This case shows how a small defect in a multimedia filter caused major downstream consequences, compromised the integrity of reverse osmosis membranes, and demonstrated the importance of a robust, reliable design. What Was Observed The featured image was taken at the inlet of a reverse osmosis (RO) pressure vessel. It shows the multi-orifice protection cover
Failure in Multimedia Filters Read More »
Scaling is a form of fouling commonly found in heat exchangers, steam generators, and cooling systems. It occurs when dissolved chemical species interact and precipitate as inorganic salts. How Phosphate Hideout Develops Calcium- and sodium-based compounds are among the most common scale-forming species. Their solubility depends on temperature and pH and can change significantly as
A Few Corrections to Avoid Hideout Effects Read More »
Cooling towers reject heat through the partial evaporation of circulating water. This evaporation rapidly concentrates the chemical species naturally dissolved in the water. Scale Formation The principal scale found in cooling towers is calcium carbonate, which forms from the decomposition of calcium bicarbonate. Other deposits may contain magnesium-, sodium-, or silica-bearing compounds. Their solubility depends
Cooling Tower Blowdown Systems Read More »
A sudden change in a flow passage—typically an increase in cross-sectional area—can cause water pressure to fall rapidly below the saturation pressure at its temperature, producing instantaneous vaporization. Expansion and Flashing Because the process is approximately adiabatic, there is no external heat exchange and total enthalpy remains essentially constant. Part of the liquid flashes into
Chemical Corrosion Damage in Adiabatic Expansions Read More »
Flash steam forms when hot water or condensate undergoes a sudden pressure reduction below its saturation pressure, causing part of the liquid to vaporize immediately. How Flashing Causes Damage The expansion is approximately isenthalpic: part of the liquid’s sensible heat supplies the latent heat needed to form steam. The resulting two-phase flow contains vapor and
Flash Steam Problems Read More »
Material selection must balance design cost with the required operating performance. Commissioning introduces demanding transient conditions that can be more severe than normal operation and may exceed the design conditions of in-line equipment. Commissioning Risk Commissioning strategies should therefore be reviewed in advance to identify equipment that may experience critical conditions and to ensure that
Sulfur Dew-Point Corrosion Read More »
Duis mollis, est non commodo luctus, nisi erat porttitor ligula, eget lacinia odio sem nec elit. Morbi leo risus, porta ac consectetur ac, vestibu lum at eros. Nulla vitae elit libero, a pharetra augue.
Coating Deficiences Read More »
FAC Corrosion When a steel surface is in contact with water under specific chemical and thermodynamic conditions, an oxide protective layer of magnetite (Fe3O4) is developed. Controlling the growth mechanism, the morphology and the solubility of such corrosion product it is possible to minimize the risk of failure and extend the life-time of the plant.
Short-Term Overheating Commissioning is likely the most critical stage in the life time of a power plant due to the transient conditions which boilers are subjected to. From the first ramp-up to normal operation, the plant is exposed to a variety of transitory conditions, thermal expansions cycles, chemical excursion and equipment adjustments that potentially increase
Short-Term Overheating Read More »
Chloride Attack on CS This photo illustrates the corrosion pattern of chloride attack on carbon steel and it was taken during an inspection carried out in a cooling water pump of a steam-water cycle. Description The pump was subject to severe degeneration due to the formation of corrosion cells in which the corrosion product forms
Chloride Attack on CS Read More »
