Provided is a natural gas liquefaction apparatus including: a cryogenic heat exchanger through which natural gas passes through and is liquefied into liquefied natural gas (LNG) through heat exchange with a first refrigerant and a second refrigerant; a first refrigerant cycle through which the first refrigerant circulates, which has some paths passing through the cryogenic heat exchanger to perform heat exchange, and which has a path of the first refrigerant divided into a plurality of paths after performing heat exchange at the cryogenic heat exchanger and performs expansion and pre-compression of the first refrigerant; and a second refrigerant cycle through which the second refrigerant circulates and which has some paths passing though the cryogenic heat exchanger.

A cold energy recovery facility includes a liquid hydrogen tank configured to store liquid hydrogen a first circuit configured to circulate a first working medium, a second circuit configured to circulate a second working medium having a freezing point higher than the first working medium, a first turboexpander provided in the first circuit, the first turboexpander being configured to be driven by the first working medium in a gas state, a second turboexpander provided in the second circuit, the second turboexpander being configured to be driven by the second working medium in a gas state, a first heat exchanger configured to vaporize the liquid hydrogen from the liquid hydrogen tank by heat exchange with the first working medium, a second heat exchanger configured to vaporize the first working medium in a liquid state by heat exchange with the second working medium, and a third heat exchanger configured to vaporize the second working medium in a liquid state by heat exchange with a heat medium, wherein the first circuit and the first turboexpander form a part of a first thermodynamic cycle that uses the liquid hydrogen as a low-temperature heat source in the first heat exchanger, and the second circuit and the second turboexpander form a part of a second thermodynamic cycle that uses the first working medium as a low-temperature heat source in the second heat exchanger.

Embodiments relate generally to systems and methods for pre-cooling a natural gas stream to a liquefaction plant. A system may include 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 to produce a chilled natural gas stream from the second pressure to a third pressure.

An LNG liquefaction plant system, wherein the refrigeration content of the external or internal refrigerant is used to liquefy and sub-cool a natural gas stream to produce liquefied natural gas (LNG) in a cold box or cryogenic exchanger. The refrigerant may be an external gas (N.sub.2) or an internal (CH.sub.4—BOG) refrigerant working fluid expanded and compressed in a twin compander arrangement and compressed by a refrigerant compressor, or an external single mixed refrigerant (SMR) working fluid compressed by a refrigerant compressor and expanded thru a JT valve.

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 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.

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.

An LNG plant comprises a cold box and a refrigeration unit fluidly coupled with a plurality of heat exchanger passes in the cold box. The refrigeration unit is configured to provide a first refrigerant stream to a first heat exchanger pass of the plurality of heat exchanger passes at a first pressure, a second refrigerant stream to a second heat exchanger pass at a second pressure, and a third refrigerant stream to a third heat exchanger pass at a third pressure. The second refrigerant stream comprises a first portion of the first refrigerant stream, and the third refrigerant stream comprises a second portion of the first refrigerant stream. The second pressure and the third pressure are both below the first pressure. The cold box is configured to produce LNG from a natural gas feed stream to the cold box using a refrigeration content from the refrigeration unit.

A cryogenic refrigeration system and a corresponding method for increasing the cooling efficiency of the system, preferably the cooling of a thermally coupled load. Accordingly, the system comprises a supply means for providing a supply flow of a cryogenic refrigerant, a compressor fluidly coupled to said supply means and configured to compress the supplied cryogenic refrigerant, and a cold box fluidly coupled to the compressor, said cold box comprising a first expansion device and a first heat exchanger, wherein the first expansion device is configured to receive the compressed cryogenic refrigerant from the compressor and expand it and provide the expanded refrigerant to the first heat exchanger, and wherein the first heat exchanger is configured to be thermally coupled to a load. The system furthermore comprises a second heat exchanger arranged in the cold box comprising at least a first and second heat exchanging section.

A process for liquefying hydrogen gas including the following is disclosed: cooling the hydrogen gas to an intermediate temperature by heat exchange with a refrigerant circulating in a refrigeration loop provided with a higher temperature expander and a lower temperature expander, wherein the outlet stream from the lower temperature expander contains some condensed refrigerant; a means is provided of separating the condensate from the circulating refrigerant; and further cooling of the hydrogen gas by heat exchange with evaporation and reheating of the said condensate.

The fluid in the refrigeration loop is typically methane (such as natural gas after removal of carbon dioxide, water vapor and other impurities), or nitrogen, or a mixture thereof.