A bubble curtain model applied in chlorate electrolysis

5.3 Results and discussion
Table 10 and Table 11 present the results for two and three liter electrolyte. This gave levels of 32 and
respectively 44 mL above the starting level where the voidage was zero. In both cases two electrodes are
used, which means there was one electrode gap of 15 cm 2 .
Table 10: The results of an electrolysis with a 2 liter solution of 500 g⁄ L NaClO 3 , 100 g⁄ L NaCl, 1. 5 g⁄ L NaOH
and 5 g⁄ L Na 2 Cr 2 O 7 . Two electrodes are used.
Time (min) Amps T (°C) pH lvl (mL) ε riser ε tot v (m/s)
19 0 34,1 8,15 76 0,00 0,000 0,0000
20 2 34,6 8,4 72 0,14 0,009 0,0013
22 5 33,9 8,51 67,4 0,26 0,020 0,0033
25 10 33,1 8,07 44 0,57 0,071 0,0065
29 15 34,6 7,92 43 0,58 0,073 0,0098
32 20 36,3 7,68 45 0,56 0,069 0,0132
34 25 38,7 7,49 44 0,57 0,071 0,0166
Table 11: The results of an electrolysis with a 3 liter solution of 500 g⁄ L NaClO 3 , 100 g⁄ L NaCl, 1. 5 g⁄ L NaOH
and 5 g⁄ L Na 2 Cr 2 O 7 . Two electrodes are used.
Time (min) Amps T (°C) pH lvl (mL) ε riser ε tot v (m/s)
38 0 34,4 8,86 50 0,00 0,000 0,0000
39 2 33,9 8,65 45 0,09 0,011 0,0013
41 5 33,3 8,6 39,6 0,17 0,023 0,0033
43 10 32,9 8,26 17,6 0,39 0,068 0,0065
47 15 33,9 7,91 10 0,44 0,082 0,0098
50 20 35,7 7,67 6 0,47 0,090 0,0131
53 25 38,4 7,76 4 0,48 0,093 0,0166
The pH is rather high because the HCl pump was not turned on since it was forgotten to turn it on. The
time in minutes is given to see the relevant timespan between two measurements, which about two or
three minutes.
Voidage is zero without current, obviously since no hydrogen is formed. The total volume of the inner
vessel measures 496 mL while the volume of the riser tube only measures 100 mL. By calculating the
total voidage the volume of the lower part of the vessel was included while for the calculation of the
voidage of the riser tube ignores the volume of the lower part of the inner vessel.
The voidage is calculated out of the level of the electrolyte that can be measured on the inner vessel. The
voidage in the riser tube equals the amount of gas in the system divided by the total amount of liquid and
gas together in the riser tube. The total voidage equals the total amount of gas divided by the total
amount of liquid and gas in the inner vessel. The total amount of gas is the difference of the level that can
be seen on the riser tube with and without a current. The level is a method of describing the total amount
of mL in the system.
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