cu/MgO as the catalyst. Cu/MgO with different compositions was prepared by co-precipitation and then characterized by X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The characterization results showed that CuO dispersed on MgO well in the cases that the Cu content in Cu/MgO was 1% by molar. In this catalytic system, MgO did not only act as the supporter, but also as the catalyst to activate the tertiary C-H of cumene. The conversion of cumene was increased by using CuO as the promoter on MgO catalyst. The cumene conversion and cumene hydroperoxide (CHP) selectivity were in a trade-off relationship because cumene oxidation was subject to the decomposition of CHP. Thus, the effects of the operating variables were investigated and the relevant mechanism was discussed.
Keywords: Cumene; Oxidation; Catalysis; Cu/MgO; Cumene Hydroperoxide
Effect of water on Cu/Zn catalyst for hydrogenation of fatty methyl ester to fatty alcohol by Hui Huang; Guiping Cao; Chunling Fan; Shaohong Wang; Shujia Wang (1574-1579).
The effect of water on Cu/Zn catalyst prepared by co-precipitation for hydrogenation of methyl laurate in a slurry phase was studied using a stirred autoclave reactor system. The catalysts were characterized by means of XRD, BET, H2-TPR, SEM and TEM. The results indicate that catalytic activity decreases with increased amount of water in methyl laurate. Correlating with the results from the above characterization, it is found that the main causes for the water deactivation of the Cu/Zn catalyst were the water occlusion of active catalyst sites by the low solubility of water in the substrate and the promotion of crystal growth, as well as the Cu/Zn catalyst agglomeration in the presence of water.
Keywords: Fatty Alcohol; Cu/Zn Catalyst; Deactivation; Water
Effect of initial solution apparent pH on the performance of submerged hybrid system for the p-nitrophenol hydrogenation by Rizhi Chen; Yan Du; Weihong Xing; Wanqin Jin (1580-1584).
Coupling nanocatalysis with ceramic membrane separation can solve the problem of nanocatalyst separation in situ from a reaction mixture. A submerged hybrid system combining nanocatalysis and ceramic membrane separation was designed for the liquid phase hydrogenation of p-nitrophenol to p-aminophenol, and the effect of initial solution apparent pH (pH a ) on the performance of submerged hybrid system was investigated in detail. It is demonstrated that as the initial solution pH a is adjusted from 4.5 to 7.5, the catalytic stability of nano-sized nickel is remarkably improved, possibly because the formation of impurity on the nickel surface can be restrained at weak alkaline condition, while the catalytic activity and selectively almost do not change. The membrane permeability is not affected significantly by the initial solution pH a .
Keywords: Apparent pH; Hybrid System; Ceramic Membrane; p-Nitrophenol; Catalytic Hydrogenation; Nano-sized Nickel
Influence of emulsifiers on particle size and particle size distribution of PVC latex synthesized by miniemulsion polymerization by Viet Hung Pham; Young Hwa Lee; Dong Ju Lee; Jin Suk Chung (1585-1590).
We synthesized poly(vinyl chloride) (PVC) latexes via miniemulsion polymerization using a mixture of cetyl alcohol (CA) and sodium lauryl sulfate (SLS). A vinyl chloride miniemulsion is easily prepared by conventional mechanical stirring. Experimental design methods were applied to investigate the effects of composition and polymerization conditions on average particle size (APS) and particle size distribution (PSD) of the latexes produced. The APS of the latexes produced ranged from 0.4–0.7 μm. When the APS of the latex produced was above 0.7 μm, the resulting latex was highly unstable. The emulsifier ratio (CA/SLS) was the most prominent factor influencing APS and PSD.
Keywords: Polyvinyl Chloride; Latex; Miniemulsion; Polymerization; Experimental Design
Kinetic parameter estimation of the Fischer-Tropsch synthesis reaction on K/Fe-Cu-Al catalysts by Yun Ha Kim; Du-Yeong Hwang; Sang Hoon Song; Sang Bong Lee; Eun Duck Park; Myung-June Park (1591-1600).
This paper addresses the development of a mathematical model for a fixed-bed reactor where the Fischer-Tropsch synthesis reaction takes place. The model includes the consumption rate of carbon monoxide and the production rates for paraffin and olefin chains (up to the length of 47). The kinetic parameters are estimated using the experimental data under various experimental conditions with the effect of temperature, space velocity, the composition of feed mixture and pressure included. The simulation results with the estimated parameters predict the CO conversion, methane selectivity, paraffin selectivity and the entire distribution of hydrocarbon products satisfactorily. A further investigation on the effect of operating conditions shows that the ratio of hydrogen to carbon monoxide and the pressure are the effective variables for the determination of the entire distribution.
Keywords: Fischer-Tropsch Synthesis; K/Fe-Cu-Al Catalyst; Mathematical Model; Fixed-bed Reactor; Entire Distribution; Hydrocarbon Products
Microwave effect in removal process of NO by electron beam irradiation and quantitative prediction of the removed NO by Dong Hwa Lee; Soog Dong Kim; Byung Nam Kim; Yang Soo Won; Do Hung Han (1601-1607).
A flow process with electron beam (EB) irradiation carried out the removal of NO in air by adding microwave (MW) to improve the removal efficiency of NO. The EB irradiation combined with MW irradiation was very effective in the range of NO removal efficiency of 70–80% and reduced required doses up to more than 30%, compared to the flow process without MW. On the other hand, MW irradiation was unlikely to affect the NO removal above 90% of removal efficiency. In addition, MW effect appeared definitely in the dose ranges of 8–24 kGy, whereas the effect became minor below 8 kGy and above 24 kGy. This study found that MW irradiation can play an auxiliary role in NO removal with EB irradiation and the effect of MW on the NO removal is based on an intrinsic kinetic to the exclusion of a thermal effect. The concentrations of removed NO could be linearly correlated as ΔC=k[NO] o +k o . Where, k was proportional to dose and ko could be related to k o /D n =aD+b, giving n value of 0.7 without MW irradiation and 0.4 with MW irradiation, respectively.
Keywords: NO Removal; Electron Beam; Microwave; Flow Process; Correlation of Removed NO
Study of pyrolysis kinetics of Alberta oil sand by thermogravimetric analysis by Young Cheol Park; Jin-Young Paek; Dal-Hee Bae; Dowon Shun (1608-1612).
