• Title/Summary/Keyword: High temperature gas separation

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Process Technology of the Direct Separation and Recovery of Iron and Zinc Metals Contained in High Temperature EAF Exhaust Gas

  • Furukawa, Takeshi;Sasamoto, Hirohiko;Isozaki, Shinichi;Tanno, Fumio
    • Proceedings of the IEEK Conference
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    • 2001.10a
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    • pp.393-397
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    • 2001
  • The innovatory process, that is the direct separation and recovery of the iron and zinc metals contained in the high temperature exhaust gas generated from the electric arc furnace fer the inn scrap melting and/or the dust treatment, has been proposed. This proposed process consists of the moving coke bed filter that is directly connected to the electric furnace, and the following heavy metal condenser. The exhaust gas passes through the filter and the condenser right after exhausting from the electric furnace. The moving coke bed filter is being controlled at about 1000℃ and collects iron and slag components contained in the high temperature exhaust gas. Heavy metals such as zinc and lead pass through the filter as vapor. Based on the thermodynamic considerations, the iron oxide and the zinc oxide are reduced in the filter. The solution loss reaction rate is comparatively low at about 1000℃ in the coke bed filter by the analysis using the mathematical simulation model. The heavy metal condenser is installed in the position after the coke bed filter, and rapidly cools the gas from about 1000℃ to 450℃ by a full of the cooling medium like the solid ceramic ball in addition to the cooling from the wall. The zinc and lead vapor condense and separate f개m the gas in a liquid state. The investigation of the characteristics of the exhaust gas of the commercial electric arc furnace, the fundamental experiments of the laboratory scale and the bench scale ensured the formation of this proposed process. A small-scale pilot plant examination is carrying out at present to confirm the formation of the process. It is certain that the dust generation of the electric arc furnace is extremely decreased, and it can save the energy consumption of usual dust treatment processes by the realization of this process.

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Breakdown Characteristics of SF6 and Liquefied SF6 at Decreased Temperature

  • Choi, Eun-Hyeok;Kim, Ki-Chai;Lee, Kwang-Sik
    • Journal of Electrical Engineering and Technology
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    • v.7 no.5
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    • pp.765-771
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    • 2012
  • $SF_6$ gas has been used as arc quenching and insulating medium for high and extra high voltage switching devices due to its high dielectric strength, its excellent arc-quenching capabilities, its high chemical stability and non toxicity. Despite of its significant contributions, the gas was classified as one of the greenhouse gas in the Kyoto Protocol. Thus, many researches are conducted to find out the replacement materials and to develop the $SF_6$ gas useless electrical equipment. This paper describes experiments on the temperature change-related breakdown characteristics of $SF_6$ gas ($SF_6$) and $SF_6$ liquid ($LSF_6$) in a model GIS(Gas-Insulated Switchgear) chamber in order to show the possibility of more stable and safe usages of $SF_6$ gas. The breakdown characteristics are classified into three stages, namely the gas stage of $SF_6$ according to Paschen's law, the coexisting stage of $SF_6$ gas with liquid in considerable deviation at lower temperature, and the stage of $LSF_6$ and remaining air. The result shows that the ability of the $LSF_6$ insulation is higher than the high-pressurized $SF_6$. Moreover, it reveals that the breakdown characteristics of $LSF_6$ are produced by bubble-formed $LSF_6$ evaporation and bubbles caused by high electric emission and the corona. In addition, the property of dielectric breakdown of $LSF_6$ is determined by electrode form, electrode arrangement, bubble formation and movement, arc extinguishing capacity of the media, difficulty in corona formation, and the distance between electrodes. The bubble formation and flow separation phenomena were identified for $LSF_6$. It provides fundamental data not only for $SF_6$ gas useless equipment but also for electric insulation design of high-temperature superconductor and cryogenic equipment machinery, which will be developed in future studies.

Review on Membrane Materials to Improve Plasticization Resistance for Gas Separations (가소화 저항 향상을 위한 기체분리막 소재 개발 동향)

  • Jo, Jin Hui;Chi, Won Seok
    • Membrane Journal
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    • v.30 no.6
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    • pp.385-394
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    • 2020
  • In the gas separation process, the separation membranes have to not only show high gas transport and selectivity but also exhibit exceptional stability at high temperature and pressure. However, when the polymeric membranes (particularly, glassy polymers) are exposed to the condensable gases (i.e., CO2, H2S, hydrocarbon, etc.), the polymer chains are prone to swell, leading to low stability. As a result, the plasticization behavior reduces the gas selectivity in the separation of mixture gases at high pressures and thus results in limited applications to the separation processes. To address these issues, many strategies have been studied such as thermal treatment, polymer blending, thermally rearrangement, mixed-matrix membranes, cross-linking, etc. In this review, we will understand the plasticization behavior and suggest potential methods based on the previously reported studies.

