• Title/Summary/Keyword: Pre-treatment process

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Simulation of Membrane-absorption Hybrid Process for LNG-FPSO (LNG-FPSO용 막-흡수 하이브리드 공정 전산모사)

  • Min, Kwang-Joon;Cho, Habin;Kim, Jin-Kuk;Kang, Sang Wook
    • Membrane Journal
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    • v.28 no.2
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    • pp.90-95
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    • 2018
  • A process design was performed for a removal of acid gases using membrane-absorption hybrid system in LNG-FPSO. Commercial process simulator Promax version 4.0 was utilized for comparing acid gases removal capabilities of amine absorption process and hybrid process. Simulation results show hybrid process could be small amine solvent circulate rate, energy consumption, equipment sizing compared to typical amine absorption process. As a result, hybrid process which is small footprint and energy saving process may be a good solution for the pre-treatment of natural gas in LNG-FPSO.

Pre-treatment of textile wastewaters containing Chrysophenine using hybrid membranes

  • lehi, Arash Yunessnia;Mousavirad, Seyed Jalaleddin;Akbari, Ahmad
    • Membrane and Water Treatment
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    • v.8 no.1
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    • pp.89-112
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    • 2017
  • Dyeing wastewaters are the most problematic wastewater in textile industries and also, growing amounts of waste fibers in carpet industries have concerned environmental specialists. Among different treatment methods, membrane filtration processes as energy-efficient and compatible way, were utilized for several individual problems. In this research, novel hybrid membranes were prepared by waste fibers of mechanical carpets as useful resource of membrane matrix and industrial graphite powder as filler to eliminate Chrysophenine GX from dyeing wastewater. These membranes were expected to be utilized for first stage of hybrid membrane filtration process including (adsorption-ultrafiltration) and nanofiltration in Kashan Textile Company. For scaling of membrane filtration process, fouling mechanism of these membranes were recognized and explained by the use of genetic algorithm, as well. The graphite increased rejection and diminished permeate flux at low concentration but in high concentration, the performance was significantly worsened. Among all hybrid membranes, 18% wt. waste fibers-1% wt. graphite membrane had the best performance and minimum fouling. The maximum pore size of this optimum membrane was ranged from 16.10 to 18.72 nm.

Performance and Stability Enhancement of Organic Solar Cells by Surface Treatment Processes of Transparent Electrodes (표면 전처리 공정에 따른 투명전극 계면 특성 변화와 유기 태양전지 성능 및 안정성 향상)

  • Lee, Kwan-Yong;Kim, Do-Hyun;Park, Sun-Joo;Kim, Young-Joo
    • Transactions of the Society of Information Storage Systems
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    • v.9 no.2
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    • pp.42-47
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    • 2013
  • In this study, we have experimentally analyzed how the surface properties of transparent electrode layer influence the photovoltaic performance of bulk heterojunction organic solar cell by the contact angle measurement and X-ray photoelectron spectroscopy(XPS) observation. As a result, the power conversion efficiency of test devices improved from 0.64% to 1.83% and 2.15% by UV-ozone exposure and $O_2$ plasma treatment, respectively. Thus, we conclude that the surface activation process is very important for better performance and stability in addition to the cleaning process of carbonate residue on the surface.

Optimization of Solid Phase Extraction Method for Quantitative Analysis of Perfluorooctanoic Acid in Serum using Liquid Chromatography-Tandem Mass Spectrometry

  • Lee, Hyun-Seok;Yim, Yong-Hyeon
    • Mass Spectrometry Letters
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    • v.5 no.1
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    • pp.30-33
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    • 2014
  • A solid phase extraction (SPE) method was optimized for the quantitative analysis of perfluorooctanoic acid (PFOA) in serum using hydrophilic-lipophilic balance SPE and LC-MS/MS. Fetal bovine serums spiked with $^{13}C_8$-PFOA before or after SPE were used as test samples for evaluation of the SPE efficiency. Simultaneous evaluation of matrix effects and absolute SPE recovery for $^{13}C_8$-PFOA in serum using different sample pre-treatments and SPE conditions allowed optimization of SPE process efficiency with minimal matrix effect and decent SPE recovery. Introduction of protein precipitation as a sample pre-treatment procedure for serum samples before SPE generally decreased matrix effect in LC-MS/MS analysis and provided more stable recovery of PFOA.