The kinetics of the thermal decomposition of Alberta oil sand has been investigated by thermogravimetric analysis (TGA) for the study of oil sand pyrolysis characteristics. The TGA experiments were carried out at four different heating rates of 10, 20, 30, 40 °C/min up to 900 °C to verify weight variation and reaction temperature. The activation energy of the thermal decomposition of Alberta oil sand obtained from the kinetic analysis was similar to that of the previous researches. Also, bitumen was extracted by solvent (toluene, THF (tetrahydrofuran)) and analyzed. Extracted bitumen was analyzed by using proximate analysis, ultimate analysis, heavy metal analysis, heating value, asphaltenes, API, SIMDIS, density, TLC, and molecular weight. The analyses of the extracted bitumen were similar to those of heavy residue.
Keywords: Kinetics; Oil Sand; Pyrolysis; Thermogravimetric Analysis; Bitumen
Gaseous ozone decomposition using a nonthermal plasma reactor with adsorbent and dielectric pellets by Young Sun Mok; Dong Jun Koh; Dong Nam Shin; Kyong Tae Kim (1613-1619).
For the treatment of gaseous ozone emission, this study investigated the adsorption and enrichment of ozone and the destruction of the adsorbed ozone by nonthermal plasma. A nonthermal plasma reactor with adsorbent pellets in it was operated in two sequential modes, adsorption and decomposition of ozone. First, the ozone-containing gas was flowed through the reactor for a given period, in which the ozone was adsorbed and concentrated. In the next step, the gas was switched to argon or nitrogen, bypassing the ozone-containing gas, and AC high voltage was applied to the reactor to produce nonthermal plasma for the decomposition of the adsorbed ozone. By this method, the gaseous ozone was effectively treated with reasonable electrical energy consumption. The adsorbed ozone was converted into molecular oxygen when argon was used as the ozone decomposition gas, whereas a small amount of nitrogen oxides was formed with nitrogen. The energy consumed to decompose the adsorbed ozone was found to be 540 and 795 kJ/g-O3 decomposed with argon and nitrogen, respectively.
Keywords: Gaseous Ozone; Nonthermal Plasma; Adsorption; Decomposition
Speed-up of the disaggregation of emission inventories and increased resolution of disaggregated maps using landuse data by Jong Ho Kim; Byoung Kyu Kwak; Chee Burm Shin; Hyeon-Soo Park; Kyunghee Choi; Sang Mok Lee; Jongheop Yi (1620-1629).
This study describes the full disaggregation process of emission inventory maps in support of environmental modeling studies in a geographical information system. Using a heuristic approach, appropriate algorithms were found to accelerate the computational disaggregation speed. The algorithms were based on scan-conversion algorithms employed in the field of computer graphics. Various algorithms were analyzed in terms of supporting emission inventories with different shapes, such as points, polylines and polygons. The algorithms were implemented by using Visual Basic, thereby enabling the efficiencies of the algorithms to be analyzed and compared with each other. For the disaggregation of polygon types, with the aim of increasing the resolution of an inventory map, we suggest the advanced polygon-disaggregation method with land use data. An air dispersion simulation was performed in order to compare the accuracy of the emission input data generated by existing disaggregation methods and the advanced method proposed in the present study.
Keywords: Emissions; Disaggregation; Scan-conversion; Dispersion; GIS; Landuse
Exposure assessment of engineered nanomaterials in the workplace by Junsu Park; Byoung Kyu Kwak; Eunjoo Bae; Jeongjin Lee; Kyunghee Choi; Jongheop Yi; Younghun Kim (1630-1636).
Nanotechnology is a rapidly growing field and numerous products containing engineered nanomaterials are already in the market. With the increasing use of engineered nanomaterials, it is expected to increase the exposures to nanomaterials in the workplace. However, the researches on the exposure assessment of nanomaterials to humans and the environment are just a beginning step, as the nanotechnology industries are expanding. Questionnaire surveys conducted by various organizations reveal that many nanotechnology companies are searching for information on exposure measurement for the protection of workers who handle nanomaterials. We analyze the trends of researches on the occupational exposure measurement of engineered nanomaterials and investigate the methodologies of exposure assessment recommended by the related working groups. This work is expected to fill the gaps in knowledge on the exposure assessment of nanomaterials.
Keywords: Nanomaterials; Risk Assessment; Toxicity; Exposure Assessment; Workplace
The optimization of the photo-oxidation parameters to remediate wastewater from the textile dyeing industry in a continuous stirred tank reactor by Sakda Kortangsakul; Mali Hunsom (1637-1644).
The remediation of textile dying wastewater was carried out at ambient temperatures in a pilot-scale continuous stirred tank reactor by using the photo-Fenton oxidation process. The preliminary results suggest that the treatment system reached a steady state condition within 5–10 min after it was started up. By using a 2 k factorial design, the effects of various parameters on the removal efficiency of color, BOD and COD were identified under steady state conditions. The removal efficiencies of color and BOD were affected by the feed rate of H2O2 and Fe2+, whereas none of the parameters in the investigated ranges affected the removal efficiency of COD. Consequently, using univariate analysis to investigate higher parameter range values, the optimum conditions for treating textile wastewater were found to be 25 ml H2O2/min, 5 ml Fe2+/min and 90 W UV-A power for 20 min. In addition, the removal of all pollutants was enhanced within the acidic pH range. Approximately 69.2, 99.4 and 48.5% of color, BOD and COD were removed, respectively. However, the concentration of TDS increased slightly during the treatment period due to the formation of new species or intermediate oxidation products. Nevertheless, all values of pollutants in the treated wastewater except COD were in the range of the standard values permitted for discharge into the environment.
Keywords: Textile Wastewater; Photo-Fenton Process; Remediation; Continuous Stirred Tank Reactor; Advance Oxidation
Rapid differentiation of new isolates with MALDI-TOF mass spectrometry via discriminant function analysis based on principal components by Berna Sariyar-Akbulut (1645-1651).
Discriminant function analysis based on principal components was applied to the spectral outputs of whole cell suspensions of nine isolates from matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry. First, based on the salt tolerance and whole cell proteins, the similarity of the isolates to moderate halophiles was established. Intact microorganisms were then inferentially clustered by MALDI-TOF mass spectroscopy taking four type strains as precursors. Two of these type strains were moderate halophilic bacteria (Halomonas salina and Halomonas halophila), one was a mesophilic bacteria (Escherichia coli), and one was a halophilic archaea (Haloarcula vallismortis). Results showed that the isolates were significantly similar to halophiles but were different from a mesophile. This investigation demonstrates the feasibility of using whole cell suspensions for rapid differentiation prior to extensive experimentation.
