System And Process For The Physical Absorption of Carbon Dioxide From a Flue Gas Stream

Abstract

Disclosed herein is a system comprising a first heat exchanger; the first heat exchanger being operative to reduce a temperature of a carbon dioxide rich flue gas stream to about −100 to about −60 C; an absorber; the absorber being located downstream of the first heat exchanger; wherein the absorber facilitates contact between the flue gas stream and a solvent to form a carbon dioxide rich solvent stream; the solvent being operative to selectively absorb carbon dioxide over other gases present in the flue gas stream; and a valve; the valve being located downstream of the absorber; the valve being operative to reduce a pressure on the carbon dioxide rich solvent stream to produce carbon dioxide and a lean carbon dioxide solvent stream.

1 . A system comprising:
 a first heat exchanger; the first heat exchanger being operative to reduce a temperature of a carbon dioxide rich flue gas stream to about −100 to about −60° C.;   an absorber; the absorber being located downstream of the first heat exchanger;   
       wherein the absorber facilitates contact between the flue gas stream and a solvent to form a carbon dioxide rich solvent stream; the solvent being operative to selectively absorb carbon dioxide over other gases present in the flue gas stream; and
 a valve; the valve being located downstream of the absorber; the valve being operative to reduce a pressure on the carbon dioxide rich solvent stream to produce carbon dioxide and a lean carbon dioxide solvent stream. 
 
     
     
         2 . The system of  claim 1 , further comprising a flash tank; the flash tank being operative to facilitate a separation of the carbon dioxide from the lean carbon dioxide solvent stream. 
     
     
         3 . The system of  claim 2 , where the lean carbon dioxide solvent stream after separation from the carbon dioxide is recycled to the absorber. 
     
     
         4 . The system of  claim 2 , where the carbon dioxide after separation from the lean carbon dioxide solvent stream is discharged to an adiabatic compressor and to a intercooled compressor. 
     
     
         5 . The system of  claim 2 , where the carbon dioxide after separation from the lean carbon dioxide solvent stream is sequestered. 
     
     
         6 . The system of  claim 1 , further comprising a first active cooling system located downstream of the first heat exchanger; the first active cooling system comprising a second heat exchanger and a compressor in fluid communication with one another and where the first active cooling system is operative to reduce the temperature of the carbon dioxide rich flue gas stream. 
     
     
         7 . The system of  claim 1 , further comprising a second active cooling system located downstream of the first heat exchanger; the second active cooling system comprising a second heat exchanger and a compressor in fluid communication with one another and where the second active cooling system is operative to reduce the temperature of the lean carbon dioxide solvent stream. 
     
     
         8 . The system of  claim 2 , further comprising a plurality of throttle valves, flash tanks and adiabatic compressors to separate the lean carbon dioxide solvent stream from the carbon dioxide. 
     
     
         9 . The system of  claim 1 , wherein the solvent is an alcohol. 
     
     
         10 . The system of  claim 9 , where the alcohol is ethanol, methanol, propanol, butanol, or a combination comprising at least one of the foregoing. 
     
     
         11 . A method for capture of carbon dioxide from a flue gas stream, the process comprising:
 receiving a carbon dioxide rich flue gas stream from an emitter; the carbon dioxide rich flue gas stream being at the pressure and temperature of the emitter;   refrigerating the carbon dioxide rich flue gas stream to a pressure of greater than or equal to about 101.325 kPa and a temperature of about 0° C. to about the melting point of carbon dioxide for a given molar concentration of carbon dioxide within the carbon dioxide rich flue gas stream;   contacting the refrigerated carbon dioxide rich flue gas stream with a lean liquid carbon dioxide solvent stream; the lean liquid carbon dioxide solvent stream having a higher solubility for carbon dioxide than of other gases present in the carbon dioxide rich flue gas stream;   absorbing carbon dioxide with a liquid solvent to provide a carbon dioxide rich solvent stream and a lean carbon dioxide flue gas stream; and   decreasing pressure of the carbon dioxide rich solvent stream to provide the lean liquid carbon dioxide solvent stream and carbon dioxide gas.   
     
     
         12 . The method of  claim 11 , wherein the temperature to which the carbon dioxide rich flue gas stream is refrigerated is between about −100 to −60° C. 
     
     
         13 . The method of  claim 11 , wherein the refrigerating comprises cooling the carbon dioxide rich glue gas stream using the lean carbon dioxide flue gas stream. 
     
     
         14 . The method of  claim 11 , further comprising adiabatically compressing the carbon dioxide gas. 
     
     
         15 . The method of  claim 14 , wherein the adiabatic compression is performed using an axial compressor. 
     
     
         16 . The method of  claim 11 , wherein decreasing pressure of the carbon dioxide rich solvent stream is performed using a valve and a flash tank. 
     
     
         17 . The method of  claim 11 , wherein decreasing pressure of the carbon dioxide rich solvent stream is performed in a series of pressure reduction stages. 
     
     
         18 . The method of  claim 17 , wherein each pressure reduction stage includes a valve and a flash tank or a turbine and a flash tank. 
     
     
         19 . The method of  claim 11 , wherein at least one of the carbon dioxide rich flue gas stream and the carbon dioxide lean solvent stream is cooled by an active cooling loop. 
     
     
         20 . The method of  claim 11 , wherein the carbon dioxide rich flue gas stream is created by one of a fossil-fired power plant, a bio-fuel fired power plant or an industrial process.