A hydrogen sulfide (H.sub.2S) scavenging system for removing H.sub.2S, mercaptans, and/or other sulfur-containing compounds from a natural gas stream. A co-current contacting system is located in-line within a pipe and receives the natural gas stream and a liquid scavenger stream. The co-current contacting system includes a co-current contactor including a droplet generator and a mass transfer section. The droplet generator generates droplets from the liquid scavenger stream and disperses the droplets into the natural gas stream. The mass transfer section provides a mixed, two-phase flow having a vapor phase and a liquid phase. The liquid phase includes the liquid scavenger stream with H.sub.2S, mercaptans, and/or other sulfur-containing compounds absorbed from the natural gas stream, and the vapor phase includes the natural gas stream. A separation system separates the vapor phase from the liquid phase.

A system and method for processing unconditioned syngas first removes solids and semi-volatile organic compounds (SVOC), then removes volatile organic compounds (VOC), and then removes at least one sulfur containing compound from the syngas. Additional processing may be performed depending on such factors as the source of syngas being processed, the products, byproducts and intermediate products desired to be formed, captured or recycled and environmental considerations.

Embodiments described herein provide methods of operating a linear contactor for absorbing contaminants from a gas stream. The gas stream flows from a first end to a second end of the linear contactor. Fresh absorbent is provided at the first end of the linear contactor based on the theoretical minimum amount of absorbent needed to remove the contaminants. Absorbent is recycled from the second end to the first end of the linear contactor. Fresh absorbent is provided at the second end based on chemical condition of the recycled absorbent. Apparatus for practicing the method is also described.

The disclosure discloses a furan skeleton-containing iminoguanidine derivative, comprising 2,5-furan-bis(iminoguanidine) and acceptable salts of 2,5-furan-bis(iminoguanidine) as well as solvates thereof. The disclosure also discloses a preparation method of 2,5-furan-bis(iminoguanidine) and its use as an acidic gas absorbent and an anionic precipitant. The 2,5-furan-bis(iminoguanidine) of the disclosure can be conveniently regenerated and recycled alter absorbing acidic gases, is low in regeneration energy consumption and has reduced cost and improved efficiency. The 2,5-furan-bis(iminoguanidine) of the disclosure is simple in preparation, mild in reaction conditions, short in reaction time, high in yield and low in cost, and is easily prepared on large scale.

Achieving the selective and reversible adsorption of CO.sub.2 from humid, low partial pressures streams such as the flue gas resulting from the combustion of natural gas in combined cycle power plants (4% CO.sub.2) is challenging due to the need for high thermal, oxidative, and hydrolytic stability as well as moderate regeneration conditions to reduce the energy of adsorption/desorption cycling. Appending cyclic primary, secondary diamines, exemplified by 2-(aminomethyl)piperidine (2-ampd), to the metal-organic frameworks Mg.sub.2(dobpdc) (dobpdc.sup.4=4,4-dioxidobiphenyl-3,3-dicarboxylate), Mg.sub.2(dotpdc) (dotpdc.sup.4=4,4-dioxido-[1,1:4,1-terphenyl]-3,3-dicarboxylate) or Mg.sub.2(pc-dobpdc) (pc-dobpdc.sup.4=dioxidobiphenyl-4,4-dicarboxylate) produces adsorbents of the classes EMM-44, EMM-45, and EMM-46, respectively, that display step-shaped adsorption of CO.sub.2 at the partial pressures required for 90% capture from natural gas flue gas at temperatures up to or exceeding 60 C. Using a cyclic diamine in place of a diamine functionalized with bulky alkyl groups enables fast adsorption/desorption kinetics with sharp CO.sub.2 adsorption and desorption steps.

The present invention relates to a hydrogen sulphide scavenging additive composition for scavenging hydrogen sulphide including sulfur containing compounds and mercaptans, particularly for scavenging hydrogen sulfide in hydrocarbons, wherein the additive composition comprises substantially reduced amount of nitrogen based hydrogen sulfide scavengers, and is also required in substantially reduced amount, and wherein the additive composition scavenges the sulfur containing compounds not only at room temperature, but also at higher temperatures, and comprises at least a combination of: (A) at least one nitrogen based hydrogen sulfide scavenger; and (B) at least one aliphatic tertiary amine, wherein the nitrogen based hydrogen sulfide scavenger comprises triazine based hydrogen sulfide scavenger. In one embodiment, it also relates to a method for scavenging hydrogen sulfide in hydrocarbons, and in another embodiment it relates to a method of using an additive composition of the present invention for scavenging hydrogen sulfide in hydrocarbons. In yet another embodiment, it relates to a composition comprising (i) a hydrocarbon and (ii) a hydrogen sulfide scavenging additive composition for scavenging hydrogen sulfide in hydrocarbons.

A method for treating sulfur contaminants is provided. The method comprises introducing a methylmorpholine-N-oxide solution to a vessel, wherein the vessel comprises a water layer and a gas layer, wherein the water layer and the gas layer comprise the hydrogen sulfide; introducing methylmorpholine-N-oxide into the water layer; and treating the water layer by allowing the methylmorpholine-N-oxide to react with the hydrogen sulfide.

Embodiments described herein provide methods of removing contaminants from a gas, the methods including providing a feed gas to a vertical contactor; flowing the feed gas in a gas flow direction through the vertical contactor; mixing a fresh absorbent makeup with a recycled absorbent to form an absorbent mixture; providing a fresh absorbent feed to the feed gas; flowing the absorbent mixture through the vertical contactor in a liquid flow direction counter to the gas flow direction; recovering a clean gas stream from the vertical contactor; and recovering the recycled absorbent from the vertical contactor.

Embodiments described herein provide methods of operating a linear contactor for absorbing contaminants from a gas stream. The gas stream flows from a first end to a second end of the linear contactor. Fresh absorbent is provided at the first end of the linear contactor based on the theoretical minimum amount of absorbent needed to remove the contaminants. Absorbent is recycled from the second end to the first end of the linear contactor. Fresh absorbent is provided at the second end based on chemical condition of the recycled absorbent. Apparatus for practicing the method is also described.

The present disclosure relates to a hydroxyl group-containing amine-based sulfur dioxide and sulfurous absorbent, and a method for preparing the same. The absorbent uses an ionic liquid in the form of a salt including a diamine compound substituted with a hydroxyl group, and can be used as an absorbent capable of removing not only sulfur dioxide (SO.sub.2) but also sulfurous acid (H.sub.2SO.sub.3) formed by combination of sulfur dioxide with water.