Keywords: Hierarchical Clustering; Discriminant Function Analysis; Principal Component Analysis; Intact Microorganisms; MALDI-TOF-MS
Production of antifungal lipopeptide from Bacillus subtilis in submerged fermentation using shake flask and fermentor by Ing-Lung Shih; Chih-Yang Lin; Jane-Yii Wu; Chienyan Hsieh (1652-1661).
Optimization of the production of antifungal lipopeptide, iturin A, by B. subtilis was carried out in submerged cultural fermentation. In a shake-flask experiment, response surface methodology (RSM) was employed to optimize the cultivation conditions of Bacillus subtilis S3 for the enhancement of iturin A production. The optimal conditions for iturin A production obtained from RSM were pH 6.0, 0.93% maltodextrin, 1.11% glucose, 0.72% corn steep powder (C.S.P), 1.5 mM MgSO4, 0.75 mM KH2PO4, rotation speed 180 rpm and area of aeration 4.35 cm2. 57% increase of iturin A productivity (from 47.19 mg/L to 74.22 mg/L) was observed using the one-factor-at -a-time technique; however, 180% increase of iturin A productivity (from 47.19 mg/L to 132.23 mg/L) was observed with RSM. The iturin A production was further studied in a 5-L fermentor with a variation of agitation speed, aeration and baffles. In the 5-L fermentor, it was found that increased agitation speed improved the growth of B. subtilis and the production of iturin A. Aeration at 2 vvm gave excellent production of iturin A (175.52 mg/L) at 6 d of fermentation. The addition of baffles in the fermentor has significantly influenced the oxygen mass transfer coefficient (KLa) and iturin A production.
Keywords: Bacillus subtilis ; Submerged Cultural Fermentation; Stirred-tank; K L a; Iturin A; Biomass; Optimization
Integrated anaerobic/aerobic biodegradation in an internal airlift loop reactor for phenol wastewater treatment by Zhouyang Zhao; Guoqiang Jiang; Shengyang Jiang; Fuxin Ding (1662-1667).
Anaerobic and aerobic biodegradation were integrated in an internal airlift loop reactor (IALR) by adding porous microbial carriers. In this bioreactor, aerobic activated sludge was suspended in the liquid bulk, while the anaerobic microbes were attached within the core of carriers. The integrated IALR was applied to the treatment of synthetic phenol wastewater. After 50 days’ acclimation according to co-substance strategy, the influent COD decreased from 3,700 mg/L to 400 mg/L (phenol removal rate was over 99%) with the residence time of 24 h. High performance could be achieved under the operation condition of superficial gas flow rate higher than 0.07 cm/s, temperature beyond 15°C and the microbial carrier volume fraction larger than 5%. Integration of anaerobic/aerobic biodegradation in IALR enhanced the synergetic effects between aerobic and anaerobic degradation; therefore, it has great potential in the treatment of phenol wastewater and other wastewater containing hard biodegradable organics.
Keywords: Anaerobic/Aerobic Biodegradation; Porous Microbial Carriers; Internal Airlift Loop Reactor; Phenol; Wastewater Treatment
Recovery of copper values from bio-heap leaching of low grade Malanjkhand chalcopyrite ore by Lala Behari Sukla; Kailash Chandra Nathsarma; Joystna Rani Mahanta; Sradhanjali Singh; Snehasis Behera; Karanam Srinivas Rao; Tondepu Subbaiah; Barada Kanta Mishra (1668-1674).
M/S Hindustan Copper Limited (HCL), India generates large amounts of lean sulfide ores of copper. The current production of lean copper ores in India is 0.55 million tons with ∼0.3% average copper content. Heap-bioleaching of the lean copper ores in 15 and 30 ton scales was undertaken at IMMT, Bhubaneswar. The leaching study showed 0.09% dissolution of copper from the ore body per day. The leach liquor was processed through solvent extraction and electrowinning. Extraction of copper from the actual leach liquor was carried out with 1.5% LIX 622N in kerosene with zero co-extraction of iron. The copper-free raffinate was fed back to the leaching unit. Stripping of copper from the loaded organic was carried out with 180 kg/m3 H2SO4. The copper pregnant electrolyte was passed through a carbon column to make it free from entrained organic and was fed to the electrowinning unit. The increase in current efficiency was due to the increase in the concentration of electrolyte. The energy consumption was 1.7 kWh/kg at a flow rate of 4.5 L/h. Smooth and bright sheets of copper of 99.99% purity were obtained.
Keywords: Lean Copper Ore; Bio-heap Leaching; Solvent Extraction and Electrowinning
Preparation and characterization of PVA/PVP/glycerin/antibacterial agent hydrogels using γ-irradiation followed by freeze-thawing by Young-Chang Nho; Youn-Mook Lim; Hui-Jeong Gwon; Eun-Kyung Choi (1675-1678).
Hydrogels for wound dressings from a mixture of poly(vinyl alcohol) (PVA), poly(N-vinylpyrrolidone) (PVP), glycerin and an antibacterial agent were obtained by a γ-irradiation combined with freeze-thawing. The physical properties such as the gelation and swelling degree of the hydrogels were examined. When the PVP/PVA ratio was 6: 4 (wt%) and prepared by combined irradiation and freeze-thawing, it showed an excellent swelling capacity (>1,200%). The antibacterial effect of the hydrogels containing the antibacterial agents was observed to be effective as the concentration of antibacterial agents increased. The results demonstrated that hydrogel in a proper blending ratio could be used as a wound dressing that can accelerate wound healing with an antibacterial effect.
Keywords: Hydrogels; Radiation; Antibacterial; Freeze-thawing
Production of 3-hydroxypropionic acid by recombinant Klebsiella pneumoniae based on aeration and ORP controlled strategy by Jian-Guo Zhu; Xiao-Jun Ji; He Huang; Jun Du; Shuang Li; Yue-Yue Ding (1679-1685).
