A hydrocarbon stream, such as natural gas, is commonly cooled together with a first refrigerant stream, against an evaporating refrigerant in a series of one or more consecutively arranged common heat exchangers. The series comprises of one or more consecutively arranged common heat exchangers comprise a first common heat exchanger, upstream of which first common heat exchanger the hydrocarbon stream and the first refrigerant stream are not commonly cooled. The hydrocarbon stream to be cooled is fed into the first common heat exchanger at a hydrocarbon feeding temperature, while the first refrigerant stream is fed into the first common heat exchanger at a refrigerant feeding temperature. The temperature difference between the hydrocarbon feeding temperature and the refrigerant feeding temperature is lower than 60 C.

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.

Methods and systems for removing contaminants, such as water and/or carbon dioxide, from a gas stream, such as a natural gas stream or a flue gas stream. One or more solid-tolerant heat exchangers are employed to chill the gas stream to a temperature at which the contaminants solidify. The solidified contaminants may then be separated and removed from the gas stream. In one or more aspects, the one or more solid-tolerant heat exchangers may include a scraped heat exchanger.

Methods and systems for removing contaminants, such as water and/or carbon dioxide, from a gas stream, such as a natural gas stream or a flue gas stream. One or more solid-tolerant heat exchangers are employed to chill the gas stream to a temperature at which the contaminants solidify. The solidified contaminants may then be separated and removed from the gas stream. In one or more aspects, the one or more solid-tolerant heat exchangers may include a scraped heat exchanger.

Embodiments relate generally to systems and methods for pre-cooling a natural gas stream to a liquefaction plant. A system may comprise a compressor configured to receive a first natural gas stream at a first pressure and produce a second natural gas stream at a second pressure; an exchanger, wherein the exchanger is configured to receive the second natural gas stream as the second pressure and cool the second natural gas stream to produce a cooled natural gas stream; and an expander, wherein the expander is configured to receive the cooled natural gas stream and expand the cooled natural gas stream from the second pressure to a third pressure.

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.

A method for liquefying a feed gas stream. A refrigerant stream is cooled and expanded to produce an expanded, cooled refrigerant stream. Part or all of the expanded, cooled refrigerant stream is mixed with a make-up refrigerant stream in a separator, thereby condensing heavy hydrocarbon components from the make-up refrigerant stream and forming a gaseous expanded, cooled refrigerant stream. The gaseous expanded, cooled refrigerant stream passes through a heat exchanger zone to form a warm refrigerant stream. The feed gas stream is passed through the heat exchanger zone to cool at least part of the feed gas stream by indirect heat exchange with the expanded, cooled refrigerant stream, thereby forming a liquefied gas stream. The warm refrigerant stream is compressed to produce the compressed refrigerant stream.

A method for liquefying a feed gas stream. A compressed first refrigerant stream is cooled and expanded to produce an expanded first refrigerant stream. The feed gas stream is cooled to within a first temperature range by exchanging heat only with the expanded first refrigerant stream to form a liquefied feed gas stream and a warmed first refrigerant stream. A compressed second refrigerant stream is provided is cooled to produce a cooled second refrigerant stream. At least a portion of the cooled second refrigerant stream is further cooled by exchanging heat with the expanded first refrigerant stream, and then is expanded to form an expanded second refrigerant stream. The liquefied feed gas stream is cooled to within a second temperature range by exchanging heat with the expanded second refrigerant stream to form a sub-cooled LNG stream and a first warmed, second refrigerant stream.

A method is disclosed for start-up of a system for liquefying a feed gas stream comprising natural gas. The system has a feed gas compression and expansion loop, and a refrigerant system comprising a primary cooling loop and a sub-cooling loop. The feed gas compression and expansion loop is started up. The refrigerant system is pressurized. Circulation in the primary cooling loop is started and established. Circulation in the sub-cooling loop is started and established. A flow rate of the feed gas stream and circulation rates of the primary cooling loop and the sub-cooling loop are ramped up.

A method for producing liquefied natural gas (LNG). A natural gas stream is transported to a liquefaction vessel. The natural gas stream is liquefied on the liquefaction vessel using at least one heat exchanger that exchanges heat between the natural gas stream and a liquid nitrogen stream to at least partially vaporize the liquefied nitrogen stream, thereby forming a warmed nitrogen gas stream and an at least partially condensed natural gas stream comprising LNG. The liquefaction vessel includes at least one tank that only stores liquid nitrogen and at least one tank that only stores LNG.