A prior art (U.S. Pat. No. 4,622,212, issued on Nov. 11, 1986) describes a process of liquid-state oxidation of hydrogen sulfide to sulfur by means of chelating complexes of iron (Lo-Cat process). In the Lo-Cat process, a catalytic reactor for conversion of hydrogen sulfide into sulfur is used, and a device to regenerate the catalyst solution.
The said process features insufficient degree of desulfurization and incapability of demercaptanization and dehydration that must be admitted as its drawbacks.
A prior art (U.S. Pat. No. 8,735,316, issued on May 27, 2014) describes a process of catalytic demercaptanization by converting mercaptans to disulfides. As a catalyst, the complex CuCl with monoethanol amine (MEA), acetonitrile, or with a monobasic alcohol is used. The process flows in presence of air oxygen, at a temperature of 22-140° C. The residual amount of mercaptan sulfur can be reduced to 20 ppm.
The said process is capable of purifying only liquid media, and no data is provided concerning its capability of hydrogen sulfide removal and/or water removal, that must be admitted as the drawbacks.
A prior art (RU patent No. 2385180 issued on Mar. 27, 2010) describes a Claus-process of conversion of hydrogen sulfide to sulfur
The said art features primary amine treatment of the gas to be purified, multiple stages of the process and insufficient conversion of hydrogen sulfide to sulfur, necessity of tail gas treatment, sophisticated technological equipment, and incapability of demercaptanization and dehydration, all these items must be admitted as the drawbacks.
A prior art (U.S. Pat. No. 5,286,697, issued on Feb. 15, 1994) also describes an improved Claus process.
The said art is also incapable of demercaptanization and dehydration, and it is less efficient in hydrogen sulfide conversion.
A prior art (RU patent No. 2,405,738, issued Apr. 27, 2010) describes a means of sulfur recovery from industrial gases by means of a catalyst that contains on dehydroxylated silica gel (97.65% by mass) impregnated with ferric phosphate (III) (2.35%), that provides sulfur formation from hydrogen sulfide that is present in gaseous hydrocarbons.
The said art features insufficient conversion of hydrogen sulfide, and catalyst production complexity, incapability of gas dehydration, that must be admitted as drawbacks.
A prior art (RU patent No. 2,398,735, issued on Sep. 10, 2010) describes a means of gas desulfurization by oxidating hydrogen sulfide to elemental sulfur in liquid state in presence of a catalyst, which contains a compound of a transition metal and an organic complexing agent. To oxidate hydrogen sulfide, it is proposed to use air oxygen as oxidizer; as a compound of transition metal, cupric halogenide is used, where the amount of copper in the solution is 0.015 to 0.1% by weight, and where as an organic complexing agents, one of the following is used: dimethylformamide, pyrrolidone, methylpyrrolidone, pyridine, or quinolone; the process flows in a solvent that is taken as one of the following: monobasic alcohol, polybasic alcohol, water, or their mixtures, kerosene, isooctane, gas condensate at temperature of 20-40° C.
The drawbacks of the said process are its capability of gas desulfurization only, incapability of gas dehydration.
The closest technical solution to one described in the current claim can be considered the prior art (RU patent 2,127,146, issued on Mar. 10, 1999) that describes a process of gaseous hydrocarbon purification to H2S level below 4 ppm vol. and dehydration with dew point temperature in between 0° C. and −18° C. The said closest technical solution provides desulfurization and dehydration of the gas by applying a solution of “amine-glycol”. The said process does not provide conversion of hydrogen sulfide into sulfur. Hydrogen sulfide extracted from the gas undergoes afterburning with generation of sulfur dioxide.
The drawbacks of the said process are related to hydrogen sulfide conversion to sulfur dioxide, that requires disposal, and incapability of demercaptanization.
USPTO Backgrounds
USPTO Backgrounds