• Journal of the Semiconductor & Display Technology
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• v.21 no.2
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• pp.144-149
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• 2022

A cryogenic Mixed Refrigerant Joule-Thomson refrigeration cycle was designed to be applied to the semiconductor etching process with non-flammable constituents. 3-stage cascade refrigerator, single mixed refrigerant Joule-Thomson refrigerator, and 2-stage cascade type mixed refrigerant Joule-Thomson refrigerator are analyzed to figure out the coefficient of performance. Non-flammable mixture of argon(Ar), tetrafluoromethane(R14), trifluoromethane (R23) and octafluoropropane(R218) were utilized to analyze the refrigeration cycle efficiency. The designed refrigeration cycle was adapted to cool down the coolant of HFE7200(Ethoxy-nonafluorobutane, C₄F₉OC₂H₅) with certain constraints. Maximum coefficient of performance of the refrigeration system is obtained as 0.289 for the cooling temperature lower than -100℃. The detailed result of the coefficient of performance according to the mixture composition is discussed in this study.

• Journal of the Semiconductor & Display Technology
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• v.23 no.2
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• pp.6-11
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• 2024

This paper presents the design and experimental analysis of a cryogenic refrigeration system for -100 ℃, primarily intended for semiconductor etching process. The refrigeration system utilizes non-flammable mixed refrigerant Joule-Thomson refrigeration cycle, incorporating a precooling stage to enhance overall performance. The selected refrigerants for the system include R1234yf for the precooling stage, and Ar, R14, R23 and R218 for the main cooling stage of the Joule-Thomson refrigeration cycle. Design results according to the system constraints and experimental results are discussed, including lowest evaporation temperature, compressor isentropic efficiency and overall pressure tendencies. The achieved refrigerant fraction from optimal design is Ar: R14: R23: R218 = 0.15: 0.4: 0.15: 0.3, indicating COP of 0.1118 at the isentropic compressor efficiency of 50%. The experimental result shows the developed system reaches steady state in approximately 3 hours.

• Journal of the Society of Disaster Information
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• v.15 no.4
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• pp.634-647
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• 2019

Purpose: Currently, many chemicals are used in industrial and real life, and many substances are used in the form of a single substance, but most of them are used in the form of a mixture, and there is a need for a criterion for judging the danger of these substances. Method: Therefore, this study aims to confirm the risk criteria of the mixture through experimental studies on flammable mixtures in order to secure the effectiveness of the details of the existing Dangerous Goods Safety Management Act angerous Goods Judgment Criteria and to ensure the reliability and reproducibility of the dangerous goods judgment. Result: Experimental results show that alcohol flash point is mixed with water, which is a non-flammable liquid. Similar flash point trends occurred around 60% on an alcohol basis. In addition, in the case of flammable-combustible mixtures, there was little change in flash point if the flash point difference of the two materials was not large, and if the flash point difference of the two materials was low, the flash point tended to increase with the increase of the high flash point material. Conclusion: In the future, the test results may provide reference data on the experimental criteria for the flammable liquids that are cracked at the fire site.

• 한국가스학회:학술대회논문집
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• 2004.11a
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• pp.97-102
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• 2004

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2002.05a
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• pp.42-45
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• 2002

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2002.11a
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• pp.300-306
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• 2002

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2000.11a
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• pp.68-73
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• 2000

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.524-535
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• 2008

위험물들은 위험물의 사용 및 관리뿐만 아니라 수송시에도 많은 위험성을 내포하고 있어 각국에서는 적당한 기준을 마련하여 특별히 관리하고 있다. 우리나라 철도 위험물안전수송에 관한 철도안전법 개정을 위하여 국내 철도 위험물의 수송량과 종류를 분석하고 국내외 위험물분류기준을 비교하였다. 우리나라는 지리적으로 대륙을 연결하기 편리한 위치에 있어 향후 국경을 넘어 대륙을 횡단하는 국제법을 채택하는 것이 유리하고, 수송되어야 할 물질의 종류가 다양해질 것을 대비하여 국제적으로 통용될 수 있는 위험물일람표를 채택하는 것을 제안하였다.

• Journal of the Korean Society of Safety
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• v.19 no.2
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• pp.54-60
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• 2004

Flammable substances are frequently used chemical industry processes. An accurate knowledge of the ALTs(Autoignition Temperatures) is important in developing appropriate prevention and control measures in industrial fire protection. The AITs describe the minimum temperature to which a substance must be heated, without the application of a flame or spark, which will cause that substance to ignite. The AITs are dependent upon many factors, namely initial temperature, pressure, volume, fuel/air stoichiometry, catalyst material, concentration of vapor, ignition delay. This study measured relationship between the AITs and the ignition delay times by using ASTM E659-78 apparatus for methanol and ethanol. The A.A.P.E.(Average Absolute Percent Error) and the A.A.D.(Average Absolute Deviation) of the experimental and the calculated delay times by the AITs for methanol were 14.59 and 1.76 respectively. Also the A.A.P.E. and the A.A.D. of the experimental and the calculated delay times by the ATIs for ethanol were 8.33 and 0.88.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1749-1751
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• 1998

Close to high power radio/radar transmitters there is a possibility that sparks may be occur at discontinuities in metallic structures. If these structures are in an area in which a flammable mixture may be present, there is a possibility that a fire or explosion may be caused by the sparking. A number of assessment procedures for quantification of the hazard have been produced. This paper reviews the bases of the British Standard covering ignition hazards by radio-frequency radiation and presents some ignition test apparatus to access these hazards.