A biosynthetic pathway for the production of 3-hydroxypropionic acid (3-HP) from glycerol was established in recombinant Klebsiella pneumoniae by introducing the aldehyde dehydrogenase gene from Escherichia coli. The activity of aldehyde dehydrogenase, which oxidized 3-hydroxypropionaldehyde (3-HPA) to 3-HP, was detected and 3-HP was produced by the recombinant strains. Three different oxygen supply strategies, associated with measuring the oxidoreduction potential (ORP) during the fermentation under these conditions, were adopted for higher production of 3-HP by the recombinant cells. About 0.8 g/l 3-HP and more 1,3-propanediol production by the recombinant Klebsiella pneumoniae were obtained under completely aerobic conditions. Under micro-aerobic conditions, 3-HP production could be increased to 2.2 g/l and 1,3-propanediol production was almost the same as in the original strain. Under the anaerobic conditions, 1,3-propanediol was the main product and about 1.3 g/l 3-HP was produced. Finally, 3-HP production of the recombinant strain was increased to 2.8 g/l under micro-aerobic condition with a further two-stage ORP controlled strategy.
Keywords: 3-Hydroxypropionic Acid; 1,3-Propanediol; Klebsiella pneumoniae ; Aldehyde Dehydrogenase; Glycerol Dehydratase
Characterization of PVA/glycerin hydrogels made by γ-irradiation for advanced wound dressings by Hui-Jeong Gwon; Youn-Mook Lim; Sung-Jun An; Min-Ho Youn; Seol-Hee Han; Ho-Nam Chang; Young-Chang Nho (1686-1688).
The aim of this study was to investigate the enhanced absorption property of PVA/Glycerin (PVA/Gly) hydrogel for advanced wound dressing. A simple crosslinking method was introduced to prepare the PVA/Gly hydrogels with the use of γ-irradiation. An absorption ratio and thermal properties of the PVA/Gly hydrogels can be controlled by varying the irradiation dose and weight ratio of the PVA/Gly. When the PVA/Gly content was 20/5 wt% and the irradiation dose at 25 kGy, the PVA/Gly hydrogels showed excellent absorption properties (>350%). These results imply that the PVA/Gly hydrogel is highly absorbent and converts wound exudates to the hydrogel matrices that create a moist and clean environment in the wound healing process. Therefore, the PVA/Gly hydrogel prepared by this method can be used as an advanced wound dressing.
Keywords: Absorption; Gamma Irradiation; PVA/Glycerin Hydrogel; Wound Healing
Production of bacterial cellulose in static conditions by a simple fed-batch cultivation strategy by Omer Shezad; Salman Khan; Taous Khan; Joong Kon Park (1689-1692).
The current study investigated fed-batch cultivation for the increased productivity of bacterial cellulose (BC) sheets by Gluconacetobacter hansenii PJK in static conditions using chemically defined medium and waste from beer fermentation broth. Fermentations were carried out in a 3 L jar fermenter without any impeller for 30 days. In the proposed fed-batch cultivation, 500 mL of the medium was initially inoculated with pre-culture in a jar fermenter while a fresh medium was fed periodically. BC production was also done by using batch cultivation which was used as a control for comparison. The results obtained revealed an overall of 2–3 times increase in BC production in fed-batch cultivation compared to batch cultivation after 30 days of cultivation. During these experiments, it was found that waste from beer fermentation broth is a superior medium for the BC production using fed-batch cultivation. The production of water soluble oligosaccharides as useful by-products was also monitored during these investigations. Fed-batch cultivation and waste from beer fermentation was also found superior for the production of these by-products. According to literature search and to the best of our knowledge, it is the first report of using fed-batch cultivation for BC production in static conditions.
Keywords: Bacterial Cellulose; Gluconacetobacter hansenii PJK; Fed-batch Cultivation; Static Culture Conditions; Water Soluble Oligosaccharides
Simple preparation of immobilized-metal affinity chromatography media by Jin-Ho Kim; Wu Sung Hwang; In Ho Kim (1693-1695).
Immobilized-metal affinity chromatography (IMAC) media was prepared. Iminodiacetic acid (IDA) was optimally coupled to the oxirane-activated gel at pH 13.0 and 60 °C in 0.1–0.15 g of IDA per ml of 2M Na2CO3 for 5–7 hours. The amount of coupled IDA was 600–800 micromoles per gram of dried gel by determining zinc (II) ion with atomic absorption spectroscopy. Adsorption and desorption of protein sample to IDA-coupled media was made and the result is compatible to ones reported previously. The efficiency of column chromatography was discussed on partially purifying β-galactosidase from E. coli as the protein sample by zinc (II) ion chelate affinity column.
Keywords: Iminodiacetic Acid; Zinc (II) Ion Chelate; Immobilized Metal Affinity Chromatography (IMAC)
Effect of Fomitopsis pinicola extract on blood glucose and lipid metabolism in diabetic rats by Wol-Suk Cha; Ji-Lu Ding; Hyun-Jae Shin; Jong-Soo Kim; Youn-Soon Kim; DuBok Choi; Hee-Duck Lee; Hyeong-Bong Kang; Chul-Won Lee (1696-1699).
This study was performed to investigate the effects of Fomitopsis pinicola extract on blood glucose and lipid metabolism in diabetic rats. The blood glucose concentration was similar to that of the control at 30 min, but after 60 min of glucose administration the blood glucose concentration rapidly decreased, and after 120 min was 100.7±4.0 mg/dL, representing an approximate 50% decrease compared to the control. In the case of the diabetic rats induced by streptozotocin, the concentration of blood glucose was decreased from 362.0±16.7 to 204.5±11.4 mg/dL after 20 days of administration. HDL- and LDL-cholesterol concentrations were 39.0±4.3 mg/L and 13.2±3.4 mg/dL, respectively, representing an approximate increase of 73% and approximate decrease of 76%, respectively, compared to the control. The activities of aspartate aminotransferase and alanine transaminase were increased. On the other hand, activities of amylase, alkaline phosphatase, lactate dehydrogenase, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase were decreased compared to that of the control. No difference was evident between test and control rats with respect to white blood cell, red blood cell, hemocyte, hemoglobin, hematocrit, and platelet counts. These results indicate that F. pinicola extract is useful as a preventative and treatment agent for damage of liver and kidney cells.
Keywords: F. pinicola ; Blood Glucose; Lipid Metabolism; Cholesterol
Hydrogen sorption characteristics of Zonguldak region coal activated by physical and chemical methods by Turkan Kopac; Atakan Toprak (1700-1705).
