A system and method of regenerating a pre-purification vessel is provided that is particularly suitable for pre-purification of a feed air stream in cryogenic air separation unit that uses an oxygen-enriched purge gas stream for regeneration of the pre-purification unit. The disclosed pre-purification systems and methods are configured to remove substantially all of the water, carbon dioxide and other impurities from a feed air stream, optionally including hydrogen and carbon monoxide impurities. The method of regenerating a pre-purification vessel preferably involves regenerating the pre-purification vessel with an oxygen-enriched purge gas after depressurization of the vessel and thereafter partially repressurizing the pre-purification vessel with an auxiliary purge gas thereby diluting the oxygen concentration of the gases contained in the pre-purification vessel and optionally depressurizing the partially repressurized vessel.

A method for vaporizing liquid propane to be supplied as a raw material to a naphtha cracking ractor. The method comprises: decompressing liquid propane to lower a vaporization point and vaporize at least a portion of the liquid propane; utilizing vaporization heat, generated during vaporization of the portion of liquid propane, as a refrigerant; compressing the vaporized propane gas to increase pressure of the propane gas and produce compressed propane gas; and preheating the compressed propane gas. By using this method, it is possible to reduce pressure of liquid propane to a significantly lower pressure than the related art method so that all the vaporization latent heat or vaporization heat included in liquid propane may be utilized as a refrigerant, while also reducing heat energy consumed in a preheat process before it is supplied to the naphtha cracking reactor.

A system and method of regenerating a pre-purification vessel is provided that is particularly suitable for pre-purification of a feed air stream in cryogenic air separation unit that uses an oxygen-enriched purge gas stream for regeneration of the pre-purification unit. The disclosed pre-purification systems and methods are configured to remove substantially all of the water, carbon dioxide and other impurities from a feed air stream, optionally including hydrogen and carbon monoxide impurities. The method of regenerating a pre-purification vessel preferably involves regenerating the pre-purification vessel with an oxygen-enriched purge gas after depressurization of the vessel and thereafter partially repressurizing the pre-purification vessel with an auxiliary purge gas thereby diluting the oxygen concentration of the gases contained in the pre-purification vessel and optionally depressurizing the partially repressurized vessel.

A process and an apparatus are disclosed for the recovery of components from a hydrocarbon gas stream containing significant quantities of components more volatile than methane (hydrogen, nitrogen, etc.). The gas stream is partially condensed, then the remaining vapor is expanded to lower pressure and supplied to a fractionation tower at a mid-column feed position. The condensed liquid is cooled and divided into two portions. The first portion is expanded to tower pressure, heated by cooling the liquid, and supplied to the tower at a lower column feed position. The second portion is further cooled, expanded to tower pressure, and supplied to the tower at a top feed position. The tower overhead vapor is heated by cooling the second portion. The quantities and temperatures of the feeds to the tower maintain the overhead temperature of the tower whereby the major portion of the desired components is recovered.

This specification relates to operating industrial facilities, for example, crude oil refining facilities or other industrial facilities that include operating plants that process natural gas or recover natural gas liquids.

A system and method for removing nitrogen from natural gas using two fractionating columns, that may be stacked, and a plurality of separators and heat exchangers, with horsepower requirements that are 50-80% of requirements for prior art systems. The fractionating columns operate at different pressures. A feed stream is separated with a vapor portion feeding the first column to produce a first column bottoms stream that is split into multiple portions at different pressures and first column overhead stream that is split or separated into two portions at least one of which is subcooled prior to feeding the top of the second column. Optional heat exchange between first column and second column streams provides first column reflux and reboil heat for a second column ascending vapor stream. Three sales gas streams are produced, each at a different pressure.

A system for conditioning a sour gas feed stream for a cryogenic distillation tower, comprising a dehydration unit configured to separate the sour gas feed stream into a first stream comprising water and a feed stream, and a sequential cooling assembly coupled to both the dehydration unit and the cryogenic distillation tower, wherein the sequential cooling assembly comprises a first stage configured to separate the feed stream into a partially cooled feed stream and a second stream comprising acid gas, a second stage configured to cool the partially cooled feed stream into a cooled feed stream and a third stream comprising acid gas, and a cooled feed stream header coupled to a cryogenic distillation tower feed inlet, wherein the first stage, the second stage, or both are configured to send at least one of the second and third streams to a bottom section of the cryogenic distillation tower.

A system for the removal of nitrogen from a liquid natural gas (LNG) stream. The system. comprises a feed heat changer and a stripper column. The heat receives the LNG stream and cools the LNG stream via heat exchange with a stripper column side-draw stream to yield a cooled LNG stream and a heated side-draw stream. The stripper column receives the cooled LNG stream at a first tray and the heated side-draw stream. The stripper column produces the stripper column side-draw stream, a stripper column overhead stream, and a stripper column bottom stream. The stripper column side-draw stream is taken from the stripper column at a second tray. The second tray is at least about 15 feet higher than the feed heat exchanger.

In a method for separating at least one lighter impurity of a gaseous mixture containing at least 30% mol of carbon dioxide, a liquid (101) enriched with carbon dioxide is drawn off into a vat of a distillation column (25), at least part (27) of the liquid enriched with carbon dioxide is vaporized and then heated to a first temperature higher than the boiling temperature thereof in the exchanger and leaves the exchanger at the hot end thereof, and at least part of the vaporized and heated liquid is sent from the hot end of the exchanger at the first temperature, without being cooled in the exchanger and without having been compressed, to the lower part of the distillation column, where it participates in the distillation while enriching itself.

The invention relates to a method for separating a feed gas containing at least 20 Mol % of CO2 and at least 20 Mol % of methane, by partial condensation and/or by distillation, the gas at a pressure of at least 40 bar abs, including expanding at least one portion of the feed gas in a turbine producing an expanded feed stream at a pressure of less than 90 bar abs, separating at least one portion of the expanded feed stream by partial condensation and/or by distillation thus obtaining a CO.sub.2-depleted gas and a CO.sub.2-enriched liquid, wherein the temperature of the expanded feed gas at the outlet of the turbine is below −56.6° C., and wherein the process does not use an external refrigeration source; and wherein the CO.sub.2-depleted gas is introduced into a supplementary separation step, in order to obtain a stream that is more depleted in CO.sub.2 and a CO.sub.2-rich stream.