Claims
- 1. A method for selectively oxidizing hydrogen sulfide to sulfur dioxide, sulfur or mixtures thereof in a gas stream containing oxidizable components other than hydrogen sulfide which comprises the step of:
a. contacting the gas stream containing hydrogen sulfide and other oxidizable components with a mixed metal oxide catalyst at a temperature equal to or less than about 400° C. in the presence of oxygen; wherein the mixed metal oxide catalyst comprises a low oxidation activity metal oxide and one or more higher oxidation activity metal oxides such that a substantial amount of the hydrogen sulfide present in the gas stream is oxidized to sulfur dioxide, sulfur or a mixture thereof and wherein less than about 25% by volume of the oxidizable components except sulfur containing compounds are oxidized by the added oxygen.
- 2. The method of claim 1 wherein the low oxidation activity metal oxide is titania, silica, alumina or mixtures thereof.
- 3. The method of claim 1 wherein less than about 10% by volume of the oxidizable components except sulfur containing compounds are oxidized.
- 4. The method of claim 1 wherein less than about 1% by volume of the oxidizable components except sulfur containing compounds are oxidized
- 5. The method of claim 1 wherein the oxidizable components other than hydrogen sulfide are selected from hydrocarbons, oxygenated hydrocarbons, sulfur-containing hydrocarbons, aromatic hydrocarbons, aliphatic hydrocarbons, hydrogen, carbon monoxide or mixtures thereof.
- 6. The method of claim 1 wherein the oxidizable components other than hydrogen sulfide are selected from hydrogen, carbon monoxide or mixtures thereof.
- 7. The method of claim 1 wherein the oxidizable components other than hydrogen sulfide are hydrocarbons, oxygenated hydrocarbons, or mixtures thereof.
- 8. The method of claim 1 wherein the oxidizable components other than hydrogen sulfide are aliphatic hydrocarbons.
- 9. The method of claim 8 wherein the aliphatic hydrocarbons comprise methane, ethane, propane, butane, pentane, hexane or mixtures thereof.
- 10. The method of claim 8 wherein the aliphatic hydrocarbon is methane.
- 11. The method of claim 1 wherein the oxidizable components other than hydrogen sulfide are aromatic hydrocarbons.
- 12. The method of claim 1 wherein the oxidizable components are benzene, toluene, ethylbenzene and xylene.
- 13. The method of claim 1 wherein the oxidizable component is CO.
- 14. The method of claim 13 wherein the CO is present in the gas stream at a level of 30% by volume of CO or more.
- 15. The method of claim 13 wherein the CO is present in the gas stream at a level of 10% by volume of CO or more.
- 16. The method of claim 13 wherein the CO is present in the gas stream at a level of 1% by volume to about 10% by volume.
- 17. The method of claim 1 wherein the gas stream is substantially hydrocarbons, oxygenated hydrocarbons or sulfur containing hydrocarbons.
- 18. The method of claim 1 wherein the gas stream comprises 1% or less by volume of benzene, toluene, ethylbenzene or xylene.
- 19. The method of claim 1 wherein the gas stream is substantially methane.
- 20. The method of claim 1 wherein the temperature at which the catalyst is contacted with the gas stream in the presence of oxygen at a temperature less than 400° C.
- 21. The method of claim 20 wherein the temperature is between about 160° C. and about 250° C.
- 22. The method of claim 20 herein the temperature is between about 170° C. and about 200° C.
- 23. The method of claim 1 wherein oxygen is present in the gas stream such that the ratio of O2/H2S therein ranges from about 0.4 to about 1.75.
- 24. The method of claim 1 wherein oxygen is present in the gas stream such that the ratio of O2/H2S therein is 0.4 or more.
- 25. The method of claim 24 wherein the ratio of O2/H2S in the gas stream ranges from 0.5 to 1.5.
- 26. The method of claim 24 wherein the ratio of O2/H2S in the gas stream is greater than about 1.5
- 27. The method of claim 24 wherein the ratio of O2/H2S in the gas stream is 1.0 or less.
- 28. The method of claim 24 wherein the ratio of O2/H2S in the gas stream is 1 or greater.
