Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Nitrogen Liquefaction: a Prototype Plant

Get access (open in a dialog) DOI: 10.1615/IHTC15.cds.009416
pages 785-797

Abstrakt

The paper presents a prototype Nitrogen liquefaction plant that has been designed to satisfy the needs of a research laboratory and has been installed at Politecnico di Torino (Torino Technical University) for cryogenic specific applications like superconducting cables and low temperature refrigeration devices. The plant is able to liquefy Nitrogen but it will be able, by means of little changes, to liquefy Hydrogen and other cryogenic fluids. The thermal energy from the fluid to be liquefied and from the internals are removed by four high speed (up to 350000 revolutions per minute) Helium turbines connected in series. The Nitrogen liquefaction is carried out by the cooling- condensation process of the gas flow, that feeds a 0.15 m3 super insulated tank that is cooled inside. The system is based upon Claude and Collins cycles, fed with Helium, providing the cold sink at 77-100 K needed for Nitrogen liquefaction at 0.6 MPa abs, or at 20- 40 K for Hydrogen liquefaction at 1.0-1.5 MPa abs. The gas compression is achieved thanks to a dedicated air cooled Helium compressor. The paper shows the characteristics of the plant main components, and the time history of the measured temperatures, pressures and flow rates during the plant start-up, as well as the steady state liquid Nitrogen production rate. From the energetic point of view the plant performance is acceptable for a research laboratory and the plant efficiency is not far from that of larger size plants.