A method and apparatus for producing liquefied natural gas. A portion of a natural gas stream is cooled in a first heat exchanger and re-combined with the natural gas stream, and heavy hydrocarbons are removed therefrom to generate a separated natural gas stream and a separator bottom stream. Liquids are separated from the separator bottom stream to form an overhead stream, which is cooled and separated to form a recycle gas stream. The recycle gas stream is compressed. A first portion of the compressed recycle gas stream is directed through the first heat exchanger and directed to the separator as a column reflux stream. The separated to natural gas stream is used as a coolant in the first heat exchanger to thereby generate a pretreated natural gas stream, which is compressed and liquefied.

A ship comprising an engine is disclosed. The ship comprising an engine comprises: a self-heat exchanger which heat-exchanges boil-off gas discharged from a storage tank; a multi-stage compressor which compresses, in multi-stages, boil-off gas that passed through the self-heat exchanger after being discharged from the storage tank; a first decompressing device which expands one portion of boil-off gas that passed through the self-heat exchanger after being compressed by the multi-stage compressor; and a second decompressing device which expands the other portion of the boil-off gas that passed through the self-heat exchanger after being compressed by the multi-stage compressor, wherein the self-heat exchanger uses boil-off gas discharged from the storage tank and boil-off gas expanded by the first decompressing device as refrigerants for cooling boil-off gas compressed by the multi-stage compressor.

Power recovery sub-systems, cryogenic energy storage systems, and methods of capturing, storing, and re-using thermal energy are disclosed.

A device for processing boil-off gas in a liquefied gas regasification system includes a fuel compressor for compressing boil-off gas at a pressured required by a fuel consumer; a high-pressure compressor installed at the rear end of the fuel compressor in series with the fuel compressor so as to compress the low-pressure boil-off gas, which has been compressed by the fuel compressor, at a pressure required by a regasified gas consumer; a low-temperature heat exchanger for cooling the high-pressure boil-off gas compressed by the high-pressure compressor; a pressure-reducing device for reducing the pressure of the high-pressure boil-off gas, which has been cooled by the low-temperature heat exchanger, to the inner pressure of a liquefied gas storage tank for storing the liquefied gas; and a liquefied gas drum for separating flash gas generated by the pressure-reducing device in the pressure-reducing process.

A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gasses put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self produced liquid nitrogen, pump it up to a runnable 420 psig pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.

There is described a method to produce LNG at gas pressure letdown stations. A high pressure gas stream is pre-cooled, dewatered, and then divided into two streams: a diverted LNG production stream (LNG stream) and a gas to end users stream (User stream). Carbon dioxide is removed from the LNG stream and the LNG stream is compressed. The LNG stream is then precooled by passing through one or more heat exchangers. Hydrocarbon condensate is removed from the LNG steam by passing the LNG stream through a first Knock Out drum. The LNG stream is then depressured by passing through a JT valve to depressurize the gas vapour exiting the first Knock Out drum and discharge it into a second Knock Out drum where the LNG is captured.

A system and method for producing an LNG product stream to provide fuel to generators, as an alternative to diesel, to power drilling and other equipment. Using sales gas from a natural gas/NGL plant containing less than 95% methane as a feed stream, production of LNG having 95% or more methane in quantities of 100,000 GPD or more LNG product are achievable with the system and method. The system and method preferably combine use of strategic heat exchange between the feed and a nitrogen-methane flash vapor stream and other streams within the LNG processing system without requiring heat exchange with process streams in the natural gas/NGL plant and a rectifier column that uses an internal knockback condenser and does not require a reboiler to remove heavier components from the sales gas feed.

A vessel comprising an engine comprises: a first self-heat exchanger for heat-exchanging boil-off gas discharged from a storage tank; a multi-stage compressor for compressing, in multi-stages, the boil-off gas, which has passed through the first self-heat exchanger after being discharged from the storage tank; a second self-heat exchanger for precooling the boil-off gas compressed by the multi-stage compressor; a first decompressor for expanding a portion of a fluid which has been cooled by the second self-heat exchanger and the first self-heat exchanger; and a second decompressor for expanding the other portion of the fluid which has been cooled by the second self-heat exchanger and the first self-heat exchanger.

A vessel includes an engine; a first self-heat exchanger for heat-exchanging boil-off gas discharged from a storage tank; a multi-stage compressor for compressing, in multi-stages, the boil-off gas, which has passed through the first self-heat exchanger after being discharged from the storage tank; a first decompressor for expanding a portion of the boil-off gas, which has passed through the first self-heat exchanger after being compressed by the multi-stage compressor; a second decompressor for expanding the other portion of the boil-off gas, which has passed through the first self-heat exchanger after being compressed by the multi-stage compressor; and a second self-heat exchanger for heat-exchanging and cooling the portion of the boil-off gas, which has been compressed by the multi-stage compressor, by using, as a refrigerant, a fluid which has been expanded by the first decompressor.

A data center is cooled by a cryogenic cooling system which is wind driven, and powered by energy stored in the cryogenic liquid. The cooling occurs through downwardly passing cryogenic liquid which is recycled and pushed back to a top of a system in a cyclic manner.