Graphic Simulator for Analyzing the Remote Operation of the Advanced Spent Fuel Conditioning Process

  • Song, Tai-Gil;Kim, Sung-Hyun;Lee, Jong-Ryul;Yoon, Ji-Sup
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.1319-1322
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    • 2003
  • KAERI is developing the Advanced Spent Fuel Conditioning Process (ACP) as a pre-disposal treatment process for spent fuel. Equipment used for such a spent fuel recycling and management process must operate in intense radiation fields as well as in a high temperature. Therefore, remote maintenance has a played a significant role in this process because of combined chemical and radiological contamination. Hence suitable remote handling and maintenance technology needs to be developed along with the design of the process concepts. To do this, we developed the graphic simulator for the ACP. The graphic simulator provides the capability of verifying the remote operability of the process without fabrication of the process equipment. In other words, by applying virtual reality to the remote maintenance operation, a remote operation task can be simulated in the graphic simulator, not in a real environment. The graphic simulator will substantially reduce the cost of the development of the remote handling and maintenance procedure as well as the process equipment, while at the same time producing a process and a remote maintenance concept that is more reliable, easier to implement, and easier to understand.

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Current status of surgery first approach (part II): precautions and complications

  • Kwon, Tae-Geon;Han, Michael D.
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.41
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    • pp.23.1-23.10
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    • 2019
  • The choice of surgical technique in orthognathic surgery is based primarily on the surgical treatment objectives (STO), which is a fundamental component of the orthognathic treatment process. In the conventional orthodontics-first approach, presurgical planning can be performed twice, during the preorthodontic (initial STO) and presurgical phases (final STO). Recently, a surgery-first orthognathic approach (SFA) without presurgical orthodontic treatment has been introduced and combined initial and final STO at the same time. In contrast to the conventional surgical-orthodontic treatment protocol that includes preoperative orthodontics for dental decompensations to maximize stable postoperative occlusion, the SFA potentially shortens the treatment period and minimizes esthetic concerns during the decompensation period because skeletal problems are corrected from the beginning. The indications for the SFA have been proposed in the literature, but no consensus exists. Moreover, because dental occlusion of the pre-orthodontic arches cannot be used as a guide for establishing the surgical treatment plan, there are fundamental limitations in accurate prediction of postsurgical results in the SFA. Recently, the concepts of postsurgical orthodontic treatment are continuously changing and evolving to overcome this inherent limitation of the SFA. The elimination of presurgical orthodontics can change the paradigm of orthognathic surgery but still requires cautious case selection and thorough discussion and collaboration between orthodontists and surgeons regarding the goals and postoperative management of the orthognathic procedure.

Application of Electrocoagulation for Printing Wastewater Treatment: From Laboratory to Pilot Scale

  • Thuy, Nguyen Thi;Hoan, Nguyen Xuan;Thanh, Dang Van;Khoa, Pham Minh;Tai, Nguyen Thanh;Hoang, Quang Huy;Huy, Nguyen Nhat
    • Journal of Electrochemical Science and Technology
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    • v.12 no.1
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    • pp.21-32
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    • 2021
  • This study reports for the first time the application of electrocoagulation (EC) from laboratory to pilot scales for the treatment of printing wastewater, a hazardous waste whose treatment and disposal are strictly regulated. The wastewater was taken from three real printing companies with strongly varying characteristics. The treatment process was performed in the laboratory for operational optimization and then applied in the pilot scale. The weight loss of the electrode and the generation of sludge at both scales were compared. The results show that the raw wastewater should be diluted before EC treatment if its COD is higher than about 10,000 mg/L. Pilot scale removal efficiencies of COD and color were slightly lower compared to those obtained from the laboratory scale. At pilot scale, the effluent CODs removal efficiency was 81.9 - 88.9% (final concentration of 448 - 992 mg/L) and color removal efficiency was 95.8 - 98.6% (final level of 89 - 202 Pt-Co) which proved the feasibility of EC treatment as an effective pre-treatment method for printing wastewater as well as other high colored and hard-biodegradable wastewaters.

