At least one gaseous impurity, for example silane, is removed by absorption from a feed gas stream, for example a gas stream comprising nitrogen and hydrogen, the gaseous impurity being less volatile than the feed gas stream. The absorption is effected by a sub-cooled absorbent at a first cryogenic temperature and a first pressure. The absorbent is typically propane. The absorption may be conducted in a liquid-vapor contact column (130). Absorbent containing impurity may be regenerated in a regeneration vessel 150 and returned to the column (130).

A process for separating a gas and a vapor is disclosed. A cross-flow horizontal spray vessel comprising horizontally-situated sections is provided. Each of the sections comprise a spray nozzle or nozzles, and a collection hopper. A carrier gas, comprising a product vapor, is passed through the sections. A contact liquid is provided through the spray nozzle or nozzles such that the carrier gas passes across the contact liquid and a portion of the product vapor desublimates, condenses, crystallizes, or combinations thereof as a product solid into the contact liquid, leaving a product-depleted carrier gas. The contact liquid and the product solid are passed to a next preceding upstream spray nozzle or nozzles such that a temperature profile is established across the sections by the contact liquids, as the contact liquids are progressively warmer. The contact liquid and the product solid are removed. The product-depleted carrier gas is removed.

A dehumidifying composition according to an embodiment of the present invention includes oil and a surfactant, wherein the oil and the surfactant may be mixed by at least one of mechanical stirring, ultrasonic stirring, ultrasonic grinding, or magnetic stirring.

Certain functionalized aldehydes scavengers may be used to at least partially scavenge sulfur-containing contaminants from fluid systems containing hydrocarbons and/or water. The contaminants scavenged or otherwise removed include, but are not necessarily limited to, H.sub.2S, mercaptans, and/or sulfides. Suitable scavengers include, but are not necessarily limited to, reaction products of glycolaldehyde with aldehydes; reaction products of glycolaldehyde with a nitrogen-containing reactant (e.g. an amine, a triazine, an imine, an aminal, and/or polyamines); non-nitrogen-containing reaction products of a hydrated aldehyde with certain second aldehydes; reaction products of 1,3,5-trioxane with hydroxyl-rich compounds (e.g. glyoxal, polyethylene glycol, polypropylene glycol, pentaerythritol, and/or sugars); and reaction products of certain aldehydes with certain phenols; and combinations of these reaction products.

Process and plant for recovering LPG in a refinery process combining the use of sponge absorber, deethanizer and debutanizer. The process and plant enable high LPG recovery and removal of hydrogen sulphide in the LPG product to low levels.

A plant comprises a feed gas source, H2S removal unit, first absorber and a second, pressure reduction stages, first and second heat exchangers, stripping unit, and a conduit. The H2S removal unit selectively removes H2S from a feed gas from the feed gas source to produce an H2S depleted feed gas. The first absorber and the second absorber remove CO2 from the H2S depleted feed gas using a semi-lean and an ultralean solvent to produce a product gas and a rich solvent. The plurality of pressure reduction stages generates a cooled flashed solvent. The first heat exchanger and the second heat exchanger use the cooled flashed solvent to cool the H2S depleted feed gas and the semi-lean solvent. The stripping unit strips the flashed solvent with dried air to produce the ultralean solvent, and the conduit combines a portion of the ultralean solvent with the H2S depleted feed gas.

An oil scrub column having a petroleum spirit section and an oil section where each section has mass transfer trays having a plurality of runoff elements that extend parallel to and at a distance from one another, to form angular profiles. The runoff elements have first and second runoff surfaces that converge to form an edge. Scrubbing media introduced onto the edges of the runoff elements flows off via the runoff surfaces at both sides of the edge. The oil section has a greater number of mass transfer trays than the petroleum spirit section. The petroleum spirit section is shorter than the oil section. The mass transfer trays of the petroleum spirit section may be sieve trays, bubble trays or valve trays.

A plant includes a pretreatment unit for H2S removal and air dehydration, and at least two absorbers that receive a feed gas at a pressure of at least 300 psig with variable CO2 content (e.g., between 5 to 60 mol %), wherein the feed gas is scrubbed in the absorbers with an ultralean and a semi-lean physical solvent, respectively, at low temperatures to at least partially remove the CO2 from the feed gas. Such configurations produces a low CO2 dry treated gas and a H2S-free CO2 for sequestration while advantageously providing cooling by expansion of the rich solvent that cools the semi-lean solvent and the feed gas, wherein an ultralean solvent is produced by stripping using dry air.

Elemental mercury is removed from a gas by contacting it with a halogen dissolved in an organic solvent. The mercury accumulates in the organic solvent and can be removed by extraction with an aqueous solution with a complexing agent, by adsorption, and by combinations. The absorption process can also operate by use of a series of absorbers which have successively higher concentrations of halogen in the solution and which successively remove more the mercury from the gas. A portion of the solvent in the last absorber can be cascaded to the previous absorber in the series. In one embodiment, the process is carried out at a temperature of absorber at less than or equal to 28 C. above the higher of the water dew point and the hydrocarbon dew point. The mercury waste from the process is produced as either an aqueous solution or a small volume of mercuric sulfide.

The invention is directed to the purification of gas streams comprising methane and hydrophobic pollutants. The invention provides a method for purifying a gas stream comprising methane and one or more hydrophobic pollutants comprising the steps of contacting the gas stream with a lean liquid stream comprising micelles of a surfactant or a separate surfactant phase. The resulting rich liquid stream comprises at least part of the hydrophobic pollutants. By subsequently changing the temperature of the rich liquid stream, a system of a pollutants-poor phase and a pollutants-rich phase is obtained. These phases are optionally separated and from the aqueous stream the lean liquid stream comprising micelles and/or surfactant can be regenerated.