Hydrogen sorption characteristics of activated carbons (ACs) produced by physical and chemical activations from two coal mines (Kilimli and Armutcuk) in the Zonguldak region, Turkey were investigated by a volumetric technique at 77 K. H2 adsorption isotherms were obtained on the samples exposed to pyrolytic thermal treatments in a temperature range of 600–900 °C under N2 flow and chemical activation using different chemical agents such as KOH, NH4Cl, ZnCl2 from the two mines. Experimental hydrogen adsorption isotherm data at 77 K were used for the evaluation of the adsorption isotherm constants of the Brunauer-Emmett-Teller (BET) and the Langmuir models, and also the amount of hydrogen adsorbed on the various samples was evaluated by using the adsorption isotherm data. Higher hydrogen adsorption capacity values were obtained for all the heat and the chemically treated activated carbon samples from the Kilimli coal samples than Armutcuk. The amount of H2 adsorbed on the original Kilimli coal samples was 0.020 wt%, and it was increased to 0.89 wt% on the samples pyrolyzed at 800 °C. The highest value of hydrogen adsorption obtained was 1.2 wt% for the samples treated with KOH+NH4Cl mixture at 750 °C followed by oxidation with ZnCl2. It was shown that chemical activations were much more effective than physical activations in increasing the surface area, pore volume and the hydrogen sorption capacities of the samples.
Keywords: Coal; Activated Carbon; Adsorption Isotherms; Chemical Activation; Hydrogen Sorption
Recovery of flared gas through crude oil stabilization by a multi-staged separation with intermediate feeds: A case study by Djebri Mourad; Otmanine Ghazi; Bentahar Noureddine (1706-1716).
Since the birth of the oil industry, flaring has been used upstream to depressurize eruptive wells and downstream to burn excess gases in refining and petrochemical plants and also in associated and natural gas treatment plants. Unfortunately, flaring produces a great number of harmful by-products such as dangerous particles, volatile organic compounds, polycyclic aromatic and many other compounds just as harmful. The separation of gas and oil phases remains the most important stage in the so-called surface production. Given the high gas oil ratio (GOR) of Algerian crude oil, the separation of this gas is carried out in three or four stages. However, the choice of the optimal number of stages of separation and intermediate values of pressure requires a rigorous computation wherein the use of a simulator is more than necessary to make possible the optimization of the separation process. The present work was performed on a new separation and compression unit in an area where all the associated gas production is being flared despite the new environmental laws. Our approach consists of first simulating the separation process with the most appropriate thermo dynamical model. The intermediate separation pressure values can be determined by empirical correlations such as the method of equal pressure ratio. In our computations we have opted for a graphical method, specifically the method of minimum compression energy, that requires rigorous calculations entailing therefore the use of the Hysis simulator. This treated gas may be valorized as a raw material for the petrochemical industry or compressed and re-injected into the reservoir in order to maintain the rate of oil production. It remains that one important way of valorizing this associated gas is to transform it into liquid through a process known as gas to liquid (GTL) technology.
Keywords: Separation; Oil; Associated Gas; Compression; Flare
Characterization of thiourea-formaldehyde chelating resin by sorption of chromium(III) in water by Ki Young Kim; Ki-Taek Byun; Ho-Young Kwak (1717-1722).
With a simple model for a surfactant consisting of a hydrophilic head group and hydrophobic tail groups connected by harmonic springs, the structural change of the association structures of the surfactant in an aqueous solution was studied by using the dissipative particle dynamics (DPD) simulation. The effect of the interaction parameter of DPD particles on the structural change of the association structures was also studied. Simulations show that the proper relative values of these interaction parameters could yield desirable changes for the association structure depending on the concentration of the surfactant. That is, a spherical structure forms at ϕ=0.15, structural change from a spherical to cylindrical one occurs at ϕ=0.26, and a hexagonal structure appears at ϕ=0.30, where ϕ is the volume fraction of surfactant SDS (sodium dodecyl sulfate), and they are in good agreement with observation.
Keywords: Association Structure; Dissipative Particle Dynamics (DPD) Simulation; Sodium Dodecyl Sulfonate (SDS); Structural Transition; Surfactant Solution
Preconcentration and determination of chromium in water with flame atomic absorption spectrometry by thiourea-formaldehyde as chelating resin by Homayon Ahmad Panahi; Amir Abdollah Mehrdad Sharif; Mehrnaz Bigonah; Elham Moniri (1723-1728).
Thiourea-formaldehyde chelating resin is synthesized simply and rapidly from thiourea and formaldehyde by condensation polymerization and characterized by IR spectra and studied for the preconcentration and determination of trace Cr(III) ion from solution samples. The optimum pH value for sorption of the metal ion was 6.5. The sorption capacity of resin for Cr(III) was determined. The chelating resin can be reused for 20 cycles of sorption-desorption without any significant change in sorption capacity. A recovery of 96% was obtained for the metal ion with 0.5M HNO3 as eluting agent. The equilibrium adsorption data of Cr(III) on modified resin were analyzed by Langmuir, Freundlich and Temkin models. Based on equilibrium adsorption data the Langmuir, Freundlich and Temkin constants were determined as 0.016, 0.040 and 0.074 at pH 6.5 and 20°C. The method was applied for chromium ion determination from river water sample.
Keywords: Solid Phase Extraction; Thiourea-formaldehyde; Chromium; Preconcentration; Isotherm Study
Adsorption of zinc (II), cadmium (II), and copper (II) with PTFE Selective Resin containing primary amine N1923 and Cyanex925 by Xiaowei Zhao; Qiong Jia; Weihong Zhou (1729-1732).
In the present study, a synergistic extraction mixture, primary amine N1923 (RNH2) and Cyanex925 (B), was loaded on PTFE powder to prepare PTFE Selective Resin and was employed for the adsorption of zinc, cadmium, and copper from chloride medium. The effects of shaking time, resin amounts, concentration of metal ions, and experimental temperature on the distribution coefficients were determined. The stoichiometry of the adsorbed complexes was determined to be MCl2·(1/2)RNH2·B with the Selective Resin. The equilibrium constants and thermodynamic quantities (ΔH, ΔG, and ΔS) were calculated. Furthermore, the Freundlich isotherm proved to be more suitable than the Langmuir isotherm to indicate the effect of concentration of M2+ on the adsorption with PTFE Selective Resin.
