A method for large-scale, air-cooled floating liquefaction, storage and offloading of natural gas gathered from onshore gas pipeline networks. Gas gathered from on-shore pipeline quality gas sources and pre-treated to remove unwanted compounds is compressed and cooled onshore before being piped to an offshore vessel for liquefaction to produce LNG.

A booster system includes: a cooling temperature regulating unit configured to regulate a temperature of an intermediate supercritical pressure liquid cooled and generated by a main cooling unit on upstream of a pump unit according to a flow rate of a supplied cooling medium; and a pressure detection unit configured to detect inlet pressure of the intermediate supercritical pressure liquid on an inlet side of the pump unit and detect outlet pressure of a target supercritical fluid on an outlet side of the pump unit. The cooling temperature regulating unit controls the flow rate of the cooling medium based on a pressure difference between the inlet pressure and the outlet pressure or a pressure ratio between the inlet pressure and the outlet pressure.

A thermodynamic system containing a working fluid is disclosed. The thermodynamic system comprises at least a working fluid collection vessel (11) adapted to contain a liquid phase and a gaseous phase of the working fluid in thermodynamic equilibrium. A chilling arrangement (51) is functionally coupled to the fluid collection vessel (11) and adapted to remove heat from the working fluid collected in the working fluid collection vessel (11) and thereby reduce pressure in said thermodynamic system. Also disclosed are methods for depressurizing a thermodynamic system containing a working fluid in liquid/gas equilibrium.

A split mixed refrigerant (MR) natural gas liquefication system, where low-pressure (LP) and medium pressure (MP) MR compressors are driven by a first gas turbine and a propane compressor and a high-pressure (HP) MR compressor is driven by a second gas turbine, is disclosed. The split MR liquefication system is configured to adjust the characteristics of the HP MR compressor to require less power when less power is available and more power when more power is available compared to the system's design point. Such adjustments allow for shifting the balance of power between the propane compressor and the HP MR compressor to improve LNG production efficiency.

A fluid cooling apparatus capable of improving liquefaction efficiency of a fluid by appropriately cooling the fluid in various temperature ranges through a simple process. The fluid cooling apparatus includes an expansion unit including a plurality of expanders, which receive refrigerants through a plurality of paths to expand the refrigerants and discharge the expanded refrigerants having different temperatures, a heat exchanger receiving the refrigerants having different temperatures from the expansion unit to cool the fluid in multistages, a precompression unit including a plurality of precompressors, which receive the refrigerants passing through the heat exchanger to compress the refrigerants and discharge the compressed refrigerants at the same pressure, a mixing tube configured to mix the refrigerants discharged from the precompression unit to supply the mixed refrigerant, and a main compression unit connected to the mixing tube to compress the mixed refrigerant and supply the compressed refrigerant to the expansion unit.

A refrigerant management system controls the supply of refrigerant from two or more variable speed and fixed speed compressors to a plurality of cryogenic refrigerators. The system employs a plurality of sensors to monitor and regulate the overall refrigerant supply to deliver an appropriate refrigerant supply to each of the cryogenic refrigerators. The amount of refrigerant to supply is based on an aggregate demand for refrigerant from the plurality of cryogenic refrigerators and a refrigerant correction metric. An appropriate supply of refrigerant is distributed to each cryogenic refrigerator by adjusting the speed of the variable speed compressors or, alternatively, selectively turning the compressors on or off. The speed of the variable speed compressors is adjusted by determining an amount of refrigerant to supply to the plurality of cryogenic refrigerators. If the aggregate demand for refrigerant exceeds the capacity of the compressors, then the speed of a refrigerator within the plurality of refrigerators is adjusted.

An inlet air cooling system used in a gas turbine for supplying power to a refrigerant compressor for compressing refrigerant in a natural gas liquefaction plant includes: an inlet air cooler for cooling inlet air of the gas turbine; chiller motors used for a chiller for cooling coolant supplied to the inlet air cooler; a first variable speed driver for supplying electric power to each of the one or more chiller motors; and an electric generator driven by the gas turbine, wherein the electric generator is electrically connected to the first variable speed driver, and electric power generated by the electric generator can be supplied to each of the chiller motors from the first variable speed driver without using a main power line of an electric power system, which enables efficient electric power supply to the motors via the variable speed driver.

A liquefied gas treatment system according to an embodiment of the present invention includes a boil-off gas heat exchanger exchanging heat between boil-off gas, pressurized by a boil-off gas compressor and recovered along a boil-off gas supply line branching off upstream of a liquefied gas-consuming unit, and the boil-off gas supplied from a liquefied gas storage tank, wherein the boil-off gas heat exchanger cools the boil-off gas, recovered along the boil-off gas supply line, with the boil-off gas, supplied from the liquefied gas storage tank, or flash gas, supplied through a vapor recovery line.

A system and method for cooling a gas using a mixed refrigerant includes a compressor system and a heat exchange system, where the compressor system may include an interstage separation device or drum with no liquid outlet, a liquid outlet in fluid communication with a pump that pumps liquid forward to a high pressure separation device or a liquid outlet through which liquid flows to the heat exchanger to be subcooled. In the last situation, the subcooled liquid is expanded and combined with an expanded cold temperature stream, which is a cooled and expanded stream from the vapor side of a cold vapor separation device, and subcooled and expanded streams from liquid sides of the high pressure separation device and the cold vapor separation device, or combined with a stream formed from the subcooled streams from the liquid sides of the high pressure separation device and the cold vapor separation device after mixing and expansion, to form a primary refrigeration stream.

A system and method for cooling a gas using a mixed refrigerant includes a compressor system and a heat exchange system, where the compressor system may include an interstage separation device or drum with no liquid outlet, a liquid outlet in fluid communication with a pump that pumps liquid forward to a high pressure separation device or a liquid outlet through which liquid flows to the heat exchanger to be subcooled. In the last situation, the subcooled liquid is expanded and combined with an expanded cold temperature stream, which is a cooled and expanded stream from the vapor side of a cold vapor separation device, and subcooled and expanded streams from liquid sides of the high pressure separation device and the cold vapor separation device, or combined with a stream formed from the subcooled streams from the liquid sides of the high pressure separation device and the cold vapor separation device after mixing and expansion, to form a primary refrigeration stream.