Technology of iodine extracting from formation and associated water of oil and gas fields

Abstract

The present invention relates to a method for extracting iodine from an aqueous brine, the method comprising the steps: Providing an aqueous brine containing iodide ions; Heating the aqueous brine containing iodide ions; Adding an acid to the aqueous brine to arrive at a pH value from 2 to 4; Adding an oxidizing agent to the aqueous brine; Desorbing iodine by means of an airflow; Adding a sorbent for chemisorbing the iodine; Crystallizing the iodine; Purifying the iodine under a layer of sulfuric acid; Sublimation of the iodine.

1 . Method for extracting iodine from an aqueous brine, the method comprising the steps:
 Providing an aqueous brine;   Heating the aqueous brine;   Adding an acid to the aqueous brine to arrive at a pH value from 2 to 4;   Adding an oxidizing agent to the aqueous brine to form iodine from iodide contained in the brine;   Desorbing the iodine by means of an airflow;   Adding a sorbent for chemisorbing the iodine;   Crystallizing the iodine;   Purifying the iodine under a layer of sulfuric acid;   Sublimation of the iodine.   
     
     
         2 . Method according to  claim 1 , wherein the aqueous brine is formation and associated waters from oil and gas fields. 
     
     
         3 . Method according to  claim 1 , wherein the aqueous brine comprises the iodide ions in an amount of at least 20 mg/l, with respect to the total volume of the aqueous brine. 
     
     
         4 . Method according to  claim 1 , wherein heating the aqueous brine comprises heating to a temperature from 45 to 50° C. 
     
     
         5 . Method according to  claim 1 , wherein the pH of the aqueous brine after adding the acid is from 2.5 to 3.5. 
     
     
         6 . Method according to  claim 1 , wherein the acid is sulfuric acid and/or hydrochloric acid. 
     
     
         7 . Method according to  claim 1 , wherein the oxidizing agent is chlorine or chlorine water. 
     
     
         8 . Method according to  claim 1 , wherein the desorbing is carried out in a vertical column apparatus filled with a desorber packing. 
     
     
         9 . Method according to  claim 1 , wherein the desorbing is carried out with an airflow rate in the range from 105 to 150 m 3 /m 3 , with respect to the volume of the aqueous brine. 
     
     
         10 . Method according to  claim 8 , wherein a water density of the desorber packing is 60 m 2 /m 3 , with respect to the vertical column apparatus cross-section square. 
     
     
         11 . Method according to  claim 1 , wherein the sorbent is sodium hydroxide and or iodine-hydrogen and sulfuric acids. 
     
     
         12 . Method according to  claim 1 , wherein the purifying of the iodine under a layer of sulfuric acid is carried out at a the temperature of 100 to 160° C. 
     
     
         13 . Reactor system for carrying out the method according to  claim 1 , comprising:
 a water heater ( 2 );   a tank for storing an oxidizing agent ( 6 );   means for carrying out iodine oxidation ( 8 );   a desorber ( 5 );   an absorption column ( 15 );   a crystallizer ( 19 );   an iodine melting node ( 21 ); and   a sublimator ( 22 ).   
     
     
         14 . Method according to  claim 9 , wherein a water density of the desorber packing is 60 m 2 /m 3 , with respect to the vertical column apparatus cross-section square.