• KSBB Journal
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• v.16 no.1
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• pp.61-65
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• 2001

In this study, a BTX degrading microbial consortium was obtained from the activated sludges of a BTX releasing sewage water and city sewage water treatment plant. The MY microbial consortium was developed for benzene and toluene degradation, whereas the MA microbial consortium was developed for xylene isomers. The major microorganism of the MA consortium was identified as Rhodococcus ruber DSM 43338T, whereas that of the MY consortium was Rhodococcus sp. In terms of the degradation of a single component, the removal rate of benzene was fastest and decreased in order; toluene, o-xylene, p-xylene and m-xylene. For degradation of mixed BTX, most BTX were degraded within 108 hours and the degradation rate showed either stimulatory or inhibitory effects depending on the composition. MA and MY microbial consortium obtained in this study may be used effectively to remove BTX biologically.

• Clean Technology
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• v.12 no.2
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• pp.95-100
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• 2006

Fractionation and hydrodealkylation (HDA) units, subparts of BTX plant, were thermodynamically analyzed using the notion of exergy. Exergy values were calculated as the sum of physical and chemical exergies due to the existence of chemical reactions. The analysis was based on the simulation results with the aid of real operating data. Driving and material exergy losses were separately defined and quantified. Locations and the reason of major exergy losses were identified and improvement strategies were suggested. It was noted that the exergy analysis could provide a sound base for adopting the concept of industrial ecology and developing loss prevention schemes.

• Fire Science and Engineering
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• v.29 no.6
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• pp.65-70
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• 2015

This research examines the removal efficiency of benzene, toluene, xylene (BTX) and total volatile organic compounds (TVOCs) by flowing VOCs, which are generated at a petrochemical complex in the Ulsan area, in a sliding arc plasma (SAP) reactor. The SAP reactor process is composed of 5 steps and the analysis was conducted using a BTX detector and TVOC measuring instrument. The removal efficiency of BTX was better at high concentration than at low concentration and the emitted TVOC concentration increased in later steps of the reactor. In addition, the removal efficiency improved, as the flow velocity increased. The maximum permissible concentration of TVOCs in the first step was about 481 ppm and showed over 94.83% efficiency when it was operated in the 2nd step at concentrations beyond 481 ppm. Therefore, there are many factors for improving the removal efficiency of SAP reactors at low concentration and measures should be prepared according to the application method for the various types of industrial reactors.

• Fire Science and Engineering
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• v.19 no.1 s.57
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• pp.20-28
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• 2005

Major petrochemical companies in the USA and the EU map out the strategies step-by-step hazard evaluation for the efficient risk management. They adopted the risk screening methods, such as Dow fire & explosion index, as a preliminary phase to execute detailed evaluation such as QRA (Quantitative Risk Assessment). In this study, The FEDI (Fire & Explosion Damage Index), which a kind of risk screening method proposed by Khan and Abbasi, was applied to the BTX plant in Korea. We showed that the FEDI can be effectively used to classify the hazard potential by comparison of the result from the FEDI and the result from QRA. And we showed that the characteristics and the quantities of chemical are the factors which have a largest effect on fire and explosion by executing relative sensitivity analysis of the FEDI. In conclusion, if the FEDI was applied as a preliminary phase of HAZOP, more efficient hazard evaluation can be possible.

• Korean Journal of Hazardous Materials
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• v.3 no.1
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• pp.52-58
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• 2015

Since the HF release in 2012 in Korea, it became one of the most significant to evaluate consequence to the vicinity of industry facilities handling hazardous materials. BTX plant is selected to assess off-site risk to check whether the facility satisfies the Chemical Control Law by Korea Government. Accident scenarios were listed using process safety information. The scenarios having effect to the off-site were selected and assessed further according to guideline provided by Korea government. Worst case and alternative scenarios including other interested scenarios were evaluated using ALOHA. Each evaluated scenario was assessed further considering countermeasures. The results showed that the facility handling chloric acid is safe enough and needed no further protections at the moment.

• Journal of the Korea Society for Simulation
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• v.4 no.1
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• pp.121-130
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• 1995

This paper deals with modeling and simulation of an industrial benzene-toluene-xylene plant. Because the fractionation unit of benzene-toluene-xylene plant has a narrow range of boiling point and doesn't have any sidecut and side reboiler, we employed boiling point estimation method in the modeling and simulation of the plant. Soave-Redlich-Kwong equation was used in the computation of thermodynamical properties. We solved resulting nonlinear equations by using Newton-Raphson method which is known to show fast convergence. Results of simulation showed good agreement with actual plant operation data.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.12
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• pp.689-695
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• 2015

