System for scrubbing alkyl halides from gases

Abstract

Alkyl halides can be effectively scrubbed from gas streams containing them by passing the gas streams through dispersers having a very small pore size into an aqueous scrubbing liquid containing a nucleophile such as thiosulfate. Optionally, the addition of a water-soluble organic compound to the scrubbing liquid may increase the rate of destruction of the alkyl halide. Alkyl halides such as methyl bromide can be effectively scrubbed from enclosed spaces containing the halide, for example in enclosures used for fumigation.

1 . An apparatus for removing an alkyl halide from a gas volume, the apparatus comprising:
 a reactor assembly comprising a reaction vessel containing a single continuous liquid phase comprising water and a nucleophile, and one or more gas dispersers having therein a plurality of holes, the holes being between 1 and 200 μm across at a widest part thereof, said one or more dispersers immersed in the liquid phase.   
   
   
       2 . The apparatus of  claim 1 , wherein a majority of the holes are between 1 and 200 μm across at a widest part thereof. 
   
   
       3 . The apparatus of  claim 1 , wherein a distance from an upper end of the one or more dispersers to an upper surface of the liquid phase is between 6 and 120 inches. 
   
   
       4 . The apparatus of  claim 1 , wherein a distance from an upper end of the one or more dispersers to an upper surface of the liquid phase is between 12 and 36 inches. 
   
   
       5 . The apparatus of  claim 1 , wherein the holes are between 10 and 50 μm across at a widest part thereof. 
   
   
       6 . The apparatus of  claim 1 , wherein the nucleophile comprises thiosulfate. 
   
   
       7 . The apparatus of  claim 1 , wherein the nucleophile is selected from the group consisting of aliphatic thiols, aromatic thiols, salts of aliphatic thiols, salts of aromatic thiols, aliphatic disulfides, aromatic disulfides, aliphatic polysulfides, aromatic polysulfides, sulfide anion, bisulfide anion, thiosulfate anion, sulfite anion, bisulfite anion, and thiocyanate anion. 
   
   
       8 . The apparatus of  claim 1 , wherein the single continuous aqueous phase is essentially free of suspended undissolved material. 
   
   
       9 . The apparatus of  claim 1 , wherein the aqueous phase further comprises between 1 and 99 wt % of an organic compound dissolved therein. 
   
   
       10 . The apparatus of  claim 1 , wherein the aqueous phase further comprises between 1 and 25 wt % of an organic compound dissolved therein. 
   
   
       11 . The apparatus of  claim 9 , wherein the organic compound does not boil below 125° C. 
   
   
       12 . The apparatus of  claim 9 , wherein the organic compound is a compound according to the formula H—(OCH 2 CHR) n —OH, wherein n is an integer from 1 to 20 and R is H or CH 3 . 
   
   
       13 . The apparatus of  claim 12 , wherein R is H. 
   
   
       14 . The apparatus of  claim 9 , wherein the organic compound is tetraethylene glycol. 
   
   
       15 . The apparatus of  claim 9 , wherein the organic compound is dimethyl formamide, N-methylpyrrolidone, or dimethyl sulfoxide. 
   
   
       16 . The apparatus of  claim 1 , comprising a plurality of reactor assemblies connected in series. 
   
   
       17 . The apparatus of  claim 1 , comprising a plurality of reactor assemblies connected in parallel. 
   
   
       18 . The apparatus of  claim 1 , wherein a distance from an upper end of the one or more dispersers to an upper surface of the liquid phase is between 12 and 36 inches, the holes are between 10 and 50 μm across, the nucleophile comprises thiosulfate, and the organic compound is a compound according to the formula H—(OCH 2 CHR) n —OH, wherein n is an integer from 1 to 20 and R is H or CH 3   
   
   
       19 - 36 . (canceled)