Helium refrigeration system for hydrogen liquefaction applications

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Kumar, J.^1 ; Nair, S.R.^1 ; Menon, R.S.^1 ; Goyal, M.^1 ; Ansari, N.A.^1 ; Chakravarty, A.^1 ; Joemon, V.^1

Cryo Technology Division, Bhabha Atomic Research Centre, Mumbai, India^1

关键词: Application requirements;    Cryogenic turboexpanders;    Helium refrigeration systems;    Hydrogen liquefaction;    Nuclear research reactor;    Operational experience;    Process heat exchangers;    Refrigeration capacity;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012029/pdf
DOI  :  10.1088/1757-899X/171/1/012029

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Liquid hydrogen around 20 K is used as cold moderator for generating "cold neutron beam" in nuclear research reactors. A cryogenic helium refrigeration system is the core upon which such hydrogen liquefaction applications are built. A thermodynamic process based on reversed Brayton cycle with two stage expansion using high speed cryogenic turboexpanders (TEX) along with a pair of compact high effectiveness process heat exchangers (HX), is well suited for such applications. An existing helium refrigeration system, which had earlier demonstrated a refrigeration capacity of 470 W at around 20 K, is modified based on past operational experiences and newer application requirements. Modifications include addition of a new heat exchanger to simulate cryogenic process load and two other heat exchangers for controlling the temperatures of helium streams leading out to the application system. To incorporate these changes, cryogenic piping inside the cold box is suitably modified. This paper presents process simulation, sizing of new heat exchangers as well as fabrication aspects of the modified cryogenic process piping.