CW intake Pipes

[Afarouk Power]

Hello Everyone,
I am looking for effective fouling removal method from CW inlet pipe to power plant, the pipe is made of GRP with 2.3 diameter laid at -6MSL for 600 m and bring sea water to intake basin inside the plant. Access is available only either from the intake basin or from offshore cofferdam.We had ROV inspection revealed thick layer of marine growth. The thick layer is sticky shells and marine life formed due to unavailability of hypochlorite injection system which had been restored recently.
Appreciate if someone one had came across such problem and had effective cleaning method other than manual cleaning by divers.

 

[EdStainless]

Nope, sorry. By hand is how this is done.
If this was metallic pipe then there would be some options, but the risk of damage to GRP is too great to risk it.
How badly did you foul the condenser?


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P.E. Metallurgy

 

[Afarouk Power]

in fact only the continuous dosing was unavailable, the shock dosing upstream bar screens and at pump suction was working normally. Therefore, we did not suffer condenser blockage,

 

[SandCounter]

I once dealt with a ship that had a mussel infestation in its sea water cooling system. The solution was to install a copper rod in the up-stream end of the system. The copper rod was connected to a DC current with a voltage regulator making it a cathode. The cathode caused the chlorine to separate from the sodium in the salt water. The chlorine then caused the mussels to let go. The crew said the strainers just prior to point of use almost instantly filled with the mussels. After emptying the strainers several times, the system was clear. They ended up dialing the voltage back during continued use because the copper rod would waste away very quickly at the initial voltage levels. Check out Cathelco Marine Growth Prevention.

 

[TugboatEng]

OP mentioned a hypochlorite (Chloropac for us mobile marine guys) injection system that had failed and is now working again. The fouling organisms will likely start dying and OP is in for a long period of strainer/condenser clogging as the remains start breaking away.

 

[EdStainless]

I have seen systems using Cu rods and Al rods. A good system switches the polarity between the rods every few hours. This prevents scaling of the passive one and evens out the metal loss. This approach works well for smaller systems but not main cooling water, the flow is too high.
I am always amazed. You tell a plant that running without bio controls will destroy it, but they still place running ahead of maintenance. I have seen entire condensers destroyed in 6 hours this way.
Depending on your residual active Cl~ levels you might try feeding the system some bursts at a higher dosage. Say for 2hrs, one time each day. But be prepared for massive die off.

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P.E. Metallurgy