Exergetic analysis of LNG regasification techniques

UDC 62-623.1, 62-68, 661.91-404, 665.6/.7

Exergetic analysis of LNG regasification techniques

FALMAN A. G., Ageysky D. E.

LNG regasification facilities are abundant in natural gas consuming countries. Energy efficiency enhancement of these facilities is a crucial task. Most of the previously built facilities do not use cold of LNG for by-production, whereas there are several modern techniques allowing energy and some other by-products to be produced along with regasification. The article estimates energy efficiency characteristics of several regasification techniques. Models describing regasification systems using Rankine and/or Brayton cycles, air and gas separation are studied. Regasification systems are compared by such energy efficiency characteristics as exergy efficiency, specific lost work, specific fuel consumption, overall energy efficiency etc. The use of Brayton cycle allows increasing exergetic efficiency of regasification to 51% that is almost by 4.5% more than for organic Rankin cycle (with fluoroform). Specific fuel consumption increases also as its combustion energy goes for working medium heating to produce more energy. Specific additional energy consumption reduces by 20 kW h/t compared with the use of coil. That makes it applicable for small regasification units. However, for big regasification facilities combination of regasification with с LNG fractionation or air separation seems to be the most useful.

Keywords: liquid natural gas (LNG), regasification, Rankine cycle, Brayton cycle, air separation, exergy analysis, energy efficiency

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