초록 ▼

The present invention generally relates to vacuum pressure swing adsorption (VPSA) processes and apparatus to recover carbon dioxide having a purity of approximately ≧80 mole percent from streams containing at least carbon dioxide and hydrogen (e.g., syngas). The feed to the CO2 VPSA can be a

The present invention generally relates to vacuum pressure swing adsorption (VPSA) processes and apparatus to recover carbon dioxide having a purity of approximately ≧80 mole percent from streams containing at least carbon dioxide and hydrogen (e.g., syngas). The feed to the CO2 VPSA can be at super ambient pressure. The CO2 VPSA unit produces two streams, a H2-enriched stream and a CO2 product stream. The process cycle steps are selected such that there is minimal or no hydrogen losses from the process. The recovered CO2 can be further upgraded, sequestered or used in applications such as enhanced oil recovery (EOR).

대표청구항 ▼

What is claimed is: 1. A vacuum pressure swing adsorption (VPSA) process for the recovery of carbon dioxide from a multi-component gas mixture containing at least carbon dioxide and hydrogen in a VPSA unit containing at least one adsorption bed containing at least one CO2-selective adsorbent, the p

What is claimed is: 1. A vacuum pressure swing adsorption (VPSA) process for the recovery of carbon dioxide from a multi-component gas mixture containing at least carbon dioxide and hydrogen in a VPSA unit containing at least one adsorption bed containing at least one CO2-selective adsorbent, the process comprising: feeding the multi-component gas mixture containing the at least carbon dioxide and the hydrogen to the at least one adsorption bed at a first pressure within a first pressure range for a predetermined time to produce a hydrogen-enriched stream; depressurizing the at least one adsorption bed in a first depressurization step from the first pressure to a second pressure within a second pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a second depressurization step from the second pressure to a third pressure within a third pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a third depressurization step from the third pressure to a fourth pressure within a fourth pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a final depressurization step from the fourth pressure to a pressure range close to ambient in a same direction as the feed flow or in a direction opposite the feed flow to produce at least a first portion of CO2 product; evacuating the at least one adsorption bed from the pressure close to ambient to a pressure at or below ambient in a direction opposite the feed flow to produce at least a second portion of CO2 product and during the evacuating step, the at least one adsorption bed receiving at least a portion of the first portion of CO2 product; pressure equalizing the at least one adsorption bed in a first pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a second pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a third pressure equalization step in a direction opposite the feed flow; and repressurizing the at least one adsorption bed in a repressurization step to the first pressure range; wherein the process is repeated cyclically. 2. The process of claim 1, wherein the number of adsorption beds comprises six beds. 3. The process of claim 1, wherein the first pressure range is between about 100-500 psia. 4. The process of claim 2 wherein the adsorption beds are in a single train configuration. 5. The process of claim 1, wherein the second pressure range is between about 80-400 psia. 6. The process of claim 1, wherein the third pressure range is between about 60-300 psia. 7. The process of claim 1, wherein the fourth pressure range is between about 50-200 psia. 8. The process of claim 1, wherein the first depressurization step is in a direction the same as the direction of the feed flow. 9. The process of claim 1, wherein the first depressurization step is in an opposite direction as the direction of the feed flow. 10. The process of claim 1, wherein the second depressurization step is in a direction the same as the direction of the feed flow. 11. The process of claim 1, wherein the second depressurization step is in an opposite direction as the direction of the feed flow. 12. The process of claim 1, wherein the third depressurization step is in a direction the same as the direction of the feed flow. 13. The process of claim 1, wherein the third depressurization step is in an opposite direction as the direction of the feed flow. 14. The process of claim 1, wherein the fourth depressurization step is in a direction the same as the direction of the feed flow. 15. The process of claim 1, wherein the fourth depressurization step is in an opposite direction as the direction of the feed flow. 16. The process of claim 1, wherein the pressure range for the pressure close to ambient is about 20 psia. 17. The process of claim 1, wherein the pressure range for the pressure below ambient is 1-12 psia. 18. The process of claim 1, wherein hydrogen-enriched stream is fed to a hydrogen recovery unit. 19. The process of claim 18, wherein the hydrogen recovery unit is a hydrogen pressure swing adsorption (PSA) unit. 20. The process of claim 1, wherein the third pressure equalization step increase CO2recovery. 