Chapter 12: Maintenance
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46 | Installation, Operation & Maintenance Instructions EASYCHLORGEN
12.2 Electrolyser cleaning
The electrolyser (electrolytic cell assembly) may require acid
cleaning periodically to remove the presence of water hardness
scaling and any heavy metal deposition e.g. iron and
manganese deposits. Cleaning of the electrolyser can be
automated or carried out manually, depending on client
specification.
Calcium scaling of the electrolyser, normally a white coloured
deposit on the electrolyser cell plate structure, is usually the
result of softener failure allowing hard water to enter the
electrolyser and/or poor quality salt being used for the
electrolytic process.
Iron and/or manganese fouling is usually a dark brown/black
coloured deposit on the surface of the cell plates and a result of
poor feed water quality and/or poor quality salt used for the
electrolytic process.
Repeated acidic chemical cleaning will likely damage the
electrolyser cell plates resulting in poor generation efficiency
e.g. low chlorine strength, high salt consumption, high voltage
conditions.
Always try to prevent the damage in the first place through good
operation principles as detailed in section 3, “Intended Use”.
One of the reasons the EASYCHLORGEN may
alarm in “VOLTAGE HIGH” is due to the electrolyser
becoming scaled with hardness salts and/or fouled
with heavy metals.
In this section, a recommended method for manual cleaning
only is detailed. Consult your supplier for information relating to
any automatic cleaning apparatus fitted where applicable.
Precondition for action:-
Perform Long-term shut down procedure, see section 11.2.
Electrolyser chemical cleaning apparatus ready
Perform the following working steps:-
1.
Drain the brine/product solution pipe work and
electrolyser(s) by opening the brine salinity sample point
valve. Allow the contents to empty into a clean plastic
container until the sample point is drip free. Close the
brine salinity sample valve.
2.
Securely connect (hand tight) the flow and return hose sets
of the electrolyser chemical cleaning kit to the side
connection cell cleaning ports of the EASYCHLORGEN.
The cleaning kit tank should only be filled with clean cold
water at this stage.
3.
Remove the electrolyser compartment window by removing
the vertical window bead retainers and then the horizontal
window bead retainers.
4.
Locate each of the two 3-way L-Port isolating ball valves at
the inlet and outlet of the electrolyser cell(s) and turn the
valve handles by rotating 90 degrees so that the “L-Port”
indicators show flow and return through the electrolyser
and chemical cleaning kit circuit.
5.
Purge the electrolyser(s) of any remaining saline water and
chlorine solution residue with clean water using the
cleaning kit pump system and safely pump away this initial
purge/rinse water volume to a waste/foul service drain –
not a surface drain!
6.
Fill the cleaning tank with chemical cleaning solution
typically a 10% HCl (muriatic acid) solution and circulate
this through the electrolyser(s) for at least 10 minutes
observing removal of precipitates. Heavy scaling/fouling
will require several cleaning volumes and increased
contact time to be removed completely.
7.
Dispose of the chemical residue carefully and responsibly
in accordance to local site rules.
8.
Rinse the electrolyser(s) with a clean tank of water prior to
removing the cleaning kit.
9.
Ensure the electrolyser compartment window is refitted
correctly back into position.
10.
Prepare the system for Start-Up as detailed in section 9.1.
Electrolyser chemical wash carried out successfully.
3 WAY L-PORT VALVE ADJUSTMENT EXAMPLE
Example of electrolyser chemical cleaning
using manual operated system.
