Disclosed is a liquefied natural gas production train, comprising at least one integrated process unit having a structural frame forming multiple process equipment floors. The at least one integrated process unit extends in vertical direction, wherein a height of the at least one integrated process unit is substantially equal to or larger than a width and a length of the at least one integrated process unit. The disclosure also provides a method of producing liquefied natural gas, using the LNG production train.

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is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a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 Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the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.

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 BOG reliquefaction system includes: a compressor; a heat exchanger cooling the BOG compressed by the compressor through heat exchange using BOG not compressed by the compressor; a pressure reducer disposed downstream of the heat exchanger and reducing a pressure of fluid cooled by the heat exchanger; and a combination of a first temperature sensor disposed upstream of a cold fluid channel of the heat exchanger and a fourth temperature sensor disposed downstream of a hot fluid channel of the heat exchanger, combination of a second temperature sensor disposed downstream of the cold fluid channel of the heat exchanger and a third temperature sensor disposed upstream of the hot fluid channel of the heat exchanger, or combination of a first pressure sensor disposed upstream of the hot fluid channel of the heat exchanger and a second pressure sensor disposed downstream of the hot fluid channel of the heat exchanger.

There is provided a system and method for producing liquefied natural gas (LNG). An exemplary method includes flowing a high-pressure stream of LNG through a first series of liquid turbines. The exemplary method also includes generating electricity by reducing the pressure of the high-pressure stream of LNG to form a low-pressure stream of LNG. The exemplary method additionally includes bypassing any one the liquid turbines that has a failure while continuing to produce electricity from the first series.

Disclosed is a BOG reliquefaction system. The BOG reliquefaction system includes: a compressor compressing BOG; a heat exchanger cooling the BOG compressed by the compressor through heat exchange using BOG not compressed by the compressor as a refrigerant; a pressure reducer disposed downstream of the heat exchanger and reducing a pressure of fluid cooled by the heat exchanger; and a second oil filter disposed downstream of the pressure reducer, wherein the compressor includes at least one oil-lubrication type cylinder and the second oil filter is a cryogenic oil filter.

Disclosed is a boil-off gas reliquefaction system for vessels. The BOG reliquefaction system for vessels includes: a multistage compressor compressing BOG; a heat exchanger cooling the BOG compressed by the multistage compressor through heat exchange using BOG not compressed by the multistage compressor as a refrigerant; a pressure reducer disposed downstream of the heat exchanger and decompressing a fluid cooled by the heat exchanger; and a bypass line through which BOG is supplied to the multistage compressor after bypassing the heat exchanger.

Systems and methods for operating a natural gas liquids (NGL) plant can include obtaining upstream flow volumes, input flows, and operating conditions of a refinery complex including the NGL plant for a first time period and a second time period. One or more features can be extracted from the upstream flow volumes, input flows, and operating conditions for multiple first time periods and used to form multiple feature vectors. A machine learning model trained with labeled data (e.g., labeled data associating upstream flow volumes, input flows, and operating conditions with incoming feed gas volumes) representing incoming feed gas of the NGL can be used to process the feature vectors to determine predicted incoming feed gas volumes.

There is provided a system and method for producing liquefied natural gas (LNG). An exemplary method includes flowing a high-pressure stream of LNG through a first series of liquid turbines. The exemplary method also includes generating electricity by reducing the pressure of the high-pressure stream of LNG to form a low-pressure stream of LNG. The exemplary method additionally includes bypassing any one the liquid turbines that has a failure while continuing to produce electricity from the first series.

A method of cooling a boil-off gas (BOG) stream from a liquefied gas tank comprising at least the step of heat exchanging the BOG stream with a first refrigerant in a heat exchanger, the heat exchanger having an entry port and a warmer exit port, and comprising at least the steps of: (a) passing the first refrigerant into the entry port of the heat exchanger and into a first zone of the heat exchanger to exchange heat with the BOG stream, to provide a first warmer refrigerant stream; (b) withdrawing the first warmer refrigerant stream from the heat exchanger at an intermediate exit port between the entry port and the warmer exit port; (c) admixing the first warmer refrigerant stream with an oil-containing refrigerant stream to provide a combined refrigerant stream; (d) passing the combined refrigerant stream into the heat exchanger through an entry port located in a second zone of the heat exchanger that is warmer than the first zone; (e) passing the combined refrigerant stream out of the heat exchanger through the warmer exit port. The present invention is a modification of a refrigerant cycle for BOG cooling, and LNG re-liquefaction in particular, that allows the use of a cost-efficient oil-injected screw compressor in the refrigerant system. The present invention is also able to accommodate the possibility of different flows or flow rates of the first refrigerant stream and the oil-containing refrigerant stream, such that there is reduced or no concern by the user of the process in relation to possible oil freezing and clogging of the heat exchanger caused by variation of the flow or flow rate of the oil-containing refrigerant stream.