Experimental study on the applicability of liquid air as the refrigerant in artificial ground freezing for subsea tunnels

Young-Jin Son; Hyeungchul Choi; Hung-Man Moon; Hangseok Choi; Tae Young Ko

doi:10.9711/KTAJ.2016.18.2.175

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Experimental study on the applicability of liquid air as the refrigerant in artificial ground freezing for subsea tunnels 해저터널을 위한 동결공법 냉매로서의 액화공기 적용성에 대한 실험적 연구

31 March 2016. pp. 175-181

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Abstract

In this paper, the liquid air was selected as the refrigerant in artificial ground freezing to be used for rapid ground freezing and to reduce the risk of suffocation and the applicability of liquid air was verified. In order to evaluate the stability of the liquid air, the oxygen concentration of mixtures with liquid nitrogen and liquid oxygen was experimentally examined to meet the oxygen concentration criteria in the Occupational Safety and Health Act. In addition, the effects of the mixture ratio of liquid nitrogen and liquid oxygen, pressure and flow rate change in the storage vessel on the oxygen concentration in the liquid air were investigated. As a result, the ratio of liquid nitrogen and liquid oxygen 8: 2 was shown to meet the oxygen concentration standards. Pressure and flow rate change in the storage vessel did not have significant effects on the oxygen concentration in the liquid air.

Keywords

Artificial ground freezing

Subsea tunnel

High water pressure

Liquid nitrogen

Liquid air

본 연구는 액체질소와 같이 급속 동결이 가능하면서 질식의 위험을 배제할 수 있는 냉매로서 액화공기를 선정하였고 이의 적용성을 평가하였다. 액화공기의 안정성을 평가하기 위해 액체질소와 액체산소가 혼합된 액화공기의 산소 농도가 산업안전보건법에 제시된 산소 농도 기준에 부합되는지를 실험적으로 검증하였으며, 액체질소 및 액체산소의 혼합 비율, 액화공기 저장용기의 압력변화 및 유량변화에 따른 액화공기 산소 농도변화를 살펴보았다. 그 결과, 액체질소 및 액체산소를 8:2로 혼합하였을 경우 산업안전보건법에 제시된 산소 농도 기준에 부합되는 것을 확인하였다. 액화공기 저장용기의 압력변화 및 유량변화는 액화공기의 산소 농도에 큰 영향을 미치지 않는 것으로 나타났다.

키워드

동결공법

해저터널

고수압

액체질소

액체공기

References

1.Daesung Industrial Gases Co. LTD (2008), DOA- 3000R Oxygen Analyzer Manual.

2.Giancoli, D.C. (1984), General physics, Prentice- Hall, New York, p. 892.

3.Harris, J.S. (1995), Ground freezing in practice, Thomas Telford, London, p. 264.

4.Ministry of Employment and Labor (2013), Occupational Safety and Health Act.

5.Sharp, D.A., Lee, J.M., Yeo, Y.K., Lee, S.C. (2008), Process design using HYSYS, A-Jin, Seoul, p. 207.

6.Son, Y.J., Lee, K.W., Ko, T.Y. (2014), “Studies of application of artificial ground freezing for a subsea tunnel under high water pressure - focused on case histories -”, Journal of Korean Tunnelling and Underground Space Association, Vol. 16, No. 5, pp. 431-443.

Information

Publisher :Korean Tunneling and Underground Space Association
Publisher(Ko) :한국터널지하공간학회
Journal Title :Journal of Korean Tunnelling and Underground Space Association
Journal Title(Ko) :한국터널지하공간학회 논문집
Volume : 18
No :2
Pages :175-181
Received Date : 2016-02-15
Revised Date : 2016-03-02
Accepted Date : 2016-03-03
DOI :https://doi.org/10.9711/KTAJ.2016.18.2.175

Journal of Korean Tunnelling and Underground Space Association ISSN:2233-8292(Print) 2287-4747(Online) 한국터널지하공간학회 논문집

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