MV Hoegh America: 25 MT/day Held, Cleaning Under 2hrs

Freshwater generator output and cleaning time

Freshwater generator output on MV Hoegh America was at risk from up to 3 mm of scale on the generator’s titanium plates. The FWG needed chemical dosing to keep running and took 24 to 48 hours to clean, and the operators wanted to cut both material and labour costs. In December 2012 an HM100 was fitted to the four inch seawater inlet pipe, about one metre before the generator inlet, for a six-month trial. Output held at 25 MT a day throughout. The plates stayed mostly clean, the small amount of loose scale that formed came off by hand in under two hours, and chemical dosing was no longer required.

The Challenges

• Freshwater generator output was threatened by up to 3 mm of scale on titanium plates
• Chemical dosing was required to keep the FWG operating
• Cleaning was taking 24 to 48 hours
• Operators wanted to cut both material and labour costs
• The trial had to prove itself over six months at sea

The Solution

• Unit installed: One HM100
• Installation point: seawater inlet pipe, about one metre before the FWG inlet
• Pipe size: four inch
• Installed: December 2012
• Trial: six months

The HM100 was fitted on the seawater inlet close to the generator and left to run for a six-month trial. The signal disrupts the conditions that bond scale to surfaces, so the plates stayed mostly clean with only loose, hand-removable scale. Chemical dosing was no longer required, freshwater generator output held at 25 MT a day, and cleaning came down to under two hours.