Extraction of Carbon Dioxide and Hydrogen From Seawater and Hydrocarbon Production Therefrom

Abstract

Apparatus for seawater acidification including an ion exchange, cathode and anode electrode compartments and cation-permeable membranes that separate the electrode compartments from the ion exchange compartment. Means is provided for feeding seawater through the ion exchange compartment and for feeding a dissociable liquid media through the anode and cathode electrode compartments. A cathode is located in the cathode electrode compartment and an anode is located in the anode electrode compartment and a means for application of current to the cathode and anode is provided. A method for the acidification of seawater by subjecting the seawater to an ion exchange reaction to exchange H + ions for Na + ions. Carbon dioxide may be extracted from the acidified seawater. Optionally, the ion exchange reaction can be conducted under conditions which produce hydrogen as well as carbon dioxide. The carbon dioxide and hydrogen may be used to produce hydrocarbons.

1 . Apparatus for treatment of seawater comprising:
 an ion exchange compartment,   a cathode electrode compartment including a cathode,   an anode electrode compartment including an anode,   cation-permeable membranes separating the cathode and anode electrode compartments from the ion exchange compartment,   means for feeding seawater through the ion exchange compartment,   means for feeding a liquid media capable of dissociating to the anode and cathode electrode compartments, and   means for application of a current to the cathode and anode to create the driving force for the ion exchange process.   
     
     
         2 . The apparatus as claimed in  claim 1 , wherein the means for application of current applies sufficient current the cathode and anode to acidify the seawater to a pH of about 6.5 or less. 
     
     
         3 . The apparatus as claimed in  claim 2 , wherein a current density resulting from applied current is from about 5 to about 200 mA/cm 2 . 
     
     
         4 . The apparatus as claimed in  claim 3 , wherein the means for feeding seawater to the ion exchange compartment feeds the seawater at a velocity of from about 20 to about 500 cm/min. 
     
     
         5 . The apparatus as claimed in  claim 4 , wherein the means for applying current applies sufficient current to generate excess hydrogen in the anode and cathode compartments. 
     
     
         6 . The apparatus as claimed in  claim 1 , wherein the means for applying current is capable of reversing the polarity of the anode and cathode to regenerate the apparatus. 
     
     
         7 . The apparatus as claimed in  claim 1 , wherein the means for application of current applies sufficient current the cathode and anode to acidify the seawater to a pH of about 4.5 or less. 
     
     
         8 . The apparatus as claimed in  claim 1 , further comprising a device for separating carbon dioxide from acidified seawater obtained from the ion exchange compartment. 
     
     
         9 . A method for treatment of seawater comprising the step of subjecting the seawater to an ion exchange reaction to exchange H +  ions for Na +  ions in the seawater under conditions sufficient to lower a pH of the seawater to less than about 6.5. 
     
     
         10 . The method as claimed in  claim 9 , wherein the conditions are sufficient to lower a pH of the seawater to less than about 4.5. 
     
     
         11 . The method as claimed in  claim 9 , wherein a current density resulting from applied current is from about 5 to about 200 mA/cm 2 . 
     
     
         12 . The method as claimed in  claim 9 , wherein the seawater is fed to the ion exchange reaction at a at a velocity of from about 20 to about 500 cm/min. 
     
     
         13 . The method as claimed in  claim 9 , wherein sufficient current is applied in the ion exchange reaction to generate excess hydrogen. 
     
     
         14 . The method as claimed in  claim 9 , further comprising the step of reversing the polarity of the anode and cathode. 
     
     
         15 . The method as claimed in  claim 9 , further comprising the step of separating carbon dioxide from acidified seawater obtained from the ion exchange reaction. 
     
     
         16 . The method of  claim 15 , further comprising the step of separating hydrogen from a liquid ion exchange media obtained from the ion exchange reaction. 
     
     
         17 . The method of  claim 15 , further comprising the step of producing hydrocarbons from the carbon dioxide obtained in the carbon dioxide separation step. 
     
     
         18 . The method of  claim 16 , further comprising the step of producing hydrocarbons from the carbon dioxide obtained in the carbon dioxide separation step and the hydrogen obtained from the liquid ion exchange media. 
     
     
         19 . The method of  claim 15 , wherein the carbon dioxide is separated from the acidified seawater by vacuum stripping. 
     
     
         20 . The method of  claim 16 , wherein the hydrogen is separated from the liquid ion exchange media by vacuum stripping.