Water is at the source of all thermal power plants as it enables cooling, expanding water vapour drives the turbines and water moderates the nuclear fission
Thermal power plants are at the core of the industrial society that we in the United Kingdom live in today and no matter whether the plant is nuclear of fossil fuel driven, its safe and reliable operation is critical and must be guaranteed.
Water is at the source of all thermal power plants as it enables cooling, expanding water vapor drives the turbines and water moderates the nuclear fission.
In fossil fuel and nuclear power plants a wide range of chemical reactions take place, some are related to normal operation but other provide important information about current or potential future faults.
Any metal corrosion of the metal components inside a power plant is caused by a reaction (pH dependant) between hydronium ions and oxygen reacting with the metal ions present.
Magnetite (a form of iron oxide) is used to keep the pH between 9.8-10.5 which keeps the surface of the boiler tubes active and helps prevents corrosion.
Voltammetry (VA) can be used to determine the iron content in power plant waters, quantification of iron is important as this is a key corrosion indicator and allows any onsite maintenance to be pre-emptive rather than reactive which to the power plant operator is a much more costly scenario.
If there are appreciable iron deposits these can also inhibit heat transfer making the power plant less efficient which can result in a boiler blow-down whereby the unit comes off line for essential maintenance.
Should this happen then the individual power plant is not operating at peak performance and generates less power - potentially the national grid has to source this short fall from elsewhere to supply the consumer - and the owners of the power plant lose important revenue making such a chain of events commercially undesirable and best prevented if possible.
Voltammetry (VA) can be used to quickly ensure that the iron content poses no risk to the continual and safe operation of a power plant using a bromate/tri-ethanolamine electrolyte that buffers the solutions to pH>9.5.
Voltammetry is a technique first introduced by Heyrovsky in 1922, but in recent years outstanding advances from Metrohm have been made with regard to the measuring cell and PC control system so that today VA represent a clean, reliable and robust technique that gives quality results day in day out.
A typical instrument configuration would be the Metrohm MVA 1 Voltammetry system.
Full control of the instrument is through the PC and a result of this key corrosion indicator (iron) obtained in little over ten minutes.
A major advantage of VA is the use of standard addition for calibration which eliminates many of the matrix effects seen in spectroscopic techniques.
Voltammetry has official established methods and two final points of importance are the running costs themselves which are minimal with no expensive gases required and the footprint which occupies less than a metre, essential in laboratories or control rooms where space is at a premium.
