A method for enhancing a LNG production train that includes connected train components. The method may include steps of: constructing an integrated surveillance system for monitoring operation of the train components; using the integrated surveillance system to measure and record operational data and event data related to, respectively, the operation and a failure event of the train components over a historical operating period; performing a correlation analysis that calculates a correlation between the occurrences of the failure event and the operational data; given results of the correlation analysis, deriving a prognostic rule that indicates a likelihood of the failure event occurring based on values of the operating parameters of the operational data; applying the prognostic rule to current values of the operating parameters and determining therefrom the likelihood of the failure event occurring; determining an advisory related to the determined likelihood of the failure event occurring; and issuing the advisory.

A drive system for liquefied natural gas (LNG) refrigeration compressors in a LNG liquefaction plant. Each of three refrigeration compression strings include refrigeration compressors and a multi-shaft gas turbine capable of non-synchronous operation. The multi-shaft gas turbine is operationally connected to the refrigeration compressors and is configured to drive the one or more refrigeration compressors. The multi-shaft gas turbine uses its inherent speed turndown range to start the one or more refrigeration compressors from rest, bring the one or more refrigeration compressors up to an operating rotational speed, and adjust compressor operating points to maximize efficiency of the one or more refrigeration compressors, without assistance from electrical motors with drive-through capability and variable frequency drives.

The invention relates to a control system which comprises: a plurality of flow valves on channels of reaction fluid, which are i) in a closed position or ii) in an open position; a plurality of control pipes connected to a source of control fluid and to a respective control pipe, all or part of the flow valves switching to the closed position when the pressure of the control fluid in the control pipe drops below a predetermined threshold; a discharge pipe connected to the control pipes, in order to discharge the control fluid from the control pipes; a safety device connected i) to each control pipe and ii) to the discharge pipe and configured to have, selectively: i) a service configuration, wherein the control fluid flows to each control pipe, thus opening each flow valve, and ii) a safety configuration, wherein the control fluid is discharged through the discharge pipe, thus closing each flow valve.

Disclosed herein is a boil-off gas reliquefaction apparatus. The boil-off gas reliquefaction apparatus includes: a plurality of compressors arranged in parallel to compress boil-off gas discharged from a storage tank; a reliquefaction unit reliquefying the boil-off gas compressed by each of the plurality of compressors; and a plurality of supply lines providing a path through which the boil-off gas is supplied from the plurality of compressors to the reliquefaction unit and a path through which the boil-off gas flows in the reliquefaction unit, wherein the plurality of supply lines is arranged independently of one another without being joined together.

Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.

The invention relates to an installation for producing liquefied gas comprising a circuit for supplying feed gas, a set of heat exchangers, a refrigerator for cooling some or all of the set of heat exchangers, the supply circuit comprising, between the set of heat exchangers and the downstream end thereof, a final expansion turbine for expanding the feed gas in liquid state, the supply circuit comprising a bypass line of the final expansion turbine fitted with a first expansion valve, a second expansion valve disposed in series upstream or downstream of the first expansion valve and of the final expansion turbine, an additional heat exchange line designed to exchange heat with a heat exchanger of the set of heat exchangers when the feed gas is expanded by the first expansion valve via the bypass line, the additional heat exchange line carrying out this heat exchange with said heat exchanger between the expansion carried out by the first expansion valve and the expansion carried out by the second expansion valve, the additional heat exchange line being located upstream or respectively downstream of the expansion carried out by the first expansion valve.

A process for liquefying and subcooling a hydrocarbon-rich fraction, particularly natural gas, is described wherein, once cooled down, the fraction is subjected to a partial condensation to remove heavy hydrocarbons, particularly benzene, by the steps of: a) the liquefied hydrocarbon-rich fraction is subcooled in a separate heat exchanger (normal mode), b) the supply of the liquefied hydrocarbon-rich fraction to the heat exchanger is interrupted at the latest when a defined solid deposition value in the heat exchanger is reached (cleaning mode), c) the solid in the heat exchanger is melted with a defrost gas and drawn off from the heat exchanger and d) the liquefied hydrocarbon-rich fraction is subsequently returned to the heat exchanger.

A fluid is liquefied from a gaseous state to a liquid state, and the liquefied fluid is stored. In one embodiment, the fluid is oxygen. Mechanisms are employed that enhance the durability, longevity, reliability, efficiency, of a system used to liquefy the fluid.

A method for producing liquefied natural gas (LNG). A natural gas stream is directed to a mechanical refrigeration unit to liquefy the natural gas stream and form a pressurized liquefied natural gas (LNG) stream with a pressure greater than 50 psia (345 kPa) and less than 500 psia (3445 kPa). A liquid refrigerant subcooling unit is provided at a first location. Liquid refrigerant is produced at a second location that is geographically separate from the first location. The produced liquid refrigerant is transported to the first location. The pressurized LNG stream is subcooled in the liquid refrigerant subcooling unit by exchanging heat between the pressurized LNG stream and at least one stream of the liquid refrigerant to thereby produce an LNG stream.

A system for the processing of a hydrocarbon flare gas. An input gas stream contains a gas component and a liquid component. A knock-out drum separates the gas component from the liquid component. An eductor has a motive inlet, a suction inlet, and a discharge outlet. The separated liquid component is introduced into the suction inlet of the eductor. A high-pressure gas stream is introduced into the motive inlet of the eductor. The high-pressure gas stream has a pressure sufficient to draw the separated liquid component from the knock-out drum and through the discharge outlet.