- 29. The method of claim 1 wherein 99% by volume or more of the hydrogen sulfide in the gas stream is converted to sulfur dioxide, sulfur or mixtures thereof.
- 30. The method of claim 1 wherein 95% by volume or more of the hydrogen sulfide in the gas stream is converted to sulfur dioxide, sulfur or mixtures thereof.
- 31. The method of claim 1 wherein 85% by volume or more of the hydrogen sulfide in the gas stream is converted to sulfur dioxide, sulfur or mixtures thereof.
- 32. The method of claim 1 wherein the hydrogen sulfide in the gas stream is converted substantially to sulfur dioxide.
- 33. The method of claim 1 wherein the ratio of hydrogen sulfide to sulfur dioxide in the gas stream after oxidation ranges from about 1:1 to about 3:1.
- 34. The method of claim 1 wherein the hydrogen sulfide in the gas stream is converted substantially to sulfur.
- 35. The method of claim 1 wherein the gas stream after oxidation comprises hydrogen sulfide and sulfur dioxide in the ratio of about 2 to 1
- 36. The method of claim 1 wherein the lower oxidation activity metal oxide is titania or a mixture of titania with silica.
- 37. The method of claim 1 wherein the lower oxidation activity metal oxide is titania.
- 38. The method of claims 1 wherein the lower oxidation activity metal oxide is an alumina.
- 39. The method of claim 38 wherein the alumina is alpha alumina or gamma alumina.
- 40. The method of claim 1 wherein the lower oxidation activity metal oxide is selected from titania, silica, alumina or mixtures thereof and the higher activity metal oxide is selected from an oxide of a metal selected from the group V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Tc, Ru, Rh, Hf, Ta, W, Au, La, Ce, Pr, Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and mixtures thereof.
- 41. The method of claim 40 wherein the higher oxidation activity metal oxide is selected from a metal oxide of a metal selected from the group consisting of Fe, Co, Mn, Cr, Cu, Mo, Nb, or mixtures thereof.
- 42. The method of claim 40 wherein the higher oxidation activity metal oxide is a metal oxide of a transition metal or a mixture of transition metals.
- 43. The method of claim 40 wherein the mixed metal oxide catalyst comprises one or more metal oxides of lanthanide metals.
- 44. The method of claim 1 wherein the low oxidation activity metal oxide is titania.
- 45. The method of claim 1 wherein the mixed metal oxide catalyst comprises titania, silica, alumina or mixtures thereof in combination with one or more metal oxides of a metal selected from Fe, Co, Mn, Cr, Cu, Mo, Nb and mixtures thereof.
- 46. The method of claim 45 wherein the mixed metal oxide catalyst comprises titania, silica, alumina or mixtures thereof in combination with two or more metal oxides of a metal selected from Fe, Co, Mn, Cr, Cu, Mo and Nb.
- 47. The method of claim 45 wherein the mixed metal oxide catalyst comprises titania, silica, alumina, or mixtures thereof in combination with three or more metal oxides of a metal selected from Fe, Co, Mn, Cr, Cu, Mo and Nb.
- 48. The method of claim 45 wherein the mixed metal oxide catalyst comprises titania, silica, alumina or mixtures thereof in combination with a metal oxide of Mo, Nb or both and in combination with a metal oxide selected from Fe, Co, Mn, Cr, and Cu.
- 49. The method of claim 45 wherein the mixed metal oxide catalyst comprises titania, an oxide of Mo, an oxide of Nb and an oxide of one or more of Fe, Co, Cr, Mn and Cu.
- 50. The method of claim 49 wherein the metal oxide catalyst comprises titania, an oxide of Mo, an oxide of Nb and an oxide of Cu or Fe.
- 51. The method of claim 1 wherein titania or a combination of titania and silica is present at a level of 50% by weight or more in the catalyst.
- 52. The method of claim 51 wherein titania or a combination of titania and silica is present at a level of 85% by weight or more in the catalyst.
- 53. The method of claim 51 wherein the metal oxide catalyst contains from about 0.1% to about 10% by weight of each of one, two, three or four metal oxides wherein the metal oxide is a metal oxide wherein the metal is selected from Fe, Co, Mn, Cr, Cu, Mo and Nb.
