Apparatus and Integrated Process for Separating a Mixture of Carbon Dioxide and at Least One Other Gas and for Separating Air by Cryogenic Distillation

Abstract

An integrated apparatus for separating a mixture of carbon dioxide and at least one other gas and for separating air by air distillation is provided. The apparatus includes a CO 2 separation unit configured to separate the mixture, an air separation unit configured to separate air by cryogenic distillation, a water cooling tower that operates by direct contact, a line for sending water to the top of the tower, a line for sending at least one portion of the nitrogen-enriched gas stream to a lower level of the tower, a cooled water line for withdrawing cooled water from the tower and means for cooling the air upstream of the air separation unit, the cooled water line being connected to means for cooling the air upstream of the air separation unit and to the inlet and/or to the outlet of the unit for separating the gaseous mixture.

1 - 15 . (canceled) 
     
     
         16 . An apparatus for separating a mixture of carbon dioxide and at least one other gas and for separating air by air distillation, the apparatus comprising:
 a CO 2  separation unit configured to separate a gaseous mixture comprising carbon dioxide and at least one other gas in order to produce a carbon dioxide-enriched gas and a carbon dioxide depleted gas;   an air separation unit (ASU) configured to separate air by cryogenic distillation in order to produce at least one nitrogen-enriched gas stream; and   a water cooling tower that operates by direct contact as well as a line for sending water to the top of the water cooling tower, a line for sending at least one portion of the nitrogen-enriched gas stream to a lower level of the water cooling tower, a cooled water line for withdrawing cooled water from the water cooling tower and means for cooling the air upstream of the air separation unit, the cooled water line being connected to means for cooling the air upstream of the air separation unit and to the inlet and/or to the outlet of the CO 2  separation unit.   
     
     
         17 . The apparatus as claimed in  claim 16 , wherein the means for cooling the air upstream of the ASU comprises a scrubbing tower with water. 
     
     
         18 . The apparatus as claimed in  claim 17 , wherein the means for cooling the air upstream of the ASU further comprises a line configured to send heated water from the scrubbing tower to the water cooling tower. 
     
     
         19 . The apparatus as claimed in  claim 16 , wherein the cooled water line is configured to send cooled water from the tower to the CO 2  separation unit such that refrigeration is provided to the gaseous mixture to be separated or to a product from the separation. 
     
     
         20 . The apparatus as claimed in  claim 16 , further comprising an oxy-fuel combustion unit, a line for sending oxygen from the ASU to the oxy-fuel combustion unit and a line for sending fumes from the oxy-fuel combustion to the CO 2  separation unit . 
     
     
         21 . The apparatus as claimed in  claim 16 , further comprising a line configured to send the carbon dioxide depleted gas to the water cooling tower and wherein possibly the level of introduction of the nitrogen-enriched gas stream is lower than the level of the tower where the carbon dioxide depleted gas is sent. 
     
     
         22 . The apparatus as claimed in  claim 16 , further comprising a mechanical refrigeration unit configured to cool the water cooled in the cooling tower upstream of the means for cooling the air upstream of the ASU and/or before it is sent to the CO 2  separation unit. 
     
     
         23 . The apparatus as claimed in  claim 16 , wherein the line for sending at least one portion of the nitrogen-enriched gas stream from the ASU is connected to a lower level of the tower without passing through a turbine or an exchanger configured to cool the gaseous mixture. 
     
     
         24 . An integrated process for separating a mixture of carbon dioxide and at least one other gas and for separating air by air distillation, comprising a CO 2  separation unit configured to separate a gaseous mixture comprising carbon dioxide and at least one other gas to produce a carbon dioxide-enriched gas and a carbon dioxide depleted gas and an air separation unit by cryogenic distillation in order to produce at least one nitrogen-enriched gas stream wherein the water is cooled in a water cooling tower that operates by direct contact with the nitrogen-enriched  gas stream, the air intended for the air separation unit is cooled with water cooled in the cooling tower and the gaseous mixture intended for the CO 2  separation unit and/or a product from the CO 2  separation unit is cooled using the cooled water coming from the cooling tower. 
     
     
         25 . The process as claimed in  claim 24 , wherein the air upstream of the air separation unit is cooled in a scrubbing tower with water supplied by water cooled in the water tooling tower. 
     
     
         26 . The process as claimed in  claim 24 , further comprising the steps of sending the oxygen from the ASU to an oxy-fuel combustion unit; and sending fumes from the oxy-fuel combustion to the CO 2  separation unit. 
     
     
         27 . The process as claimed in  claim 24 , further comprising sending carbon dioxide depleted gas from the CO 2  separation unit to the water cooling tower, 
     
     
         28 . The process as claimed in  claim 27 , wherein the level of introduction of the nitrogen-enriched gas stream is lower than the level of the tower where the carbon dioxide depleted gas is sent. 
     
     
         29 . The process as claimed in  claim 24 , wherein the cooled water is cooled in the cooling tower by means of a mechanical refrigeration unit before sending it to the means for cooling air upstream of the air separation unit and/or before sending it to the CO 2  separation unit. 
     
     
         30 . The process as claimed in  claim 24 , wherein the carbon dioxide depleted gas is expanded in a valve to a pressure lower than that at which the nitrogen-enriched gas stream is introduced in the water cooling tower. 
     
     
         31 . The process as claimed in  claim 24 , wherein at least one other gas in the mixture is selected from the group consisting of nitrogen, oxygen, argon, hydrogen, carbon monoxide, methane, NO 2 , and combinations thereof, and the mixture contains at least 40 mol. % of carbon dioxide. 
     
     
         32 . The process as claimed in  claim 24 , wherein at least one other gas in the mixture is selected from the group consisting of hydrogen, carbon monoxide, methane, and combinations thereof, and wherein a wet gas exiting from the top of the water cooling tower is used as a fuel.