Gas processing plants and methods are contemplated in CO.sub.2 is effectively removed to very low levels from a feed gas to an NRU unit by adding a physical solvent unit that uses waste nitrogen produced by the NRU as stripping gas to produce an ultra-lean solvent, which is then used to treat the feed gas to the NRU unit. Most preferably, the physical solvent unit includes a flash unit and stripper column to produce the ultra-lean solvent.

The method is carried out for continuously producing a liquefied methane gas (LMG) from a pressurized mixed methane gas feed stream. It is particularly well adapted for use in relatively small LMG distributed production plant, for instance those ranging from 400 to 15,000 MT per year, and/or when the mixed methane gas feed stream has a wide range of nitrogen-content proportions, including nitrogen being substantially absent. The proposed concept can also be very useful in the design of medium-scale and/or large-size plants, including ones where the nitrogen content always remains above a certain threshold. The methods and arrangements proposed herein can mitigate losses of methane gas when venting nitrogen, for instance in the atmosphere.

The present techniques are directed to a system and method for generating power and producing liquefied natural gas (LNG). The system includes a power plant configured to generate power, wherein an exhaust gas from the power plant provides a gas mixture including nitrogen and carbon dioxide. The system also includes a dehydration system configured to dehydrate the gas mixture to generate a nitrogen refrigerant stream and a refrigeration system configured to produce LNG from a natural gas stream using the nitrogen refrigerant stream.

The system is provided for generating a mixed methane gas feed stream using at least one source of biogas and an alternate source of methane gas. The system includes a biogas subsystem, a control device for the methane gas from the at least one alternate source of methane gas, and a vertically-extending gas mixing vessel. A method of controlling a methane gas mass flow rate of a mixed methane gas feed stream is also disclosed. The proposed concept is particularly well adapted for situations where an uninterrupted and relatively constant input of methane gas is required to ensure an optimum operation of, for instance, a LMG production plant.

A transportable apparatus for production of liquefied natural gas (LNG) having include a housing, a natural gas feed inlet, a heat exchanger, a phase separator, a liquid outlet disposed on the cold end of the heat exchanger, an LNG product outlet disposed on the cold end of the heat exchanger, a first refrigeration supply, a second refrigeration supply, and wherein the heat exchanger, the phase separator, the first expansion valve, the first refrigeration supply, and the second refrigeration supply are all disposed within the housing. The first refrigeration supply includes expansion of a portion of the LNG product, and the second refrigeration supply can include expansion of another portion of the LNG product or expansion and heat exchange with a supply of liquid nitrogen. The production of LNG is achieved without the external supply of electricity.

A method for the production of liquefied natural gas (LNG) without the use of externally provided electricity is provided The method may include the steps of: providing a transportable apparatus, wherein the transportable apparatus comprises a housing, a heat exchanger, a phase separator, a first refrigeration supply, and a second refrigeration supply, wherein the first refrigeration supply and the second refrigeration supply are configured to provide refrigeration within the heat exchanger; introducing a natural gas stream into the transportable apparatus at a first pressure under conditions effective for producing an LNG stream; withdrawing the LNG stream from the transportable apparatus; and withdrawing a warm natural gas stream from the transportable apparatus, wherein the warm natural gas stream is at a second pressure, wherein the second pressure is lower than the first pressure.

A method includes receiving input corresponding to a proposed configuration of a liquefaction facility and identifying a plurality of components utilized to produce LNG and/or LIN at the facility. The method includes determining an alternative configuration that is different from the proposed configuration. Determining the alternative configuration may include identifying resources accessible to a proposed location for the liquefaction facility and whether at least one of the resources accessible to the proposed location corresponds to a resource generated by a component identified by the proposed configuration, and determining whether to omit at least one component of the plurality of components identified by the proposed configuration. The method includes omitting the at least one component from the alternative configuration, and generating a report based on the proposed configuration and the alternative configuration. The report includes information indicating a difference between the proposed configuration and the alternative configuration.

A method for the production of liquefied natural gas is provided. The method may include providing a high pressure natural gas stream, splitting the high pressure natural gas stream into a first portion and a second portion, and liquefying the first portion of the high pressure natural gas stream to produce an LNG stream. The refrigeration needed for cooling and liquefaction of the natural gas can be provided by a closed nitrogen refrigeration cycle and letdown of the second portion of the high pressure natural gas stream.

A method for the production of liquefied natural gas and liquid nitrogen is provided. The method may include providing a high pressure natural gas stream, splitting the high pressure natural gas stream into a first portion and a second portion, and liquefying the first portion of the high pressure natural gas stream to produce an LNG stream. The refrigeration needed for cooling and liquefaction of the natural gas and liquefaction of the nitrogen can be provided by a nitrogen refrigeration cycle and letdown of the second portion of the high pressure natural gas stream.

A method for the production of liquefied natural gas (LNG) and nitrogen is provided. The method may include the steps of: a) providing a nitrogen production facility, wherein nitrogen production facility comprises: a main heat exchanger, an air separation unit, a nitrogen recycle compressor, a first nitrogen refrigeration supply configured to provide refrigeration to the main heat exchanger for cooling a main air feed, b) providing a secondary refrigeration supply; c) liquefying a natural gas stream using refrigeration from the secondary refrigeration supply to form an LNG product stream; wherein the secondary refrigeration supply is configured to compress and expand a refrigerant to produce refrigeration, wherein the refrigerant of the secondary refrigeration supply is shared with refrigerant of the first nitrogen refrigeration supply