Keywords: Adsorption; PTFE Selective Resin; Primary Amine N1923; Cyanex925
Modeling of aqueous electrolyte solutions based on perturbed-chain statistical associating fluid theory incorporated with primitive mean spherical approximation by Bong-Seop Lee; Ki-Chang Kim (1733-1747).
In this work an equation of state applicable to the system containing electrolytes has been developed by coupling the perturbed chain statistical associating fluid theory (PC-SAFT) with the primitive mean spherical approximation. The resulting electrolyte equation of state is characterized by 4 ion parameters for each of the cation and anion contained in aqueous solutions, and 4 ion specific parameters for each of six cations (Li+, Na+, K+, Rb+, Mg2+ and Ca2+) and six anions (Cl−, Br−, I−, HCO 3 − , NO 3 − and SO 4 2− ) were estimated, based upon the individual ion approach, from the fitting of experimental densities and mean ionic activity coefficients of 26 aqueous single-salt solutions at 298.15 K and 1 bar. The present equation of state with the estimated individual ion parameters has been found to satisfactorily describe not only the densities and mean ionic activity coefficients, but also osmotic coefficients and water activities of single-salt aqueous solutions. Furthermore, the present model was extended to two-salt aqueous solutions, and it has been found that thermodynamic properties such as mentioned above, of two-salt solutions, can be well predicted with the present model, without any additional adjustable parameters.
Keywords: Electrolyte; Electrolyte Equation of State; Individual Ion Parameters; PC-SAFT; Primitive Mean Spherical Approximation
Surface modified granular activated carbon for enhancement of nickel adsorption from aqueous solution by Sang-Hoon Byeon; Dhamodaran Kavitha; Kanagasabai Ponvel; Kyung-min Kim; Chang-Ha Lee (1748-1753).
Coal-based granular activated carbon was modified with acetates of sodium, potassium and lithium at concentrations of 10 and 15% and used as adsorbents to explore the adsorption mechanism of nickel ion in aqueous solution. Acetate treatment reduced surface area and pore volume of the activated carbons, but the adsorption amount of Ni(II) on the modified activated carbons (MAC) was greater than that on the virgin activated carbon. The adsorption depended on pH of the solution with an optimum at 4.5 and the adsorbed nickel could be fully desorbed by using 0.05M HCl solution. The maximum adsorption capacity of nickel ion on Li (15 wt%) modified activated carbon was 151.3 mg/g and the adsorption isotherm follows Langmuir, Sips, and Redlich-Peterson isotherm models better than the Freundlich isotherm model. The kinetic data was better fitted by a non-linear form of the pseudo-first order than the pseudo-second order, but the difference between two kinetic models was small.
Keywords: Activated Carbon; Surface Treatment; Nickel; Adsorption; Desorption
High-pressure vapor-liquid equilibrium measurement for the binary mixtures of carbon dioxide+n-butanol by Jong Sung Lim; Cheol Hun Yoon; Ki-Pung Yoo (1754-1758).
High-pressure vapor-liquid equilibrium data for the binary mixtures of CO2+n-butanol were measured at various isotherms of (313.15, 323.15, 333.15 and 343.15) K, respectively. The equilibrium compositions of vapor and liquid phases and pressures at each temperature were measured in a circulation-type equilibrium apparatus. To facilitate easy equilibration, both vapor and liquid phases were circulated separately in the experimental apparatus and the equilibrium composition was analyzed by an on-line gas chromatograph. The experimental data were compared with literature results and correlated with the Peng-Robinson (PR) equations of state using the Wong-Sandler mixing rules. Calculated results with the PR EOS showed good agreement with our experimental data.
Keywords: High-pressure VLE; Carbon Dioxide; n-Butanol; Peng-Robinson Equation of State; Wong-Sandler Mixing Rule; SCORR
Layered liquid-liquid flow in microchannels having selectively modified hydrophilic and hydrophobic walls by Yoshikazu Yamasaki; Masato Goto; Akira Kariyasaki; Shigeharu Morooka; Yoshiko Yamaguchi; Masaya Miyazaki; Hideaki Maeda (1759-1765).
When two immiscible liquids make contact in a microchannel, the flow pattern is affected by the affinity between channel walls and liquids. In this study, microchannels (200 µm in width and 200 µm in depth) having a T-shaped bifurcation point were fabricated on PMMA plates. The inner walls of the microchannels were modified in a zone-selective manner to be either hydrophilic or hydrophobic, based on verification accomplished via a laser interference fringe technique. The microchannel was placed horizontally, and water and octane were introduced into the upper-side channel (hydrophilic) and into the lower-side channel (hydrophobic), respectively. The experimental results showed that water and octane formed a stable layered flow, and the two liquids were virtually completely separated at the T-shaped section, even when static pressure was intentionally applied to the outlets. CFD simulation, using FLUENT 6.3 software, was performed to explain the role of zone-selective modification of microchannel walls.
Keywords: Microchannel; Layered Flow; Wettability; Surface Modification; CFD Simulation
Characterization of FePt film electrodeposited with a ferric electrolyte by Serhiy Cherevko; Jie Fu; Ki Youn Song; Chan-Hwa Chung (1766-1769).
The electrodeposition of FePt alloy film in a novel ferric electrolyte that could be an alternative electrolyte to the usual non-stable baths was investigated. The influence of the applied current density and electrolyte temperature on the composition of the alloy was studied. It was found that co-deposition of oxygen can be reduced by deposition at higher temperature of 65 °C than room temperature. The as-deposited film had a face-centered cubic (γ-Fe,Pt) structure, and after an additional annealing process, the structure was changed to a face-centered tetragonal structure. The as-deposited FePt film also shows good resistance to corrosion and its coercivity was about 0.1T, which makes it suitable for use in applications compatible with silicon technology.
Keywords: Alloys; Electromechanical Techniques; Magnetic Structures
Experimental characterization of a short electrical mobility spectrometer for aerosol size classification by Panich Intra; Nakorn Tippayawong (1770-1777).
