Integrated Method and Installation for Cryogenic Adsorption and Separation for Producing Co2

Abstract

An integrated process and installation implementing a unit of adsorption ( 3 ) and a cryogenic unit ( 9 ), in which a gas of food containing of CO 2 is sent to the unit of adsorption ( 3 ) where it separates in a first flow enriched out of CO 2 ( 6 ) and a first flow impoverished of CO 2 ( 5 ), first flow enriched out of CO 2 being sent to the cryogenic unit ( 9 ) where it is separate in a second flow rich in CO 2 ( 11 ) and a second flow low in CO 2 ( 10 ). The first flow enriched out of CO 2 ( 6 ) resulting from the unit from adsorption ( 3 ) is sent towards means of homogenization ( 17 ), a such storage capacity or analogue, making it possible to attenuate the cyclic variations of flow, composition and/or gas pressure, then subjected to at least a stage of intermediate compression ( 7 ) before its entry in the cryogenic unit ( 9 ). The first gas enriched out of CO 2 ( 6 ) outgoing by the unit by adsorption ( 3 ) contains between 40 and 95% of CO 2 , preferentially between 60 and 85% of CO 2 .

1 - 17 . (canceled) 
     
     
         18 - 34 . (canceled) 
     
     
         35 . An integrated method using an adsorption unit and a cryogenic unit, in which a feed gas containing CO 2  is sent to the adsorption unit where it is separated into a first CO 2  enriched stream and a first CO 2  depleted stream, the first CO 2  enriched stream being sent to the cryogenic unit where it is separated into a second CO 2  rich stream and a second CO 2  depleted stream, wherein the first CO 2  enriched stream issuing from the adsorption unit contains between about 40% and about 95% CO 2  preferably between about 60% and about 85% CO 2 , and is sent to gas homogenizing means for attenuating cyclic variations in pressure, flow rate and/or composition of said gas, and is then subjected to at least one intermediate compression step before it enters the cryogenic unit. 
     
     
         36 . The method of  claim 35 , wherein the gas homogenizing means comprise at least one storage vessel or reservoir, the vessel or reservoir being preferably maintained at a substantially constant pressure. 
     
     
         37 . The method of  claim 35 , wherein the first CO 2  enriched stream issuing from the adsorption unit has a pressure lower than about 4 bar, and preferably lower than about 2 bar. 
     
     
         38 . The method of  claim 35 , wherein the second CO 2  rich stream issuing from the cryogenic separation unit has a CO 2  content above about 80%, preferably above about 90%, and even more preferably above about 95%. 
     
     
         39 . The method of  claim 35 , wherein at least part of the second CO 2  depleted gas leaving the cryogenic unit is returned to the adsorption unit. 
     
     
         40 . The method of  claim 39 , wherein at least part of the second CO 2  depleted gas leaving the cryogenic unit is returned either to the suction inlet of a compressor feeding the adsorption unit, or upstream of the adsorber(s) of the adsorption unit, or in the adsorber(s) of the adsorption unit during a repressurizing step, in cocurrent or countercurrent, or during an adsorption step. 
     
     
         41 . The method of  claim 35 , wherein a refrigerating unit of the cryogenic unit is also used to cool the feed gas entering the adsorption unit. 
     
     
         42 . The method of  claim 35 , wherein the first CO 2  depleted stream produced by the adsorption unit is expanded in a turbine to produce refrigerating capacity for the cryogenic unit. 
     
     
         43 . The method of  claim 35 , wherein at least part of the second CO 2  depleted gas leaving the cryogenic unit is expanded in a turbine. 
     
     
         44 . The method of  claim 43 , wherein at least part of the second CO 2  depleted gas expanded in a turbine is recycled to the adsorption unit. 
     
     
         45 . The method of  claim 44 , wherein the expanded second CO 2  depleted gas is recycled either to the suction inlet of a compressor feeding the adsorption unit, or upstream of the adsorber(s) of the adsorption unit, or in the adsorber(s) during a repressurizing step, in cocurrent or countercurrent, or during an adsorption step. 
     
     
         46 . The method of  claim 43 , wherein before entering the turbine, the recycled gas is previously heated. 
     
     
         47 . The method of  claim 35 , wherein at least part of the CO 2  enriched stream compressed in the intermediate compression step is cooled to a temperature above about 0° C., and the liquid part which condenses is preferably removed. 
     
     
         48 . The method of  claim 35 , wherein the incondensable compounds leaving the cryogenic unit are sufficiently cooled to freeze CO 2  in the form of dry ice and to separate the CO 2  thereby frozen from the stream containing the incondensable compounds. 
     
     
         49 . An integrated installation for producing CO 2  from a feed gas containing CO 2  comprising:
 a) an adsorption unit for separating the gas containing CO 2  into a first CO 2  enriched stream and a first CO 2  depleted stream the adsorption unit feeding a cryogenic unit with said first CO 2  enriched stream, and   b) a cryogenic unit for separating the first CO 2  rich stream issuing from the adsorption unit and producing a second CO 2  rich stream and a second CO 2  poor stream,   
       wherein it further comprises gas homogenizing means for attenuating cyclic variations in pressure, flow rate and/or composition of said gas, and intermediate compression means, arranged on the path of the first CO 2  enriched stream, between the adsorption unit and the cryogenic unit. 
     
     
         50 . The installation of claim  32 , wherein the gas homogenizing means comprise at least one storage vessel or reservoir. 
     
     
         51 . The installation of claim  32 , wherein the intermediate compression means comprise one or a plurality of gas compressors.