A method for producing liquid nitrogen using a residual gas stream derived from a flue gas of a power plant is provided. The residual gas stream is purified in a front-end purification unit to remove freezable components and then the purified stream is compressed. Following compression, the stream can be divided into a first portion and a second portion, wherein the first portion is cooled and sent to a distillation column, wherein oxygen and argon are separated, thereby leaving an essentially pure gaseous nitrogen stream. The gaseous nitrogen stream can then be liquefied using refrigeration provided by expanding the second portion of the purified stream. In a preferred embodiment, the second portion is expanded in two turbines, and the gaseous nitrogen is compressed in a cold nitrogen booster, which is powered by one of the two turbines. In an additional embodiment, after warming, the expanded second portion of the purified stream can be used to regenerate the front-end purification unit.

Method and plant for generating a synthesis gas which consists mainly of carbon monoxide and hydrogen and has been freed of acid gases, proceeding from a hydrocarbonaceous fuel, and air and steam, wherein low-temperature fractionation separates air into an oxygen stream, a tail gas stream and a nitrogen stream, wherein the tail gas stream and the nitrogen stream are at ambient temperature and the nitrogen stream is at elevated pressure, wherein the hydrocarbonaceous fuel, having been mixed with the oxygen stream and steam at elevated temperature and elevated pressure, is converted to a synthesis gas by a method known to those skilled in the art, and wherein acid gas is subsequently separated therefrom by low-temperature absorption in an absorption column, wherein the nitrogen stream generated in the fractionation of air is passed through and simultaneously cooled in an expansion turbine and then used to cool either the absorbent or the coolant circulating in the coolant circuit of the compression refrigeration plant.

A system and method for producing an LNG product stream to provide fuel to generators, as an alternative to diesel, to power drilling and other equipment. Using sales gas from a natural gas/NGL plant containing less than 95% methane as a feed stream, production of LNG having 95% or more methane in quantities of 100,000 GPD or more LNG product are achievable with the system and method. The system and method preferably combine use of strategic heat exchange between the feed and a nitrogen-methane flash vapor stream and other streams within the LNG processing system without requiring heat exchange with process streams in the natural gas/NGL plant and a rectifier column that uses an internal knockback condenser and does not require a reboiler to remove heavier components from the sales gas feed.

A nitrogen liquefier configured to be integrated with an argon and nitrogen producing cryogenic air separation unit and method of nitrogen liquefaction are provided. The integrated nitrogen liquefier and associated methods may be operated in at least three distinct modes including: (i) a nil liquid nitrogen mode; (ii) a low liquid nitrogen mode; and (iii) a high liquid nitrogen mode. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

An integrated industrial unit is provided, which can include: a nitrogen source comprising an air separation unit that is configured to provide pressurized gaseous nitrogen and liquid nitrogen; a hydrogen source; a hydrogen liquefaction unit, wherein the hydrogen liquefaction unit comprises a precooling system, and a liquefaction system; and a liquid hydrogen storage tank, wherein the precooling system is configured to receive the gaseous hydrogen from the hydrogen source and cool the gaseous hydrogen to a temperature between 70K and 100K, wherein the precooling system comprises a primary refrigeration system and a secondary refrigeration system, wherein the liquefaction system is in fluid communication with the precooling system and is configured to liquefy the gaseous hydrogen received from the precooling system to produce liquid hydrogen, wherein the liquid hydrogen storage tank is in fluid communication with the liquefaction system and is configured to store the liquid hydrogen received from the liquefaction system.

A nitrogen liquefier configured to be integrated with an argon and nitrogen producing cryogenic air separation unit and method of nitrogen liquefaction are provided. The integrated nitrogen liquefier and associated methods may be operated in at least three distinct modes including: (i) a nil liquid nitrogen mode; (ii) a low liquid nitrogen mode; and (iii) a high liquid nitrogen mode. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

A nitrogen liquefier configured to be integrated with an argon and nitrogen producing cryogenic air separation unit and method of nitrogen liquefaction are provided. The integrated nitrogen liquefier and associated methods may be operated in at least three distinct modes including: (i) a nil liquid nitrogen mode; (ii) a low liquid nitrogen mode; and (iii) a high liquid nitrogen mode. The present systems and methods are further characterized in an oxygen enriched stream from the lower pressure column of the air separation unit is an oxygen enriched condensing medium used in the argon condenser.

A small to mid-scale liquefied natural gas production system and method is provided. The disclosed liquefied natural gas production system employs a nitrogen-based refrigerant, at least one heat exchanger, three turbine/expanders and two or more refrigerant compression stages. The expansion ratio of one turbine/expander is appreciably lower than the expansion ratio of the other turbine/expanders such that the temperature of the exhaust stream from the turbine/expander with the lower expansion ratio is above the critical point temperature of the compressed natural gas containing feed stream but colder than -15° C.

A method and system for liquefying a natural gas feed stream and removing nitrogen therefrom.

Systems, devices, and methods for recovering mixed refrigerant and/or nitrogen within liquefaction systems are provided. The systems, devices, and methods facilitate recovering mixed refrigerant (MR) and/or nitrogen vapor that can leak from a compressor, separating the MR from the nitrogen, and reusing the MR and/or the nitrogen within the liquefaction system. Recovering and reusing MR and/or nitrogen can minimize loss of MR and nitrogen which can lower the total operating cost of a liquefaction system. Additionally, recovering the MR, rather than burning it, can reduce environmental emissions by reducing the amount of MR that is burned.