概览
River water in feedwater treatment
Instrumentation in water treatment
High quality boiler feed-water, having low conductivity, dissolved oxygen, silica and other impurity levels is essential for long boiler and turbine life. The water treatment processes are often designed in multiple steps, the choice of process steps varies and depends on the water quality and process concept. Some water with lower quality requirements can be extracted for example for the cooling towers. Pre-treatment by filtration removes mechanical impurities or solid matter. Ion exchanges remove dissolved ions and further softens the feed-water. For the highest boiler feed-water quality there are further treatment steps - for example using reverse osmosis or EDI. As a final step mixed bed ion exchangers are used for polishing. Removal of dissolved ions like Na, K, Cl, Ca, Mg causes the conductivity to get lower.
Flows can be economically measured within the first treatment steps (up to temperatures of 180 °C) using OPTIFLUX electromagnetic flowmeters. At low conductivities OPTIBAR DP flowmeters or OPTISONC 3400 ultrasonic flowmeters should be used. The OPTIBAR DP 7060 C is ideal for measuring differential pressure across filters, strainers, heat exchangers and ion exchangers. SMARTPAD or OPTISENS are the relevant liquid analysers available.