- 54. The method of claim 1 wherein the metal oxide catalyst contains from 0.1% to about 10% by weight of oxide of Mo, an oxide of Nb or both and contains from about 1% to about 10% by weight of an oxide of Fe, Cu or Co.
- 55. The method of claim 1 wherein the catalyst comprises about 1 to 10% by weight copper oxide, about 1 to 10% by weight niobium oxide, 0.1 to 1% by weight molybdenum oxide with the remainder being titania or a mixture of titania and silica.
- 56. The method of claim 1 wherein the catalyst comprises about 1 to 10% by weight Iron oxide, about 1 to 10% by weight niobium oxide, 0.1 to 1% by weight molybdenum oxide with the remainder being titania or a mixture of titania and silica.
- 57. The method of claim 1 wherein the catalyst comprises about 1 to 10% by weight cobalt oxide, about 1 to 10% by weight niobium oxide, 0.1 to 1% by weight molybdenum oxide with the remainder being titania or a mixture of titania and silica.
- 58. The method of claim 1 wherein the mixed metal oxide catalyst comprises about 0.4 to 0.6% by weight molybdenum oxide, about 4 to 6% by weight niobium oxide, about 4 to 6% by weight of copper oxide, cobalt oxide, iron oxide, or a mixture thereof with the remainder being titania or a mixture of titania and silica.
- 59. The method of claim 1 wherein the mixed metal oxide catalyst comprises up to about 10% by weight of a binder.
- 60. The method of claim 59 wherein the binder is silica.
- 61. The method of claim 1 wherein the mixed metal oxide catalyst comprises titania in combination with one or more mixed metal oxides wherein the metal is selected from Fe, Cu, Co, Mo, Nb, Mn and Cr and wherein the temperature at which step a is conducted ranges between about 160° C. to about 250° C.
- 62. The method of claim 61 wherein the amount of oxygen in the gas stream is such that the ratio of O2/H2S is about 0.4 to about 1.75.
- 63. The method of claim 62 wherein the amount of oxygen in the gas stream is such that the ratio of O2/H2S is about 1:1.
- 64. The method of claim 1 wherein the catalyst is co-formed.
- 65. The method of claim 1 wherein the catalyst is formed into pellets or is extruded.
- 66. The method of claim 1 wherein the catalyst has a surface area ranging from about 50 to about 150 m2/g.
- 67. The method of claim 1 wherein the catalyst is sulfated on contact with hydrogen sulfide, sulfur dioxide or sulfur.
- 68. The method of claim 1 wherein the catalyst is prepared by calcining a mixed metal oxide powder at a temperature of about 300° C. to 550° C.
- 69. The method of claim 1 wherein the catalyst is prepared by calcining a mixed metal oxide powder at a temperature of about 400° C. to 450° C.
- 70. The method of claim 1 wherein the mixed metal oxide catalyst is prepared by co-forming.
- 71. The method of claim 1 wherein the gas stream also contains water vapor.
- 72. The method of claim 1 wherein the gas stream also contains CO2.
- 73. A method for removing hydrogen sulfide from a feed gas stream containing other oxidizable components which comprises the steps of
a. selectively oxidizing hydrogen sulfide in the feed gas stream using the method of claim 1 to generate sulfur, SO2 or both in a product gas stream b. optionally removing at least a portion of sulfur, sulfur dioxide or both in the product gas stream; and c. optionally returning the product gas stream from which sulfur, SO2 or both have been removed to step a, if necessary, to generate additional sulfur, sulfur dioxide or both and repeating step b and c until the undesired hydrogen sulfide is removed from the gas stream.
- 74. The method of claim 73 wherein the metal oxide catalyst comprises titania or a mixture of titania and silica in combination with an oxide of Fe, Co or Cu, a metal oxide of Mo, and a metal oxide of Nb.
- 75. The method of claim 73 where in step a the temperature of operation, catalyst and the O2/H2S ratio in the feed gas stream are selected to generate a product gas stream which by itself or when blended with the feed gas stream generates a product gas stream in which the H2S/SO2 ratio is about 2 to 1 and further comprising the step of treating the product gas stream by liquid phase Claus sulfur recovery process in which SO2 and H2S are reacted to form sulfur and water.