A prototype of a short column electrical mobility spectrometer (EMS) for size measurement of aerosol particle was design, constructed, and experimentally characterized. The short EMS consists of a particle charger, a size classifier column, and a multi-channel electrometer. Its particle size resolution is derived from a 10 channel electrometer detector. The short EMS is capable of size measurements in the range between 10 nm to 1,000 nm with a time response of about 50 s for full up and down scan. Particle number concentration in which the short EMS can measure ranges from 1011 to 1013 particles/m3. The operating flow rate of the short EMS is set for the aerosol flow rate of 1.0–2.0 l/min and the sheath air flow rate fixed at 10.0 l/min. The inner electrode voltage of the classifier can be varied between 500–3,000 VDC. The short EMS operates at sub-atmospheric pressure, typically at 526 mbar. Validation of the short EMS performance was performed against a scanning electron microscope (SEM). Good agreements were obtained from comparison between sizes determined from the short EMS classifier and the SEM analysis. Signal current from the detector was also analyzed to give rise to number concentration of particles. Experimental results obtained appeared to agree well with the theoretical predictions.
Keywords: Aerosol; Particle; Electrical Mobility; Size Distribution; Spectrometer
Characterization of octadecyltrichlorosilane self-assembled monolayers on silicon (100) surface by Mi-Hee Jung; Ho-Suk Choi (1778-1784).
Both monolayers and multilayers were obtained from a dilute solution of n-octadecyltrichlorosilane [OTS, CH3(CH2)17SiCl3] on a SiO2/Si surface after a low pressure O2 plasma treatment. A close-packed monolayer of good quality was formed on the SiO2/Si surface. The resulting self-assembled layers were characterized by goniometry, atomic force microscopy (AFM), ellipsometry and Fourier transformed infrared attenuated total reflection (FTIR-ATR) spectroscopy. An examination of the time-dependent water contact angle measurements as a function of the OTS concentration revealed rapid monolayer formation at the initial stage. The contact angle measurements showed that the surface structure of the OTS monolayer was quite resistant to environmental changes as a result of the polymerization of OTS molecules and the formation of covalent bonds between the monolayer and substrate surface. The surface was covered with islands (observed by AFM) that were in-filled to produce in a smooth surface. The FRIR-ATR spectra showed symmetric (νs(CH2)) and asymmetric (νas(CH2)) components perpendicular to the surface.
Keywords: n-Octadecyltrichlorosilane; Self Assembled Monolayer; Silane; Silicon
Synthesis and optimization of porous anodic aluminum oxide nano-template for large area device applications by Younghee Na; Umme Farva; Sung Min Cho; Chinho Park (1785-1789).
A simplified anodized aluminum oxide (AAO) nano-template fabrication process was developed in this study, which can be suited for the large area device applications. The pores of various sizes and depths were realized from the thin (less than 1 µm) aluminum film deposited on the sapphire substrate. The optimum morphological structure was obtained by adjusting the applied voltage, types of acid solution, its concentration and temperature which has evolved after two phases of anodization followed by chemical etching. The Ar plasma pre-treatment method was developed and applied to improve the surface roughness of thin aluminum film without severely sacrificing the deposited layer thickness.
Keywords: Anodized Aluminum Oxide; Nano-Template; Plasma Treatment
Controlled thin layer coating of carbon nanotube-polymer composites for UV-visible light protection by Jaebeom Lee; Sang-Jun Park; Young-Kyun Moon; Soo-Hyung Kim; Kwangnak Koh (1790-1794).
A highly dispersed solution of multi-wall carbon nanotubes (MWCNT) and counterpart polymers was prepared in aqueous solution. A thin layer coating was deposited on glass substrates by using the layer-by-layer (LBL) method. A negative charged dispersion solution of MWCNT was obtained by oxidizing the MWCNT by immersion in nitric acid. Counterpart polymers, poly(diallydimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA), were used as base materials. The zeta potential measurements of the MWCNT solution showed the strongest potential at pH 4 and strong polyanionic surfaces at pH 5. A home-made automatic LBL machine was used to coat the polycationic/anionic materials on glass substrates. The substrate was coated homogeneously by the LBL method and the transmittance from the range of ultraviolet (UV) to visible light was manipulated in the coating process. This simple technique might be effectively utilized for fabrication of micro-sensing and energy harvesting devices, and UV light protection.
Keywords: Layer-by-layer; Carbon Nanotubes; Coating; Thin Film; Transmittance; Dispersion
Characterization of zero valent iron prepared from by-product of pickling line and its decomposition reaction activity by Byung Hoon Kim; Chol Park; Yu-Bong Kim; Dong-Suk Jung; Hyoung-Chan Cho; Sung Hoon Park; Deog-Gwan Ra; Do-Jin Lee; Sang-Chul Jung (1795-1799).
Zero valent iron (ZVI) was produced by using wasted acid and iron oxide that are by-products of a pickling line at a steel work. The reaction activity of the produced ZVI was evaluated through decomposition experiments of Orange II aqueous solution. The ZVI particles produced directly from wasted acid (A-ZVI) were not easy to handle because they were very small (10-200 nm) and were easily oxidized in the air. The size of ZVI particles produced from the iron oxide recovered from the regeneration process of wasted acid (O-ZVI) increased with reduction temperature due to coalescence. Correspondingly, the specific surface area of O-ZVI decreased with increasing reduction temperature. The decomposition efficiency of synthesized ZVI particles was higher at a lower pH. In particular, no significant decomposition reaction was observed at pH of 4 or higher with O-ZVI. The decomposition efficiency of A-ZVI was higher than that of O-ZVI or commercially purchased ZVI, but it is not easy to handle. On the other hand, O-ZVI is easier to handle, but has the drawback of low reaction activity at high pH. Further elaboration is required for practical applications of these synthesized ZVIs.
Keywords: Zero Valent Iron; Azo Dye; Iron Oxide; pH; Specific Surface Area
Morphologies and properties of NiO particles prepared from NiCl2·6H2O by spray pyrolysis by Dong-Jun Kang; Sun-Geon Kim (1800-1805).
Nickel oxide particles were prepared by spray pyrolysis of aqueous solution of NiCl2·6H2O. In the reactor the salt droplets were first converted to hollow particles by drying and then they were collapsed by oxidation to reduce their size. Each oxide particle was composed of many small nuclei with voids among them due to extremely low rate of sintering. The particle size decreased with the temperature as the sintering and crystallization proceeded. The size as well as the crystallinity of the particles increased with the initial salt concentration. When the salt droplets were preliminarily dried in diffusion dryer before entering the reactor, the collapse of the particles was considerably reduced, resulting in lower hollowness and higher sphericity. Numerical simulation on the drying of the droplets provided insight on the initial stage of spray pyrolysis.
