ICCP Impressed Current Cathodic Protection on ships

Impressed Current Cathodic Protection On Ships ICCP

                Corrosion by sea water  is an electrochemical process in which the ship hull acts as electrode and sea water as electrolyte. As you know,  when two metals having different electrode potentials  come into contact in an electrolyte then one will become anode and other act as cathode . Due to the electrode
potential between two electrodes,  metallic irons will move from anode to cathode with in the metal. This leads the corrosion of anode.
                 In ship, hull acts as electrode and seawater act as an electrolyte. As discussed above, some potential difference is required to make the cathode and anode within the ship hull. In the absence of any  potential difference within the ship hull,  it won't corrode, that is what ICCP is doing. It makes the ship hull always cathode. 

        ICCP consist of anodes connected to a DC power source. Power source may be rectifier connected by AC power or DC source, which deliver enough current to provide protection even if the electrolyte resistivity is high. The effect of these electrons at the ship hull being protected is the same as that derived from the sacrificial anode type of cathodic protection system. However, the anode material serves only as a source of electrons and need not be consumed in providing protective current.


     In actual Ship ICCP system consists of number of anodes fitted below water line on ship hull at selected places, and control equipment which automatically regulate the anode current. To regulate the anode current, we need to measure the natural corrosion current  So we add one more electrode – reference cell, completely  passive metal. The potential difference between the hull and reference cell will form the natural corrosion current.
      From Ship’s 440v 60hz  3-phase AC distribution system DC current supplied to the anodes by the help of rectifiers. Control unit comprise of  reference electrode, amplifier and one more transformer rectifier unit.

Form This Article You Can Answer,
> Explain iccp system working principle with diagram
> Draw the iccp system design in ship
> impressed current cathodic protection principle in ship

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