Temperature profile analysis on cryogenic activated carbon column of helium purification testing facility

Abstract

Cryogenic activated carbon testing facility (CACTF) is an apparatus built to purify helium gas from impurities such as oxygen, nitrogen, and gas of fission products. Because of oxygen and nitrogen have a small molecular size, the cryogenic (very low temperature) condition is needed. CACTF has a cryogenic vessel, activated carbon column, liquid nitrogen storage tank, and helium storage tank (pure and dirty). This paper discusses the investigation of temperature changes in the activated carbon column that installed inside a cryogenic vessel. The objective of research is find out the lowest temperature can be achieved in the inner of the activated carbon column so the optimum purification process can be done. The methodology used was modeling with ChemCAD software and CACTF experiments. CACTF has been modeled and simulated with ChemCAD software. Cryogenic model simulation by ChemCAD showed that the lowest temperature of-190°C will be achieved by 300 kg/hour of liquid nitrogen injection, while the laboratory experiment resulted -160°C of temperature as well. The inside vessel temperature differences it caused by heat losses to the environment during the apparatus experiment. By using ChemCAD, the optimum pressure of the cryogenic carbon column is 30 bars based on the adsorption simulation process of the cryogenic carbon column model.