Gas Permeation Characteristics of Silica Membrane Prepared by Ultrasonic Spray Pyrolysis (초음파 분무 열분해법에 의해 합성한 실리카 막의 기체 투과 특성)

  • Lee Kew-Ho;Youn Min-Young;Park Sang-Jin;Lee Dong-Wook;Sea Bongkuk
    • Membrane Journal
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    • v.15 no.2
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    • pp.105-113
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    • 2005
  • Silica membranes were prepared on a porous metal sheet by ultrasonic spray pyrolysis method for gas separation at high temperatures. In order to improve the permselectivity, silica was deposited in the sol-gel derived $silica/\gamma-alumina$ intermediate layer by pyrolysis of tetraethyl orthosilicate (TEOS) at 873 K. The pyrolysis with forced cross flow through the porous wall of the support was very effective in plugging mesopores, Knudsen diffusion regime, that were left unplugged in the membranes. At permeation temperature of 523 K, the silica/alumina composite membrane showed $H_2/N_2$ and water/methanol selectivity as high as 17 and 16, respectively, by molecular sieve effect.

Preparation, Characterization, and Gas Permeation Properties of Carbon Molecular Sieve Membranes Derived from Dense P84-Polyimide Film

  • Park, Ho-Bum;Nam, Sang-Yong;Jang, Jeong-Gyu;Lee, Young-Moo
    • Korean Membrane Journal
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    • v.4 no.1
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    • pp.25-35
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    • 2002
  • The gas permeation properties have been studied on carbon molecular sieve (CMS) membranes prepared by pyrolysis of P84 polyimide under various conditions. P84 polyimide shows high permselectivities (O$_2$/N$_2$= 9.17 and CO$_2$/N$_2$= 35) for various gas pairs and has a good processibility because it is easily soluble in high polar solvents such as N-methylpyrrolidinone (NMP), dimethylformamide (DMF), and N,N-dimethylacetamide (DMAc). After pyrolysis under Ar flow, the change in the heating rate was found to affect the gas permeation properties to some extent. The permeabilities of the selected gases were shown to be in the order He > CO$_2$> O$_2$> N$_2$for all the CMS membranes, whose order was in accordance with the order of kinetic gas diameters. It also revealed that the pyrolysis temperature considerably influenced the gas permeation properties of the CMS membranes derived from P84 polyimide. The CMS membranes pyrolized at 700$\^{C}$ temperature exhibited the highest permeability with relatively targe loss in permselectivity. This means that the pyrolysis temperature should be varied in accordance with target gases to be separated.

Study on the Temperature Separation Phenomenon in a Vortex Chamber (와류실의 온도 분리 현상에 대한 연구)

  • Ye, A Ran;Zhang, Guang;Kim, Heuy Dong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.9
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    • pp.731-737
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    • 2014
  • A vortex chamber is a simple device that separates compressed gas into a high-temperature stream and a low-temperature stream. It is increasing in popularity as a next-generation heat exchanger, but the flow physics associated with it is not yet well understood. In the present study, both experimental and numerical analyses were performed to investigate the temperature separation phenomenon inside the vortex chamber. Static pressures and temperatures were measured using high-sensitivity pressure transducers and thermocouples, respectively. Computational fluid dynamics was applied to simulate 3D unsteady compressible flows. The simulation results showed that the temperature separation is strongly dependent on the diameter of the vortex chamber and the supply pressure at the inlet ports, where the latter is closely related to the viscous work. The previous concept of a pressure gradient wave may not be a reasoning for temperature separation phenomenon inside the vortex chamber.

Preparation of Alumino-silicate Membrane and Its Application to a Gas Separation

  • 김태환
    • Proceedings of the Membrane Society of Korea Conference
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    • 2002.04a
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    • pp.23-46
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    • 2002
  • The cryogenic, pressure swing adsorption and membrane methods have been used to separate air into nitrogen and oxygen. The air separation membrane is made of the polymers, of which manufacturing process is complicate and it causes a little high production cost. Polymer membrane has temperature limit in usage and low durability even at moderate temperature. Therefore, inorganic membranes have been studied for years. As formation of unit alumino-silicate membrane, unit cells of membrane were made with a few coating methods. In this study the dipping of substrate into sols, application of vacuum to the opposite side of substrate with coating and rotating of the substrate in the sols were found as good coating memthods to make a uniform coating and to control the thickness of membrane. The membrane coats were examined by SEM and XRD. The sample ESZl-1 was compared with those of samples that prepared by another method. The present developed coating methods could be applied to the various types of zeolite membrane formation, that is A- X-, Y- ZSM- and MCM-types of membranes. Also these membrane forming methods could be applied to formation of catalyst absorbed zeolite membrane, of which zeolite absorb the catalytic metals. The product obtained from these coating methods could be applied to the industrial gas and liquid phase catalytic reaction and separation processes.

