Hydrogen evolved during electrolysis of a brine solution will be proportional to the weight of NaOCl being produced and progressively increasing as the electrolyte passes through the electrolysis cells.
As the volume of hydrogen proportionally increases it has the effect of increasing the apparent electrical resistivity of the electrolyte, consequently requiring a higher than would otherwise be anticipated voltage to drive the DC current.
To minimise the effect of the Hydrogen maintaining a pressure within the Electrolysers as close to the design operating pressure as is reasonable will minimise the effect. The higher the operating pressure the lower the volume of the Hydrogen in relation to the volume of the carrier stream, and subsequently a lesser impact on the resistivity.
For large (e.g. >=50kg/h) electrolysers to operate efficiently in series the Hydrogen could be subject to hydrocyclone interstage degassing between electrolysers. This is removing the Hydrogen from the discharge of one Electrolyser before the carrier stream is introduced to the next Electrolyser in the series. This is necessary to minimise the voltage requirement by minimising the hydrogen effect on the electrolyte resistivity.
