Sea Water Line online dechoking technology

[patibar]

In one of our unit, we have cement lined carbon steel piping for sea water (72" line and 15000 m³/h). Return line is having two multi hole orifices, which are getting choked with cement material. In 2006, we have provided one more plastic lining to protect the cement lines. But this time, orifices are getting choked with plastic lining lamination material and thereby unit is forced to take frequent shutdowns. Normally Ethylene plant run time is 8 years and choking of orifice is inevitable during this period, we are looking for online dechoking technics if any available.

Any other plant, which is having cement lined carbon steel piping, how they are handling this issue. If there is no orifice in return line, it is ok. But we have two orifices in return line.

Thanks