Apparatus for electrolyzing sulfuric acid and method for electrolyzing sulfuric acid

Abstract

The present invention relates to an apparatus to produce oxidizing agent-rich sulfuric acid by electrolysis of sulfuric acid. More specifically, it relates to the apparatus by which dilute sulfuric acid of the specified temperature and concentration is formed within the electrolysis system and then, by electrolysis of the formed dilute sulfuric acid, electrolytic sulfuric acid containing richly oxidizing agent is formed at a high efficiency and safely under the temperature control. The apparatus for electrolyzing sulfuric acid and the method for electrolyzing sulfuric acid by the present invention comprise the anode side dilute sulfuric acid generation loop A in which concentrated sulfuric acid, as feed material, is diluted and controlled to the specified temperature and concentration, and the anode side electrolytic sulfuric acid generation loop B in which electrolytic sulfuric acid is formed by electrolysis of dilute sulfuric acid with the temperature and concentration controlled to the specified range in the anode side dilute sulfuric acid generation loop A, in, at least, the anode side electrolysis part of the apparatus for electrolyzing sulfuric acid having the anode side electrolysis part and the cathode side electrolysis part.

1 . An apparatus for electrolyzing sulfuric acid wherein:
 in the apparatus for electrolyzing sulfuric acid  1  comprising the anode side electrolysis part  20  and the cathode side electrolysis part  23 ,   the anode side dilute sulfuric acid generation loop A in which concentrated sulfuric acid, as feed material, is diluted and controlled to a specified temperature and concentration, and the anode side electrolytic sulfuric acid generation loop B in which the dilute sulfuric acid generated in the anode side dilute sulfuric acid generation loop A is electrolyzed to form electrolytic sulfuric acid and the formed electrolytic sulfuric acid is controlled to a specified temperature and concentration are provided at least in the anode side electrolysis part  20 ;   in the anode side dilute sulfuric acid generation loop A, the anode side tank  31 , the anode side concentrated sulfuric acid supply part  32  and the anode side cooler  34  are disposed in this order constituting a loop being connected by the anode side by-pass pipe  36 , to which the anode side pure water supply pipe  10  is connected to feed pure water to the anode side dilute sulfuric acid generation loop A at any point wherever in the anode side dilute sulfuric acid generation loop A; the anode side concentrated sulfuric acid supply pipe  27  is connected to feed concentrated sulfuric acid to the anode side concentrated sulfuric acid supply part  32 ;   in the anode side electrolytic sulfuric acid generation loop B, the anode side tank  31  and the anode compartment  4  provided internally with the anode  3  of the electrolytic cell  2  comprising the anode compartment  4  and the cathode compartment  7  separated by the diaphragm  5  constitute a loop being connected by the anode side circulation pipe  37 ;   the concentrated sulfuric acid supplied to the anode side concentrated sulfuric acid supply part  32  from the anode side concentrated sulfuric acid supply pipe  27  is diluted with pure water supplied by the anode side pure water supply pipe  10 ;   the diluted sulfuric acid of a low concentration is controlled to a specified temperature and concentration while being circulated in the anode side dilute sulfuric acid generation loop A to form dilute sulfuric acid of the specified temperature and concentration;   the formed dilute sulfuric acid is supplied to the anode compartment  4  of the electrolytic cell  2  via the anode side circulation pipe  37  constituting the anode side electrolytic sulfuric acid generation loop B;   electrolytic sulfuric acid is formed in the anode compartment  4  and the formed electrolytic sulfuric acid is controlled to a specified temperature and concentration while being circulated in the anode side electrolytic sulfuric acid generation loop B; and   electrolytic sulfuric acid of the specified temperature and concentration is generated.   
     
     
         2 . The apparatus for electrolyzing sulfuric acid as defined in  claim 1 , wherein:
 in the cathode side electrolysis part  23 , the cathode side dilute sulfuric acid generation loop A′ in which concentrated sulfuric acid, as feed material, is diluted to sulfuric acid of a low concentration and the sulfuric acid of a low concentration is controlled to a specified temperature and concentration, and the cathode side electrolysis loop B′ in which the dilute sulfuric acid formed in the cathode side dilute sulfuric acid generation loop A′ is circulated through the cathode compartment  7  are provided;   in the cathode side dilute sulfuric acid generation loop A′, the cathode side tank  38 , the cathode side concentrated sulfuric acid supply part  39  and the cathode side cooler  41  are disposed in this order, constituting a loop being connected by the cathode side by-pass pipe  43 , to which the cathode side pure water supply pipe  12  is connected to feed pure water to the cathode side dilute sulfuric acid generation loop A′ at any point wherever in the cathode side dilute sulfuric acid generation loop A′ and the cathode side concentrated sulfuric acid supply pipe  29  is connected to feed concentrated sulfuric acid to the cathode side concentrated sulfuric acid supply part  39 ;   in the cathode side electrolysis loop B′, the cathode side tank  38  and the cathode compartment  7  provided internally with the cathode  6  of the electrolytic cell  2  comprising the anode compartment  4  and the cathode compartment  7  separated by the diaphragm  5  constitute a loop being connected by the cathode side circulation pipe  44 ;   the concentrated sulfuric acid supplied to the cathode side concentrated sulfuric acid supply part  39  from the cathode side concentrated sulfuric acid supply pipe  29  is diluted with pure water supplied via the cathode side pure water supply pipe  12 ;   the diluted sulfuric acid of a low concentration is controlled to a specified temperature and concentration while being circulated in the cathode side dilute sulfuric acid generation loop A′ to form dilute sulfuric acid of the specified temperature and concentration;   the formed dilute sulfuric acid is supplied to the cathode compartment  4  of the electrolytic cell  2  via the cathode side circulation pipe  44  constituting the cathode side electrolysis loop B′; and   the dilute sulfuric acid controlled to the specified temperature and concentration is electrolyzed while being circulated in the cathode side electrolysis loop B′.   
     
