PRODUCTION OF VANADIUM ELECTROLYTE FOR A VANADIUM FLOW CELL
A Vanadium chemistry flow cell battery system is described. Methods of forming the electrolyte, a formulation for the electrolyte, and a flow system utilizing the electrolyte are disclosed. In some embodiments, the vanadium electrolyte is sulfate-free.
1 . A method for providing an electrolyte solution, comprising:
forming a solution of a vanadium oxide and hydrochloric acid;
adjusting ionic species in the solution to form a mixture of V(III) and V(IV); and
adjusting the acidity of the solution to form the electrolyte solution.
2 . The method of claim 1 , wherein the solution of vanadium oxide includes V 2 O 3 and adjusting the ionic species includes oxidizing the solution.
3 . The method of claim 2 , wherein the solution of vanadium oxide further includes V 2 O 5 and adjusting the ionic species includes adjusting the relative concentrations of V 2 O 5 and V 2 O 3 added to the solution.
4 . The method of claim 2 , wherein the source of vanadium is from one or more of a group of secondary sources that includes oil residues, power station fly ash, spent catalyst and V slags.
5 . The method of claim 2 , wherein oxidizing the solution includes an air oxidation.
6 . The method of claim 2 , wherein oxidizing the solution includes bubbling oxygen through the solution.
7 . The method of claim 1 , wherein the solution is substantially sulfate free.
8 . The method of claim 1 , wherein the electrolyte solution includes a balanced solution of V 3+ and V 4+ .
9 . The method of claim 1 , wherein adjusting the acidity of the solution results in a solution of approximately 2.5 M vanadium in about 4 M HCl.
10 . The method of claim 1 , wherein adjusting the acidity of the solution results in a solution of VO 2+ in HCl, where VO 2+ concentration can be 1 to 4 molar and acid concentration can be 1 to 9 molar.
11 . The method of claim 1 , further including addition of a catalyst to the acidic aqueous solution.
12 . The method of claim 10 , wherein the catalyst is about 1 ppm to about 100 ppm of Bismuth(III) salts.
13 . The method of claim 10 , wherein the catalyst is chosen from a group consisting of lead, indium, tin, antimony, bismuth and thallium.
14 . A method of forming a sulfate-free vanadium electrolyte, comprising:
mixing V 2 O 3 and V 2 O 5 with hydrochloric acid in a reactor; and allowing a reaction to complete to form a solution with V(III) and V(IV) in hydrochloric acid; and
filtering the solution to provide the electrolyte.
15 . The method of claim 14 , wherein mixing V 2 O 3 and V 2 O 5 with hydrochloric acid in a reactor includes
measuring out an appropriate weight ratio of V 2 O 3 and V 2 O 5 ;
adding an HCL solution to a reactor;
adding the V 2 O 3 and V 2 O 5 to the reactor;
16 . The method of claim 14 , wherein allowing the reaction to complete includes stirring the solution in the reactor until a reaction in the reactor is complete.
17 . The method of claim 14 , further including adding water to the solution in the reactor.
18 . The method of claim 16 , further including removing a sample from the reactor for testing periodically to determine whether the reaction is complete.
19 . The method of claim 16 , further including waiting a period of time for the reaction in the reactor to complete.
20 . The method of claim 15 , wherein measuring out an appropriate weight ratio of V 2 O 3 and V 2 O 5 includes measuring a ratio of between 2:1 and 6:1 of V 2 O 3 to V 2 O 5 .
21 . The method of claim 14 , wherein mixing V 2 O 3 and V 2 O 5 with hydrochloric acid in a reactor includes
measuring out an appropriate weight ratio of V 2 O 3 and V 2 O 5 into separate containers;
adding distilled water and hydrochloric acid to a reactor;
adding about half the measured quantity of V 2 O 3 to the reactor;
stirring the solution
heating to a set temperature;
adding the V 2 O 5 in multiple parts separated by a period of time; and
adding the remainder of the V 2 O 3 to the reactor after a wait time.
22 . The method of claim 14 , wherein allowing a reaction to complete includes heating the solution to a second temperature for a reaction time.
23 . The method of claim 21 , wherein measuring out an appropriate weight ratio of V 2 O 3 and V 2 O 5 includes measuring a ratio of between 2:1 and 6:1 of V 2 O 3 to V 2 O 5 .
24 . An electrolyte, comprising a sulfate-free solution of V 3+ and V 4+ in a hydrochloric acid solution.
25 . The electrolyte of claim 24 , further including a catalyst.
26 . The electrolyte of claim 24 , wherein an operating temperature range of the electrolyte is between −20° C. and 60° C.
27 . The electrolyte of claim 23 , wherein a viscosity of the electrolyte is less than 3.1 over a range of 20° C. to 45° C.
28 . The electrolyte of claim 23 , with vanadium concentration of at least 2.5M.