Process for separation of hydrogen and oxygen produced from photocatalytic water splitting by absorption

Abstract

Embodiments of the invention are directed to methods, processes, and systems for safely and reliably purifying hydrogen from a gas mixture containing hydrogen and oxygen.

1 .- 20 . (canceled) 
     
     
         21 . A process for separating hydrogen and oxygen from a gas mixture produced from photocatalytic splitting of water comprising:
 (a) compressing a feed source gas comprising oxygen and hydrogen to at least 1.0 MPa at ambient temperature;   (b) pressurizing a solvent to at least 1.0 MPa at ambient temperature, wherein the solvent is capable of selectively adsorbing oxygen when under a pressure of at least 1.0 MPa;   (c) separating hydrogen and oxygen present in the feed source by solvent adsorption comprising,   (i) passing the compressed solvent through an adsorption column at a pressure of at least 1.0 MPa; and   (ii) passing the compressed feed source gas through an adsorption column at a pressure of at least 1.0 MPa counter to the pressurized solvent, the pressurized solvent selectively adsorbing oxygen from the feed source gas producing an enriched hydrogen product gas and an oxygen enriched solvent; and   (iii) separating the hydrogen product gas and the oxygen enriched solvent; and   (d) collecting, storing, or utilizing the hydrogen product gas;   wherein the solvent comprises dimethyl ether of polyethylene glycol.   
     
     
         22 . A hydrogen product gas produced by the process of  claim 21 . 
     
     
         23 . A gas purification system comprising:
 (a) an adsorption column configured to (i) receive a feed source gas in the lower half of the column so that the feed gas travels up the column, and (ii) receive a solvent in the upper half of the column so that the solvent travels down the column, wherein the solvent selectively adsorbs oxygen and exits the column as an oxygen enriched solvent and the feed source gas is processed while traversing the column and exits the top of the column as a hydrogen product gas; and   (b) a solvent reservoir or source configured to provide lean solvent to the adsorption column; and   (c) a feed gas source configured to provide a feed source gas to the adsorption column.   
     
     
         24 . The gas purification system of  claim 23 , wherein the solvent comprises dimethyl ether of polyethylene glycol. 
     
     
         25 . The process gas purification system of  claim 23 , wherein the feed source gas consists of 70 mol % hydrogen, 25 mol % oxygen, and 5 mol % carbon dioxide. 
     
     
         26 . The process gas purification system of  claim 23 , further comprising a solvent regeneration unit configured to depressurize and deoxygenate solvent exiting the adsorption column to produce oxygen off gas. 
     
     
         27 . The process gas purification system of  claim 23 , further comprising a hydrogen storage device to collect and store at least a portion of the hydrogen product gas. 
     
     
         28 . The process gas purification system of  claim 23 , wherein the absorption column is a tray column, a packed column, spray tower, bubble column, or a centrifugal contactor. 
     
     
         29 . The process gas purification system of claim  3 , wherein the absorption column is selected from the group consisting of a tray column, a packed column, spray tower, bubble column and a centrifugal contactor. 
     
     
         30 . The process gas purification system of  claim 23 , wherein the adsorption column is a packed column. 
     
     
         31 . The process gas purification system of  claim 23 , wherein the adsorption column is a tray column. 
     
     
         32 . The process gas purification system of  claim 23 , wherein the adsorption column is a spray tower. 
     
     
         33 . The process gas purification system of  claim 23 , wherein the adsorption column is a bubble column. 
     
     
         34 . The process gas purification system of  claim 23 , wherein the adsorption column is a centrifugal contactor. 
     
     
         35 . The process gas purification system of  claim 23 , wherein the feed source is compressed and transferred to the lower half of the absorption column. 
     
     
         36 . The process gas purification system of  claim 23 , further comprising a depressurization unit to regenerate the solvent from the oxygen enriched solvent. 
     
     
         37 . The process gas purification system of  claim 23 , wherein the process gas purification system is zone 0 classified to minimize spark generation. 
     
     
         38 . The process gas purification system of  claim 23 , wherein the solvent exits at the lower half of the adsorption column. 
     
     
         39 . The process gas purification system of  claim 23 , further comprising a recovery unit to recover oxygen from the oxygen enriched solvent. 
     
     
         40 . The process gas purification system of  claim 26 , further comprising an oxygen storage device to collect and store at least a portion of the oxygen off gas.