     
         3 . The apparatus for electrolyzing sulfuric acid as defined in  claim 1 , featuring that above the anode side tank  31 , the anode side gas-liquid separator  91  and the anode side mist separator  92  are connected sequentially in series via the anode side gas vent pipe  102 , and the respective bottoms of the anode side gas-liquid separator  91  and the anode side mist separator  92  are provided with a draining means of a communicating vessel structure for the common use by the anode side gas-liquid separator  91  and the anode side mist separator  92  to drain liquid accumulated at the bottom of the respective separators. 
     
     
         4 . The apparatus for electrolyzing sulfuric acid as defined in  claim 2 , featuring that above the anode side tank  31 , the anode side gas-liquid separator  91  and the anode side mist separator  92  are connected sequentially in series via the anode side gas vent pipe  102 , and the respective bottoms of the anode side gas-liquid separator  91  and the anode side mist separator  92  are provided with a draining means of a communicating vessel structure for the common use by the anode side gas-liquid separator  91  and the anode side mist separator  92  to drain liquid accumulated at the bottom of the respective separators,
 and above the cathode side tank  38 , the cathode side gas-liquid separator  96  and the cathode side mist separator  97  are connected sequentially in series via the cathode side gas vent pipe  103 , and the respective bottoms of the cathode side gas-liquid separator  96  and the cathode side mist separator  97  are provided with a draining means of a communicating vessel structure for the common use by the cathode side gas-liquid separator  96  and the cathode side mist separator  97  to drain liquid accumulated at the bottom of the respective separators. 
 
     
     
         5 . The apparatus for electrolyzing sulfuric acid as defined in  claim 3  featuring that the ozone decomposition mechanism  93  is connected to the anode side mist separator  92 . 
     
     
         6 . The apparatus for electrolyzing sulfuric acid as defined in  claim 4  featuring that the hydrogen treatment mechanism is connected to the cathode side mist separator  97 . 
     
     
         7 . The apparatus for electrolyzing sulfuric acid as defined in  claim 1  featuring to have such configuration that more than one of anode side tank are installed in parallel in the anode side dilute sulfuric acid generation loop A, generated electrolytic sulfuric acid containing oxidizing agent is once stored in one of the tanks, then the valve is switched to other anode side tanks where electrolytic sulfuric acid containing oxidizing agent of the specified concentration is formed. 
     
     
         8 . The apparatus for electrolyzing sulfuric acid as defined in  claim 7  featuring to have such configuration that while electrolytic sulfuric acid containing oxidizing agent of the specified concentration stored in one anode side tank is being transferred to a location of use outside the apparatus for electrolyzing sulfuric acid, electrolytic sulfuric acid containing oxidizing agent of the specified concentration is formed in another anode side tank. 
     
     
         9 . The apparatus for electrolyzing sulfuric acid as defined in  claim 1  featuring that the anode  3  is a conductive diamond electrode. 
     
     
         10 . The apparatus for electrolyzing sulfuric acid as defined in  claim 1  featuring that the diaphragm  5  is a fluororesin type cation exchange membrane or a hydrophilically treated porous fluororesin membrane. 
     
     
         11 . A method for electrolyzing sulfuric acid wherein electrolytic sulfuric acid controlled to the specified temperature and concentration is formed by applying the apparatus as defined in  claim 1 . 
     
     
         12 . The method for electrolyzing sulfuric acid wherein the apparatus as defined in  claim 1  is applied, a porous fluororesin membrane is applied as the diaphragm  5 , and overflowing of the cathode side tank  38  is prevented by draining periodically or draining a specified quantity when the liquid level of the cathode side tank  38  has reached a specified point because of an increase of the dilute sulfuric acid solution circulating in the cathode side electrolysis loop B′ of the cathode side electrolysis part  23  due to entrained water brought by cation at the time of passing through the porous fluororesin membrane. 
     
     
         13 . The method for electrolyzing sulfuric acid wherein the apparatus as defined  claim 1  is applied, a porous fluororesin membrane is applied as the diaphragm  5 , and concentrated sulfuric acid is replenished to the cathode side concentrated sulfuric acid supply part  39  in order to maintain a certain range of dilute sulfuric acid concentration when the sulfuric acid concentration of the dilute sulfuric acid solution formed in the cathode side dilute sulfuric acid generation loop A′ of the cathode side electrolysis part  23  has decreased to or below the specified level of concentration due to entrained water brought by cation at the time of passing through the porous fluororesin membrane. 
     
     
         14 . The method for electrolyzing sulfuric acid as defined in  claim 11  featuring that the temperature of dilute sulfuric acid before electrolysis in the anode side dilute sulfuric acid generation loop A of the anode side electrolysis part  20  or in the cathode side dilute sulfuric acid generation loop A′ of the cathode side electrolysis part  23  is controlled to 30 degrees Celsius or less. 
     
     
         15 . The method for electrolyzing sulfuric acid as defined in  claim 11  featuring that the temperature of electrolyzed electrolyte in the anode side electrolytic sulfuric acid generation loop B of the anode side electrolysis part  20  or in the cathode side electrolysis loop B′ of the cathode side electrolysis part  23  is controlled to 30 degrees Celsius or less. 
     
     
         16 . The method for electrolyzing sulfuric acid as defined in  claim 11  featuring that the sulfuric acid concentration of dilute sulfuric acid before electrolysis in the anode side dilute sulfuric acid generation loop A of the anode side electrolysis part  20  or in the cathode side dilute sulfuric acid generation loop A′ of the cathode side electrolysis part  23  is controlled to the range of 2˜10 mol/L.