THERMODYNAMIC PERFORMANCE ANALYSIS OF GAS LIQUEFACTION CYCLES FOR CRYOGENIC APPLICATIONS

Ceyhun Yilmaz

doi:10.18186/thermal.513038

Abstract

In this paper presents an analysis of the thermodynamic cycles the most commonly used for the liquefaction of gases in order to evaluate and compare their performance under given working conditions and system component efficiencies. The cycles considered are simple Linde-Hampson cycle, precooled Linde-Hampson cycle, Claude cycle, and Kapitza cycle. First and second law relations are investigated for each cycle and performance parameters are evaluated. Thermodynamically performances criteria are compared of cycles with respect to the each other. Cycles are model in the computer environment and analyzed with Engineering Equation Solver (EES) software program. Cycles of the liquefaction fractions, coefficient of performances and second law of efficiencies are calculated for the liquefaction of different gases. Second law efficiencies are calculated as 13.4%, 21.8%, 62.9%, and 77.2% for simple Linde-Hampson cycle, pre-cooled Linde-Hampson cycle, Claude cycle, and Kapitza cycle, respectively. Claude and Kapitza cycles give better performance but simple and precooled Linde-Hampson cycle has the advantages of the simplicity of their setup.&nbsp;

Highlights

Liquefaction is a key branch of cryogenics and has wide application areas including producing commercial liquid gases and cryogenic engineering applications
The main objectives of the study are as follows: (i) First and second laws of thermodynamic relations are developed for each cycle. (ii) Liquefaction cycles performance parameters are evaluated. (iii) Liquefaction fractions, coefficient of performances COP and second law of efficiencies II are calculated for the liquefaction of different gases. (iv) Effect of inlet gas temperature on the liquefaction fraction, net work input, and second law efficiencies are investigated
The work inputs for these liquefaction cycles are 5485, 2118, 1165, and 949 kJ kg-1, respectively

Summary

Introduction

Liquefaction is a key branch of cryogenics and has wide application areas including producing commercial liquid gases and cryogenic engineering applications. The main scope of cryogenic engineering is the design, development and improvement of low temperature systems and components. In today’s world, cryogenics and low-temperature refrigeration are taking on increasingly significant roles. Low temperatures usually obtained by using liquefied gases such as liquid nitrogen or liquid helium. Liquefaction of gases is an important area for cryogenic technologies. There are three main methods for producing refrigeration; liquid expansion, Joule-Thomson expansion and expansion engine. Liquid expansion cycles are conventional refrigeration cycles and suitable for obtaining temperatures around -70°C. Kanoglu [1] performed an exergy analysis of a cascade refrigeration system for producing LNG

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Conclusion