Boiler water monitoring is the core link for the safe and stable operation of industrial boilers, especially those in thermal power plants. Its core basis is the national standard "Industrial Boiler Water Quality" (GB1576-2018), which controls water quality indicators to prevent corrosion, scaling and other problems, ensuring power generation efficiency and equipment life.
Natural water contains cations (calcium, magnesium, ferrous ions, etc.) and anions (bicarbonate, sulfate ions, etc.), which can easily form scale and damage equipment during boiler evaporation and concentration. Therefore, monitoring needs to be carried out in stages. In the water production process, the alkalinity, conductivity, hardness, and pH of the raw water inlet need to be monitored. After treatment with anion bed, cation bed, membrane filtration, etc., turbidity, residual chlorine, etc. also need to be monitored. The final effluent is used for boiler power generation, and the monitoring indicators are dynamically adjusted according to the type of unit (heating/power supply) and pressure.
Core monitoring indicators must strictly comply with national standards:
PH valueThe water supply is controlled at 8.8-9.2, and the boiler water is 9-11 (not exceeding 12). If it is too high, it is prone to alkaline corrosion, while if it is too low, scaling will accelerate corrosion. Its abnormalities are often caused by organic matter in the raw water and acidic substances decomposed from resin.
conductivityWater supply conductivity ≤ 0.3 μ S/cm; Boiler water is classified according to pressure, with low pressure (≤ 1.0MPa) ≤ 1400 μ S/cm and high pressure (>9.8MPa) ≤ 2500 μ S/cm. Exceeding the standard means excessive ions, which can easily cause equipment problems.
dissolved oxygenSteam boilers with an evaporation rate greater than 2t/h and hot water boilers with a capacity of ≥ 4.2MW must be deoxygenated. Boiler feedwater with a pressure less than 5.83MPa must be ≤ 15 μ g/L, and supercritical boilers must be ≤ 5 μ g/L. Effective deoxygenation is the key to protecting the thermal system.
Other indicatorsSodium ion ≤ 10 μ g/kg, anti-corrosion and scaling control; The total hardness is adjusted according to the type and pressure of the boiler, such as steam boiler feedwater ≤ 0.03mmol/L within 3.8MPa; Silicates with a concentration of ≤ 250 μ g/L in boiler water and ≤ 25 μ g/L in steam water in thermal power plants can easily form silicate scale and cause furnace tube leakage if exceeding the standard.
In practice, monitoring requires the use of professional equipment and sampling devices. Online monitoring instruments include pH meters (138 × 138 universal sizes), conductivity meters, dissolved oxygen meters, silicon meters, phosphorus meters, etc., suitable for different monitoring scenarios; Sampling relies on dry plates (cooling and pressure reduction) and wet plates (constant temperature control, manual sampling comparison). Wet plates can also achieve real-time instrument measurement and manual data calibration. In some scenarios, auxiliary equipment such as residual chlorine meters and turbidity meters are required to ensure controllable water quality throughout the entire process from the water production workshop to the boiler operation.