Union Carbide Corporation

Engelhard Corporation

Kenneth F Butwell

William Bachop Dolan

Steven M Kuznicki

Paul W Sigmund

Paulino Forte

Jose A Vidueira

Daniel J Kubek

John Byrne

John Edward Kendall

Paul J Capobianco

Edward J Kossakowski

A process for adsorbing hydrocarbons from an acid gas stream includes passing the acid gas stream through an adsorbent which selectively removes hydrocarbons, desorbing the hydrocarbons from the adsorbent and contacting the desorbed hydrocarbons with an acid gas removal solution to remove acid gases which have been coadsorbed with the hydrocarbons. The process is particularly useful in removing hydrocarbons from a hydrogen sulfide-containing stream which is being directed to Claus processing for conversion into elemental sulfur. Useful adsorbents include crystalline titanium silicate molecular sieves containing titania octahedral sites such as ETS-10 and similar materials, as well as high silica aluminosilicate zeolite.

Claus feed gas hydrocarbon removal

A process for adsorbing hydrocarbons from an acid gas stream includes passing the acid gas stream through an adsorbent that selectively removes hydrocarbons, desorbing the hydrocarbons from the adsorbent and contacting the desorbed hydrocarbons with an acid gas removal solution to remove acid gases which have been coadsorbed with the hydrocarbons. The process is particularly useful in removing hydrocarbons from a hydrogen sulfide-containing stream that is being directed to Claus processing for conversion into elemental sulfur. Useful adsorbents include Y-type zeolites having a silica to alumina mole ratio of less than 15 and a reduced sodium content.

A pressure swing adsorption process for the separation of nitrogen from a mixture of same with methane, utilizing two separate PSA stages, one containing a nitrogen selective adsorbent and the second containing a methane-selective adsorbent. In the process, the first PSA unit containing a nitrogen selective adsorbent forms a product methane stream and a waste stream rich in nitrogen which is passed to a second PSA unit containing a methane selective adsorbent which forms a product nitrogen stream and a waste stream rich in methane. The waste stream rich in methane can be treated to remove heavy hydrocarbons therefrom before the methane is recycled to feed.

Pressure swing adsorption process

A pressure swing adsorption process for the separation of nitrogen from natural gas utilizes two separate pressure swing adsorption stages, the first containing a hydrocarbon-selective adsorbent and the second containing a nitrogen-selective adsorbent. In the process, the product stream from the first pressure swing adsorption unit contains a natural gas stream having a reduced hydrocarbon content and the product stream from the second pressure swing adsorption unit is a natural gas stream having a reduced nitrogen concentration. The product from the second pressure swing adsorption unit is used to desorb the hydrocarbons from the first pressure swing adsorption unit so as to add the hydrocarbons, which have heat value to the product natural gas stream. Periodically, heating the nitrogen-selective adsorbent with heated product stream from the second pressure swing adsorption unit has been found to improve the capacity of the nitrogen-selective adsorbent to adsorb nitrogen.

Selective removal of nitrogen from natural gas by pressure swing adsorption

A pressure swing adsorption process for the separation of hydrogen from a mixture of the same with methane, utilizing two separate PSA stages, one containing a nitrogen selective crystalline zeolite, and the second containing a methane selective adsorbent.

This invention discloses mixtures of alkyl dialcohol amines and mono alkyl ethers of polyethylene glycols which are useful in removing acidic gases from gaseous mixtures. The solvent mixtures contain between 1.5 N and 5.0 N methyl diethanolamine (MDEA), 10 to 40 percent water and the balance is methoxytriglycol (MTG). The overall heat of reaction of the solution is typically less than 500 BTU/lb CO.sub.2, and remains as a single liquid phase during normal gas scrubber operating conditions.

Mixed solvent system for treating acidic gas

An improvement to a continuous solvent extraction-steam distillation process for the recovery of aromatic hydrocarbons in the range of C.sub.6 -C.sub.16 from a feed stream containing such aromatics and aliphatic hydrocarbons in the range of C.sub.5 -C.sub.16 which resides in utilizing two heat exchangers wherein the heat of condensation of the overhead stripper vapor and vapor sidedraw products is recovered and utilized to vaporize the stripping water, thereby producing stripping steam which in turn is compressed up to the pressure present at the bottom of the stripper and resulting in the reduction of the heat load of the process.

