Liquefier arrangements configured for flexible co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) are provided. Each liquefier arrangement comprises separate and independent nitrogen recycle circuits or loops, including a warm recycle circuit and a cold recycle circuit with a means for diverting nitrogen refrigerant between the two recycle circuits or loops. The warm recycle circuit includes a booster loaded warm turbine, a warm booster compressor and warm recycle compression whereas the cold recycle circuit includes a booster loaded cold turbine, a cold booster compressor and a separate cold recycle compression.

Certain embodiments of the invention relate to a facility for refrigerating a fluid to a cryogenic temperature, comprising a circuit for the fluid to be refrigerated, comprising an upstream end connected to a source and a downstream end connected to a refrigerated and/or liquefied fluid collection member, the facility comprising at least one exchanger for precooling the fluid leaving the upstream end, the precooling exchanger exchanging heat with a precooling circuit composed of a flow of vaporization gas from a user, the facility further comprising a heat exchanger assembly for cooling by heat exchange with the circuit of fluid to be cooled downstream of the precooling exchanger, the facility comprising a device for cooling by heat exchange with at least a part of the cooling heat exchanger assembly, said cooling device comprising a first refrigerator with a refrigeration cycle of a cycle gas in a working circuit, the cycle gas preferably comprising hydrogen and/or helium, the working circuit of the first refrigerator comprising a member for compressing the cycle gas, a member for cooling the cycle gas, a member for expanding the cycle gas and a member for heating the cycle gas, the precooling exchanger being composed of at least one of the following materials: stainless steel or grades of stainless steel, Inconel, nickel, titanium or plastic material compatible with use at cryogenic temperatures.

Described herein are systems and processes of removing contaminants in a liquid nitrogen (LIN) stream used to produce liquefied natural gas (LNG). Greenhouse gas contaminants are removed from the LIN using a greenhouse gas removal unit. The LNG is compressed prior to being cooled by the LIN.

A system and method for cooling a liquid cryogenic fluid user with an inert and non-pressurized liquid cryogen in 120K to 200K temperature range is provided. This includes maintaining the first liquid cryogenic fluid within a first predetermined temperature range with the sub-cooler and/or the recirculation pump, maintaining the second liquid cryogenic fluid within a second predetermined temperature range with the heat exchanger, and recondensing the second liquid cryogenic fluid using the pressurized first liquid cryogenic fluid.

A natural gas liquefaction system and method for effectively and efficiently removing heavy hydrocarbons and converting natural gas into liquefied natural gas. Natural gas streams entering the system may consist of varied gas compositions, pressures, and temperatures. In embodiments the system may comprise a natural gas (NG)-to-liquefied natural gas (LNG) portion and a closed-loop refrigeration portion comprising a closed-loop single mixed refrigerant system. In other embodiments the system may comprise an NG-to-LNG portion and a closed-loop refrigeration portion comprising a closed-loop gaseous nitrogen expansion refrigeration system. All embodiments utilize an integrated heat exchanger with cold-end and warm-end sections and integrated multi-stage compressor and expander configurations (e.g. compander) in order to increase overall operation flexibility and efficiency. This optimized method and system is capable of more efficiently producing a liquefied natural gas product at a desired capacity using a minimum amount of equipment and a modularized design to reduce construction costs.

A natural gas liquefaction method and system having integrated nitrogen removal. Recycled LNG gas is cooled in a separate and parallel circuit from the natural gas stream in the main heat exchanger. Cooled recycled gas and natural gas streams are directed to a nitrogen rectifier column after the warm bundle. The recycle stream is introduced to the rectifier column above the natural gas stream and at least one separation stage is located in the rectifier column between the recycle stream inlet and the natural gas inlet. The bottom stream from the rectifier column is directed to a cold bundle of the main heat exchanger where it is subcooled.

A system and method for producing liquefied natural gas (LNG) from a natural gas stream. Each of a plurality of LNG trains liquefies a portion of the natural gas stream to generate a warm LNG stream in a first operating mode, and a cold LNG stream in a second operating mode. A sub-cooling unit is configured to, in the first operating mode, sub-cool the warm LNG streams to thereby generate a combined cold LNG stream. The warm LNG streams have a higher temperature than a temperature of the cold LNG streams in the second operating mode and the combined cold LNG stream. The combined cold LNG stream has, in the first operating mode, a higher flow rate than the flow rate of the cold LNG streams in the second operating mode.

A method for increasing the reliability and availability of a cryogenic fluid reliquefaction system is provided. Wherein the liquid cryogenic fluid is supplied to a cryogenic liquid user in the absence of a pump by elevating the storage height of the main cryogenic storage tank relative to the liquid cryogenic liquid user to a minimum predetermined height. Wherein the temperature of the liquid cryogenic fluid downstream of the sub-cooler is at least 1 degree Celsius above the freezing point of the cryogenic fluid at the internal pressure. The method also includes controlling the internal pressure of the main cryogenic tank by adjusting the recirculation flow to the, and maintaining the cold supply to the liquid cryogenic fluid user when the sub-cooling line is reduced or stopped by venting the vaporized cryogenic fluid.

Liquefier arrangements configured for co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) configured to operate in two distinct operating modes are provided.

Liquefier arrangements configured for co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) configured to operate using direct drive motor/generator arrangement for the warm and/or cold booster compressors and turbines. Alternatively, the use of a conventional generator with a bull gear in lieu of the direct drive motor/generator arrangement on the warm turbine and warm booster compressor coupling is also disclosed.