- 76. The method of claim 75 wherein sulfur is condensed and removed from the product stream prior to blending with the feed gas stream or prior to treatment of the product gas stream by the liquid phase Claus process.
- 77. The method of claim 73 where in step a the temperature of operation, catalyst and the O2/H2S ratio in the feed gas stream are selected to generate a product gas stream in which sulfur generated by H2S oxidation is maximized and SO2 generated by H2S oxidation is minimized and in which sulfur is removed from the product gas stream and which further comprises the step of treating the product gas stream with a liquid redox process for removal of remaining H2S.
- 78. The method of claim 73 where in step a the temperature of operation, catalyst and the O2/H2S ratio in the feed gas stream are selected to generate a product gas stream in which sulfur generated by H2S oxidation is maximized and SO2 generated by H2S oxidation is minimized and in which sulfur is removed from the product gas stream and which further comprises the step of treating the product gas stream with a biological sulfur removal process for removal of remaining H2S.
- 79. The method of claim 73 where in step a the temperature of operation, catalyst and the O2/H2S ratio in the feed gas stream are selected to generate a product gas stream in which sulfur generated by H2S oxidation is maximized and SO2 generated by H2S oxidation is minimized and in which sulfur is removed from the product gas stream and which further comprises the step of treating the product gas stream with a scavenger process for removal of remaining H2S.
- 80. The process of claim 73 wherein in step a the temperature of operation, catalyst and the O2/H2S ratio in the feed gas stream are selected to generate a product gas stream in which sulfur generated by H2S oxidation is maximized and SO2 generated by H2S oxidation is minimized and in which sulfur is removed from the product gas stream and which further comprises the step of treating the product gas stream in an amine separation unit to separate H2S, SO2 or both from the product gas to generate a feed gas stream containing H2S, SO2 or both which is thereafter returned to step a.
- 81. The process of claim 73 wherein the feed gas stream is a natural gas stream containing H2S.
- 82. The method of claim 73 wherein the metal oxide catalyst comprises titania or a mixture of titania and silica in combination with an oxide of Fe, Co or Cu, a metal oxide of Mo, and a metal oxide of Nb.
- 83. A method for desulfurization of a gas stream containing carbon monoxide and hydrogen which comprises the step of
a. contacting the gas stream with a mixed metal oxide catalyst at a temperature equal to or less than about 400° C. in the presence of a selected amount of oxygen; wherein the mixed metal oxide catalyst comprises a low oxidation activity metal oxide and one or more higher oxidation activity metal oxides such that a substantial amount of the hydrogen sulfide present in the gas stream is oxidized to sulfur dioxide, sulfur or a mixture thereof and wherein less than about 10% by volume of the carbon monoxide and hydrogen are oxidized.
- 84. The method of claim 83 wherein the low oxidation activity metal oxide is selected from titania, silica, alumina or a mixture thereof.
- 85. The method of claim 83 wherein the higher oxidation activity metal oxide is selected from a metal oxide in which the metal is selected from V, Cr, Mn, Fe, Co, Ni, Cu, Nb, Mo, Tc, Ru, Rh, Hf, Ta, W, Au, La, Ce, Pr, Nd, Pm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu and mixtures thereof.
- 86. The method of claim 83 wherein the higher oxidation activity metal oxide is selected from a metal oxide in which the metal is selected from Fe, Co, Cr, Cu, Mo, Nb and mixtures thereof.
- 87. The method of claim 83 wherein the mixed metal oxide catalyst comprises titania, alumina, silica or mixtures thereof in combination with one or more metal oxides in which the metal is Fe, Co, Cr, Cu, Mo, Nb and mixtures thereof.
- 88. The method of claim 83 wherein the mixed metal oxide catalyst comprises about 0.1% to about 1% by weight of an oxide of Mo, about 1% to about 10% by weight of an oxide of Nb and optionally from about 1% to about 10% by weight of an oxide of Fe, Cu, Co or mixtures thereof.
- 89. The method of claim 83 wherein the remainder of the mixed metal oxide catalyst is titania or a mixture of titania and silica.
- 90. The method of claim 83 wherein the mixed metal oxide catalyst comprises titania in combination with about 0.5 to 1% by weight molybdenum oxide, and about 4 to 6% by weight niobium oxide.