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Research Trends of Polybenzimidazole-based Membranes for Hydrogen Purification Applications (수소 분리 응용을 위한 폴리벤즈이미다졸 기반 분리막의 연구 동향)

  • Kim, Ji Hyeon;Kim, Kihyun;Nam, Sang Yong
    • Applied Chemistry for Engineering
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    • v.31 no.5
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    • pp.453-466
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    • 2020
  • As the demand for eco-friendly energy increases to overcome the energy shortage and environmental pollution crisis, hydrogen economy has been proposed as a potential solution. Accordingly, an economical and efficient hydrogen production is considered to be an essential industrial process. Research on applying hydrogen separation membranes for H2/CO2 separation to the production of highly concentrated hydrogen by purifying H2 and capturing CO2 simultaneously from synthetic gas produced by gasification is in progress nowadays. In high temperature environments, the membrane separation process using glassy polymeric membrane with H2 selectivity has the potential for CO2 capture performance, and is an energy and cost effective system since polybenzimicazole (PBI)-based separators show excellent chemical and mechanical stability under high-temperature operation conditions. Thus, the development of high-performance PBI hydrogen separators has been rapidly progressing in recent years. This overview focuses on the recent developments of PBI-based membranes including structure modified, cross-linked, blended and carbonized membranes for applications to the industrial hydrogen separation process.

A High-speed Miniature Screening Gaschromatograph with Flame Ionization Detector

  • Banik Rahul;Lee Dong-Yeon;Gweon Dae-Gab
    • Journal of Mechanical Science and Technology
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    • v.19 no.12
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    • pp.2197-2204
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    • 2005
  • The combination of Gas chromatography (GC) for separation and Flame Ionization Detection (FID) for detection and identification of the components of a mixture of compounds is a fast and strongly proved method of analytic chemistry. The objective of this research was to design a combined High-speed miniature screening Gas chromatograph along with a Flame Ionization Detector for quick, quantitative and qualitative analysis of gas components. This combined GC-FID system is suitable to detect the volatile and semi-volatile hydrocarbons present in a gas mixture. The construction made it less expensive, easy to use and movable. The complete gas path was developed. On/off valves, temperature and flow sensors and their interface electronics were used for controlling purpose. A Microcontroller was programmed to measure the temperature and gas flow using the sensors and to control and regulate them using the electronics and valves. A pocket PC with its touch screen served as a user interface for the system. Software was developed for the pocket PC, which makes the communication possible with the Microcontroller. The system parameters can be indicated in the Pocket PC as simple text and also the analysis result can be displayed.

Elucidation of the Mechanism of Propylene/Propane Separation through Faujasite Zeolite Membrane (Faujasite 제올라이트 분리막을 통한 프로필렌/프로판 분리 메카니즘 규명에 대한 연구)

  • Min, Hae-Hyun;Park, You-In;Chang, Jong-San;Park, Yong-Ki;Cho, Churl-Hee
    • Membrane Journal
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    • v.28 no.5
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    • pp.351-360
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    • 2018
  • In this study, propylene/propane separation mechanism through NaY zeolite membrane was investigated. As permeation temperature increased, both propylene and propane permeances increased, saturated and decreased again, and a maximum selectivity was shown at around 50 to $60^{\circ}C$. Propane permeance in mixed gas experiment was much smaller than that in single gas experiment, and propylene/propane mixed gas selectivity was much larger than single gas permselectivity. As permeation time increased in transient permeation experiment, propylene permeance initially increased and saturated, while propane permeance decreased and saturated. All the experimental results announced that propylene/propane separation through NaY zeolite membrane was from preferentially adsorbed propylene molecules. The adsorbed propylene molecules efficiently prevented propane molecules from permeating through the membrane, and sufae diffused through the membrane. NaY zeolite capillary membrane prepared in the present study showed a high mixed gas selectivity of 12 and high propylene permeance of 497 GPU for a propylene/propane (89 : 11) mixture at $50^{\circ}C$ and 4 bar. Therefore, it was concluded that NaY zeolite membrane is one of promising membrane materials for propylene/propane separation due to the low cost and high separation performance.