REFRIGERATION AND LIQUEFACTION

The purpose of tliis clrapter is to present a thermodynamic analysis of refrigeration and liquefactionprocesses.However, the details of equipment design are left to specializedbooks.  

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A thermodynamic measure of the quality of a low-temperature refrigeration and liquefaction system is its reversibility. The second law, or more precisely the entropy increase, is an effective guide to the degree of irreversibility associated with such a system. However, to obtain a clearer picture of what these entropy increases mean, it has become convenient to relate such an analysis to the additional work required to overcome these irreversibilities. The fundamental equation for such an analysis is... 

Liquefied Natural Gas (LNG) is a clean burning fossil fuel. It offers an energy density comparable to petrol and diesel fuels, and produces less pollution. LNG is about 0.2% of the volume of natural gas at standard temperature and pressure, thus making it more economical to transport over long distances. The refrigeration and liquefaction are the key sections of the LNG plant, which typically account for 30-40% of the capital cost of the overall plant (Shukri, 2004). There are several licensed processes available for LNG, but most fall into either a cascade refrigeration or mixed refrigerant scheme. 

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