Keywords: NiO Particles; Spray Pyrolysis; NiCl2·6H2O; Droplet Evaporation
Application of grinding kinetics analysis of inorganic powders by a stirred ball mill by Heekyu Choi; Woong Lee; Seongsoo Kim; Jinyeon Hwang (1806-1812).
The need for ultra fine particles has been increasing in the preparation field of raw powders such as fine ceramics and high functional products. A series of wet grinding experiments were carried out on inorganic powders such as calcite, pyrophyllite and talc by a stirred ball mill. The grinding rate constant K’ in the equation of grinding kinetics was examined based on the grinding kinetics analysis as the same type of function of a previous paper on a vertical type planetary ball mill. The experimental particle size distribution of the ground products was obtained in various grinding conditions. The grinding rate constants K and K’ were expressed by empirical equation involving experimental conditions by a stirred ball mill. The empirical equation on the grinding rate constant was expressed in terms of a function involving the ball diameter of grinding balls, the median diameter of feed material, and Bond’s work index of material, in the experimental conditions. The values of empirical constants C1 and C2 were 21.13 and 0.0109 on K, while C1 and C2 were 120.99 and 0.0192 on K′, respectively. And the particle size distribution of ground products of each test material for a given grinding time was found to be expressing the selection function (the specific rate of breakage) which was obtained from the grinding kinetics analysis. In this study, the grinding rate change on calcite and pyrophyllite was similar at the same experimental operation condition. However, in the case of talc, it was observed that the grinding rate was not increased compared with other samples.
Keywords: Ultra Fine Grinding; Stirred Ball Mill; Grinding Kinetics; Selection Function; Grinding Rate Constant
Preparation of molecularly imprinted polymer membrane with blending trimethoprim-MIP and polysulfone and its transport properties by Peimin Fan; Bing Wang (1813-1820).
An imprinted polymer membrane (IPM) with blending trimethoprim-MIP and polysulfone (PSF) was prepared by bulk polymerization and membrane preparation. In the process of the preparation, the influencing factors on membrane structure and properties, such as the concentration of PSF, the content of additive polyethelene glycol (PEG) and TMP imprinted polymer, were thoroughly investigated by scanning electron microscopy (SEM) and the membrane performance tester. The adsorption properties and selectivity properties of IPM to different substrates were estimated by using the method of equilibrium binding experiments. Finally, the transport properties of the membranes were investigated by using the diffusion chambers. The results showed that the imprinted polymer membrane exhibited a high selectivity for TMP.
Keywords: Imprinted Polymer Membrane; Molecularly Imprinted Polymer; High Selectivity; SEM; Transport Properties
Effect of a non-ionic surfactant on skin-retention of cationic minoxidil microparticles suspended in an anionic surfactant solution by Jin-Chul Kim (1821-1824).
The effect of Brij 78, a nonionic surfactant, on the interactions between cationic minoxidil (MXD) microparticles and sodium lauryl ether sulfate (SLES) in an aqueous phase was investigated. Cationic MXD microparticles were prepared by high pressure homogenization, where distearyldimethylammonium chloride (DSDMAC) was used as a cationic dispersant. The positive surface charge of MXD microparticles was neutralized at the equimolar ratio of SLES/DSDMAC and became negative in the presence of excess amount of SLES, whether Brij 78 was included in the MXD suspensions or not. On the other hand, when nonionic surfactant was included in the suspension so that the molar ratio of Brij 78/DSDMAC was 0.063: 1, the suspension of the cationic microparticles was stable in terms of turbidity change even in the presence of excess amount of SLES. It means that while electrostatic interactions between DSDMAC and SLES were occurring, the aggregation of cationic MXD microparticles was prevented with the aid of Brij 78. Due to the cationic microparticle-stabilizing effect of Brij 78 in the presence of the anionic surfactant, the substantivity of the cationic MXD microparticles having Brij 78 was about two times higher than that of the microparticles without the nonionic surfactant.
Keywords: Minoxidil; Distearyldimethylammonium Chloride; Brij 78; Sodium Lauryl Ether Sulfate; Substantivity
Comparison of gamma ray and electron beam irradiations on the degradation of carboxymethylcellulose by Jong-il Choi; Jae-Hun Kim; Kwang-Won Lee; Beom-Suk Song; Yohan Yoon; Myung-Woo Byun; Ju-Woon Lee (1825-1828).
Carboxymethylcellulose (CMC) is used for a variety of applications due to its superior properties of high viscosity at a low concentration. In this study, the difference between a gamma ray (GR) irradiation from Co-60 and an electron beam (EB) irradiation with 10 MeV Energy on the viscosity change in CMC solution was compared. At the same irradiation doses, the viscosity of the CMC solution was more severely decreased by GR. Electron spin resonance spectroscopy revealed that the radicals in the CMC were more generated by GR, but there was no difference in the Fourier transform infrared spectra of both irradiated CMC solutions. Also, the degree of substitution in CMC was not changed by both irradiation events. From these results, it can be concluded that EB irradiation could better minimize the decrease in the viscosity of the solution with CMC for the sterilization than GR.
Keywords: Carboxymethylcellulose; Gamma Ray; Electron Beam; Viscosity; Electron Spin Resonance
A simplified mathematical modeling for thermo-catalytic decomposition of methane over carbon black catalyst in a fluidized bed reactor by Eun Hwa Jang; Myung Wu Woo; Seung Chul Lee; Ki June Yoon; Gui Young Han (1829-1831).
A mathematical model for thermo-catalytic decomposition of methane over carbon black catalysts in a fluidized bed was proposed. The simplified isothermal, uniform flow model was considered and implemented into a computer code to predict the reactor performance. The experiment of methane decomposition into hydrogen and carbon was carried out in a fluidized bed of I.D of 0.055 m and height of 1.0 m. The range of reaction temperature was 850–900 °C, gas velocity was 1.0–3.0 U mf , and catalyst loading was 50–200 g. The reaction parameters for model equation were determined from the curve fittings and the comparison of experimental data with simulation results showed good agreement for fluidized bed reactor system. From the simulation results, the fluidized bed performance with different operating conditions were obtained, and this simple model can be used to predict the performance of a larger scale fluidized bed reactor and also in determining the optimum operating conditions.
Keywords: Mathematical Modeling; Thermo-catalytic Decomposition of Methane; Fluidized Bed