LNG imports to the U.S. are projected to increase significantly in the near future. Whilesecuring LNG supply through long-term contracts will continue, acquiring spot LNG cargoes fromseveral foreign producers will also rise in popularity. Consequently, a receiving terminal in the U.S. isexpected to see batches of imported LNG with wide compositional variations.Presently a significant part of the LNG produced worldwide has higher heating value than theU.S. market demands. It will be the responsibility of a receiving terminal owner to assure the re-gasifiedLNG meets “gas interchangeability”. KBR is active in assisting terminal owners through thefollowing three general approaches:? removing heavier components? diluting with inert gases or? a combination of above approachesThe practice of removing heavier components is the ultimate solution, but its economicattractiveness depends also on exterior premises, such as identifying buyers for the extracted products.In contrast, injecting inert gas is a straightforward solution. The combined practice is to extract someheavy components for a specific market, and dilute the remaining gas with an inert.This paper addresses the impact of nitrogen injection on LNG heating values based on themaximum nitrogen content acceptable to pipelines. The pros and cons of five nitrogen injectionschemes are detailed, which range from simple gaseous pipeline injection to the dual practice ofgaseous and liquid nitrogen injections. It is concluded that introducing gaseous nitrogen through therecondenser requires the least compression horsepower and is the least costly approach.
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