21. The process of claim 1, wherein the at least first and at least second portions of the CO2 product are combined to form a final CO2 product. 22. The process of claim 1, wherein each at least one bed contains a water-selective adsorbent and a CO2-selective adsorbent. 23. The process of claim 22, wherein the water-selective adsorbent is selected from the group comprising: activated alumina, silica gel, zeolite molecular sieve and combinations thereof. 24. The process of claim 22, wherein the CO2-selective adsorbent is selected from the group comprising: NaY, HY, NaX, silica gel, activated carbon and combinations thereof. 25. A vacuum pressure swing adsorption (VPSA) process for the recovery of carbon dioxide from a multi-component gas mixture containing at least carbon dioxide and hydrogen in a VPSA unit containing at least one adsorption bed containing at least one CO2-selective adsorbent, the process comprising: feeding the multi-component gas mixture containing the at least carbon dioxide and the hydrogen to the at least one adsorption bed at a first pressure within a first pressure range for a predetermined time to produce a hydrogen-enriched stream; depressurizing the at least one adsorption bed in a first depressurization step from the first pressure to a second pressure within a second pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a second depressurization step from the second pressure to a third pressure within a third pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a final depressurization step from the third pressure to a pressure range close to ambient in a same direction as the feed flow or in a direction opposite the feed flow to produce at least a first portion of CO2 product; evacuating the at least one adsorption bed from the pressure close to ambient to a pressure at or below ambient in a direction opposite the feed flow to produce at least a second portion of CO2 product and during the evacuating step, the at least one adsorption bed receiving at least a portion of the first portion of CO2 product; pressure equalizing the at least one adsorption bed in a first pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a second pressure equalization step in a direction opposite the feed flow; and repressurizing the at least one adsorption bed in a repressurization (RP) step to the first pressure range; wherein the process is repeated cyclically. 26. The process of claim 25, wherein the number of adsorption beds comprises five beds. 27. The process of claim 25, wherein the first pressure range is between about 100-500 psia. 28. The process of claim 26 , wherein the adsorption beds are in a single train configuration. 29. The process of claim 25, wherein the second pressure range is between about 80-400 psia. 30. The process of claim 25, wherein the third pressure range is between about 60-300 psia. 31. The process of claim 25, wherein the first depressurization step is in a direction the same as the direction of the feed flow. 32. The process of claim 25, wherein the first depressurization step is in an opposite direction as the direction of the feed flow. 33. The process of claim 25, wherein the second depressurization step is in a direction the same as the direction of the feed flow. 34. The process of claim 25, wherein the second depressurization step is in an opposite direction as the direction of the feed flow. 35. The process of claim 25, wherein the third depressurization step is in a direction the same as the direction of the feed flow. 36. The process of claim 25, wherein the third depressurization step is in an opposite direction as the direction of the feed flow. 37. The process of claim 25, wherein the pressure range for the pressure close to ambient is about 20 psia. 38. The process of claim 25, wherein the pressure range for the pressure below ambient is 1-12 psia. 39. The process of claim 25, wherein the hydrogen-enriched stream is fed to a hydrogen recovery unit. 40. The process of claim 39, wherein the hydrogen recovery unit is a hydrogen pressure swing adsorption (PSA) unit. 41. The process of claim 25, wherein the at least first and at least second portions of the CO2 product are combined to form a final CO2 product. 42. The process of claim 25, wherein each at least one bed contains a water-selective adsorbent and a CO2-selective adsorbent. 43. The process of claim 42, wherein the water-selective adsorbent is selected from the group comprising: activated alumina, silica gel, zeolite molecular sieve and combinations thereof. 44. The process of claim 42, wherein the CO2-selective adsorbent is selected from the group comprising: NaY, HY, NaX, silica gel, activated carbon and combinations thereof. 