The present disclosure provides a method of dehydrating a feed stream processed in a distillation tower. The method may include (a) introducing a feed stream comprising a first contaminant stream into a distillation tower; (b) forming a solid from the feed stream in a controlled freeze zone section of the distillation tower; (c) feeding a second contaminant stream into the feed stream outside the distillation tower; and (d) removing water from the feed stream with a second contaminant stream by feeding the second contaminant stream.

Disclosed are processes, apparatuses, and systems that can be used in natural gas pipelines to significantly reduce the CO2 emissions of the natural gas pipelines, by capturing combusted flue gas which is normally wasted and putting it back to the pipelines, which can also be monetized (e.g., carbon credits). One example process may include producing a captured CO2 stream from a combustion gas of a gas turbine in a natural gas pipeline, compressing the captured CO2 stream, and combining the compressed CO2 stream with natural gas transported in the natural gas pipeline.

Carbon dioxide gas in a high-pressure gas to be treated is stably separated using a separation membrane. Upon separating carbon dioxide gas in a high-pressure gas to be treated using a separation membrane module including a separation membrane, a preliminary boosted gas is supplied to the separation membrane module before the supply of natural gas is started to boost a pressure on a primary side of the separation membrane to a preliminary pressure between a stand-by pressure and an operating pressure. Thus, when the supply of a high-pressure gas to be treated is started to increase the pressure of the separation membrane module to an operating pressure, an abrupt decrease in temperature of the gas to be treated can be suppressed.

The invention relates to a method for membrane permeation of a gas flow including methane and carbon dioxide, wherein said gas flow is cooled to a temperature of 0° C. to −60° C. before being fed into a membrane separation unit.

The present disclosure pertains to materials for CO.sub.2 adsorption at pressures above 1 bar, where the materials include a porous material with a surface area of at least 2,800 m.sup.2/g, and a total pore volume of at least 1.35 cm.sup.3/g, where a majority of pores of the porous material have diameters of less than 2 nm as measured from N.sub.2 sorption isotherms using the BET (Brunauer-Emmett-Teller) method. The present disclosure also pertains to materials for separation of CO.sub.2 from natural gas at partial pressures of either component above 1 bar, where the materials include a porous material with a surface area of at least 2,200 m.sup.2/g, and a total pore volume of at least 1.00 cm.sup.3/g, where a majority of pores of the porous material have diameters of greater than 1 nm and less than 2 nm as measured from N.sub.2 sorption isotherms using the BET method.

A pretreatment system and method for a floating liquid natural gas (“FLNG”) facility are presented. The inlet natural gas stream flows through a membrane system to remove carbon dioxide and a heat exchanger, producing first and second cooled CO.sub.2-depleted non-permeate streams. The first cooled CO.sub.2-depleted non-permeate stream is routed to additional pretreatment equipment, while the second cooled CO.sub.2-depleted non-permeate stream is routed directly to a LNG train. Alternatively, the inlet natural gas stream may flow through a membrane system to produce a single cooled CO.sub.2-depleted non-permeate stream that is routed to the LNG train after sweetening and dehydration. Because the pretreatment system delivers the incoming gas stream to the LNG train at a lower temperature than conventional systems, less energy is needed to convert the gas stream to LNG. In addition, the pretreatment system has a smaller footprint than conventional pretreatment systems.

Disclosed is a process for regenerating a hybrid solvent used to remove contaminants from a fluid stream and to provide an improved yield of purified fluid. Said process comprises at least one purification unit (12) and at least one regeneration unit (40) wherein condensed water 62 from the regeneration unit is recycled back into the purification unit and none of the condensed water is reintroduced into the regeneration unit.

A pretreatment system and method for a floating liquid natural gas (“FLNG”) facility are presented. The inlet natural gas stream flows through a membrane system to remove carbon dioxide and a heat exchanger, producing first and second cooled CO.sub.2-depleted non-permeate streams. The first cooled CO.sub.2-depleted non-permeate stream is routed to additional pretreatment equipment, while the second cooled CO.sub.2-depleted non-permeate stream is routed directly to a LNG train. Alternatively, the inlet natural gas stream may flow through a membrane system to produce a single cooled CO.sub.2-depleted non-permeate stream that is routed to the LNG train after sweetening and dehydration. Because the pretreatment system delivers the incoming gas stream to the LNG train at a lower temperature than conventional systems, less energy is needed to convert the gas stream to LNG. In addition, the pretreatment system has a smaller footprint than conventional pretreatment systems.

The present disclosure provides a method for separating a feed stream in a distillation tower. The method includes operating a controlled freeze zone section in a distillation tower that separates a feed stream at a temperature and pressure at which the feed stream forms a solid in the controlled freeze zone section, wherein the feed stream includes a first contaminant; maintaining a melt tray assembly in the controlled freeze zone section; introducing the feed stream to the controlled freeze zone section; and accumulating a liquid in the melt tray assembly until the liquid is at a predetermined liquid level in the controlled freeze zone section, by: feeding a second contaminant to the controlled freeze zone section; and adding the second contaminant to the melt tray assembly, wherein the liquid comprises the second contaminant.

An absorbent for removing carbon dioxide from a fluid stream, comprising an aqueous solution a) of an amine of the general formula (I)

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in which R.sub.1, R.sub.2 and R.sub.3 are each independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; X is OH or NH(CR.sub.1R.sub.2R.sub.3); m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is 0 or 1; and b) at least one activator selected from b1) a sterically unhindered primary amine and/or a sterically unhindered secondary amine; and a carboanhydrase. The absorbent allows rapid absorption of carbon dioxide from fluid streams.