Surface coating of condenser tubing and CO2 sparging for preventing fouling and water use reduction

Fouling reduces heat transfer efficiency and increases the amount of water use, which result in lower energy production and increased fuel consumption in thermoelectric power plants. The current study was to investigate the effects of coating and CO2 sparging on fouling prevention and cooling water use reduction. Bench-scale experiments were conducted to simulate the cooling system in power plants and to evaluate fouling rates on treated and untreated condenser tubes. Four bench-scale experiments (two without CO2 sparging and two with CO2 sparging) were performed. In each of those experiments, water from the Monongahela River (Morgantown, West Virginia) was used as cooling water and pumped through tested condenser tubes that placed inside a muffle furnace with a temperature of 450ºC. The cooling water was heated through the muffle furnace by about 10--15ºC and cooled down by a cooling tower, and then the water came back to a reservoir for recirculation. Fouling rates were evaluated by analyzing daily cooling water samples and fouling materials on the tested condenser tubes. In addition, morphology of fouling materials was investigated using a Scanning Electron Microscope (SEM). The current study found that coating on the condenser tubes prevented fouling to some extent. This was supported by the results that concentrations of major metals on the surface of the coated tubes were generally lower than those on the uncoated tubes, especially the concentrations of calcium. Results from SEM displayed consistent evidence that more dense fouling materials on the uncoated tubes than those on the coated tubes. Comparisons of fouling rates between experiments with and without CO2 indicated that CO 2 was effective in fouling control. Designing an integrated system incorporating surface coating and CO2 sparging is expected to reduce water consumption, improve energy efficiency, and reduce economic loss in thermoelectric power plants