Nitrogen and helium liquefier design and simulation using aspen plus

Abstract

Cryogenics is the branch of engineering that is applied to very low temperature refrigeration applications such as in liquefaction of gases and in the study of physical phenomenon near temperature of absolute zero. The various cryogenic cycles as Linde cycle, Collins cycle etc. govern the liquefaction of various industrial gases, namely, Nitrogen, Helium etc. Aspen Plus solves the critical engineering and operating problems that arise throughout the lifecycle of a chemical process by doing process simulation using thermodynamic data and operating conditions of the process with the help of rigorous Aspen Plus equipment models. The process simulation capabilities of Aspen Plus using mass and energy balances, phase and chemical equilibrium, and reaction kinetics helps the engineers to predict the behaviour of a process. In this project work nitrogen and helium liquefier have been designed with the help of the simulation tool ASPEN Plus and the simulation work was carried out at steady state using Peng-Robinson equation of state in order to get the desired liquefied output. The different process conditions were varied to find out that for maximum pressure of 10 atmosphere inside the Linde-Hampson liquefier system, the liquefied output of nitrogen was found to be maximum which is 92.23 % and the liquefaction of helium using Aspen plus could not be carried out as the cooling components of Aspen plus could not cool below 10 K temperature.