Electricity producers that use fossil fuels (oil, gas, coal) or nuclear fuels as energy source. Photometric measurement is used for a number of different purposes in these plants:
The treatment equipment for feeding the water/steam circuits includes the same treatment steps before the ion exchangers that are found in potable water treatment, and therefore the same detection systems for turbidity, absorption, and fluorescence.
In the water circuit itself, turbidity detection is used to monitor corrosion: the amount of scattered light exhibits a direct correlation with the water's iron concentration, as the following Figure shows:
Where heavy fuel oil is fired, the oil is heated in heat exchangers before it is burned. These exchangers are susceptible to leaks, which means the condensate may become contaminated with oil. Continuous oil trace measurement makes it possible to return the condensate safely to the circuit; otherwise it has to be discarded with a resultant loss of heat and pure water.
The amount of hydrocarbons the wastewater effluent from power plants may contain is limited by law, and many countries prescribed that it be monitored continuously. The Sigrist fluorescence instrument performs this function efficiently without requiring any reagents (oil trace measurement).
Fluorescence measurement is also used to monitor the heat exchanger in the cooling circuit for the turbine lube oil.
Finally, Sigrist photometers are used to check the flue gas leaving the combustion chambers. The German Clean Air Law (TA Luft) prescribes that systems firing light fuel oil in the 5 MW to 25 MW range must be equipped with continuous smoke spot number monitors. In the case of desulfurization equipment, it is important to monitor the sulfuric acid mist and the dust content. Flue gas monitoring