- 91. The method of claim 83 wherein the mixed metal oxide catalyst comprises titania in combination with about 0.5 to 1% by weight molybdenum oxide, and about 5% by weight niobium oxide.
- 92. The method of claim 83 wherein step a is conducted at a temperature between about 100° C. and about 400° C.
- 93. The method of claim 83 wherein step a is conducted at a temperature of about 200° C.
- 94. The method of claim 83 wherein H2S is oxidized into elemental sulfur, sulfur dioxide (SO2) or both.
- 95. The method of claim 83 wherein the space velocity of step a is between about 500 and 20,000 m3 of gas/m3 of catalyst/hour.
- 96. The method of claim 83 wherein step a is conducted at ambient pressure.
- 97. The method of claim 83 wherein step a is conducted at a pressure above ambient up to about 1000 psig.
- 98. A catalytic reactor system for selectively oxidizing hydrogen sulfide in a gas stream containing hydrogen sulfide to sulfur dioxide, sulfur or mixtures thereof which comprises:
a catalytic reactor containing a mixed metal oxide catalyst in which an entering gas stream containing hydrogen sulfide and an oxygen-containing gas are contacted with the catalyst, a sulfur condenser for removing sulfur produced in the catalytic reaction from the gas stream to generate a gas stream with decreased levels of hydrogen sulfide; and a outlet for exiting the treated gas stream for release of the gas stream with decreased levels of hydrogen sulfide from the system or for passage of the exiting gas stream with decreased levels of hydrogen sulfide to downstream processing; wherein the mixed metal oxide catalyst comprises a low oxidation activity metal oxide and one or more higher oxidation activity metal oxides such that a substantial amount of the hydrogen sulfide present in the gas stream is oxidized to sulfur dioxide, sulfur or a mixture thereof, wherein the entering gas stream contains oxidizable components other than sulfur containing compounds and wherein less than about 25% by volume of the oxidizable components except sulfur containing compounds in the entering gas stream are oxidized by the added oxygen.
- 99. The catalytic reactor system of claim 98 wherein the catalytic reactor is operated at a temperature less than or equal to 400° C.
- 100. The catalytic reactor system of claim 98 wherein the catalytic reactor is operated at a temperature between about 160° C. and about 250° C.
- 101. The catalytic reactor system of claim 98 wherein the downstream processing is selected from the groups consisting of:
treating the exiting gas stream with scavenging chemicals; passing the exiting gas stream into a liquid phase redox sulfur removal system; passing the exiting gas stream into a tail gas treatment system; passing the exiting gas stream into a liquid Claus sulfur removal system; or passing the exiting gas stream into a Claus reactor.
- 102. The catalytic reactor of claim 101 wherein the gas stream after downstream processing contains 4 ppmv of hydrogen sulfide or less.
- 103. The catalytic reactor of claim 98 further comprising an entering gas stream bypass for directing a portion of the entering gas stream directly to downstream processing.
- 104. The catalytic reactor of claim 98 further comprising a recycling system for directing at least a portion of the gas stream exiting the catalytic reactor, the gas stream exiting downstream processing or both into the entering gas stream.
- 105. The catalytic reactor of claim 98 further comprising a recycling system for directing at least a portion of the gas stream exiting downstream processing into the gas stream exiting the catalytic reactor for another passage through downstream processing.
- 106. The catalytic reactor of claim 98 wherein the entering gas stream is a natural gas stream or a synthesis gas stream.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application takes priority under 35 U.S.C. 119(e) from U.S. provisional applications Nos. 60/367,891, filed Mar. 25, 2002; 60/388,322, filed Jun. 13, 2002; and 60/420,694, filed Oct. 22, 2002, all of which are incorporated in their entirety by reference herein.
REFERENCE TO GOVERNMENT FUNDING
[0002] The work leading to this invention was funded at least in part by the United States Government through Department of Energy grant Nos. DE-FC26-99FT40725 and DE-FC26-99FT40497. The United States Government has certain rights in this invention.
Provisional Applications (3)
|
Number |
Date |
Country |
|
60367891 |
Mar 2002 |
US |
|
60388322 |
Jun 2002 |
US |
|
60420694 |
Oct 2002 |
US |