45. A vacuum pressure swing adsorption (VPSA) process for the recovery of carbon dioxide from a multi-component gas mixture containing at least carbon dioxide and hydrogen in a VPSA unit containing at least one adsorption bed containing at least one CO2-selective adsorbent, the process comprising: feeding the multi-component gas mixture containing the at least carbon dioxide and the hydrogen to the at least one adsorption bed at a first pressure within a first pressure range for a predetermined time to produce a hydrogen-enriched stream; depressurizing the at least one adsorption bed in a first depressurization step from the first pressure to a second pressure within a second pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a second depressurization step from the second pressure to a third pressure within a third pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a third depressurization step from the third pressure to a fourth pressure within a fourth pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a final depressurization step from the fourth pressure range to a pressure range close to ambient in a same direction as the feed flow or in a direction opposite the feed flow to produce at least a first portion of CO2 product; evacuating the at least one adsorption bed from the pressure close to ambient to a pressure at or below ambient in a direction opposite the feed flow to produce at least a second portion of CO2 product; pressure equalizing the at least one adsorption bed in a first pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a second pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a third pressure equalization step in a direction opposite the feed flow; and repressurizing the at least one adsorption bed in a repressurization step to the first pressure range; wherein the process is repeated cyclically. 46. The process of claim 45, wherein the number of adsorption beds comprises six beds. 47. The process of claim 45, wherein the first pressure range is between about 100-500 psia. 48. The process of claim 46, wherein the adsorption beds are in a single train configuration. 49. The process of claim 45, wherein the second pressure range is between about 80-400 psia. 50. The process of claim 45, wherein the third pressure range is between about 60-300 psia. 51. The process of claim 45, wherein the fourth pressure range is between about 50-200 psia. 52. The process of claim 45, wherein the first depressurization step is in a direction the same as the direction of the feed flow. 53. The process of claim 45, wherein the first depressurization step is in an opposite direction as the direction of the feed flow. 54. The process of claim 45, wherein the second depressurization step is in a direction the same as the direction of the feed flow. 55. The process of claim 45, wherein the second depressurization step is in an opposite direction as the direction of the feed flow. 56. The process of claim 45, wherein the third depressurization step is in a direction the same as the direction of the feed flow. 57. The process of claim 45, wherein the third depressurization step is in an opposite direction as the direction of the feed flow. 58. The process of claim 45, wherein the fourth depressurization step is in a direction the same as the direction of the feed flow. 59. The process of claim 45, wherein the fourth depressurization step is in an opposite direction as the direction of the feed flow. 60. The process of claim 45, wherein the pressure range for the pressure close to ambient is about 20 psia. 61. The process of claim 45, wherein the pressure range for the pressure below ambient is about 1-12 psia. 62. The process of claim 45, wherein the hydrogen-enriched stream is fed to a hydrogen recovery unit. 63. The process of claim 62, wherein the hydrogen recovery unit is a hydrogen pressure swing adsorption (PSA) unit. 64. The process of claim 45, wherein the first pressure equalization step increase CO2 recovery. 65. The process of claim 45, wherein the second pressure equalization step increase CO2 recovery. 66. The process of claim 45, wherein the fourth pressure equalization step increase CO2 recovery. 67. The process of claim 45, wherein the at least first and at least second portions of the CO2 product are combined to form a final CO2 product. 68. The process of claim 45, wherein each at least one bed contains a water-selective adsorbent and a CO2-selective adsorbent. 69. The process of claim 68, wherein the water-selective adsorbent is selected from the group comprising: activated alumina, silica gel, zeolite molecular sieve and combinations thereof. 70. The process of claim 68, wherein the CO2-selective adsorbent is selected from the group comprising: NaY, MY, NaX, silica gel, activated carbon and combinations thereof. 