Device for producing and distributing nitrogen, in particular for liquefied gas carrier

Abstract

The invention discloses a device (410) for producing and distributing nitrogen, in particular for a liquefied gas carrier, comprising: nitrogen generators (412) each comprising an air inlet (412a) anda nitrogen outlet (412b), at least one of these generators (412) comprising a compressor (426) comprising an air compression rotor, and a buffer tank (414) for storing nitrogen, characterized in thatit comprises at least one system (464) for varying the frequency or speed of the rotor of said at least one compressor generator, and in that it further comprises main means (416b) for distributing nitrogen leaving said at least one compressor generator, without passing through said buffer tank, for supplying nitrogen to at least two different consumers (418, 420, 422).

Description

technical field [0001] The present invention relates to a device and method for producing and distributing nitrogen, especially for liquid gas transport ships. Background technique [0002] Ships for the transport of liquefied gases, such as liquid natural gas, are usually equipped with devices for generating and distributing nitrogen, which can be used by several consumers. [0003] In the present application, a "consumer", in particular a consumer of nitrogen, means a system which is operated with nitrogen or which is designed to be supplied with nitrogen. [0004] For example, transport ships are equipped with three types of nitrogen consumers. [0005] A first type (Type I) of nitrogen consumers comprises means for supplying nitrogen to a seal, for example a seal of a bearing of a marine compressor. Compressors for ships, for example for pumping boil-off gases, are equipped with plain bearings for guiding rotating parts. These bearings are housed in housings whose lab...

AI Technical Summary

Problems solved by technology

[0014] However, this technique has disadvantages

[0015] As mentioned earlier, the consumption curve of the type I consumer is stable and constant, not suitable for the buffer tank and nitrogen generator cycle operation

[0016] This operation imposes a large number of start and stop operating cycles on the generator (approximately 2000 per year for ships), which shortens the lifetime of the generator and requires frequent maintenance operations

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