EDF Le Havre Fossil Plant
This coal-fired power plant along France’s Le Havre harbor was experiencing significant efficiency loss due to mussel growth in the water structures and condenser water boxes. Le Havre also suffered from sedimentation, corrosion and scaling. These problems were unsuccessfully controlled with conventional chlorine and other water treatments.
Mexel was adopted throughout the plant resulting in fewer waterbox cleanings due to the near elimination of fouling from mussels. The annual corrosion rate from 283 μm per year to an average of 58 μm per year. The cleanliness level of cement tunnel surfaces, metal water boxes and condenser tubes were consistently maintained. Estimated annual operating costs for water treatment were reduced by about 35% when compared to chlorination. Additional financial benefits accrued from extending the life of equipment susceptible to corrosion and the simplified operations and maintenance.
Mid-Atlantic Nuclear Power Plant
This 1675 MW nuclear power plant suffered extensive fouling in the cooling water system that impaired optimal power production and created burdensome operating and maintenance conditions. Maintaining the safety and reliability of performance were key factors. The most significant problems were in the intake bays, the pipes between the main cooling water pumps and the condensers, and in the condenser inlet and outlet water boxes. The cooling water was brackish.
Mexel succeeded in significantly reducing fouling in challenging conditions in which a wide variety of other treatments and coatings had failed. This reduction significantly improved maintenance requirements and operating performance throughout the treated cooling water circuit.
Tennessee Valley Authority, Kingston Fossil Plant
Mexel 432/0 water treatment was demonstrated in a condenser cooling water system at this 1450 MW coal-fired power plant against an identical untreated unit. On a quantitative and qualitative basis it was determined to improve performance, reduce corrosion, metal discharges, and biofouling along with simplifying maintenance.
In-house methods for evaluating condenser performance indicated that Mexel was successful in reducing the efficiency losses and lowering maintenance costs. Most significant was maintaining higher cleanliness factors throughout the peak demand season.
Power Plant Using Sea Water
The Northport Fossil Power Station on Long Island Sound treated one quadrant of a condenser with Mexel. The main problem stemmed from deposits of mud in the condenser tubes, which required hydro-blasting weekly to maintain efficiency. A secondary problem was mussel accumulations in the cellblocks (chambers that distribute the water to the four quadrants of each unit), the pipes to the circulating pumps, and the forebay. A crew of 17 persons was required to hydro-blast the condenser tubes and the four quadrants needed nightly cleaning.
Mexel altered the deposits making them less adherent to the tubes and contained almost no organic matter demonstrating that Mexel had eliminated the biofouling from system surfaces. At the end of the season when the Unit was cleaned, there were no live mussels in the forebay, cellblocks, or piping. In contrast, the untreated units accumulated normal-to-heavy amounts of mussels and hydroids. It was evident that treatment with Mexel had a positive effect on overall fouling with an increase in condenser efficiency of ~0.5% compared to the untreated units.