A system for conditioning a sour gas feed stream for a cryogenic distillation tower. A dehydration unit separates the sour gas feed stream into a first stream including water and a feed stream. A sequential cooling assembly is coupled to both the dehydration unit and the cryogenic distillation tower. The sequential cooling assembly includes: a first stage that separates the feed stream into a partially cooled feed stream and a second stream including acid gas; a second stage that cools the partially cooled feed stream into a cooled feed stream and a third stream including acid gas; and a cooled feed stream header coupled to a cryogenic distillation tower feed inlet. The first stage, the second stage, or both send at least one of the second and third streams to a bottom section of the cryogenic distillation tower.

An acid gas purification system is described herein that includes a primary membrane system with a CO.sub.2- and H.sub.2S-enriched permeate stream effluent and a hydrocarbon stream effluent; a first compression stage arranged to receive the CO.sub.2- and H.sub.2S-enriched permeate stream and produce a compressed stream; and a cryogenic separation system to receive the compressed stream, the cryogenic separation system including a cooler followed by a fractionator, wherein the fractionator produces a CO.sub.2- and H.sub.2S liquid stream and a hydrocarbon gas stream.

A process for producing liquefied natural gas and liquid carbon dioxide from a natural gas feed gas comprising at least the following steps: Separation of a natural gas feed gas into a CO.sub.2-enriched gas stream and a natural gas stream; Cooling of said natural gas in a heat exchanger; Purification of the in step 1 from compounds containing at least six carbon atoms; At least partial condensation of said gas stream resulting from step 3 to form a two-phase stream; Separation of said two-phase stream resulting from step 4 to form a gas stream and a liquid stream; Condensation of the gas stream resulting from step 5 to form a liquefied gas containing less than 5 ppm by volume of compounds containing at least six carbon atoms; Liquefaction of the CO.sub.2-enriched gas stream resulting from step 1 with a portion of the liquid stream resulting from step 5.

Processes for purifying and liquefying natural gas in conjunction and integration with cryogenic processing natural gas to recover natural gas liquids (NGL) is disclosed. In the process, the natural gas stream to be purified and liquefied is taken from top outlet stream of demethanizer in the cryogenic NGL recovery plant, first purified and then cooled under moderate pressure to condense it as a liquefied natural gas (LNG) product stream. Some of the cooling required for the demethanizer reflux stream is provided by natural gas liquefaction section before supplied to top of the column to serve as reflux. The top outlet stream from the demethanizer preferentially contains up to 3 mole percent of CO.sub.2 and the majority of methane and small portion of any hydrocarbon heavier than methane, a split portion of this stream is taken and routed to cryogenic CO.sub.2 removal section, in which a molecular sieve that forms a physical adsorption column is used to extract pure CO.sub.2 as a product stream, then purified stream is routed to the liquefaction section where only two stages of coil-wound exchangers with a Semi-C3-MR cycle are used to liquefy natural gas. This present invention process is suited for LNG production in small-scale. This zeolite-based small-scale LNG process can be integrated with the design of any new natural gas facility and the technology can also be retrofitted to existing natural gas liquid (NGL) recovery plants, allowing for co-production of LNG and CO.sub.2 with high purity.

The invention relates to a method for treating a mixture in order to separate carbon dioxide and hydrogen from said mixture, in which: i) the mixture is cooled and partially condensed and a first liquid is separated from the rest of the mixture in a first phase separator; ii) a gas from or derived from a gas from the first phase separator is treated in a hydrogen pressure swing adsorption module in order to produce a hydrogen-rich gas and a hydrogen-depleted residual gas; and iii) said hydrogen-depleted residual gas or a gas derived from said depleted gas is cooled and partially condensed and a second liquid is separated from the remaining gas in a second phase separator, separate from the first phase separator, wherein the first and/or second liquid being rich in carbon dioxide. The invention also relates to an installation for implementing such a method.

In a process for distilling a gas mixture of CO2 and at least one component lighter than CO2, a partially purified liquid CO2 stream is withdrawn at an intermediate level of the distillation column at least one theoretical plate below the top of the distillation column and at least one theoretical plate above the bottom of the distillation column and the stream extracted at the intermediate level of the distillation column is vaporized by heat exchange with the gas mixture, with which it is then compressed.

A combined plant for cryogenic separation and liquefaction of methane and carbon dioxide in a biogas stream, including a mixing means, a compressor, a first exchanger, a distillation column, a second exchanger, a separating means, an expanding means, and a separator vessel. Wherein, the mixing means is configured such that the recycle gas is the overhead vapour stream, and the first exchanger and the expanding means are combined.

The present invention provides a method of mineralisation of carbon dioxide. The method comprises forming an alkaline in aqueous solution containing carbonate anions by dissolving the carbon dioxide and an alkali such as ammonia in water. Next, the method comprises mixing the alkaline aqueous solution with a water source (such as a connate/formation brine or produced water or industrial waste waters or re-constituted mineral-bearing waters) containing magnesium and calcium cations. A first product (e.g. PCC) containing calcium cations and carbonate anions is precipitated in a first precipitation step at a first pH (e.g. around pH7.5) and then a second product (e.g. nesquehonite (NQ) a type of PMC) containing magnesium cations and carbonate anions is precipitated in a second precipitation step at a second, higher pH e.g. around pH 9.5.

A method and a system for feeding a feed gas including methane (CH.sub.4) and carbon dioxide (CO.sub.2) to a cryogenic distillation column are provided herein. The method includes flowing a freeze zone CO.sub.2 vapor stream into a freezing section of the column to produce an overhead stream that exits the column. The method includes heating the overhead stream via a heating component to reduce or prevent solidification of the CO.sub.2 in the overhead stream.

A system for melting contaminant-laden solids that have been separated from a hydrocarbon-containing vapor stream in a hydrocarbon distillation tower, comprising at least one plate positioned where the solids form within the hydrocarbon distillation tower, hollow tubing forming an integral part of each of the at least one plate, and a heating medium disposed to flow through the hollow tubing at a higher temperature than a temperature of the solids to at least partially melt the solids.