Ari Technologies, Inc.

Merichem Company

Wheelabrator Clean Air Systems Inc.

U.S. Filter/engineered Systems

Merichem Chemicals & Refinery Services LLC

U.S. Filter/gas Technology Products

Derek McManus

Myron Reicher

Gary J Nagl

Arthur E Martell

Dian Chen

Leslie C Hardison

Edward J Dowd

Frederick R Kin

Barry Ferm

Barret A Ferm

An improved oxidizer for liquid reduction-oxidation desulphurization processes uses a hollow fiber membrane contactor. A pressurized, oxygen containing gas stream is introduced into the interior of the hollow fiber membrane while a liquid reduction-oxidation catalyst solution contacts the exterior of the membrane. Oxygen diffuses through the membrane into the liquid reduction-oxidation catalyst solution whereby the solution is oxidized and can be recycled for further us in a desulphurization process.

Oxidizer and oxidation process for a desulphurization process

An improved oxidizer for liquid reduction-oxidation desulphurization processes uses a hollow fiber membrane contactor. A pressurized, oxygen containing gas stream is introduced into the interior of the hollow fiber membrane while a liquid reduction-oxidation catalyst solution contacts the exterior of the membrane. Oxygen diffuses through the membrane into the liquid reduction-oxidation catalyst solution whereby the solution is oxidized and can be recycled for further use in a desulphurization process.

A process is provided for the removal of hydrogen sulfide out of a gas stream by contacting the hydrogen sulfide contaminated gas with a solution of chelated metal catalyst, such as iron EDTA, in a scrubbing vessel so as to result in a cleaned gas and a scrubbing solution containing elemental sulfur and a reduced chelated metal catalyst. A portion of the hydrogen sulfide contaminated feed gas is branched off from the rest of the hydrogen sulfide contaminated feed gas, at a location upstream of the scrubbing vessel, and injected into a bisulfide generating vessel where it is contacted with an aqueous caustic solution, such as an aqueous solution of potassium hydroxide, wherein the hydrogen sulfide reacts with the caustic solution to result in a cleaned gas and a solution containing bisulfide ions. The solution containing bisulfide ions and the scrubbing solution containing elemental sulfur and reduced chelated metal catalyst are both injected into an oxidation vessel where they are contacted with an oxygen containing gas which oxidizes the reduced chelated metal catalyst back into its reactive oxidation state and also oxidizes the bisulfide ions into thiosulfate ions. The regenerated scrubbing solution containing reactive chelated metal catalyst and thiosulfate ions are recycled back to the scrubbing vessel for further contact with the hydrogen sulfide containing gas. The thiosulfate ions protect the chelated metal catalyst from degradation.

Method for continuously producing thiosulfate ions

A class of pyridine phosphonate compounds is disclosed that are useful as ligands in the one manufacture of oxidation-reduction catalysts. In particular, pyridine-2,6-disphosphonic acid is a specie of the pyridine phosphonate ligands that can be combined with a polyvalent metal to produce a catalyst to convert hydrogen sulfide to solid sulfur.

Pyridine-based compounds, especially phosphonates

An improved oxidation-reduction process is disclosed that uses a non-aqueous polyvalent metal catalyst system to remove volatile sulfur contaminants from gas streams. In addition to desulfurizing, the process also is useful for decarbonating and dehydrating process gas streams.

Oxidation-reduction process

Novel pyridine phosphonate ligands are disclosed that when combined with polyvalent metals results in useful catalyst compositions for the conversion of hydrogen sulfide to solid sulfur. Catalysts containing these novel ligands exhibit resistance to metal precipitation and demonstrate little or no oxidative chemical degradation when employed to convert hydrogen sulfide to elemental sulfur.

Tridentate metal ligands of certain pyridine phosphonic acids

An improved oxidation-reduction process is disclosed that uses catalysts formulated from novel pyridine phosphonate ligands. When these ligands are combined with polyvalent metals the resulting catalyst compositions are useful for the conversion of hydrogen sulfide to solid sulfur. Catalysts containing these novel ligands exhibit resistance to metal precipitation and demonstrate little or no oxidative chemical degradation when employed to convert hydrogen sulfide to elemental sulfur.

A method and apparatus for the hydrothermal treatment of a catalytic polyvalent metal redox absorption solution, after absorption of the H.sub.2 S from an H.sub.2 S containing gas stream, to avoid substantial buildup of thiosulfate salts, cyanide salts, and cyanide complexes in the catalytic polyvalent metal redox solution. The method and apparatus of the present invention is particularly useful for treating gas streams containing both H.sub.2 S and HCN concurrently for destruction of the cyanide salts and cyanide complexes and conversion of H.sub.2 S and by-product salts to elemental sulfur.

Method and apparatus for removal of h2s from a process gas, including

A method and apparatus for treating a catalytic polyvalent metal redox absorption solution, after absorption of H.sub.2 S from a gas, in a first hydrothermal treatment, to separate the polyvalent metal, for example as a polyvalent metal sulfide precipitate, and thereafter treating the redox solution in a higher temperature hydrothermal treatment to decompose thiosulfate salts and, if present, thiocyanide and other cyanide salts and metal-cyanide complexes to decompose the salts and complexes to molecules that can be treated in the H.sub.2 S-absorption process for recovery of sulfur and alkali values.

Process and apparatus for removal of H.sub.2 S from a process gas

The in situ formation of a supported active metal phthalocyanine catalyst is disclosed. The supported metal phthalocyanine catalyst is useful in sweetening sour petroleum distillates containing mercaptans.

Method of making a metal phthalocyanine catalyst

In a cyclic hydrogen sulfide oxidation-catalyst regeneration process using an aqueous chelated polyvalent metal catalyst solution, excessive degradation of the aminopolycarboxylic acid chelating agent is prevented by incorporating in the solution an effective amount of a stabilizing agent capable of retarding or preventing rupture of nitrogen-carbon bonds in the chelating agent during oxidative regeneration of the catalyst solution. Alkaline thiosulfates are the preferred stabilizing agents. Particularly good results are obtained using an alkaline thiosulfate stabilizer in a catalyst solution comprising the dimer form of the NTA-iron complex.

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Roselle, IL, United States of America

Derek McManus