Decomposition Characteristics of Dissolved Organic Compounds in the Landfill Leachate by Ozone Oxidation (오존산화에 의한 매립지 침출수내 용존성 유기화합물의 분해 특성)

  • 정승현;이헌모;정병곤
    • Journal of environmental and Sanitary engineering
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    • v.18 no.1
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    • pp.23-29
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    • 2003
  • The effect of ozone oxidation on bio-degradability of leachate was studied. Ozone oxidation process was used as pre-treatment process to enhance performance of biological process in treating landfill leachate. Optimum ozone injection rate and contact time in this experiment was $160{\;}mg{\;}O_/{\ell}{\cdot}hr$ and 45 minutes, respectively. Bio-degradability was enhanced 5.08% by ozone oxidation. The ratio of ozone demand/DOC concentration was $0.049~0.091{\;}mg{\;}O_3/mg{\;}DOC$. The increase of bio-degradability depending on ozone injection rate(D) and contact time(T) can be expressed as follows ; The rate of bio-degradation of DOC was increased proportionally with the increase of ozone injection rate and contact time irrespective of landfill site age. The increase of bio-degradability by ozone addition was not satisfactory. It is hard to expect significant increase in bio-degradability by ozone treatment only. Thus, it is evaluated that ozone oxidation can not increase biodegradability significantly in concentrated wastewater composed of complex organic compound such as leachate.

Effect of Ozone Oxidation on Biodegradability of Dissolved Organic Compounds in the Landfill Leachate (오존산화가 매립지 침출수내 용존성 유기화합물의 생분해도에 미치는 영향)

  • Jeong, Seung-Hyun;Jeong, Byung-Gon
    • Journal of Korean Society on Water Environment
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    • v.21 no.1
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    • pp.1-6
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    • 2005
  • The effect of ozone oxidation on biodegradability of leachate was studied. Ozone oxidation process was used as pre-treatment process to enhance performance of biological process in treating landfill leachate. Optimum ozone dosing rate and contact time in this experiment was $160mg\;O_3/L$ hr and 45 minutes, respectively. Biodegradability was enhanced 5.08% by ozone oxidation. The ratio of ozone demand/DOC concentration was $0.049{\sim}0.091mg\;O_3/mg$ DOC. The increase of biodegradability depending on ozone dosing rate(D) and contact time(T) can be expressed as follows ; ${\Delta}E=0.00479{\cdot}D^{0.773}{\cdot}T^{0.800}$ The biodegradation rate of DOC was increased proportionally with the increase of ozone dosing rate and contact time irrespective of landfill site age. The increase of biodegradability by ozone addition was not satisfactory. It is hard to expect significant increase in biodegradability by ozone treatment only. Thus, it is evaluated that ozone oxidation can not increase biodegradability significantly in concentrated wastewater composed of complex organic compound such as leachate.

Treatment Efficiency of Complex Wastewater by Fenton's Oxidation Condition (펜톤산화에 따른 복합폐수의 처리효율연구)

  • Sung, Il-Wha
    • Journal of Environmental Health Sciences
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    • v.32 no.5 s.92
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    • pp.446-450
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    • 2006
  • In order to treat the wastewater containing organic compound, pre-treatment system connected with MSP(molecular separation process) was investigated. With the aim of selecting an optimum process of Fenton's oxidation, removal efficiency of each process in the optimum reaction condition was recommended. The $Fe/H_{2}O_{2}$(ferric sulfate to hydrogen peroxide)reagent is referred to as the Fenton's regent, which produces hydroxyl radicals by the interaction of Fe with $H_{2}O_{2}$. The powerful oxidizing ability and extreme kinetic reactively of the hydroxyl radical was well established. Increasing dosage of $Fe/H_{2}O_{2}$ increased removal efficiency as molar ratio of $Fe/H_{2}O_{2}$ between 0.2 and 2.5. Optimum dosage of molar ratio was 1. The removal efficiency for reaction condition was increased as pH decreased when the molar ratio of $Fe/H_{2}O_{2}$ was 1.7. Fenton's oxidation was most efficient in the reaction time 35 min for complex wastewater. Also, coagulation aid experiments using kaolin resulted in 3% of kaolin dosage.