A biofilm filtration for the removal of gaseous pollutants has been recognized as a process with a complex interaction between the gas flow characteristics and the process operating variables. This study aims to develop an one dimensional dynamic numerical model which can be utilized as a tool for the analysis of biofilm filtration process operated in plug flow mode. Since, in a plug flow system, minor environmental changes in a gaseous unit process cause a drastic change in reaction and the interaction between the pollutants is an influencing factor, plug flow system was generalized in developing the model. For facilitation of the model development, dispersion was simplified based on the principles of material balance. Several reactions such as competition, escalation, and control between the pollutants were included in the model. The applicability of the developed model was evaluated by taking the calibration and verification steps on the experimental data performed for the removal of BTX at both low and high flow concentration. The model demonstrated a correlation coefficient ($R^2$) greater than 0.79 under all the experimental conditions except for the case of toluene at high flow condition, which suggested that this model could be used for the generalized gaseous biofilm plug flow filtration system. In addition, this model could be a useful tool in analyzing the design parameters and evaluating process efficiency of the experiments with substantial amount of complexity and diversity.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.9-18
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• 2000

Accident analysis are useful in the design stage of chemical plants and their surrounding structures. Also, analysis results are required for safety management of existing plants. In this paper, the fire and explosion effect by BTX released was evaluated. The computer program was prepared for accident analysis and adopted for evaluating the magnitude of fire (pool fire) and explosion (UVCE) effect. The thermal radiation was used as a measure of fire magnitude and the overpressure as a measure of explosion magnitude. And probit analysis was made for each case. As a case study, benzene tank model was used. The simulation results of explosion of benzene showed that the damage within 20 meters from the accident spot was severe and the damage beyond 60 meters was negligible. The simulation results of fire of benzene showed that the damage in summer is bigger than that in winter. And the damage of city located inland seems to be bigger than that of city in seaside. And thermal radiation effects was negligible beyond 40 meters-distance from the accident spot.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.168-178
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• 2017

In order to prevent major and chemical accidents, some of the plants which would like to install and operate hazard chemicals handling facilities must submit Off-site Consequence Analysis due to recent arisen leak accidents since 2015. A lot of chemical industrials choose gas detectors as mitigation equipment to early detect gas vapor. The way of placement of gas detectors has two methods; Code-based Design(CBD) and Performance-based Design. The CBD has principles for gas detectors to be installed with consideration for the place that is expected to accumulate gas, and the leak locations according to legal standards and technical guidelines, and has a possibility to be unable to detect by these rules to locate gas detectors by vapor density information. The PBD has two methods; a Geographic Method and Scenario based Method. The Scenario-based Method has been suggested to make up for the Geographic Coverage Method. This Scenario-based Method draw the best optimum placement of gas detectors by considering leak locations, leak speed information, leak directions and etc. However, the domestic placement guidelines just refers to the CBD. Therefore, this study is to compare existing placement location of gas detectors by the domestic CBD with placement locations, coverages and the number of gas detectors in accordance with the Scenario-based Method. Also this study has measures for early detecting interest of Vapor Cloud and suitable placement of gas detectors to prevent chemical accidents. The Phast software was selected to simulate vapor cloud dispersion to predict the consequence. There are two cases; an accident hole size of leak(8 mm) from API which is the highst accident hole size less than 24.5 mm, and a normal leak hole size from KOSHA Guide (1.8 mm). Detect3D was also selected to locate gas detectors efficiently and compare CBD results and PBD results. Currently, domestic methods of gas detectors do not consider any risk, but just depend on domestic code methods which lead to placement of gas detectors not to make personnels recognize tolerable or intolerable risks. The results of the Scenario-based Method, however, analyze the leak estimated range by simulating leak dispersion, and then it is able to tell tolerable risks. Thus it is considered that individuals will be able to place gas detectors reasonably by making objectives and roles flexibly according to situations in a specific plant.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.296-303
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• 2005

The co-pyrolysis characteristics of polyvinylchloride (PVC) and acrylonitrile butadiene styrene (ABS) mixtures with various mixing ratios and effect of addition of CaO and $Cu_2O$ have been studied using thermogravimetry (TG) and gas chromatograph-mass spectrometry (GC-MS). In an isothermal decomposition conducted at $500^{\circ}C$, the yields of styrene monomers and aromatic compounds increased as the mixing ratio of ABS increased, and the yield of BTX compounds reached its maximum (16.14%) when the mixing ratios of PVC and ABS was 4:1. In an isothermal decomposition added with metal oxides, the maximum yield of liquid product was 73% when CaO [CaO/(PVC+ABS)=0.4] was added and it was 70% when $Cu_2O$ [$Cu_2O$/(PVC+ABS)=0.4] was added, respectively, where HCl contained in the gaseous product was completely removed when added with CaO [CaO/(PVC+ABS)=0.5] and $Cu_2O$ [$Cu_2O$/(PVC+ABS)=1.0]. Therefore, to obtain the highest yield of liquid product it appears to be the reaction condition: the reaction temperature of $500^{\circ}C$ and mixing ratios of CaO and $Cu_2O$ are 0.5 and 1.0, respectively.