An LNG production plant is constructed from a plurality of containerised LNG liquefaction units. Each containerised LNG liquefaction unit can produce a predetermined quantity of LNG. For example, up to 0.3 MPTA. A manifold system enables connection between the plurality of containerised LNG liquefaction units, and at least a feed stream of natural gas, a source of electrical power, and an LNG storage facility. The production capacity of the plant is incrementally changed by connecting or disconnecting containerised LNG liquefaction units to or from the plant via the manifold system. Each unit contains its own liquefaction plant having a closed loop SMR circuit. Refrigerant within the SMR circuit is circulated solely by pressure differential generated by refrigerant compressors in the liquefaction plant.

An LNG production system including a boil off gas recondenser that can recondense boil off gas without using a BOG compressor and without depending on an LNG liquefaction process is provided.

A method of recycling liquefied natural gas (LNG) boil-off gas (BOG) in natural gas liquefaction plants can include: supplying a feed gas to a liquefaction subsystem; liquefying the feed gas to produce LNG and end-flash gas (EFG); compressing the EFG to compressed EFG; using the compressed EFG as fuel gas; storing the LNG in one or more LNG tanks; compressing LNG BOG from the one or more LNG tanks to produce compressed LNG BOG; and either (1) operating in a recycle mode by supplying at least a portion of the compressed LNG BOG to the feed gas via a bidirectional line, or (2) operating in a fuel mode by (a) supplying a portion of the feed gas to the fuel gas via the bidirectional line and (b) supplying the compressed LNG BOG to the fuel gas.

A method for start-up of a liquefied natural gas (LNG) plant, the plant including a liquefaction unit arranged in a flow path of the plant, including removing LNG from a first location in the flow path downstream of the liquefaction unit; vaporizing the removed LNG, or heating the removed LNG so that the removed LNG is transformed to gas phase; and re-admitting the vaporized or transformed LNG to the flow path at a second location upstream of the liquefaction unit. A corresponding LNG plant is also provided.

A power supply and cooling system for a floating structure having a tank, includes a supply circuit having at least one compression device, the supply circuit being configured to supply gas to a gas-consuming device, and a cooling circuit having a heat exchanger configured to participate in managing the internal pressure of the tank, the cooling circuit being connected to the supply circuit on either side of the compression device. The compression device includes two compression stages, and the power supply and cooling system includes a control device configured to connect the compression stages in series or in parallel.

A liquefaction apparatus that automatically adjusts the load on the liquefaction apparatus correspondingly with an upper limit value of contracted power in different time slots, and which is capable of maximizing the amount of liquefied product produced and of achieving optimum operating efficiency is provided. In certain embodiments, the liquefaction apparatus can include: a production amount calculation unit 91 for obtaining an actual production amount of a liquefied product; a predicted power calculation unit 92 for obtaining a predicted power amount after a predetermined time has elapsed, on the basis of an integrated power value obtained by integrating a usage power; and a power demand control unit 93 for comparing the predicted power amount and a moving average of instantaneous power, and controlling a discharge flow rate of a compressor 3 in such a way as to come infinitely close to a target value, without exceeding the target value, and while using the larger value of the predicted power amount and the moving average of instantaneous power as a value being controlled.

A method for supplying gas to a gas-consuming apparatus provided on a ship including a tank containing the gas in the liquid state and in the gaseous state, in which the method includes: supplying the gas-consuming apparatus with gas withdrawn in the gaseous state from the tank and by a supply unit; condensing at least a part of the gas withdrawn in the gaseous state from the tank by a condensation unit having at least one heat exchanger configured to perform a heat exchange between gas withdrawn between the supply unit and the gas-consuming apparatus and gas flowing between the tank and the supply unit; and cooling the heat exchanger prior to the condensing and at least partially simultaneously with the supplying.

A system and method for cooling an oxygen stream by heat exchange with a warming supply nitrogen stream having of a heat exchanger having at least a Zone A and a Zone B, the system having indirect heat exchange between a gaseous oxygen stream, and a high-pressure liquid nitrogen stream split into at least a first portion which passes through a Zone A, and a second portion which passes through a Zone B during a first phase of operation. And a high-pressure liquid nitrogen stream passing through Zone A, thereby producing a high-pressure nitrogen vapor stream, which passes through an expansion turbine, thereby producing an expansion turbine outlet stream which then passes through Zone B, during a second phase of operation, thereby producing a liquid oxygen stream.

The present techniques are directed to a flexible liquefied natural gas (LNG) plant that may be tied to an external electric grid for importing or exporting electric power. Exemplary embodiments provide a method for producing LNG that includes producing a base load capacity of refrigeration capacity for LNG production from a first compression system. Electricity may be produced from a second compressor string if electricity is needed by an external power grid, or a second amount of refrigeration capacity may be provided by the second compressor string is natural gas feed is available and the external grid does not need power.

A gas processing system according to an embodiment of the present invention includes a heater which is configured to increase a temperature of liquefied gas compulsorily vaporized by a forcing vaporizer before the liquefied gas is joined with Boil Off Gas (BOG) compressed by a BOG compressor.