71. A vacuum pressure swing adsorption (VPSA) process for the recovery of carbon dioxide from a multi-component gas mixture containing at least carbon dioxide and hydrogen in a VPSA unit containing at least one adsorption bed containing at least one CO2-selective adsorbent, the process comprising: feeding the multi-component gas mixture containing the at least carbon dioxide and the hydrogen to the at least one adsorption bed at a first pressure within a first pressure range for a predetermined time to produce a hydrogen-enriched stream; depressurizing the at least one adsorption bed in a first depressurization step from the first pressure to a second pressure within a second pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a second depressurization step from the second pressure to a third pressure within a third pressure range in a same direction as or an opposite direction as the feed flow; depressurizing the at least one adsorption bed in a final depressurization step from the third pressure to a pressure range close to ambient in a same direction as the feed flow or in a direction opposite the feed flow to produce at least a first portion of CO2 product; evacuating the at least one adsorption bed from the pressure close to ambient to a pressure at or below ambient in a direction opposite the feed flow to produce at least a second portion of CO2 product; pressure equalizing the at least one adsorption bed in a first pressure equalization step in a direction opposite the feed flow; further pressure equalizing the at least one adsorption bed in a second pressure equalization step in a direction opposite the feed flow; and repressurizing the at least one adsorption bed in a repressurization step to the first pressure range; wherein the process is repeated cyclically. 72. The process of claim 71, wherein the number of adsorption beds comprises five beds. 73. The process of claim 71, wherein the first pressure range is between about 100-500 psia. 74. The process of claim 72 ,wherein the adsorption beds are in a single train configuration. 75. The process of claim 71, wherein the second pressure range is between about 80-400 psia. 76. The process of claim 71, wherein the third pressure range is between about 60-300 psia. 77. The process of claim 71, wherein the first depressurization step is in a direction the same as the direction of the feed flow. 78. The process of claim 71, wherein the first depressurization step is in an opposite direction as the direction of the feed flow. 79. The process of claim 71, wherein the second depressurization step is in a direction the same as the direction of the feed flow. 80. The process of claim 71, wherein the second depressurization step is in an opposite direction as the direction of the feed flow. 81. The process of claim 71, wherein the third depressurization step is in a direction the same as the direction of the feed flow. 82. The process of claim 71, wherein the third depressurization step is in an opposite direction as the direction of the feed flow. 83. The process of claim 71, wherein the pressure range for the pressure close to ambient is about 20 psia. 84. The process of claim 71, wherein the pressure range for the pressure below ambient is 1-12 psia. 85. The process of claim 71, wherein the hydrogen-enriched stream is fed to a hydrogen recovery unit. 86. The process of claim 71, wherein the hydrogen recovery unit is a hydrogen pressure swing adsorption (PSA) unit. 87. The process of claim 71, wherein the at least first and at least second portions of the CO2 product are combined to form a final CO2 product. 88. The process of claim 71, wherein each at least one bed contains a water-selective adsorbent and a CO2-selective adsorbent. 89. The process of claim 88, wherein the water-selective adsorbent is selected from the group comprising: activated alumina, silica gel, zeolite molecular sieve and combinations thereof. 90. The process of claim 88, wherein the CO2-selective adsorbent is selected from the group comprising: NaY, HY, NaX, silica gel, activated carbon and combinations thereof. 91. A vacuum pressure swing adsorption (VPSA) process for the recovery of carbon dioxide from a multi-component gas mixture containing at least carbon dioxide and hydrogen in a VPSA unit containing at least two adsorption beds in a single train configuration, each bed containing at least one CO2-selective adsorbent, the process comprising: cyclically maintaining the at least two beds in a step selected from the group comprising: a feed step, a depressurization step, an evacuation step, a pressure equalization step and a repressurization step; wherein a hydrogen-enriched stream is produced and a final CO2 product is produced from at least one CO2 product stream; and wherein the final CO2 product is at a purity of approximately ≧80 mole% CO2. 92. The process of claim 91, wherein the number of adsorption beds comprises five beds. 93. The process of claim 91, wherein the number of adsorption beds comprises six beds. 94. The process of claim 91, wherein the number of adsorption beds comprises seven beds. 95. The process of claim 69, wherein the number of adsorption beds comprises eight beds. 96. The process of claim 91, wherein the number of adsorption beds comprises eleven beds. 97. The process of claim 91, wherein each bed contains a water-selective adsorbent and a CO2-selective adsorbent. 98. The process of claim 97, wherein the water-selective adsorbent is selected from the group comprising: activated alumina, silica gel, zeolite molecular sieve and combinations thereof. 99. The process of claim 97, wherein the CO2-selective adsorbent is selected from the group comprising: NaY, HY, NaX, silica gel, activated carbon and combinations thereof. 100. The process of claim 91, wherein the hydrogen-enriched stream is fed to a hydrogen recovery unit. 101. The process of claim 100, wherein the hydrogen recovery unit is a hydrogen pressure swing adsorption (PSA) unit.