Thermochem - On-Line Steam Quality and Purity Instruments - Brochure

Process and turbine inlet steam contains impurities, such as silica, sodium, chloride, iron and solid particulates, which can cause corrosion, scaling and erosion of power plant equipment, especially steam turbines. Impurities such as sodium, chloride and silica may be present as dissolved species in liquid water, or as particulate material, such as solid NaCL Volatile silica and chloride may exist in high-temperature or superheated steam, but dissolves rapidly in liquid water. In order to determine the amount of these impurities in steam, isokinetic sampling is required.  The isokinetic steam sampling system incorporates a probe with isokinetic nozzles to obtain representative steam samples across the pipeline diameter. Isokinetic sampling minimizes errors due to non-representative collection of particles and droplets relative to the bulk vapor phase.