Process for the separation of aromatic hydrocarbons from petroleum

A vapor-liquid contacting tray wherein a perforated portion of the tray member forms an active surface area for vapor-liquid contact in the interior of the tray member. The active surface area portion of the tray member is circumscribed by an imperforate peripheral portion of the tray member with a width of from 0.05 to 0.35 times the radius of the tray. The disclosed tray provides upwardly directed laminar jetting of liquid over the tray perforation openings for high selectivity vapor-liquid contacting and has particular utility in the absorption of hydrogen sulfide from a gas mixture containing hydrogen sulfide and carbon dioxide.

Vapor-liquid contacting system

A continuous process for acid gas removal from process gas streams by contact with an aqueous alkanolamine solution such as MEA wherein the temperature of the MEA solution is controlled by placing an intercooler at the lower end of the absorption column such that the temperature of the down-coming MEA solution is cooled to allow increased mole loading of acid gas in the solution, but is not so cooled that the mass transfer rate of the acid gas from the process gas to the MEA solution is slowed to an unacceptable level. The lower temperature highly loaded MEA solution is then passed to a heat exchanger-flash-heat exchanger arrangement where the temperature is increased to provide satisfactory flash efficiency and then heated again prior to introduction into the stripper to reduce the sensible heat duty in the stripper. The combination of optimally positioned intercooler and flash together with the temperature ranges recited permit the obtainment of a net energy demand lower than can be expected from the addition of the intercooler effect and the flash effect.

Process for CO.sub.2 removal

Novel process for removing polymer from aqueous absorbent solutions used to contact organic gas-containing gas streams comprising the steps of adjusting the polymer-containing aqueous absorbent solutions to a pH of not more than about 8.5, preferably not more than about 7.5, for example, about 6.0 to about 8.5, preferably about 7.0 to about 7.5, and removing the polymer from the resulting solutions by decantation and/or filtration. The novel process is particularly applicable to the system of removing acid gas from hydrocarbon-containing feed gases which contain one or more polymerizable components wherein the feed gas is contacted with an aqueous absorbent solution which absorbs the acid gas and, thereafter, the absorbent solution is stripped to rid it of said acid gas. The adjustment of pH can be accomplished by increasing the acid gas loading in the aqueous absorbent or by adding an acid, preferably one which will not form a heat stable salt with the absorbent. The pH adjustment, e.g., acidification, and filtration can be performed on the total mainstream or a portion thereof, i.e., a sidestream, before it is stripped.

Process for separating polymeric contaminants from aqueous absorbent

A continuous process for the selective absorption of hydrogen sulfide from a feed gas comprising an acid gas mixture of carbon dioxide and hydrogen sulfide is provided which comprises counter-currently contacting the feed gas with an aqueous alkanolamine solution in an absorption zone having from two to ten separate stages, contacting the feed gas in each stage with lean aqueous alkanolamine solution and withdrawing rich aqueous alkanolamine solution from the bottom of each stage, in each stage maximizing the equilibrium approach between the hydrogen sulfide in the gas and liquid phases and minimizing the equilibrium approach between the carbon dioxide in the gas and liquid phases, and maintaining the rich solution loading in each stage within the range from about 0.1 to about 0.3 mole of acid gas per mole of alkanolamine. The absorption zone is operated in combination with a stripping zone to which rich aqueous alkanolamine solution is passed and in which lean solution is generated. The particular multi-stage absorption process of the invention allows for the recovery as stripping zone overhead of gaseous product in which the combined molar ratio of carbon dioxide to hydrogen sulfide is no greater than about 6.

Process for acid gas removal

A continuous process for acid gas removal such as the removal of carbon dioxide, from a feed mixture of process gas and acid gas which comprises introducing the gaseous feed mixture to an absorption zone at an absorption zone inlet temperature in the range of about 35.degree. C. to 150.degree. C., treating the gaseous feed mixture in the absorption zone with an aqueous solution of alkanolamine under specified conditions, the absorption zone inlet temperature for the solution being in the range of about 30.degree. C. to about 75.degree. C., passing the aqueous solution of alkanolamine having acid gas absorbed therein to a stripping zone at an inlet temperature essentially the same as the absorption zone outlet temperature for said solution, removing solution from the bottom of the stripping zone at a bottoms outlet temperature in the range of about 100.degree. C. to about 150.degree. C., and wherein the conditions in the absorption zone are selected so as to provide an absorption zone outlet temperature for the aqueous alkanolamine solution having acid gas absorbed therein in a range the lowest point of which is no lower than 22.degree. C. less than the bottom outlet temperature of the stripping zone and the highest point of which is about 150.degree. C.

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Newburgh, NY, United States of America

Kenneth F Butwell